Date: Tue, 15 Feb 2005 21:28:48 +0900 (JST) From: "Michael Leonhard" Subject: [SDL] resize bug on Win32 and patch This is my first post to this mailing list. In this email I will detail a bug in the behavior of resizable SDL windows on Win32. Then I will explain the solution and provide a patch. Symptoms: Under Windows, an SDL display created with the SDL_RESIZABLE flag exhibits quirky behavior when being maximized. The window is resized to the proper size, but it is shifted upwards about half the height of the title bar. Similarly, a window whose origin is above the top of the screen will spontaneously move its upper-left origin upon being resized. After two such resize-induced moves, the title bar will be entirely off the top edge of the screen. Subsequently, when the mouse is clicked and released on the window border, the window will shrink its height spontaneously. This height shrinkage occurs even if the user did not resize the border. To observe this curious situation, please invoke: SDL-1.2.8/test/testwm.exe -resize Cause: A pair of integers, SDL_windowX and SDL_windowY, are defined in video/wincommon/SDL_sysevents.c. They are used by the DirectX video driver and the DIB video driver: video/windx5/SDL_dx5video.c video/windib/SDL_dibvideo.c As I understand the source code, the primary use of these variables is to create a rectangle that represents the surface area in CLIENT SPACE. Client space refers to a coordinate system that originates at the upper left corner of a Win32 Window's drawable area. This is just inside the window border and title bar. This client space rectangle, called bounds, is subsequently converted to screen space with a call to AdjustWindowRectEx. The problem is found in SDL's handling of the WM_WINDOWPOSCHANGED message. According to MSDN, "The WM_WINDOWPOSCHANGED message is sent to a window whose size, position, or place in the Z order has changed as a result of a call to the SetWindowPos function or another window-management function." I have confirmed that this message is indeed being sent to the SDL window when the mouse is clicked on the window border, even if the window border is not dragged. In video/wincommon/SDL_sysevents.c, on line 464, in response to the WM_WINDOWPOSCHANGED message, the (potentially) new client rectangle is obtained. This rectangle is translated into screen coordinates and THEN assigned to the SDL_windowX and Y variables. Thus screen coordinates are being assigned to client coordinate variables. Once this is understood, the solution is apparent: assign SDL_windowX and Y before translating the rectangle to screen coordinates. This is accomplished by the following patch. -Mike_L

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Using the Simple DirectMedia Layer with MacOS 7,8,9 on PPC
==============================================================================

These instructions are for people using the Apple MPW environment:
http://developer.apple.com/tools/mpw-tools/

CodeWarrior projects are available in the CWprojects directory.

==============================================================================
I.  Building the Simple DirectMedia Layer libraries:
    (This step isn't necessary if you have the SDL binary distribution)

  First, unpack the MPWmake.sea.hqx archive and move SDL.make into the
  SDL directory.

  Start MPW

  Set the current directory within MPW to the SDL toplevel directory.

  Build "SDL"  (Type Command-B and enter "SDL" in the dialog)

  If everything compiles successfully, you now have the PPC libraries
  "SDL" and "SDLmain.o" in the 'lib' subdirectory.

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II. Building the Simple DirectMedia Layer test programs:

  First, unpack the MPWmake.sea.hqx archive, move the new rsrc directory to
  the main SDL directory, and move the makefiles in the new test subdirectory
  to the SDL 'test' subdirectory.

  Start MPW

  Set the current directory within MPW to the SDL 'test' subdirectory.

  Build the programs that have an associated MPW makefile (file ending
  with .make), including "testwin", "testalpha", and "graywin".

  Copy the SDL library file into the test directory, and run!

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III. Building the Simple DirectMedia Layer demo programs:

  Copy one of the test program Makefiles to the demo directory
  and modify it to match the sources in the demo.

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IV.  Enjoy! :)

  If you have a project you'd like me to know about, or want to ask questions,
  go ahead and join the SDL developer's mailing list by sending e-mail to:

	sdl-request@libsdl.org

  and put "subscribe" into the subject of the message. Or alternatively you
  can use the web interface:

	http://www.libsdl.org/mailman/listinfo/sdl
  
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