Recent Posts

Runtime, a Computer Science and Software Engineering “Children’s Book”

Runtime is a children’s book written and illustrated by Jasmine Patel – Author and Cal Poly Computer Science / Software Engineering (CSSE’20) Alumna. “Runtime,” is a children’s book that highlights the creative and fun elements of computer science to inspire youth to pursue computer science.

Front Cover

Amazon Description

“Runtime is a whimsical adventure jam-packed with educational computer science concepts. Follow the main character, Char, as she embarks on a colorful journey through the magical land of Runtime. She solves puzzles, finds bugs, and makes friends along the way!”

About the Book

The book’s character, Char, falls into her birthday gift, a new computer. Reading the readme file, Char is told, that in order to return home, to find bugs and some traveling objects. While I won’t spoil the story, Char explores heaps, algorithms, parenthesis matching, dining philosophers, decision trees, stacks, loops, queues, traveling salesperson, objects, object relationships, attributes and more.

“Computer science is a great field to get into, and as there are more and more computer science jobs available, it is important to get young children exposed and interested,” Jasmine said. “Also, there are not enough girls in computer science, and if little girls read this book where the protagonist is a little girl, that might inspire them to get into computer science.”

My Take

I ordered a copy of the book from Amazon last Friday and received it yesterday. The book is fun to read for computer scientists, software engineers and techies of all ages and genders. Runtime would make a great Christmas/Holiday/Birthday gift for every computer inclined child, grandchild or the child techie within all of us.

Note: I should mention that I am a graduate of the Cal Poly Computer Science department (BS CSc 1973) and long time member of the department’s Industry Advisory Board (IAB).

Back Cover

References

Runtime (Hardcover) – August 16, 2020 – by Jasmine Patel – Amazon

CSSE Grad Creates Children’s Book, Hoping to Encourage Youth to Pursue Computer Science

Cal Poly Alumna Publishes Children’s Book About Computer Science

Runtime – A Puzzle Piece Publishing book

Technology News Worth Reading

Here are a few technology news stories that I’ve read in the past week or so.

News Headlines

How to Convert a PDF to PNG or JPG in Java

This article reviews three Conversion APIs that will allow you to convert any PDF document into an image. This includes conversion to a PNG or JPG array with one image created per page in your document. The article also discusses how you can merge and stack your PDF pages for conversion into a single PNG, or “tall” image. The goal for this tutorial is to simplify and improve your versatility for document display and sharing. Furthermore, as most documents can be converted to PDF, you can apply these APIs to any file, post-PDF-conversion. Read the DZone article.

Popular JavaScript Frameworks to Build API and Microservices

This Dzone post discusses the most popular JavaScript frameworks used to build APIs and Microservices. Microservices and APIs are often being confused for each other. In reality, they are 2 separate concepts altogether, where API is a communication pattern and microservices are an architectural pattern. Read the DZone article.

How to Build Real-Time Notification Service Using Server-Sent Events (SSE)

Most of the communication on the Internet comes directly from the clients to the servers. The client usually sends a request, and the server responds to that request. There are some scenarios in which the server needs to send a message to the client without the preceding request. In such cases, developers have a couple of options: use short and long polling, webhooks, websockets, or event streaming platforms like Kafka. However, there is another technology, not popularized enough, which in many cases, is just perfect for the job. This technology is the Server-Sent Events (SSE) standard. Read the DZone article.

Facebook Announces Beta Messenger API Support for Instagram

Facebook announces updates to the Messenger API to support Instagram messaging, giving businesses new tools to manage their customer communications on Instagram at scale. The new API features enable businesses to integrate Instagram messaging with their preferred business applications and workflows; helping drive more meaningful conversations, increase customer satisfaction and grow sales. The updated API is currently in beta with a limited number of developer partners and businesses. Read the Facebook announcement.

IBM Unveils New Capabilities for Preserving Aging Infrastructure Using AI, 3D Modeling and Data Capture

IBM announces new capabilities in IBM Maximo for Civil Infrastructure to help prolong the lifespan of aging bridges, tunnels, highways, and railways. New enhancements include the ability to deploy on Red Hat OpenShift for hybrid cloud environments, as well as new AI and 3D model annotation tools that can provide deep industry and task-specific insights to support engineers. “Tools like AI, predictive maintenance, drones and hybrid cloud will play an important role in meeting the challenge of rising infrastructure costs, and helping these vital structures endure for future generations,” said Bjarne Jørgensen, Executive Director, Asset Management at Sund and Baelt. “These solutions can help determine the exact need for maintenance in near real-time to assist organizations in extending the lifetime of structures.” Read the press release.

13 Tools to Monitor Remote Teams (Plus Tips)

How do employers ensure that their remote teams remain productive? This is where remote monitoring tools come into the picture. Remote monitoring tools are an excellent way for companies to continue moving with the tide without compromising the productivity of their remote employees or micromanaging them. This DZone article discusses 13 of the most popular remote monitoring tools.

Building a C++ VCL Customer/Sales Master/Detail/Charting Application with 1 Line of Code

These days low-code development is en vogue. Various research groups, such as Gartner, put the low-code application development platform market at ~$10M billion in 2019 and project CAGR to be greater than 20% from 2020 to 2027. This post shows how you can build a Windows C++ Customer/Sales, Master/Detail/Charting application that only needs 1 line of code.

Things to consider when running visual tests in CI/CD pipelines

This blog post contains a summary of the author’s recent webinar and focuses on demos that show how to handle visual testing in CI/CD. The demos focused on 3 different CI/CD scenarios: Azure DevOps, GitHub Actions and Container Based Pipelines.

An Open Source Sorting Algorithms Visualizer

This GitHub project is a tool, made with python and pygame, for visualizing sorting algorithms in an educational way. The project’s purpose is to portray several sorting algorithms so the user can understand how a computer “move some pieces” to achieve the goal of having sorted data at the end!

A faster way to prototype your APIs using OpenAPI 3 and Swagger UI

The goal of this GitHub project is to create a generator that conveniently creates API definitions in the OpenAPI 3 format using marshmallow classes and saves them into a YAML file. You can think this project as programmable API definitions/documentation for your API (your API can be written in any language, not only in Python). Python is used here just for convenience of describing classes and has less code yet strong typing. Then you can inject the generated YAML file with Swagger UI to any project (just a page that renders Swagger UI HTML code which requests the generated YAML file).

Fun With SQL Using Postgres and Azure Data Studio

Azure Data Studio is a cross-platform database tool for data professionals using the Microsoft family of on-premises and cloud data platforms on Windows, macOS, and Linux. It is very easy to install and offers a modern editor experience with IntelliSense, code snippets, source control integration, and an integrated terminal. It’s engineered with the data platform user in mind, with the built-in charting of query result sets and customizable dashboards. You can learn more about it from the official website on this link. ADS also has notebooks that are similar to Jupiter notebooks for python and other languages and are great for combining formatted text with code. You can execute queries via a query window or via a notebook window. This post discusses some of the basics and at the same time shares the author’s experience using Azure Data Studio.

AppSec vs. DevSecOps, and what that means for developers

Traditional application security is different in two key ways from what has come to be known as DevSecOps. First, modern software companies are integrating application security into their DevOps pipelines, so security becomes part of the flow. Second, it’s also about DevOps being built into application security. In this SD Times article, Patrick Carey, who leads product strategy in the Software Integrity Group at security solutions provider Synopsys, explains these differences. By building application security into your automated development environment, he said, security “is initiated through events, rather than necessarily a phase where somebody at the end of the line, whose job it is to make sure that you didn’t screw up and code a vulnerability,” does the testing. On the other side of that coin, building DevOps into AppSec, eliminates the gates created by traditional DAST or pen-testing tools, creating instead guardrails that allow the team to move forward with relatively low friction but to stay on track. In the traditional gated pass-fail system, “if you fail you got your vulnerability report that just said you know there were a bunch of vulnerabilities, but oh, by the way we can’t tell you exactly where those are in your code; your developer’s going to have to go figure that out.”

5 edge computing predictions for 2021

The new business models that will push edge computing “from science project to real value” in 2021 are largely based around two factors, Forrester said: Cloud platforms having to compete with artificial intelligence, and the widespread proliferation of 5G will make edge use cases more practical. With those two drivers in mind, Forrester made five predictions about how the tech world will evolve in 2021 that will directly impact edge computing. Read the article that lists Forrester’s predictions.

Technology News Worth Reading

Here are a few technology news stories that I’ve read in the past week or so.

News Headlines

Cloud Native Computing Foundation Announces Rook Graduation

Rook is an open source cloud native storage orchestrator for Kubernetes, providing the platform, framework, and support for a diverse set of storage solutions to natively integrate with cloud native environments. Rook delivers its services via a Kubernetes Operator for each storage provider. It was originally accepted as a CNCF project in 2018. It is the thirteenth CNCF project, and the first project based on block, file, or object storage, to graduate. Read the announcement article

How is Robotics Changing the Healthcare Industry?

Robotics is changing the healthcare industry in a lot of fundamental ways. Robots can manage the monotonous and repetitive tasks while leaving the doctors and nurses free to do the critical tasks they were trained for. This article discusses the wide variety of applications that robotics has in healthcare to make the lives of both doctors and patients much easier. Read the article.

Looking for the Next Step in Cloud Performance? Look to Data Center Design

In the near future, data centers will need specialized storage and compute areas that are segregated from each other. For example, when designing a floor plan, it’s likely we’ll see data center operators walling off Compute-as-a-Service from Storage-as-a-Service. This can help solve issues around cooling, which is paramount to eliminating waste and improving performance. However, it doesn’t fully solve the issue of accessibility and latency speeds. Read the post.

Object Detection from 9 FPS to 650 FPS

This article is a practical deep dive into making a specific deep learning model (Nvidia’s SSD300) run fast on a powerful GPU server, but the general principles apply to all GPU programming. The SSD300 is an object-detection model trained on COCO, so output will be bounding boxes with probabilities for 81 classes of object.

Product Demo Sucks Because It’s Focused on Your Product

In this exclusive interview, Falcone shares the structure of a winning product demo and the tactics he’s discovered to convince people that they need your product in just one conversation. one of the easiest and biggest mistakes he sees is that companies don’t effectively craft their demo to fit their specific audience — i.e. they don’t distill their dozens of features and selling points into the few that will really resonate with this particular investor, prospect, or even prospective employee.

Computer Scientists Break Traveling Salesperson Record

In a paper posted online, Klein and his advisers at the University of Washington, Anna Karlin and Shayan Oveis Gharan, have finally achieved a goal computer scientists have pursued for nearly half a century: a better way to find approximate solutions to the traveling salesperson problem. Read the article. Read the paper.

The Gap: Where Machine Learning Education Falls Short

As the field of machine learning has become ever more popular, a litany of online courses has emerged claiming to teach the skills necessary to “build a career in AI”. But before signing up for such a course, you should know whether the skills acquired will directly allow you to apply machine learning better. These questions are not limited to online courses but rather encompass machine learning classes that have begun to fill lecture halls at many universities. Are these classes that students flock towards actually helping them achieve their practical goals? Read the article.

10 Popular Backend APIs

A Backend API is an Application Programming Interface that developers can use to integrate with backend services. A great place to find these APIs is in the Backend or Backend as a Service categories in the ProgrammableWeb API directory. This article gives details to the ten most popular Backend APIs on ProgrammableWeb, based on website traffic.

The unreasonable effectiveness of the Julia programming language

Six years ago, the author wrote about the enduring prominence of Fortran for scientific computing and compared it with several other languages. That article with a prediction that, in 10 years, a new language called Julia stood a good chance of becoming the one that scientists would turn to when tackling large-scale numerical problems. The author’s prediction was not very accurate, though. It actually only took Julia about half that time. Read the article.

Big Tech, Out-of-Control Capitalism and the End of Civilization

“Our digital era is a blend of “utopia and dystopia,” says Tristan Harris, who left Google to cofound The Center for Humane Technology (a phrase that sounds increasingly oxymoronic). “I can hit a button on my phone and a car shows up in 30 seconds and I can go exactly where I need to go. That is magic.” But Harris fears tech’s ill effects are outweighing its benefits. “If we don’t agree on truth,” he says, “or even that there is such a thing as truth, we’re toast.” Read the complete Scientific American article.

10 Best Text Annotation Tools and Services for Machine Learning

In the AI research and development industries, annotated data is gold. Large quantities of high-quality annotated data is a goldmine. On the other hand, sometimes finding or creating this data can be an expensive and arduous task for your team. Fortunately, there are a variety of text annotation tools and services available that can provide you with the data you need. Some of these services include entity extraction, part-of-speech tagging, sentiment analysis, and more. Read the DZone article.

30+ Tools List for GitOps

Speaking of the right tools for the job, there are countless tools to help you integrate the GitOps approach with your existing workflows. Some of the tools supporting GitOps are so popular that you may even be using it in your existing pipeline. To help you get started, here are the tools that we recommend if you want to incorporate GitOps. Read the post.

Using Python4Delphi with C++Builder VCL applications

Some C++ developers also use Python for their application development. There are several ways to integrate the two languages together. One way is to create Python extension modules containing C++ functions that implement new object types and functions. Another way is to use the Boost Python C++ library that enables interoperability between the Python and C++ languages. A third way is to use the productivity, resusability, and encapsulation of components to to integrate C++Builder and Python. In this chapter you’ll learn how to use the Python4Delphi open source components in your VCL applications.

Introduction to Python4Delphi (and C++Builder)

Python for Delphi (P4D) is a set of free components (MIT Open Source License), created by Kiriakos Vlahos author of the popular PyScripter Python IDE, that wrap up the Python DLL into Delphi. The components allow you to create or extend your Delphi and C++Builder applications to execute Python scripts, create new Python modules and new Python types. You can also create Python extensions as DLLs and much more.

You’ll find Python4Delphi on GitHub at https://github.com/pyscripter/python4delphi. The GitHub project includes a readme file, installation notes, supported platforms, how Python4Delphi finds your Python distributions, tutorials and demos.

Jim McKeeth recently hosted a webinar with Kiriakos, “Python for Delphi Developers Part 1 – Introduction” (replay is available on YouTube). A Part 2 Python for Delphi Developers will take place on Wednesday, October 14, 2020 at 7am Pacific Time. While this webinar series focuses on Delphi programming, it also provides information about the Python4Delphi components and Python programming that can help C++Builder developers.

While the webinar and Python4Delphi speaks to Delphi developers, C++Builder developers can compile and install the components for use in their Win32 and Win64 C++ VCL applications. To build and install the Python4Delphi components you can use all editions of C++Builder (community, professional, enterprise and architect) and RAD Studio (professional, enterprise and architect) for versions 10.3.3, 10.4 and 10.4.1. If you only have C++Builder, you’ll learn how to use the included Delphi DCC32 and DCC64 command line compilers to build the Delphi component package project and install the components.

Installing Python for Windows (32 and 64 bit)

Before you start using the Python4Delphi components in your C++Builder VCL applications you’ll need to make sure you have Python for Win32 and Win64 installed on your computer.

You can download and install releases of Python from the Python.org web site. For Win32 and Win64 you will find installers at https://www.python.org/downloads/windows/

To find Python distributions installed on your computer, use the “where python.exe” Windows command.

By default, Python for Win32 installs into the C:\Users\david\AppData\Local\Programs\Python\Python39-32\ folder (or wherever you tell the install to put the distribution).

By default, Python for Win64 installs into the C:\Users\david\AppData\Local\Programs\Python\Python39\ folder (or wherever you tell the install to put the distribution).

Installing Python4Delphi and Using the Components

The following are the steps I followed to download and build the Python4Delphi components for use with C++Builder 10.3.3, 10.4 and 10.4.1. While I used RAD Studio (which includes C++Builder and Delphi), you can also use C++Builder along with the Delphi command line compilers to compile and install the components.

Step 1 – Download the latest release of the Python4Delphi

Grab the python4delphi-master.zip file (https://github.com/pyscripter/python4delphi) and unzip it to your hard drive (I put it in my C:\Users\david\Documents\Embarcadero\Studio\Projects/ folder).

Step 2 – In the IDE open the Python_D package project file (RAD Studio editions)

In the C++Builder 10.4.1 RAD Studio IDE, open the Python_D.dproj package project file (you’ll find it in the “python4delphi-master\Packages\Delphi\Delphi 10.4+” folder).

Step 3 – Add an $IFDEF around the requires DesignIDE unit

Look at the Python_D.dpk source file, if you don’t see an $IFDEF around the DesignIDE unit, add it to avoid a compiler error when using the Win64 C++ compiler – DesignIDE is only required for Win32 since the IDE is a 32-bit Windows app.

Notice (in the source code above) that the LibSuffix Delphi compiler directive is set to “AUTO”. This can be done in source code or in the Project | Options | Description page (in the image below) to match the package file suffix with other compiled package files. The suffix is applied before the file extension. In drop down list, you can select the $(Auto) option for the suffix to represent the compiler version suffix for binary package files.

There is a separate Python_D.dpk package source file for versions 10.3 and earlier in the “python4delphi-master\Packages\Delphi\Delphi 10.3-” folder. In this package source file there are $IFDEFs to set the LIBSUFFIX for several recent Delphi compiler releases.

If you are going to use this earlier Python_D.dpk project you may need to comment out (or remove) the “{$R *.res}” statement at the front of the package source file (it may have already been removed in the latest commit of Python4Delphi).

Step 4a – Build and Install the Python4Delphi components with RAD Studio

There are two ways to build and install the components depending on whether you have RAD Studio or one of the C++Builder editions. If you only have C++Builder skip to “Step 4b” to learn how to use the Delphi command line compilers for Win32 and Win64.

Set the Python4Delphi Project Options for the Delphi Compiler | C/C++ Output file generation for Win32 and Win64 platform (all configurations – debug and release). Build and Install the Python4Delphi components for Win32 and Win64 targets.

Building and installing the components will make sure you have the generated C++ header files, package import library files and package static library files for your C++ VCL Win32 and Win64 projects.

From the help file: the “Generate all C++Builder files (including package libs)” option generates the package and all Delphi pieces, along with all necessary header files (.hpp), package import library file (.bpi), and package static library file (.lib and .a) for C++ projects. This is the default in desktop platforms.

Set the Delphi Compiler Search Path to include the Python4Delphi source directory so that the compiler will find any required include files and other files.

Step 4b – Use the Delphi command line compilers to Build and Installing the components

You can use batch files (or other script files) that run the Delphi command line compilers for Win32 (DCC32.exe) and Win64 (DCC64.exe). These Delphi compilers (included in the bin folder) will build the Python4Delphi package file and create the C++ header files, compiled package file, static library and other files required for use in your C++ applications.

CompilePython4DelphiPackage4Win32.bat

@ECHO OFF
ECHO Compiling Python4Delphi Component Package for Win32
dcc32 Python_D.dpk ^
-I"C:\Users\david\Documents\Embarcadero\Studio\Projects\Python4Delphi\python4delphi-master\Source" ^
-LE"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Bpl" ^
-LN"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp" ^
-NH"C:\Users\Public\Documents\Embarcadero\Studio\20.0\hpp\Win32" ^
-NB"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp" ^
-E"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp" ^
-JL ^
--lib-suffix:260 ^
-NSsystem;vcl;winapi;system.win ^
-u"c:\program files (x86)\embarcadero\studio\20.0\lib\win32\release"

move /y "C:\Users\david\Documents\Embarcadero\Studio\Projects\Python4Delphi\python4delphi-master\Packages\Delphi\Delphi 10.3-\Python_D.lib" "C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp\Python_D.lib"

ECHO Completed Python4Delphi Component Package Win32
pause

CompilePython4DelphiPackage4Win64.bat

@ECHO OFF
ECHO Compiling Python4Delphi Component Package for Win64
dcc64 Python_D.dpk ^
-I"C:\Users\david\Documents\Embarcadero\Studio\Projects\Python4Delphi\python4delphi-master\Source" ^
-LE"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Bpl\Win64" ^
-LN"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp\Win64" ^
-NH"C:\Users\Public\Documents\Embarcadero\Studio\20.0\hpp\Win64" ^
-NB"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp\Win64" ^
-E"C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp\Win64" ^
-JL ^
--lib-suffix:260 ^
-NSsystem;vcl;winapi;system.win ^
-u"c:\program files (x86)\embarcadero\studio\20.0\lib\win64\release"

move /y "C:\Users\david\Documents\Embarcadero\Studio\Projects\Python4Delphi\python4delphi-master\Packages\Delphi\Delphi 10.3-\Python_D.a" "C:\Users\Public\Documents\Embarcadero\Studio\20.0\Dcp\Win64\Python_D.a"

ECHO Completed Python4Delphi Component Package Win64
pause

Install he Python4Delphi Package

In the C++Builder IDE, use the Components | Install Packages menu item and click the “Add…” button.

Navigate to the C:\Users\Public\Documents\Embarcadero\Studio\21.0\Bpl folder (the number will depend on which version of C++Builder you have) and select the Design time package (BPL) file and click the Open button. This will add the package and components to the IDE. You’ll now see “Components for Python” in the list of Design time packages. Highlight the entry and click the Components button to display the list of components in the package.

Step 4c – Verify that the generated Python4Delphi files for C++ use are generated

After you compile the Python4Delphi package project for Win32 and Win64 target platforms the following files will be generated:

C:\Users\Public\Documents\Embarcadero\Studio\21.0\hpp\Win32
Python_D.hpp
PythonEngine.hpp
PythonGUIInputOutput.hpp
MethodCallBack.hpp
WrapDelphi.hpp
C:\Users\Public\Documents\Embarcadero\Studio\21.0\hpp\Win64
Python_D.hpp
PythonEngine.hpp
PythonGUIInputOutput.hpp
MethodCallBack.hpp
WrapDelphi.hpp
C:\Users\Public\Documents\Embarcadero\Studio\21.0\Dcp
Python_D.bpi
Python_D.dcp
Python_D.lib
C:\Users\Public\Documents\Embarcadero\Studio\21.0\Dcp\Win64
Python_D.a
Python_D.bpi
Python_D.dcp
C:\Users\Public\Documents\Embarcadero\Studio\21.0\Bpl
Python_D270.bpl
C:\Users\Public\Documents\Embarcadero\Studio\21.0\Bpl\Win64
Python_D270.bpl
Python_D270.rsm

In the IDE you’ll now see the components in the Component Palette window.

Building Your First C++Builder Python4Delphi VCL Application

Using RAD Studio, I opened the Python4Delphi Demo1 Delphi project and tested it to make sure that I had the components and Python working. C:\Users\david\Documents\Embarcadero\Studio\Projects\Python4Delphi\python4delphi-master\Demos\Demo01

Use File | New | C++Builder VCL application to create a starting C++Builder project (note: the source code for the project is in a zip file listed in the References section). I copied all of the components from the Delphi version of the Demo01 form file.

Demo01Unit.dfm file

object Form2: TForm2
  Left = 0
  Top = 0
  Caption = 'Demo 01 Python (C++, VCL)'
  ClientHeight = 344
  ClientWidth = 534
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Splitter1: TSplitter
    Left = 0
    Top = 153
    Width = 534
    Height = 3
    Cursor = crVSplit
    Align = alTop
    Color = clBtnFace
    ParentColor = False
    ExplicitWidth = 536
  end
  object Memo1: TMemo
    Left = 0
    Top = 156
    Width = 534
    Height = 144
    Align = alClient
    Font.Charset = DEFAULT_CHARSET
    Font.Color = clWindowText
    Font.Height = -13
    Font.Name = 'Consolas'
    Font.Pitch = fpVariable
    Font.Style = []
    Lines.Strings = (
      'print(2+2)')
    ParentFont = False
    ScrollBars = ssBoth
    TabOrder = 0
  end
  object Panel1: TPanel
    Left = 0
    Top = 300
    Width = 534
    Height = 44
    Align = alBottom
    BevelOuter = bvNone
    TabOrder = 1
    object Button1: TButton
      Left = 0
      Top = 6
      Width = 115
      Height = 25
      Caption = 'Execute script'
      TabOrder = 0
      OnClick = Button1Click
    end
    object Button2: TButton
      Left = 167
      Top = 6
      Width = 91
      Height = 25
      Caption = 'Load script...'
      TabOrder = 1
      OnClick = Button2Click
    end
    object Button3: TButton
      Left = 264
      Top = 8
      Width = 89
      Height = 25
      Caption = 'Save script...'
      TabOrder = 2
      OnClick = Button3Click
    end
  end
  object Memo2: TMemo
    Left = 0
    Top = 0
    Width = 534
    Height = 153
    Align = alTop
    Font.Charset = DEFAULT_CHARSET
    Font.Color = clWindowText
    Font.Height = -13
    Font.Name = 'Consolas'
    Font.Pitch = fpVariable
    Font.Style = []
    ParentFont = False
    ScrollBars = ssBoth
    TabOrder = 2
  end
  object PythonEngine1: TPythonEngine
    IO = PythonGUIInputOutput1
    Left = 32
    Top = 32
  end
  object OpenDialog1: TOpenDialog
    DefaultExt = '*.py'
    Filter = 'Python files|*.py|Text files|*.txt|All files|*.*'
    Title = 'Open'
    Left = 240
    Top = 32
  end
  object SaveDialog1: TSaveDialog
    DefaultExt = '*.py'
    Filter = 'Python files|*.py|Text files|*.txt|All files|*.*'
    Title = 'Save As'
    Left = 328
    Top = 32
  end
  object PythonGUIInputOutput1: TPythonGUIInputOutput
    UnicodeIO = True
    RawOutput = False
    Output = Memo2
    Left = 128
    Top = 32
  end
end

Demo01Unit.h file

//---------------------------------------------------------------------------

#ifndef Demo01UnitH
#define Demo01UnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
#include "PythonEngine.hpp"
#include <Vcl.Dialogs.hpp>
#include <Vcl.ExtCtrls.hpp>
#include "PythonGUIInputOutput.hpp"
//---------------------------------------------------------------------------
class TForm2 : public TForm
{
__published:	// IDE-managed Components
	TSplitter *Splitter1;
	TMemo *Memo1;
	TPanel *Panel1;
	TButton *Button1;
	TButton *Button2;
	TButton *Button3;
	TMemo *Memo2;
	TPythonEngine *PythonEngine1;
	TOpenDialog *OpenDialog1;
	TSaveDialog *SaveDialog1;
	TPythonGUIInputOutput *PythonGUIInputOutput1;
	void __fastcall Button1Click(TObject *Sender);
	void __fastcall Button2Click(TObject *Sender);
	void __fastcall Button3Click(TObject *Sender);
private:	// User declarations
public:		// User declarations
	__fastcall TForm2(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm2 *Form2;
//---------------------------------------------------------------------------
#endif

Next, add OnClick event handlers for the 3 buttons.

Demo01Unit.cpp file

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Demo01Unit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma link "PythonEngine"
#pragma link "PythonGUIInputOutput"
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm2::Button1Click(TObject *Sender)
{
	PythonEngine1->ExecStrings( Memo1->Lines );
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button2Click(TObject *Sender)
{
	if (OpenDialog1->Execute()) {
		Memo1->Lines->LoadFromFile( OpenDialog1->FileName );
	}
}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button3Click(TObject *Sender)
{
	if (SaveDialog1->Execute()) {
		Memo1->Lines->SaveToFile( SaveDialog1->FileName );
	}
}
//---------------------------------------------------------------------------

Save the project to a folder.

Compile and Run the C++ VCL Demo program and try some Python code

In the TMemo at the bottom of the form, type in some Python code. In my example I print the sum of two numbers, print the value of Pi from the Python math library and print the Python version # from the Python platform library. You can also use the Load and Save script buttons to bring up dialog boxes to load and save Python script files. Click the Execute script button to see the results show up in the upper TMemo.

References

Python4Delphi and PyScripter

Python4Delphi on GitHub by Kiriakos Vlahos – https://github.com/pyscripter/python4delphi

Webinar Replay – Python for Delphi Developers – Part 1 – Introduction – https://blogs.embarcadero.com/webinar-replay-python-for-delphi-developers-part-1-introduction/

PyScripter on GitHub by Kiriakos Vlahos – https://github.com/pyscripter/pyscripter

Python for Windows

Python Releases for Windows (python.org) – https://www.python.org/downloads/windows/

Embarcadero DocWiki

Creating Packages and DLLs – http://docwiki.embarcadero.com/RADStudio/en/Creating_Packages_and_DLLs

Project | Options | Output – C/C++ – http://docwiki.embarcadero.com/RADStudio/en/Output_-_C/C%2B%2B

Project | Options | Description – http://docwiki.embarcadero.com/RADStudio/en/Descripti

Package Files Created by Compiling – http://docwiki.embarcadero.com/RADStudio/en/Package_Files_Created_by_Compiling

DCC32.EXE, the Delphi Command Line Compiler – http://docwiki.embarcadero.com/RADStudio/en/DCC32.EXE,_the_Delphi_Command_Line_Compiler

DCC64.EXE, the Delphi 64-bit Command Line Compiler – http://docwiki.embarcadero.com/RADStudio/en/DCC64.EXE,_the_Delphi_64-bit_Command_Line_Compiler

Delphi 32-bit compiler (DCC32.exe) cmd line help (from C++Builder Community Edition 10.3.3)

Embarcadero Delphi for Win32 compiler version 33.0
Copyright (c) 1983,2018 Embarcadero Technologies, Inc.

Syntax: dcc32 [options] filename [options]

  -A<unit>=<alias> = Set unit alias
  -B = Build all units             
  -CC = Console target             
  -CG = GUI target                 
  -D<syms> = Define conditionals   
  -E<path> = EXE/DLL output directory
  -F<offset> = Find error          
  -GD = Detailed map file          
  -GP = Map file with publics      
  -GS = Map file with segments     
  -H = Output hint messages        
  -I<paths> = Include directories  
  -J = Generate .obj file          
  -JPHNE = Generate C++ .obj file, .hpp file, in namespace, export all
  -JL = Generate package .lib, .bpi, and all .hpp files for C++
  -K<addr> = Set image base addr   
  -LE<path> = package .bpl output directory
  -LN<path> = package .dcp output directory
  -LU<package> = Use package       
  -M = Make modified units         
  -NU<path> = unit .dcu output directory
  -NH<path> = unit .hpp output directory
  -NO<path> = unit .obj output directory
  -NB<path> = unit .bpi output directory
  -NX<path> = unit .xml output directory
  -NS<namespaces> = Namespace search path
  -O<paths> = Object directories   
  -P = look for 8.3 file names also
  -Q = Quiet compile               
  -R<paths> = Resource directories 
  -TX<ext> = Output name extension 
  -U<paths> = Unit directories     
  -V = Debug information in EXE    
  -VR = Generate remote debug (RSM)
  -VT = Debug information in TDS   
  -VN = TDS symbols in namespace   
  -W[+|-|^][warn_id] = Output warning messages
  -Z = Output 'never build' DCPs   
  -$<dir> = Compiler directive     
  --help = Show this help screen   
  --version = Show name and version
  --codepage:<cp> = specify source file encoding
  --default-namespace:<namespace> = set namespace
  --depends = output unit dependency information
  --doc = output XML documentation 
  --drc = output resource string .drc file
  --no-config = do not load default dcc32.cfg file
  --description:<string> = set executable description
  --inline:{on|off|auto} = function inlining control
  --legacy-ifend = allow legacy $IFEND directive
  --zero-based-strings[+|-] = strings are indexed starting at 0
  --peflags:<flags> = set extra PE Header flags field
  --peoptflags:<flags> = set extra PE Header optional flags field
  --peosversion:<major>.<minor> = set OS Version fields in PE Header (default: 5.0)
  --pesubsysversion:<major>.<minor> = set Subsystem Version fields in PE Header (default: 5.0)
  --peuserversion:<major>.<minor> = set User Version fields in PE Header (default: 0.0)
  --lib-version:<version> = Output package name version
  --lib-suffix:<suffix> = Output package name suffix
Compiler switches: -$<letter><state> (defaults are shown below)
  A8  Aligned record fields         
  B-  Full boolean Evaluation       
  C+  Evaluate assertions at runtime
  D+  Debug information             
  G+  Use imported data references  
  H+  Use long strings by default   
  I+  I/O checking                  
  J-  Writeable structured consts   
  L+  Local debug symbols           
  M-  Runtime type info             
  O+  Optimization                  
  P+  Open string params            
  Q-  Integer overflow checking     
  R-  Range checking                
  T-  Typed @ operator              
  U-  Pentium(tm)-safe divide       
  V+  Strict var-strings            
  W-  Generate stack frames         
  X+  Extended syntax               
  Y+  Symbol reference info         
  Z1  Minimum size of enum types    
Stack size: -$M<minStackSize[,maxStackSize]> (default 16384,1048576)

Delphi 64-bit compiler (DCC64.exe) cmd line help (C++Builder Community Edition 10.3.3)

Embarcadero Delphi for Win64 compiler version 33.0
Copyright (c) 1983,2018 Embarcadero Technologies, Inc.

Syntax: dcc64 [options] filename [options]

  -A<unit>=<alias> = Set unit alias
  -B = Build all units             
  -CC = Console target             
  -CG = GUI target                 
  -D<syms> = Define conditionals   
  -E<path> = EXE/DLL output directory
  -F<offset> = Find error          
  -GD = Detailed map file          
  -GP = Map file with publics      
  -GS = Map file with segments     
  -H = Output hint messages        
  -I<paths> = Include directories  
  -J = Generate .obj file          
  -JPHNE = Generate C++ .obj file, .hpp file, in namespace, export all
  -JL = Generate package .lib, .bpi, and all .hpp files for C++
  -K<addr> = Set image base addr   
  -LE<path> = package .bpl output directory
  -LN<path> = package .dcp output directory
  -LU<package> = Use package       
  -M = Make modified units         
  -NU<path> = unit .dcu output directory
  -NH<path> = unit .hpp output directory
  -NO<path> = unit .obj output directory
  -NB<path> = unit .bpi output directory
  -NX<path> = unit .xml output directory
  -NS<namespaces> = Namespace search path
  -O<paths> = Object directories   
  -P = look for 8.3 file names also
  -Q = Quiet compile               
  -R<paths> = Resource directories 
  -TX<ext> = Output name extension 
  -U<paths> = Unit directories     
  -V = Debug information in EXE    
  -VR = Generate remote debug (RSM)
  -VT = Debug information in TDS   
  -VN = TDS symbols in namespace   
  -W[+|-|^][warn_id] = Output warning messages
  -Z = Output 'never build' DCPs   
  -$<dir> = Compiler directive     
  --help = Show this help screen   
  --version = Show name and version
  --codepage:<cp> = specify source file encoding
  --default-namespace:<namespace> = set namespace
  --depends = output unit dependency information
  --doc = output XML documentation 
  --drc = output resource string .drc file
  --no-config = do not load default dcc64.cfg file
  --description:<string> = set executable description
  --inline:{on|off|auto} = function inlining control
  --legacy-ifend = allow legacy $IFEND directive
  --zero-based-strings[+|-] = strings are indexed starting at 0
  --peflags:<flags> = set extra PE Header flags field
  --peoptflags:<flags> = set extra PE Header optional flags field
  --peosversion:<major>.<minor> = set OS Version fields in PE Header (default: 5.0)
  --pesubsysversion:<major>.<minor> = set Subsystem Version fields in PE Header (default: 5.0)
  --peuserversion:<major>.<minor> = set User Version fields in PE Header (default: 0.0)
  --lib-version:<version> = Output package name version
  --lib-suffix:<suffix> = Output package name suffix
Compiler switches: -$<letter><state> (defaults are shown below)
  A8  Aligned record fields         
  B-  Full boolean Evaluation       
  C+  Evaluate assertions at runtime
  D+  Debug information             
  G+  Use imported data references  
  H+  Use long strings by default   
  I+  I/O checking                  
  J-  Writeable structured consts   
  L+  Local debug symbols           
  M-  Runtime type info             
  O+  Optimization                  
  P+  Open string params            
  Q-  Integer overflow checking     
  R-  Range checking                
  T-  Typed @ operator              
  V+  Strict var-strings            
  W-  Generate stack frames         
  X+  Extended syntax               
  Y+  Symbol reference info         
  Z1  Minimum size of enum types    
Stack size: -$M<minStackSize[,maxStackSize]> (default 16384,1048576)

C++ Demo project and Delphi command line package build batch files (zip file)

A zip file is available for download at http://davidi.com/code/Python4DelphiDemo01.zip

Technology News Worth Reading

Here are a few technology news stories that I’ve read in the past week or so.

News Headlines

Microsoft’s 10 app store principles to promote choice, fairness and innovation

For software developers, app stores have become a critical gateway to some of the world’s most popular digital platforms. We and others have raised questions and, at times, expressed concerns about app stores on other digital platforms. However, we recognize that we should practice what we preach. So, today, we are adopting 10 principles – building on the ideas and work of the Coalition for App Fairness (CAF) – to promote choice, ensure fairness and promote innovation on Windows 10, our most popular platform, and our own Microsoft Store on Windows 10. Read Microsoft’s blog post.

PostMan’s 2020 State of the API Report

Every year, Postman surveys industry members to get a picture of the API industry—to understand who is working with APIs, how they are getting their work done, and where they see the industry going. More than 13,500 developers, testers, executives, and others took our 2020 survey and provided insights on everything from how they spend their time to what they see as the biggest issues and opportunities for APIs. Three key findings: API investments stay strong, The pandemic has changed the world, but it didn’t stop APIs, and APIs are the nucleus of digital transformation. Read and download the report on the Postman website.

Hybrid cloud is where the action is

Multicloud is definitely a thing. However, it’s not exactly clear what that “thing” is. According to new survey data from database vendor MariaDB, 71% of survey respondents report running databases on at least two different cloud providers today. Yet when asked what would keep them from going all in on a cloud database, a vendor’s “lack of a multicloud offering” ranked dead last. In other words, everyone is doing multicloud, but no one knows why. Read Matt Assay’s InfoWorld article.

Nvidia claims Cambridge-1 is the U.K.’s fastest supercomputer

Cambridge-1, which Nvidia expects to come online by year-end 2020, is a joint project between GSK, AstraZeneca, Guy’s and St Thomas’ NHS Foundation Trust, King’s College London, and Oxford Nanopore. Built on Nvidia’s DGX SuperPOD architecture, it’s anticipated to deliver over 400 petaflops of AI performance and 8 petaflops of Linpack performance. That would rank it 29th on the TOP500 list of the world’s most powerful supercomputers and among the top three most-energy-efficient machines in the Green500. Read Kyle Wiggers’ VentureBeat article.

Survey finds cloud complexity increases challenges

Aptum’s Global Cloud Impact Study reveals this with 62 percent of respondents citing complexity and abundance of choice as a hindrance when planning a cloud transformation. One of the biggest sources of complexity that crops up in more advanced cloud projects are legacy systems. The “abundance of choice” or the need to select the best of breed is a prime culprit. This usually results in a technological smorgasbord, where hundreds of decoupled cloud dev and migration teams make their own calls around what technology to use. Complexity naturally arises when it’s time to join and coordinate those apples and oranges. Read David Linthicum’s InfoWorld article.

The art of code reviews

According to Phil Hughes, front-end engineer at GitLab, it’s about how you provide and convey that feedback — and that’s an art form and a skill that is learned over time. “Reviewing code efficiently is a skill that gets learned the more you do it. Spending time coming up with a workflow that works for yourself is just as important”. Read the SD Times article by Christina Cardoza.

An AI can simulate an economy millions of times to create fairer tax policy

Scientists at the US business technology company Salesforce think AI can help. Led by Richard Socher, the team has developed a system called the AI Economist that uses reinforcement learning—the same sort of technique behind DeepMind’s AlphaGo and AlpahZero—to identify optimal tax policies for a simulated economy. The tool is still relatively simple (there’s no way it could include all the complexities of the real world or human behavior), but it is a promising first step toward evaluating policies in an entirely new way. “It would be amazing to make tax policy less political and more data driven,” says team member Alex Trott. Read the MIT Technology Review article by Will Douglas Heaven.

The most valuable software developer skills in 2020

Which developer skills are the most valuable in today’s market? We’ve pored through the data to find the most bankable developer skills for the coming years—and how best to set yourself up for success in a fraught job market: Don’t put all your eggs in one basket, Some skills are hotter than others, Going cloud native, Ordering the full stack, Data is still the new oil, and Formal education isn’t everything. Read the InfoWorld article by By Scott Carey.

Justices wary of upending tech industry in Google v. Oracle Supreme Court fight

The dispute concerns about 11,500 lines of code that Google used to build its popular Android mobile operating system, which were replicated from the Java application programming interface developed by Sun Microsystems. At the end of an hour and a half of arguments, Justice Stephen Breyer, who at one point read aloud some code, seemed to be the only sure vote. Several of the other justices, including Chief Justice John Roberts, suggested they were sympathetic to Oracle’s copyright claims. Several of the court’s conservatives, including Justices Brett Kavanaugh and Samuel Alito, noted that Google’s allies had warned that the “sky will fall” if Oracle won. But those comments were also peppered with skepticism. “I’m not aware that the sky has fallen in the last five or six years,” Kavanaugh said, noting that Google had lost its first appeals court battle in the case in 2014. Read the CNBC article by Tucker Higgins.

Section 230 will be on the Chopping Block at the Next Big US Congressional Hearing

Will Section 230 be on the chopping block at the next US congressional tech hearing. Hearing will focus on Section 230 of the Communications Decency Act, the key law that shields online platforms from legal liability for the content their users create. What is clear: Tinkering with such a foundational law could have a huge cascade of effects for the internet as we know it and isn’t something to be undertaken lightly — if at all. Read the TechCrunch article by Taylor Hatmaker.

To the moon and beyond: How HoloLens 2 is helping build NASA’s Orion spacecraft

When workers for Lockheed Martin began assembling the crew seats for a spacecraft designed to return astronauts to the moon and pave the way for human exploration to Mars, they had no need for paper instructions or tablet screens to work from. Everything they needed to see, including animations of how pieces fit together, engineering drawings and torque values for tightening bolts, was visible in HoloLens 2 devices that they wore. Read the TechXplore article by Jennifer Langston, Microsoft.

Affordable AI: Nvidia Launches $59, 2GB Jetson Nano Computer

While Raspberry Pi boards are great for doing all kinds of tasks and they’re capable of doing object recognition, they can be a little slow when it comes to real-time image recognition. In 2019, Nvidia came out with an A.I.-focused Pi competitor in the $99 Jetson Nano. Fast forward to 2020 and Nvidia is back with a 2GB version of the Jetson Nano that sells for a more reasonable $59 and, for consumers in some markets (including America), comes with a compatible USB Wi-Fi dongle in the box. Due out later this month, the new Nvidia Jetson Nano 2GB is designed to make A.I. more accessible to hobbyists, kids and aspiring developers. Read the Toms Harware article by Avram Piltch.

Microsoft’s VS Code comes to Raspberry Pi and Chromebook – new v1.50 update is out

An official Microsoft build of the Visual Studio Code editor is now available for Linux Armv7 and Arm64 architecture devices, extending Microsoft’s popular cross-platform code editor to Chromebooks, the Raspberry Pi and rival Arm-based single-board Linux computers such as Odroid. Read the ZDNet article by Liam Tung.

Why Apple needed the FDA to sign off on its EKG but not its blood oxygen monitor

The features on the Apple Watch that track heart rate and heart rhythm, though, have a key difference from the blood oxygen monitor: the heart-tracking features are cleared by the Food and Drug Administration (FDA), and the oxygen monitor is not. Apple went through a long, extensive process to develop and validate an EKG feature so that the watch could detect a condition called atrial fibrillation. It didn’t need to do the same thing for the pulse oximeter. Blood oxygen monitors, or pulse oximeters, are considered Class II medical devices by the FDA. Read TheVerge article by Nicole Wetsman.

JDK 16: What’s coming in Java 16 (due March 2021)

Java Development Kit (JDK) 16 has begun to take shape, with proposed features including concurrent thread-stack processing for garbage collection, support for C++ 14 language features, and an “elastic metaspace” capability to more quickly return unused class metadata memory to the OS. Read the InfoWorld article by Paul Krill.

Microsoft launches Playwright for Python for automating testing

Microsoft is trying to make it easier for developers to automate their end-to-end tests. The company has announced a preview of Playwright for Python, which allows developers and testers to write such tests in Python. According to Microsoft, automated end-to-end tests have become more important than ever as teams build apps that run on a number of different kinds of devices. The increase in the number of targets coupled with increased delivery speed has put more pressure on the testing process, and automation is crucial to enable testing at the speed it needs to be done. Playwright for Python provides timeout-free automation, which makes it more reliable. Read the SD Times article by Jenna Sargent.

Definitely not Windows 95: What operating systems keep things running in space?

To deal with unforgiving deadlines, spacecraft like Solar Orbiter are almost always run by real-time operating systems that work in an entirely different way than the ones you and I know from the average laptop. Operating systems used in space add at least one more central criterion: a computation needs to be done correctly within a strictly specified deadline. When a deadline is not met, the task is considered failed and terminated. And in spaceflight, a missed deadline quite often means your spacecraft has already turned into a fireball or strayed into an incorrect orbit. There’s no point in processing such tasks any further; things must adhere to a very precise clock. Read the ArsTechnica article by Jacek Krywko.

GitHub Code scanning is now available!

One year ago, GitHub welcomed Semmle. We’ve since worked to bring the revolutionary code analysis capabilities of its CodeQL technology to GitHub users as a native capability. At GitHub Satellite in May, we released the first beta of our native integration: code scanning. Now, thanks to the thousands of developers in the community who tested and gave feedback, we’re proud to announce that code scanning is generally available. Read the GitHub blog post by Justin Hutchings.

4 common C programming mistakes — and 5 tips to avoid them

Common C mistake: Not freeing malloc-ed memory (or freeing it more than once). Common C mistake: Reading an array out of bounds. Common C mistake: Not checking the results of malloc. Common C mistake: Using void* for generic pointers to memory. Read the InfoWorld article by Serdar Yegulalp.

Windows Printing with C++Builder using VCL and FMX

Do you need to add printer support to your C++ applications using the Visual Component Library (VCL) or FireMonkey (FMX) GUI ? In this blog post I’ll show you how to build Windows applications that support printing image bitmaps using the VCL and FMX frameworks. One of my favorite C++Builder RTL features is that both frameworks provide similar printer components and ways of programming with only a few subtle differences.

Build VCL and FMX Application Projects

Use the “File | New | Windows VCL Application – C++Builder” menu item and create a starting C++ VCL application. Save the product to a folder.

File | New | Windows VCL Application – C++Builder

Next, in the Project Window, right mouse click on the ProjectGroup node and select the “Add New Project…” menu item.

Add New Project to the Project Group

In the popup dialog choose to create a Multi-Device Application.

Add New Multi-Device Application

Click the OK button and on the next screen choose to create a “Blank Application”.

Multi-Device Project templates list – choose Blank Application

Use the File | Save All menu item (or type Shift+Ctrl+S) to save both starting projects and the project group to a folder.

Project Group with VCL and FMX Starting Projects

Each of the VCL and FMX projects have a main form (.dfm and .fmx extensions respectively). While most of the IDE will look the same, if you select each form’s unit you will see different looks for each of their form designers.

VCL Form Designer
FMX Form Designer

There are many videos, articles and help files that describe the details of each designer (check out links in the reference section below). For now, let’s dig into the VCL and FMX printer examples I’ve created.

A Simple UI for each Printer Test Project

On each of the VCL and FMX main forms you’ll see the following components.

VCL form’s components in the Structure Window
FMX form’s components in the Structure Window

Each project’s main menu contains a File and Destination menu. The Destination menu item allows the user to choose to override the printing destination (Printer or File).

The File menu provides an OpenPictureDialog (VCL) or OpenDialog (FMX), PrintPicture dialog for choosing the printer and other printing options, PrinterSetup dialog to set additional printer setup options, Panel (aligned to the top of the form)with a label and ComboBox which will list the available printer device names, and an Image component (aligned to the client area) to contain the picture bitmap.

The VCL and FMX forms look like the following.

VCL app form with components
FMX app form with components

Right mouse click on the form and choose “View as Text” from the popup menu. Now you can see all of the form and component properties and sub-properties that have been set from their default values. You can also make changes in this text form mode but be careful to not make any errors.

To switch back to the form mode click the right mouse button (or hit Alt-F12) and choose “View as Form” from the popup menu.

VCLPrintUnit.dfm (View as Text)

object MainVCLForm: TMainVCLForm
  Left = 0
  Top = 0
  Caption = 'Printer Test (C++, VCL)'
  ClientHeight = 473
  ClientWidth = 667
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  Menu = MainMenu1
  OldCreateOrder = False
  OnShow = FormShow
  PixelsPerInch = 96
  TextHeight = 13
  object Image1: TImage
    Left = 0
    Top = 41
    Width = 667
    Height = 432
    Align = alClient
    Proportional = True
    ExplicitLeft = 104
    ExplicitTop = 102
    ExplicitWidth = 424
    ExplicitHeight = 317
  end
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 667
    Height = 41
    Align = alTop
    TabOrder = 0
    object Label1: TLabel
      Left = 10
      Top = 12
      Width = 41
      Height = 13
      Caption = 'Printers:'
    end
    object PrintersComboBox: TComboBox
      Left = 57
      Top = 9
      Width = 250
      Height = 21
      TabOrder = 0
      Text = 'PrintersComboBox'
    end
  end
  object PrintDialog1: TPrintDialog
    Options = [poPrintToFile]
    Left = 176
    Top = 56
  end
  object PrinterSetupDialog1: TPrinterSetupDialog
    Left = 304
    Top = 64
  end
  object OpenPictureDialog1: TOpenPictureDialog
    DefaultExt = 'bmp'
    InitialDir = 'c:\temp'
    Left = 56
    Top = 56
  end
  object MainMenu1: TMainMenu
    Left = 424
    Top = 64
    object File1: TMenuItem
      Caption = 'File'
      object File2: TMenuItem
        Caption = 'Open Picture'
        OnClick = File2Click
      end
      object PrintPicture1: TMenuItem
        Caption = 'Print Picture'
        Enabled = False
        OnClick = PrintPicture1Click
      end
      object PrinterSetup1: TMenuItem
        Caption = 'Printer Setup'
        Enabled = False
        OnClick = PrinterSetup1Click
      end
      object PrintPicture2: TMenuItem
        Caption = 'Exit'
        OnClick = PrintPicture2Click
      end
    end
    object Destination1: TMenuItem
      Caption = 'Destination'
      object PrintToPrinterDestinationMenuItem: TMenuItem
        Caption = 'Print to Printer'
        Checked = True
        OnClick = PrintToPrinterDestinationMenuItemClick
      end
      object PrintToFileDestinationMenuItem: TMenuItem
        Caption = 'Print to File'
        OnClick = PrintToFileDestinationMenuItemClick
      end
    end
  end
end

FMXPrintUnit.fmx (View as Text)

object MainFMXForm: TMainFMXForm
  Left = 0
  Top = 0
  Caption = 'Printer Test (C++, FMX)'
  ClientHeight = 380
  ClientWidth = 640
  Position = Designed
  WindowState = wsMaximized
  FormFactor.Width = 320
  FormFactor.Height = 480
  FormFactor.Devices = [Desktop]
  OnShow = FormShow
  DesignerMasterStyle = 0
  object Image1: TImage
    MultiResBitmap = <
      item
      end>
    Align = Client
    Size.Width = 640.000000000000000000
    Size.Height = 339.000000000000000000
    Size.PlatformDefault = False
  end
  object PrintDialog1: TPrintDialog
    Options = [poPrintToFile]
    Left = 68
    Top = 40
  end
  object PrinterSetupDialog1: TPrinterSetupDialog
    Left = 190
    Top = 42
  end
  object OpenDialog1: TOpenDialog
    DefaultExt = 'bmp'
    Filter = '*.bmp'
    InitialDir = 'c:\temp'
    Left = 312
    Top = 44
  end
  object MainMenu1: TMainMenu
    Left = 418
    Top = 46
    object FileMenu: TMenuItem
      Text = 'File'
      object OpenBitmapMenuItem: TMenuItem
        Locked = True
        Text = 'Open Bitmap'
        OnClick = OpenBitmapMenuItemClick
      end
      object PrintMenuItem: TMenuItem
        Enabled = False
        Locked = True
        Text = 'Print'
        OnClick = PrintMenuItemClick
      end
      object PrinterSetupMenuItem: TMenuItem
        Enabled = False
        Locked = True
        Text = 'Printer Setup'
        OnClick = PrinterSetupMenuItemClick
      end
      object ExitMenuItem: TMenuItem
        Locked = True
        Text = 'Exit'
        OnClick = ExitMenuItemClick
      end
    end
    object DestinationMenu: TMenuItem
      Text = 'Destination'
      object PrintToPrinterDestinationMenuItem: TMenuItem
        Locked = True
        IsChecked = True
        Text = 'Print to Printer'
        OnClick = PrintToPrinterDestinationMenuItemClick
      end
      object PrintToFileDestinationMenuItem: TMenuItem
        Locked = True
        Text = 'Print to File'
        OnClick = PrintToFileDestinationMenuItemClick
      end
    end
  end
  object Panel1: TPanel
    Align = Top
    Size.Width = 640.000000000000000000
    Size.Height = 41.000000000000000000
    Size.PlatformDefault = False
    object PrintersComboBox: TComboBox
      Position.X = 72.000000000000000000
      Position.Y = 8.000000000000000000
      Size.Width = 233.000000000000000000
      Size.Height = 22.000000000000000000
      Size.PlatformDefault = False
    end
    object Label1: TLabel
      Position.X = 8.000000000000000000
      Position.Y = 9.000000000000000000
      Size.Width = 57.000000000000000000
      Size.Height = 17.000000000000000000
      Size.PlatformDefault = False
      Text = 'Printers:'
    end
  end
end

Additional comments about component properties and event handlers are included in the source code for the projects.

The Source Code

Below you will find the header files for the VCL and FMX form units. The header files will show the component declarations, event handlers and any public/private declarations.

VCLPrintUnit.h

//---------------------------------------------------------------------------

#ifndef VCLPrintUnitH
#define VCLPrintUnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
#include <Vcl.Dialogs.hpp>
#include <Vcl.ExtCtrls.hpp>
#include <Vcl.ExtDlgs.hpp>
#include <Vcl.Menus.hpp>
#include <Vcl.WinXCtrls.hpp>
//---------------------------------------------------------------------------
class TMainVCLForm : public TForm
{
__published:	// IDE-managed Components
	TPrintDialog *PrintDialog1;
	TPrinterSetupDialog *PrinterSetupDialog1;
	TImage *Image1;
	TOpenPictureDialog *OpenPictureDialog1;
	TMainMenu *MainMenu1;
	TMenuItem *File1;
	TMenuItem *File2;
	TMenuItem *PrintPicture1;
	TMenuItem *PrintPicture2;
	TMenuItem *Destination1;
	TMenuItem *PrintToPrinterDestinationMenuItem;
	TMenuItem *PrintToFileDestinationMenuItem;
	TMenuItem *PrinterSetup1;
	TPanel *Panel1;
	TLabel *Label1;
	TComboBox *PrintersComboBox;
	void __fastcall File2Click(TObject *Sender);
	void __fastcall FormShow(TObject *Sender);
	void __fastcall PrintToPrinterDestinationMenuItemClick(TObject *Sender);
	void __fastcall PrintToFileDestinationMenuItemClick(TObject *Sender);
	void __fastcall PrintPicture1Click(TObject *Sender);
	void __fastcall PrinterSetup1Click(TObject *Sender);
	void __fastcall PrintPicture2Click(TObject *Sender);
private:	// User declarations
    bool PictureLoaded;  // boolean for whether a picture is loaded or not
public:		// User declarations
	__fastcall TMainVCLForm(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TMainVCLForm *MainVCLForm;
//---------------------------------------------------------------------------
#endif

FMXPrintUnit.h

//---------------------------------------------------------------------------

#ifndef FMXPrintUnitH
#define FMXPrintUnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <FMX.Controls.hpp>
#include <FMX.Forms.hpp>
#include <FMX.Controls.Presentation.hpp>
#include <FMX.StdCtrls.hpp>
#include <FMX.Types.hpp>
#include <FMX.Objects.hpp>
#include <FMX.Dialogs.hpp>
#include <FMX.Printer.hpp>
#include <FMX.Menus.hpp>
#include <FMX.ListBox.hpp>
//---------------------------------------------------------------------------
class TMainFMXForm : public TForm
{
__published:	// IDE-managed Components
	TImage *Image1;
	TPrintDialog *PrintDialog1;
	TPrinterSetupDialog *PrinterSetupDialog1;
	TOpenDialog *OpenDialog1;
	TMainMenu *MainMenu1;
	TMenuItem *FileMenu;
	TMenuItem *OpenBitmapMenuItem;
	TMenuItem *PrintMenuItem;
	TMenuItem *PrinterSetupMenuItem;
	TMenuItem *ExitMenuItem;
	TPanel *Panel1;
	TComboBox *PrintersComboBox;
	TLabel *Label1;
	TMenuItem *DestinationMenu;
	TMenuItem *PrintToPrinterDestinationMenuItem;
	TMenuItem *PrintToFileDestinationMenuItem;
	void __fastcall PrintMenuItemClick(TObject *Sender);
	void __fastcall OpenBitmapMenuItemClick(TObject *Sender);
	void __fastcall ExitMenuItemClick(TObject *Sender);
	void __fastcall PrinterSetupMenuItemClick(TObject *Sender);
	void __fastcall FormShow(TObject *Sender);
	void __fastcall PrintToPrinterDestinationMenuItemClick(TObject *Sender);
	void __fastcall PrintToFileDestinationMenuItemClick(TObject *Sender);
private:	// User declarations
	BOOL PictureLoaded;  // boolean for whether a picture is loaded or not
public:		// User declarations
	__fastcall TMainFMXForm(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TMainFMXForm *MainFMXForm;
//---------------------------------------------------------------------------
#endif

Below you will find the source code for the VCL and FMX form units.

VCLPrinterUnit.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#include <Vcl.Imaging.GIFImg.hpp>
#include <Vcl.Imaging.jpeg.hpp>
#include <Vcl.Imaging.pngimage.hpp>
#include <Vcl.Printers.hpp>

#pragma hdrstop

#include "VCLPrintUnit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TMainVCLForm *MainVCLForm;
//---------------------------------------------------------------------------
__fastcall TMainVCLForm::TMainVCLForm(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::File2Click(TObject *Sender)
{
	if (OpenPictureDialog1->Execute()) {
		Image1->Picture->LoadFromFile(OpenPictureDialog1->FileName);
		PictureLoaded = true;
		PrintPicture1->Enabled = true;
        PrinterSetup1->Enabled = true;
	}
}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::FormShow(TObject *Sender)
{

	PictureLoaded = false;
	PrintToPrinterDestinationMenuItem->Checked = true;
	PrintToFileDestinationMenuItem->Checked = false;

	// get printers list and put in combobox
	PrintersComboBox->Items = Printer()->Printers;

	// make the currently selected printer the Item in the ComboBox
	PrintersComboBox->ItemIndex = 0;
	for (int i = 0; i < Printer()->Printers->Count-1; i++) {
		if (Printer()->Printers->Strings[Printer()->PrinterIndex] == PrintersComboBox->Items->Strings[i]) {
			PrintersComboBox->ItemIndex = i;
		}
	}

}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::PrintToPrinterDestinationMenuItemClick(TObject *Sender)
{
	// set menu item checked for print to printer
	PrintToPrinterDestinationMenuItem->Checked = true;
	PrintToFileDestinationMenuItem->Checked = false;
	// set PrintDialog PrintToFile checkbox off
	// Note: to allow user to override the menu item - make sure
	//   PrintDialog Options poPrintToFile is set to true
	//   so that the PrintToFile checkbox appears in the dialog
	PrintDialog1->PrintToFile = false;
}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::PrintToFileDestinationMenuItemClick(TObject *Sender)
{
	// set menu item checked for print to file
	PrintToPrinterDestinationMenuItem->Checked = false;
	PrintToFileDestinationMenuItem->Checked = true;
	// set PrintDialog PrintToFile checkbox on
	// Note: to allow user to override the menu item - make sure
	//   PrintDialog Options poPrintToFile is set to true
	//   so that the PrintToFile checkbox appears in the dialog
	PrintDialog1->PrintToFile = true;
}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::PrintPicture1Click(TObject *Sender)
{

	// check if a picture is loaded
	if (PictureLoaded) {
		if (PrintDialog1->Execute()) {

			// Call BeginDoc - to get the dimensions for selected printer
			Printer()->BeginDoc();

			try {
				// use StretchDraw to do full size bitmap printing
				// notes:
				//   printer settings can be made using the
				//     PrintDialog and PrinterSetupDialog
				//   you can also control page layout in code:
				//     Property is Orientation:
				//       poPortrait
				//       poLandscape
				Printer()->Canvas->StretchDraw(
					Rect(0, 0, Printer()->PageWidth,Printer()->PageHeight),
					Image1->Picture->Graphic);
			}
			__finally {
				// end the document and the printing will begin
				Printer()->EndDoc();
			}
		}
	}

}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::PrinterSetup1Click(TObject *Sender)
{
	// Printer Setup
    PrinterSetupDialog1->Execute();
}
//---------------------------------------------------------------------------
void __fastcall TMainVCLForm::PrintPicture2Click(TObject *Sender)
{
    Application->Terminate();
}
//---------------------------------------------------------------------------

FMXPrinterUnit.cpp

//---------------------------------------------------------------------------

#include <fmx.h>
#include "FMX.Printer.hpp"
#include "System.SysUtils.hpp"
#pragma hdrstop

#include "FMXPrintUnit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.fmx"
TMainFMXForm *MainFMXForm;
//---------------------------------------------------------------------------
__fastcall TMainFMXForm::TMainFMXForm(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TMainFMXForm::PrintMenuItemClick(TObject *Sender)
{
	TRectF SrcRect, DestRect;

	if (PrintDialog1->Execute()) {
		// Set the default DPI for the printer. The SelectDPI routine defaults
		//	 to the closest available resolution as reported by the driver.
		// Printer->ActivePrinter->SelectDPI(1200, 1200);

		// Printer->ActivePrinter->ActiveDPIIndex = 1; // you can also the DPI index

		// Set canvas filling style
		// Printer->Canvas->Fill->Color = claBlack;
		// Printer->Canvas->Fill->Kind = TBrushKind(1);

		// Start printing
		Printer::Printer()->BeginDoc();

		// Set the Source and Destination TRects

		SrcRect = TRectF(0, 0, Image1->Bitmap->Width, Image1->Bitmap->Height);
		DestRect = TRectF(0, 0, Printer::Printer()->PageWidth, Printer::Printer()->PageHeight);

		// Print the picture, on all the surface of the page and all opaque.
		Printer::Printer()->Canvas->DrawBitmap(Image1->Bitmap, SrcRect, DestRect, 1);

		// Finish the printing job
		Printer::Printer()->EndDoc();
	}

}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::OpenBitmapMenuItemClick(TObject *Sender)
{
	// open a bitmap for printing
	if (OpenDialog1->Execute()) {
		Image1->Bitmap->LoadFromFile(OpenDialog1->FileName);
		PrintMenuItem->Enabled = true;
		PrinterSetupMenuItem->Enabled = true;
        PictureLoaded = true;
	}
}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::ExitMenuItemClick(TObject *Sender)
{
	// exit the application
    Application->Terminate();
}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::PrinterSetupMenuItemClick(TObject *Sender)
{
	// use the Printer Setup dialog box
	PrinterSetupDialog1->Execute();
}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::FormShow(TObject *Sender)
{
	// on form show event handler

	PictureLoaded = false;
	PrintToPrinterDestinationMenuItem->IsChecked = true;
	PrintToFileDestinationMenuItem->IsChecked = false;

	// populate the ComboBox with the printer device names
	PrintersComboBox->ItemIndex = 0;
	for (int i = 0; i < Printer::Printer()->Count-1; i++) {
		PrintersComboBox->Items->Add(Printer::Printer()->Printers[i]->Title);
		// set the ComboBox ItemIndex to the active printer
		if (Printer::Printer()->Printers[i]->Title == Printer::Printer()->ActivePrinter->Title) {
			PrintersComboBox->ItemIndex = i;
		}
	}
}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::PrintToPrinterDestinationMenuItemClick(TObject *Sender)
{
	// set menu item checked for print to printer
	PrintToPrinterDestinationMenuItem->IsChecked = true;
	PrintToFileDestinationMenuItem->IsChecked = false;
	// set PrintDialog PrintToFile checkbox off
	// Note: to allow user to override the menu item - make sure
	//   PrintDialog Options poPrintToFile is set to true
	//   so that the PrintToFile checkbox appears in the dialog
	PrintDialog1->PrintToFile = false;
}
//---------------------------------------------------------------------------

void __fastcall TMainFMXForm::PrintToFileDestinationMenuItemClick(TObject *Sender)
{
	// set menu item checked for print to file
	PrintToPrinterDestinationMenuItem->IsChecked = false;
	PrintToFileDestinationMenuItem->IsChecked = true;
	// set PrintDialog PrintToFile checkbox on
	// Note: to allow user to override the menu item - make sure
	//   PrintDialog Options poPrintToFile is set to true
	//   so that the PrintToFile checkbox appears in the dialog
	PrintDialog1->PrintToFile = true;
}
//---------------------------------------------------------------------------

The VCL and FMX applications in Action

VCL app in action
FMX app in action

References

VCL Printing

Printing in VCL Applications
Vcl.Printers

FMX Printing

Printing from a FireMonkey Application
FMX.Printer

YouTube Videos

Creating your First VCL Application for Windows with C++Builder
Creating Your First C++ Windows App
Why C++Builder?

Source Code

Source Code for VCL and FMX printing projects (zip file)

About C++Builder

C++Builder Product Page – Native Apps that Perform. Build Windows C++ Apps 10x Faster with Less Code

C++Builder Product Editions – C++Builder is available in four editions – Professional, Enterprise, Architect and Community (free). C++Builder is also available as part of the RAD Studio development suite.

Bjarne Stroustrup’s CppCon 2020 Plenary is Available on YouTube

Bjarne Stroupstrup’s CppCon 2020 plenary sesson, “The Beauty and Power of Primitive C++“, is now available on the CppCon YouTube channel.

From his CppCon 2020 talk description: This is an exploration of a design space close to the hardware and of the use of C++ in that space, rather than a standards proposal or the presentation of a mature tool chain. And, no, by “primitive”, I don’t mean “old-fashioned, C-like” code; some of the general techniques are old, but some of the code requires C++17 and much could be done better given features we are unlikely to get even in C++23.

Links to other replays of Bjarne’s talks at past CppCon (the C++ conference) events

A Few More Bjarne Videos (there are many others)

My Online Conversations with Bjarne Stroustrup

I’ve also had two opportunities to talk live online with Bjarne about the C++ language during past Embarcadero CodeRage online conferences:

You will find ISO C++ articles, news, books, podcasts, training courses, events, videos, product news, standardization activities, etc. on the Standard C++ Foundation site.


Technology News Worth Reading

Here are a few technology news stories that I’ve read in the past week or so.

News Headlines

Reading Code Is a Skill

The problem is not that we shouldn’t write readable code. Of course we should aim to write readable code, if only for our own poor selves further down the line (there is no one less capable of reading my code the following week than me). The problem is that these two issues are not mutually exclusive. It’s not “write readable code” or “learn to read code”. Read the DZone article by Trisha Gee.

When a digital twin becomes the evil twin

A digital twin is a digital replica of some physical entity, such as a person, a device, manufacturing equipment, or even planes and cars. The idea is to provide a real-time simulation of a physical asset or human to determine when problems are likely to occur and to proactively fix them before they actually arise. Read the InfoWorld article by David Linthicum.

The NVIDIA-Arm merger could change how we work

If the merger between Arm and NVIDIA is approved (I expect Great Britain, the EU, and China will have reservations), the result could be a massive change in AI capability. And, given that Arm is dominant in mobile devices and IoT, and NVIDIA is dominant in both graphics and AI training, it’s a merger that could have a dramatic impact on how we work as well. Read the ComputerWorld article by Rob Enderle.

Don’t write off government algorithms: Responsible AI can produce real benefits

There are many cases in which government bodies can deploy AI technology in lower risk, high-impact scenarios that can improve lives, particularly if they don’t directly use personal data. So before we leap full pelt into AI cynicism we should consider benefits as well as risks it offers, and demand a more responsible approach to AI development and deployment. Read the TechXplore article by Allison Gardner.

Postman’s New Schema Validation Feature Helps Encourage API Spec Literacy

Postman, an API development platform provider, has announced that its API Builder is gaining the ability to validate API schemas in real-time via a new UI pane that is accessible in the tool’s define tab. The addition of this functionality helps to provide developers with real-time feedback and encourage API specification literacy. Read the ProgrammableWeb article by Kevin Sundstrom.

Microsoft open-sources fuzzing test framework

Microsoft is looking to help developers continuously fuzz-test code prior to release, via the open source OneFuzz framework. Described as a self-hosted fuzzing-as-a-service platform, OneFuzz enables developer-driven fuzzing to identify software vulnerabilites during the development process. Read the InfoWorld article by Paul Krill. Access the OneFuzz framework on GitHub.

IoT Platform – Binding the IoT Ecosystem Together

The word IoT has meant many different things to different people, none of it is wrong in any sense. It has been just a matter of perspective. Device and sensor manufacturers think of it as the sensors at the center of the IoT ecosystem with some connectivity and software around the sensors to capture and transmit data. Network services providers think of IoT as a secure network that connects a bunch of commodity sensors to a backend data store. BI and Big Data platform providers think of their role in IoT as the most important; after all if you cannot process a large amount of data coming through and extract intelligence from it, what’s the point in putting all these sensors and networks in place. Read this DZone article by Seemant Ahuja

Tourists on Tech’s Toll Roads

The recent trend is toward systems that are increasingly more closed. Unfortunately it’s only the latest in an ongoing cycle throughout the history of computing between open highways and private roads. Each swing in the pendulum moves from public, open, shared innovation that lays the open roads to private companies who use those public roads to build their for-profit toll roads. Those companies fight to ensure that no matter what signs you follow, you end up on their private road. Read the blog post by Kyle Rankin.

4 Python type checkers to keep your code clean

Over the last few years, though, Python has added support for type annotations, inspiring a whole culture of software devoted to type checking Python during development. Python doesn’t check types at runtime — at least, not yet. But by taking advantage of a good type checker, riding shotgun with you in your IDE of choice, you can use Python’s type annotations to screen out many common mistakes before they hit production. Read the InfoWorld article by Serdar Yegulalp.

Interview with Homage’s Gillian Tee on how technology can serve the world’s aging population

According to the United Nations, the fastest-growing age bracket worldwide is aged 65-years-old and older. At the same time, there is also an acute shortage of caregivers in many countries, complicated by high rates of burnout in the profession. Read the TechCrunch interview with Homage’s co-founder and chief executive Gillian Tee in an article by Catherine Shu.

Refactoring from single to multi purpose

For the second time this year I’m refactoring a program from a single purpose to have two or more modes of operation. Both times the start and end result is similar, just the processing is different. A classic case of using polymorphism. The first program was a tool to process videos from speakers, find a face and export the subframe around it into a new video. The first mode was a good approach to test it, and gave results for some speakers. The second mode did a complete scan first, and then gave a smoother video for some videos. Read the Meeting C++ blog post by Jens Weller.

Using the Eigen C++ Template Library with C++Builder and VCL

It’s been almost 50 years since I took a Linear Algebra and Matrices course as one of my Computer Science electives at Cal Poly San Luis Obispo, CA. The textbook for the course was “Mathematics Of Matrices: First Book Of Matrix Theory And Linear Algebra” by Philip J Davis. While I have used arrays and vectors in many programming projects, I have to be honest and say that I have not used a lot of matrix math in my code.

Now that the Eigen C++ Template Library is available for download inside the C++Builder IDE using the GetIt Package Manager, I decided to re-introduce myself to matrix math, manipulations and linear algebra (not bad for a 69 year old software engineer). This blog post will show C++ developers how to download, install and use the Eigen C++ library using C++Builder and VCL.

Installing Eigen via the GetIt Package Manager

Inside the C++Builder IDE, use the Tools | GetIt Project Manager menu item to bring up the list of available add-on components, libraries and demos. Type “Eigen” in the search box to see what is available.

Click the Install button to download, install, build and run tests the Eigen C++ library with your release of C++Builder (I used C++Builder version 10.4.1). As part of the Eigen installation you will see two additional windows.

Dependency notice about minimal changes made to allow Eigen to work with C++Builder
Eigen Installation Window showing progress of the download, installation and tests

Once the download and installation is completed, you can start using Eigen in your applications. To learn more about the Eigen C++ Template Library I’ve included some reference links at the end of this post. To dust off my matrix and linear algebra cobwebs and learn a little bit about Eigen, I created three sample C++Builder VCL applications using Eigen.

Simple Eigen Test C++ VCL Application

This first example Button onClick event handler displays the Eigen version number, creates a 3×3 matrix, populates it with random floating point numbers (between -1 and 1) and uses the addition, subtraction and multiplication operators.

The VCL Form containing a button and memo
Application Output using addition, subtraction and multiplication

The Source Code

MainUnit.h

//---------------------------------------------------------------------------

#ifndef MainUnitH
#define MainUnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:	// IDE-managed Components
	TButton *Button1;
	TMemo *MatrixOutputMemo;
	TMemo *DemoCodeMemo;
	TLabel *Label1;
	TLabel *Label2;
	TLabel *EigenVersionLabel;
	void __fastcall Button1Click(TObject *Sender);
private:	// User declarations
public:		// User declarations
	__fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

MainUnit.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include <Eigen/Dense>
using Eigen::MatrixXd;
using Eigen::IOFormat;

#include "MainUnit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;

// create string stream from Eigen Matrix
  static std::string ConvertToString(const Eigen::MatrixXd& mat){
	std::stringstream ss;
	IOFormat CleanFmt(Eigen::FullPrecision, 0, ", ", "\n", "[", "]");
	ss << mat.format(CleanFmt);
	return ss.str();
}

//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
	// first sample app adapted from Eigen documentation and put in VCL app

	// display Eigen version number
	EigenVersionLabel->Caption = "Eigen version: "
		+ IntToStr(EIGEN_WORLD_VERSION)
		+ "."
		+ IntToStr(EIGEN_MAJOR_VERSION)
		+ "."
		+ IntToStr(EIGEN_MINOR_VERSION);

	// define a 3x3 matrix of doubles
	MatrixXd m(3,3);
	// Fill matrix with random numbers between -1 and +1
	m.setRandom(3,3);
	// Change three matrix items using + - and *
	m(0,2) = m(0,0) + m(0,1);
	m(1,2) = m(1,0) - m(1,1);
	m(2,2) = m(2,0) * m(2,1);

	// output matrix using strings
	MatrixOutputMemo->Lines->Clear();
	MatrixOutputMemo->Lines->Text = ConvertToString(m).c_str();
}
//---------------------------------------------------------------------------

Matrix Operations C++ VCL Application

The second Eigen C++ VCL application exercises several Eigen operations including adding and subtracting two matricies, multiplying and dividing a matrix by a scalar, multiplying two matricies, transposing a matrix, invert a matrix and sum all elements of a matrix. There are many additional features to explore in Eigen for vector and matrix operations.

In the UI for the application you’ll see a RadioGroup for selecting one of the operations, three StringGrids to display matrix contents, an EditBox for inputing a scalar (I used Pi), and a Label for the summing result.

The Matrix Operations example VCL form
Example Output after subtracting the x and y matrices giving z

The Source Code

MainUnit.h

//---------------------------------------------------------------------------

#ifndef MainUnitH
#define MainUnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
#include <Vcl.Grids.hpp>
#include <Vcl.ExtCtrls.hpp>
#include <Vcl.Samples.Spin.hpp>

//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:	// IDE-managed Components
	TStringGrid *StringGridX;
	TStringGrid *StringGridY;
	TStringGrid *StringGridZ;
	TLabel *Label1;
	TLabel *Label2;
	TLabel *Label3;
	TRadioGroup *RadioGroup1;
	TButton *Button1;
	TLabel *Label4;
	TEdit *ScalarEdit;
	TLabel *ResultLabel;
	void __fastcall FormShow(TObject *Sender);
	void __fastcall Button1Click(TObject *Sender);
private:	// User declarations
    void __fastcall displayMatricies();
public:		// User declarations
	__fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

MainUnit.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include <Eigen/Dense>
using Eigen::MatrixXd;

#include <System.SysUtils.hpp>
#include "MainUnit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;

MatrixXd x(3,3);
MatrixXd y(3,3);
MatrixXd z(3,3);

void TForm1::displayMatricies() {
	// display contents of x, y and z matricies
	int numberRows = x.rows();
	int numberColumns = y.cols();
	for (int r=0 ; r < numberRows ; r++) {
		for (int c = 0; c < numberColumns; c++) {
			StringGridX->Cells[r][c] = FloatToStrF(x(r,c),ffFixed,5,3);
			StringGridY->Cells[r][c] = FloatToStrF(y(r,c),ffFixed,5,3);
			StringGridZ->Cells[r][c] = FloatToStrF(z(r,c),ffFixed,5,3);
		}
	}
}

//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormShow(TObject *Sender)
{
	// populate x and y matricies and their string grids with random numbers
	x.setRandom(5,5);
	y.setRandom(5,5);
	z.setZero(5,5);

	// clear selections in the string grids
	TGridRect gr;

	gr.Left = StringGridX->ColCount;
	gr.Top = StringGridX->RowCount;
	StringGridX->Canvas->Brush->Color = clWindow;
	StringGridX->Canvas->FillRect(Rect(StringGridX->Left,StringGridX->Width,StringGridX->Top,StringGridX->Height));

	gr.Left = StringGridY->ColCount;
	gr.Top = StringGridY->RowCount;
	StringGridY->Canvas->Brush->Color = clWindow;
	StringGridY->Canvas->FillRect(Rect(StringGridY->Left,StringGridY->Width,StringGridY->Top,StringGridY->Height));

	gr.Left = StringGridZ->ColCount;
	gr.Top = StringGridZ->RowCount;
	StringGridZ->Canvas->Brush->Color = clWindow;
	StringGridZ->Canvas->FillRect(Rect(StringGridZ->Left,StringGridZ->Width,StringGridZ->Top,StringGridZ->Height));

	// display current values of matricies
	displayMatricies();
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
	// do the operation that is currently selected in the Radio Button Group
	// 0 = addition, 1= subtraction, 2 = multiplication,
	// 3 = division, 4 = dot product
	switch(RadioGroup1->ItemIndex) {
		case 0: // addition
			z = x + y;
			break;
		case 1: // subtraction
			z = x - y;
			break;
		case 2: // multiply x by scalar and save result in z
			z = x * StrToFloat(ScalarEdit->Text);
			break;
		case 3: // divide x by scalar and save result in z
			z = x / StrToFloat(ScalarEdit->Text);
			break;
		case 4:  // multiply x * y and save result in z
			z.noalias() = x * y;
			break;
		case 5: // transpose x and save result in z
			z = x.transpose();
			break;
		case 6: // invert x and save result in z
			z = x.inverse();
			break;
		case 7: // sum all elements of x and save in result
			ResultLabel->Caption = "Result: "+FloatToStr(x.sum());
			break;
	}

	// display current values of matricies
	displayMatricies();
}
//---------------------------------------------------------------------------

Shopping Linear Algebra C++ VCL Application

I wanted to use a “real world” linear algebra example to showcase a few additional features of the Eigen C++ template library. There are many matrix and linear algebra courses and examples out on the Internet. After a quick search I decided to use “Real-world Applications of Linear Algebra Tools” by E. Ulrychova, postgradual student at the University of Economics, Department of Mathematics, Prague, Czech Republic.

The scenario has three people who want to each shop for baked goods at only one of two stores. Each person has a quantity of rolls, buns, cakes and breads that they want to purchase. Each store has a list of prices that they charge for each of the baked goods. This linear algebra example calculates a spending analysis for each person at each store to show where each person should shop.

The user interface includes a button to run code that calculates the lowest shopping cost for each person, a StringGrid for the baked goods demand matrix for each person, a StringGrid for the store pricing for each baked good, and a StringGrid for the results of the optimal spending analysis for each person.

The VCL Form for the UI
The demand matrix of baked goods for each person, the prices for each baked good by shop and the resulting optimal shop spending for each person

The Source Code

ShoppingUnit.h

//---------------------------------------------------------------------------

#ifndef ShoppingUnitH
#define ShoppingUnitH
//---------------------------------------------------------------------------
#include <System.Classes.hpp>
#include <Vcl.Controls.hpp>
#include <Vcl.StdCtrls.hpp>
#include <Vcl.Forms.hpp>
#include <Vcl.Grids.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:	// IDE-managed Components
	TButton *Button1;
	TStringGrid *DemandMatrixStringGrid;
	TLabel *Label1;
	TStringGrid *PriceMatrixStringGrid;
	TLabel *Label2;
	TStringGrid *ResultStringGrid;
	TLabel *Label3;
	void __fastcall Button1Click(TObject *Sender);
private:	// User declarations
public:		// User declarations
	__fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

ShoppingUnit.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include <Eigen/Dense>
using Eigen::MatrixXd;
using Eigen::VectorXd;
using Eigen::IOFormat;


#include "ShoppingUnit.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{

	// Calculate results of spending analysis by person by store
	//    R = PQ
	// from:
	// Real-world Applications of Linear Algebra Tools
	// by E. Ulrychova, postgradual student
	// University of Economics, Department of Mathematics, Prague, Czech Republic
	// https://www.mff.cuni.cz/veda/konference/wds/proc/pdf06/WDS06_106_m8_Ulrychova.pdf


	int r,c;  // row and column indexes used throughout this event handler

	// matricies used for spending analysis
	MatrixXd DemandMatrix(4,3);   // Q
	MatrixXd PriceMatrix(2,4);    // P
	MatrixXd ResultMatrix(2,3);   // R

	// vectors used for dot product analysis of spending by person by shop
	VectorXd DemandVector(4);
	VectorXd PriceVector(4);


	// Demanded quantity of foodstuffs per person (3 people, 4 foodstuffs)
	DemandMatrix <<  // Q
		6,3,3,  // foodstuff quantities for rolls for each of the 3 people
		5,6,4,  // foodstuff quantities for buns for each of the 3 people
		3,2,3,  // foodstuff quantities for cakes for each of the 3 people
		1,2,1;  // foodstuff quantities for breads for each of the 3 people

	// Prices for each foodstuff in each shop (4 foodstuffs, 2 shops)
	PriceMatrix <<  //P
		1.50,2.00,5.00,16.00,  // prices for foodstuffs at Shop 1
		1.00,2.50,4.50,17.00;  // prices for foodstuffs at Shop 2


	// Calculate results of spending analysis by person by store
	//    R = PQ

	int ResultMatrixNumberRows = ResultMatrix.rows();
	int ResultMatrixNumberColumns = ResultMatrix.cols();

	for (r=0 ; r < ResultMatrixNumberRows ; r++) {
		for (c = 0; c < ResultMatrixNumberColumns; c++) {
			// create price and demand vectors
			DemandVector = DemandMatrix.col(c);
			PriceVector = PriceMatrix.row(r);
			// use dot product of demand and price to get a result
			ResultMatrix(r,c) = DemandVector.dot(PriceVector);
		}
	}

	// set heading and column strings for Demand Matrix rows and columns
	DemandMatrixStringGrid->Cells[1][0] = "roll";
	DemandMatrixStringGrid->Cells[2][0] = "bun";
	DemandMatrixStringGrid->Cells[3][0] = "cake";
	DemandMatrixStringGrid->Cells[4][0] = "bread";
	DemandMatrixStringGrid->Cells[0][1] = "p1";
	DemandMatrixStringGrid->Cells[0][2] = "p2";
	DemandMatrixStringGrid->Cells[0][3] = "p3";

	// set heading and column strings for Price Matrix rows and columns
	PriceMatrixStringGrid->Cells[1][0] = "s1";
	PriceMatrixStringGrid->Cells[2][0] = "s1";
	PriceMatrixStringGrid->Cells[0][1] = "roll";
	PriceMatrixStringGrid->Cells[0][2] = "bun";
	PriceMatrixStringGrid->Cells[0][3] = "cake";
	PriceMatrixStringGrid->Cells[0][4] = "bread";

	// set heading and column strings for Result Matrix String Grid rows and columns
	ResultStringGrid->Cells[1][0] = "s1";
	ResultStringGrid->Cells[2][0] = "s1";
	ResultStringGrid->Cells[0][1] = "p1";
	ResultStringGrid->Cells[0][2] = "p2";
	ResultStringGrid->Cells[0][3] = "p3";

	int DemandMatrixNumberRows = DemandMatrix.rows();
	int DemandMatrixNumberColumns = DemandMatrix.cols();

	// populate string grid with the Demand Data
	for (r=1 ; r <= DemandMatrixNumberRows ; r++) {
		for (c = 1; c <= DemandMatrixNumberColumns; c++) {
			DemandMatrixStringGrid->Cells[r][c] = FloatToStrF(DemandMatrix(r-1,c-1),ffFixed,5,3);
		}
	}

	int PriceMatrixNumberRows = PriceMatrix.rows();
	int PriceMatrixNumberColumns = PriceMatrix.cols();

	// populate string grid with the Price Data
	for (r=1 ; r <= PriceMatrixNumberRows ; r++) {
		for (c = 1; c <= PriceMatrixNumberColumns; c++) {
			PriceMatrixStringGrid->Cells[r][c] = FloatToStrF(PriceMatrix(r-1,c-1),ffFixed,5,3);
		}
	}


	// With the supplied data this program shows it is optimal
	//  for person p1 to buy in the shop s2,
	//  for person p2 to buy in shop s1
	//  and person p3 will pay the same price in shop s1 and s2

	int ResultNumberRows = ResultMatrix.rows();
	int ResultNumberColumns = ResultMatrix.cols();

	// populate string grid with the results
	for (r=1 ; r <= ResultNumberRows ; r++) {
		for (c = 1; c <= ResultNumberColumns; c++) {
			ResultStringGrid->Cells[r][c] = FloatToStrF(ResultMatrix(r-1,c-1),ffFixed,5,3);
		}
	}

}
//---------------------------------------------------------------------------

References

C++Builder DocWiki information

GetIt Package Manager

C++ Libraries in GetIt

Eigen C++ Template Library information

Eigen C++ Template Library main page

Eigen Library Documentation (version 3.3.7 as of this posting)

Eigen Quick Reference Guide

Eigen latest development version documentation (ver 3.3.90 as of this posting)

Eigen Advanced Initialization

Eigen IOFormat Class Reference

Eigen and Linear Algebra Tutorials and Information

Real-world Applications of Linear Algebra Tools by E. Ulrychova, postgradual student University of Economics, Department of Mathematics, Prague, Czech Republic (PDF)

Eigen Tutorial – CS2240 Interactive Computer Graphics (PDF) by Daniel Ritchie, Assistant Professor of Computer Science at Brown University

Eigen Library for Matrix Algebra in C++ by The Quantcademy

C++Builder Product Information

C++Builder Product Page – Native Apps that Perform. Build Windows C++ Apps 10x Faster with Less Code

C++Builder Product Editions – C++Builder is available in four editions – Professional, Enterprise, Architect and Community (free). C++Builder is also available as part of the RAD Studio development suite.

My C++Builder Eigen VCL Example Applications

Source Code zip file for all 3 examples

New in C++Builder/Delphi 10.4.1 IDE: Package LibSuffix Auto Choice

The C++Builder and Delphi Project | Options | Description page allows developers to

  • Choose and Set build target configurations
  • Write a description for the package
  • Set strings for the package library filename’s prefix, suffix and version
  • Define the use of the package (designtime, runtime or both)
  • Specify how the package is built (rebuild as needed or explicit rebuild)

In previous versions (version 10.3 and earlier) of C++Builder and Delphi developers building packages needed to manually set their package’s library suffix setting. The DocWiki “What’s new in version 10.4.1” mentions a new IDE projects option for setting the library suffix:

“Package AUTO libsuffix: packages can now have an automatic version suffix, instead of manually updating and specifying the right version suffix with each new release. (The compiler quietly supported this in 10.4, but full support for the feature in the IDE and package project settings is introduced in 10.4.1.)”

While you can still set a string for the library filename suffix, selecting the new ComboBox choice, “$(Auto)”, allows the compiler to set the suffix to match the package build version used by the compiler. For each target build (debug and release) and OS platform the resulting package filename follows a pattern:

Win32 and Win64: <prefix>Package1<suffix>.<version>.bpl
Android: <prefix>Package1<suffix>.so.<version>
macOS and iOS: <prefix>Package1<suffix>.<version>.dylib

Creating and building a package with Delphi and C++Builder version 10.4.1, choosing the $Auto option for the suffix and setting other Description page settings results in a filename like the test package project images shown below.

C++Builder and Delphi also support package-specific compiler directives to include in a package project’s source code.

C++Builder Product Information

C++Builder Product Page – Native Apps that Perform. Build Windows C++ Apps 10x Faster with Less Code
C++Builder Product Editions – C++Builder is available in four editions – Professional, Enterprise, Architect and Community (free). C++Builder is also available as part of the RAD Studio development suite.