73 lines
2.2 KiB
C
73 lines
2.2 KiB
C
#include "geom.h"
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#include "image.h"
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#include "color.h"
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#include <glib.h>
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void RrImageDraw(RrPixel32 *target, RrTextureRGBA *rgba, RrRect *area)
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{
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RrPixel32 *draw = rgba->data;
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gint c, i, e, t, sfw, sfh;
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sfw = area->width;
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sfh = area->height;
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g_assert(rgba->data != NULL);
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if ((rgba->width != sfw || rgba->height != sfh) &&
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(rgba->width != rgba->cwidth || rgba->height != rgba->cheight)) {
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double dx = rgba->width / (double)sfw;
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double dy = rgba->height / (double)sfh;
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double px = 0.0;
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double py = 0.0;
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int iy = 0;
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/* scale it and cache it */
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if (rgba->cache != NULL)
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g_free(rgba->cache);
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rgba->cache = g_new(RrPixel32, sfw * sfh);
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rgba->cwidth = sfw;
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rgba->cheight = sfh;
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for (i = 0, c = 0, e = sfw*sfh; i < e; ++i) {
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rgba->cache[i] = rgba->data[(int)px + iy];
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if (++c >= sfw) {
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c = 0;
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px = 0;
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py += dy;
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iy = (int)py * rgba->width;
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} else
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px += dx;
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}
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/* do we use the cache we may have just created, or the original? */
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if (rgba->width != sfw || rgba->height != sfh)
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draw = rgba->cache;
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/* apply the alpha channel */
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for (i = 0, c = 0, t = area->x, e = sfw*sfh; i < e; ++i, ++t) {
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guchar alpha, r, g, b, bgr, bgg, bgb;
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alpha = draw[i] >> RrDefaultAlphaOffset;
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r = draw[i] >> RrDefaultRedOffset;
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g = draw[i] >> RrDefaultGreenOffset;
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b = draw[i] >> RrDefaultBlueOffset;
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if (c >= sfw) {
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c = 0;
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t += area->width - sfw;
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}
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/* background color */
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bgr = target[t] >> RrDefaultRedOffset;
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bgg = target[t] >> RrDefaultGreenOffset;
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bgb = target[t] >> RrDefaultBlueOffset;
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r = bgr + (((r - bgr) * alpha) >> 8);
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g = bgg + (((g - bgg) * alpha) >> 8);
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b = bgb + (((b - bgb) * alpha) >> 8);
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target[t] = (r << RrDefaultRedOffset)
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| (g << RrDefaultGreenOffset)
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| (b << RrDefaultBlueOffset);
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}
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}
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}
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