sdlgfxblitfunc.h File Reference

(986a3bf)

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Functions
int	SDLgfxBlitRGBA (const SDL_Surface *const src, const SDL_Rect *const srcrect, SDL_Surface *const dst, const SDL_Rect *const dstrect)

Function Documentation

SDLgfxBlitRGBA()

int SDLgfxBlitRGBA	(	const SDL_Surface *const	src,
		const SDL_Rect *const	srcrect,
		SDL_Surface *const	dst,
		const SDL_Rect *const	dstrect
	)

Definition at line 437 of file sdlgfxblitfunc.cpp.

{
    SDL_Rect sr;
    SDL_Rect dr;
    int srcx;
    int srcy;
    int w;
    int h;
 
    /*
    * Make sure the surfaces aren't locked
    */
    if (src == nullptr ||
        dst == nullptr)
    {
        reportAlways("SDLgfxBlitRGBA: passed a NULL surface")
        return -1;
    }
 
    /*
    * If the destination rectangle is NULL, use the entire dest surface
    */
    if (dstrect == nullptr)
    {
        dr.x = 0;
        dr.y = 0;
        dr.w = CAST_U16(dst->w);
        dr.h = CAST_U16(dst->h);
    }
    else
    {
        dr = *dstrect;
    }
 
    /*
    * Clip the source rectangle to the source surface
    */
    if (srcrect != nullptr)
    {
        int maxw;
        int maxh;
 
        srcx = srcrect->x;
        w = srcrect->w;
        maxw = src->w - srcx;
        if (maxw < w)
            w = maxw;
 
        srcy = srcrect->y;
        h = srcrect->h;
        maxh = src->h - srcy;
        if (maxh < h)
            h = maxh;
    }
    else
    {
        srcx = 0;
        srcy = 0;
        w = src->w;
        h = src->h;
    }
 
    /*
    * Clip the destination rectangle against the clip rectangle
    */
    const SDL_Rect *const clip = &dst->clip_rect;
    int dx;
    int dy;
 
    dx = clip->x - dr.x;
    if (dx > 0)
    {
        w -= dx;
        dr.x += dx;
        srcx += CAST_S16(dx);
    }
    dx = dr.x + w - clip->x - clip->w;
    if (dx > 0)
        w -= dx;
 
    dy = clip->y - dr.y;
    if (dy > 0)
    {
        h -= dy;
        dr.y += dy;
        srcy += CAST_S16(dy);
    }
    dy = dr.y + h - clip->y - clip->h;
    if (dy > 0)
        h -= dy;
 
    if (w > 0 && h > 0)
    {
        sr.x = CAST_S16(srcx);
        sr.y = CAST_S16(srcy);
        sr.w = dr.w = CAST_U16(w);
        sr.h = dr.h = CAST_U16(h);
        return _SDL_gfxBlitRGBACall(src, &sr, dst, &dr);
    }
 
    return 0;
}

References _SDL_gfxBlitRGBACall(), CAST_S16, CAST_U16, and reportAlways.

Referenced by SDLImageHelper::combineSurface(), and TestLauncher::testBlitSpeed().