1 files changed, 93 insertions, 0 deletions
diff --git a/render/scale.c b/render/scale.c
new file mode 100644
index 00000000..1fad5a0b
--- /dev/null
+++ b/render/scale.c
@@ -0,0 +1,93 @@
+#include <fitz.h>
+
+static void
+scalerow(unsigned char *src, int w, int denom, unsigned char *dst, int ncomp)
+{
+	int x, left, n;
+	int sum[32];
+
+	left = 0;
+	for (n = 0; n < ncomp; n++)
+		sum[n] = 0;
+
+	for (x = 0; x < w; x++)
+	{
+		for (n = 0; n < ncomp; n++)
+            sum[n] += src[x * ncomp + n];
+		if (++left == denom)
+		{
+			left = 0;
+			for (n = 0; n < ncomp; n++)
+			{
+				dst[n] = sum[n] / denom;
+				sum[n] = 0;
+			}
+			dst += ncomp;
+		}
+	}
+
+	/* left overs */
+	if (left)
+		for (n = 0; n < ncomp; n++)
+			dst[n] = sum[n] / left;
+}
+
+static void
+scalecols(unsigned char *src, int stride, int w, int denom, unsigned char *dst, int ncomp)
+{
+	int x, y, n;
+	unsigned char *s;
+	int sum[32];
+
+	for (x = 0; x < w; x++)
+	{
+		s = src + (x * ncomp);
+		for (n = 0; n < ncomp; n++)
+			sum[n] = 0;
+		for (y = 0; y < denom; y++)
+			for (n = 0; n < ncomp; n++)
+				sum[n] += s[y * stride + n];
+		for (n = 0; n < ncomp; n++)
+			dst[n] = sum[n] / denom;
+		dst += ncomp;
+	}
+}
+
+fz_error *
+fz_scalepixmap(fz_pixmap *src, fz_pixmap *dst, int xdenom, int ydenom)
+{
+	assert(src->n == dst->n);
+	assert(src->a == dst->a);
+	assert((src->w + xdenom - 1) / xdenom == dst->w);
+	assert((src->h + ydenom - 1) / ydenom == dst->h);
+
+	int ncomp = src->n + src->a;
+	unsigned char scratch[dst->stride * ydenom];
+
+	int y, iy, oy;
+
+	for (y = 0, oy = 0; y < (dst->h - 1) * ydenom; y += ydenom, oy++)
+	{
+		for (iy = 0; iy < ydenom; iy++)
+			scalerow(src->samples + (y + iy) * src->stride, src->w, xdenom,
+				scratch + iy * dst->stride, ncomp);
+		scalecols(scratch, ncomp * dst->w, dst->w, ydenom,
+			dst->samples + (oy * dst->stride), ncomp);
+	}
+
+	ydenom = src->h - y;
+	if (ydenom)
+	{
+		for (iy = 0; iy < ydenom; iy++)
+			scalerow(src->samples + (y + iy) * src->stride, src->w, xdenom,
+				scratch + iy * (ncomp * dst->w), ncomp);
+		scalecols(scratch, ncomp * dst->w, dst->w, ydenom,
+			dst->samples + (oy * dst->stride), ncomp);
+	}
+
+//printf("unscaled image ");fz_debugpixmap(src);getchar();
+//printf("scaled image ");fz_debugpixmap(dst);getchar();
+
+	return nil;
+}
+