- RrPixel32 *draw = rgba->data;
- gint c, i, e, t, sfw, sfh;
- sfw = area->width;
- sfh = area->height;
-
- g_assert(rgba->data != NULL);
-
- if ((rgba->width != sfw || rgba->height != sfh) &&
- (rgba->width != rgba->cwidth || rgba->height != rgba->cheight)) {
- double dx = rgba->width / (double)sfw;
- double dy = rgba->height / (double)sfh;
- double px = 0.0;
- double py = 0.0;
- int iy = 0;
-
- /* scale it and cache it */
- if (rgba->cache != NULL)
- g_free(rgba->cache);
- rgba->cache = g_new(RrPixel32, sfw * sfh);
- rgba->cwidth = sfw;
- rgba->cheight = sfh;
- for (i = 0, c = 0, e = sfw*sfh; i < e; ++i) {
- rgba->cache[i] = rgba->data[(int)px + iy];
- if (++c >= sfw) {
- c = 0;
- px = 0;
- py += dy;
- iy = (int)py * rgba->width;
- } else
- px += dx;
+ 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;