[SDL] Bad math in SDL_RenderCopy Mason Wheeler to sdl When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this: if (dstrect->w != real_dstrect.w) { int deltax = (dstrect->x - real_dstrect.x); int deltaw = (dstrect->w - real_dstrect.w); real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w; real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w; } if (dstrect->h != real_dstrect.h) { int deltay = (dstrect->y - real_dstrect.y); int deltah = (dstrect->h - real_dstrect.h); real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h; real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;

To compile and install SDL:

    1.  Run './configure; make; make install'

        If you are compiling for Windows using gcc, read the FAQ at:
        http://www.libsdl.org/faq.php?action=listentries&category=4#42

        If you are compiling using Visual C++ on Win32, you should read
        the file VisualC.html

    2.  Look at the example programs in ./test, and check out the HTML
        documentation in ./docs to see how to use the SDL library.

    3.  Join the SDL developer mailing list by sending E-mail to
    	sdl-request@libsdl.org
        and put "subscribe" in the subject of the message.

        Or alternatively you can use the web interface:
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That's it!
Sam Lantinga <slouken@libsdl.org>