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view src/video/SDL_pixels_c.h @ 3333:b334b4f7dfa0

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[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;
author Sam Lantinga <slouken@libsdl.org>
date Sat, 03 Oct 2009 16:23:16 +0000
parents 502adab079a4
children f7b03b6838cb
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Useful functions and variables from SDL_pixel.c */

#include "SDL_blit.h"

/* Pixel format functions */
extern SDL_PixelFormat *SDL_AllocFormat(int bpp,
                                        Uint32 Rmask, Uint32 Gmask,
                                        Uint32 Bmask, Uint32 Amask);
extern SDL_PixelFormat *SDL_InitFormat(SDL_PixelFormat * format, int bpp,
                                       Uint32 Rmask, Uint32 Gmask,
                                       Uint32 Bmask, Uint32 Amask);
extern void SDL_FormatChanged(SDL_Surface * surface);
extern void SDL_FreeFormat(SDL_PixelFormat * format);

/* Blit mapping functions */
extern SDL_BlitMap *SDL_AllocBlitMap(void);
extern void SDL_InvalidateMap(SDL_BlitMap * map);
extern int SDL_MapSurface(SDL_Surface * src, SDL_Surface * dst);
extern void SDL_FreeBlitMap(SDL_BlitMap * map);

/* Miscellaneous functions */
extern int SDL_CalculatePitch(SDL_Surface * surface);
extern void SDL_DitherColors(SDL_Color * colors, int bpp);
extern Uint8 SDL_FindColor(SDL_Palette * pal, Uint8 r, Uint8 g, Uint8 b);
extern void SDL_ApplyGamma(Uint16 * gamma, SDL_Color * colors,
                           SDL_Color * output, int ncolors);
/* vi: set ts=4 sw=4 expandtab: */