render/image.c (raw)
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#include "geom.h" #include "image.h" #include "color.h" #include <glib.h> #define AVERAGE(a, b) ( ((((a) ^ (b)) & 0xfefefefeL) >> 1) + ((a) & (b)) ) static void scale_line(RrPixel32 *dest, RrPixel32 *source, gint w, gint dw) { gint num_pixels = dw; gint int_part = w / dw; gint fract_part = w % dw; gint err = 0; while (num_pixels-- > 0) { *dest++ = *source; source += int_part; err += fract_part; if (err >= dw) { err -= dw; source++; } } } static RrPixel32* scale_half(RrPixel32 *source, gint w, gint h) { RrPixel32 *out, *dest, *sourceline, *sourceline2; gint dw, dh, x, y; sourceline = source; sourceline2 = source + w; dw = w >> 1; dh = h >> 1; out = dest = g_new(RrPixel32, dw * dh); for (y = 0; y < dh; ++y) { RrPixel32 *s, *s2; s = sourceline; s2 = sourceline2; for (x = 0; x < dw; ++x) { *dest++ = AVERAGE(AVERAGE(*s, *(s+1)), AVERAGE(*s2, *(s2+1))); s += 2; s2 += 2; } sourceline += w << 1; sourceline2 += w << 1; } return out; } static RrPixel32* scale_rect(RrPixel32 *fullsource, gint w, gint h, gint dw, gint dh) { RrPixel32 *out, *dest; RrPixel32 *source = fullsource; RrPixel32 *oldsource = NULL; RrPixel32 *prev_source = NULL; gint num_pixels; gint int_part; gint fract_part; gint err = 0; while (dw <= (w >> 1) && dh <= (h >> 1)) { source = scale_half(source, w, h); w >>= 1; h >>= 1; g_free(oldsource); oldsource = source; } num_pixels = dh; int_part = (h / dh) * w; fract_part = h % dh; out = dest = g_new(RrPixel32, dw * dh); while (num_pixels-- > 0) { if (source == prev_source) { memcpy(dest, dest - dw, dw * sizeof(RrPixel32)); } else { scale_line(dest, source, w, dw); prev_source = source; } dest += dw; source += int_part; err += fract_part; if (err >= dh) { err -= dh; source += w; } } g_free(oldsource); return out; } void RrImageDraw(RrPixel32 *target, RrTextureRGBA *rgba, gint target_w, gint target_h, RrRect *area) { RrPixel32 *dest; RrPixel32 *source; gint sw, sh, dw, dh; gint col, num_pixels; sw = rgba->width; sh = rgba->height; /* keep the ratio */ dw = area->width; dh = (int)(dw * ((double)sh / sw)); if (dh > area->height) { dh = area->height; dw = (int)(dh * ((double)sw / sh)); } if (sw != dw || sh != dh) { /*if (!(rgba->cache && dw == rgba->cwidth && dh == rgba->cheight))*/ { g_free(rgba->cache); rgba->cache = scale_rect(rgba->data, sw, sh, dw, dh); rgba->cwidth = dw; rgba->cheight = dh; } source = rgba->cache; } else { source = rgba->data; } /* copy source -> dest, and apply the alpha channel */ col = 0; num_pixels = dw * dh; dest = target + area->x + target_w * area->y; while (num_pixels-- > 0) { guchar alpha, r, g, b, bgr, bgg, bgb; alpha = *source >> RrDefaultAlphaOffset; r = *source >> RrDefaultRedOffset; g = *source >> RrDefaultGreenOffset; b = *source >> RrDefaultBlueOffset; /* background color */ bgr = *dest >> RrDefaultRedOffset; bgg = *dest >> RrDefaultGreenOffset; bgb = *dest >> RrDefaultBlueOffset; r = bgr + (((r - bgr) * alpha) >> 8); g = bgg + (((g - bgg) * alpha) >> 8); b = bgb + (((b - bgb) * alpha) >> 8); *dest = ((r << RrDefaultRedOffset) | (g << RrDefaultGreenOffset) | (b << RrDefaultBlueOffset)); dest++; source++; if (col++ >= dw) { col = 0; dest += target_w - dw; } } } |