Bug in SDL_CreateCursor on Windows?

WB1 · April 13, 2020, 9:23am

With SDL 2.0.10, when creating cursors with SDL_CreateCursor on Windows 7 64bit inverted colours do not seem to work correctly.

On https://wiki.libsdl.org/SDL_CreateCursor it states ‘inverted color if possible, black if not’ so technically I am getting the ‘if not’ behaviour. But this is undesirable and likely a bug?

So far in SDL’s code I have been looking at the function WIN_CreateCursor():

github.com

SDL-mirror/SDL/blob/master/src/video/windows/SDL_windowsmouse.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
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  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
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     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

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I suspect all cursor creation is going through it (I haven’t had time to set things up to build and debug the source yet). At a guess maybe this was a bug that crept in when ‘SDL_CreateColorCursor’ was added? Which doesn’t unfortunately support XOR coloured data.

By using the simple raw Win32 API cursor functions I can create cursors correctly with inverted colours. But then I end up in a ‘SetCursor’ fight with SDL to ensure my self created cursor with inverted colours doesn’t get swapped out. So I am debating what to do there as I do also want to support animated cursors, and full coloured XOR stuff eventually (but from what I am reading so far animating the cursor by repeated SetCursor calls seems like it’s maybe fine).