Programs and classes in Borland C++ 4.0 ObjectWindows Library OWL 2.0

ObjectWindows Library was Borland's object oriented encapsulation of the Windows API. Treating Windows objects as standard C++ objects with member variables, member functions, and functions for responding to Windows messages (later to be called properties, methods, and events) made it much easier to learn how to write a Windows GUI program.

The Borland C++/OWL package included the OWL source code, 7 printed books (2,715 pages) of well-written reference documentation and walk-through tutorials, plus example projects demonstrating how to use nearly every OWL feature. Back in the days before free trial downloads, this was a tremendous bargain in educational materials even at its price of $329. It made learning C++ and Windows programming fun. These projects were ones I developed while learning.

In support of the OWLNext project (described further down this page), the Borland spin-off company Embarcadero Technologies has released OWL, including source code, for download at http://cc.embarcadero.com/item/24574.

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Each project link below goes to a separate page with a more complete program description, a code listing, and, if the project is large, a link for downloading its zip file.

The Images link at the top of this page goes to image galleries created by several of these programs.

ObjectWindows Library Programs

Text link goes to the project page. Thumbnail link goes to full-sized image.

Chess.cpp	Uses a TLayoutWindow to create an invertible chess board with pieces on it. As you move the pieces, it creates a record of the game which can be saved to disk, reloaded, and animated. The program does not, however, play chess, but you can play a game on the board it provides. The page also has links to some chess-related websites.
Neural Network with graphic display	A multi-layer backpropagation artificial neural net program that uses graphics to show the status of the network nodes as they "think". There is also a listing of the earlier (and simpler) MSDOS version of the program, and a link to the most recent Microsoft Visual C++ version.
Natural Language Processing chatbot	An Eliza-like program that converses with you, while performing natural language processing (NLP) on your input in an attempt to extract information, accumulate world knowledge, and learn correct grammatical constructions.
Mandelbrot set	Continuously generates random regions at random magnifications that are filtered (screened) to avoid displaying blank or boring areas. Full-featured program with zooming by quadrant or area select, color cycling (animation), fast palette swapping, and palette manipulation. The project also includes the predecessor MSDOS C++ version of the program and a Java application version.
Logistic Map Bifurcation Diagram	Displays the logistic map bifurcation diagram of the equation X=RX(1-X) as discovered by Robert May and described in Chaos, by James Gleick. This program was derived from the Mandelbrot program, works the same, and has its fancy features, including continuous generation mode.
Iterated function set (IFS) fractals	Continuously draws color fractals based on randomly-generated Iterated Function System (IFS) sets. Multiple drawing windows. Manually edit transform sets. Crossbreed sets using a genetic algorithm with mutation.
Game of Life cellular automaton	Plays the Game of Life, a cellular automaton originated by John Conway. Allows standard, random, or custom born/survive/die rules. User-adjustable field size also adjusts cell size from 1 pixel to very big for easier viewing.
Artificial life, evolution, adaptation demonstration	Creates imaginary animals (as dots) that move around the screen according to a self-contained program, eating each other or producing offspring using a genetic algorithm, such that the programs evolve by natural selection, survival determined by which ones are most effective at obtaining food or producing offspring.
Bitmap file animator	Displays .BMP bitmap files sequentially to animate them.

OWL-based utility classes

Other OWL pages

Bugs

1. .RTF file incompatibility -- Some of the largest of these projects have .RTF documents to be used for creating Help files with the Microsoft Help Compiler. However, they were edited with Word 2003 before being added to the project zip files. Word 2003 added some metadata that causes parse errors when the files are compiled with the Help Compiler for Windows 3.1. The solution is to open the .RTF file in Word 6.0 and save it. Word 6 strips out the incompatible data.

Windows 3.1-compiled OWL code does not run in Windows XP

These programs were all written in the Borland C++ 4.0 IDE. When I compile them in that environment on my Windows 3.1 computer and copy the executables to my Windows XP computer, they will not run properly. They crash on launch with an error something like GDI Error or GDI Failure. They crash regardless whether they were compiled for a Win16 or Win32 target (Win32s), even if the exact same executables run perfectly in Windows 3.1 with Win32s. I don't know the cause. Windows XP's backwards compatibility is supposed to be good. There must either be code common to all my programs that was allowable in Windows 3.1 but not in XP, or there is something in the OWL 2.0 infrastructure that is no longer allowable in WinXP. So far I've found no simple fix or work-around, but the solution that might be most likely to succeed, which I have not tried, is in the next section.

OWLNext

OWL has been ported to Windows 95/98/NT/2000/XP/Vista and Linux by a project called OWLNext.

To use it, first install the last official version of OWL, Version 5, from Embarcadero Technologies. Then install OWLNext to upgrade OWL to OWLNext. 

The OWLNext site also has a comprehensive set of OWL resources that includes articles, tutorials, OWL projects, links to other OWL-related sites, and more.

The OWL Usenet discussion group is a place to ask OWL-related questions.

Converting programs from ObjectWindows to Microsoft Visual C++ .NET

The reason I didn't make much of an effort to extend the life of my OWL programs was that when I finally got a Windows XP computer, I was most interested in learning something new, even if it meant completely rewriting the programs over a long period of time.

It turns out to be relatively easy to convert Borland OWL code to Microsoft Visual C++ and .NET even though the process is a rewrite more than a conversion. I've created this forum thread to describe some of the issues involved, and for discussion. 

Text substitutions are often all that's required to convert Borland's BIDS TArray classes to the Standard Template Library. The two are reasonably similar.

Screen elements like windows, menus, and other objects must be built from scratch, but the Visual C++ form designer interface makes that relatively easy. The hard part was designing the elements in the first place, and that's already done.

Learning the new .NET Framework equivalents of the OWL methods can be difficult and time-consuming, but the .NET methods are incredibly powerful and the results are very good.

I've done a few project conversions so far. If you have your own OWL code to convert, comparing the two versions might provide you with tips how to proceed.