8-bit rendering and span scissoring

1 files changed, 139 insertions, 0 deletions

diff --git a/render/renderpath.c b/render/renderpath.c
new file mode 100644
index 00000000..9e805a53
--- /dev/null
+++ b/render/renderpath.c
@@ -0,0 +1,139 @@
+#include <fitz.h>
+
+enum { HS = 17, VS = 15 };
+
+static fz_error *pathtogel(fz_gel *gel, fz_pathnode *path, fz_matrix ctm)
+{
+	float flatness = 0.3 / ctm.a;
+	if (flatness < 0.1)
+		flatness = 0.1;
+
+	if (path->paint == FZ_STROKE)
+	{
+		if (path->dash)
+			return fz_dashpath(gel, path, ctm, flatness);
+		return fz_strokepath(gel, path, ctm, flatness);
+	}
+	return fz_fillpath(gel, path, ctm, flatness);
+}
+
+static void blitcolorspan(int y, int x0, int n, short *list, void *userdata)
+{
+	fz_renderer *gc = userdata;
+	fz_pixmap *pix = gc->acc;
+	unsigned char sa;
+	unsigned char ssa;
+	unsigned char *p;
+	unsigned char r = gc->r;
+	unsigned char g = gc->g;
+	unsigned char b = gc->b;
+
+	sa = 0;
+
+	while (x0 < pix->x)
+	{
+		sa += *list++;
+		x0 ++;
+		n --;
+	}
+
+	if (n > pix->w)
+		n = pix->w;
+
+	p = &pix->samples[(y - pix->y) * pix->stride + (x0 - pix->x) * 4];
+
+	while (n--)
+	{
+		sa += *list++;
+		ssa = 255 - sa;
+
+		p[0] = fz_mul255(r, sa) + fz_mul255(p[0], ssa);
+		p[1] = fz_mul255(g, sa) + fz_mul255(p[1], ssa);
+		p[2] = fz_mul255(b, sa) + fz_mul255(p[2], ssa);
+		p[3] = sa + fz_mul255(p[3], ssa);
+
+		p += 4;
+	}
+}
+
+static void blitalphaspan(int y, int x0, int n, short *list, void *userdata)
+{
+	fz_pixmap *pix = userdata;
+	unsigned char a;
+	unsigned char *p;
+
+	a = 0;
+
+	while (x0 < pix->x)
+	{
+		a += *list++;
+		x0 ++;
+		n --;
+	}
+
+	if (n > pix->w)
+		n = pix->w;
+
+	p = &pix->samples[(y - pix->y) * pix->stride + (x0 - pix->x) * 4];
+
+	while (n--)
+	{
+		a += *list++;
+		*p++ = a;
+	}
+}
+
+fz_error *
+fz_rendercolorpath(fz_renderer *gc, fz_pathnode *path, fz_colornode *color, fz_matrix ctm)
+{
+	fz_error *error;
+	float rgb[3];
+
+	fz_resetgel(gc->gel, HS, VS);
+
+	error = pathtogel(gc->gel, path, ctm);
+	if (error)
+		return error;
+
+	fz_sortgel(gc->gel);
+
+	fz_convertcolor(color->cs, color->samples, gc->model, rgb);
+	gc->r = rgb[0] * 255;
+	gc->g = rgb[1] * 255;
+	gc->b = rgb[2] * 255;
+
+	fz_scanconvert(gc->gel, gc->ael,
+		path->paint == FZ_EOFILL,
+		gc->y, gc->y + gc->h,
+		blitcolorspan, gc);
+
+	return nil;
+}
+
+fz_error *
+fz_renderpath(fz_renderer *gc, fz_pathnode *path, fz_matrix ctm)
+{
+	fz_error *error;
+
+	fz_resetgel(gc->gel, HS, VS);
+
+	error = pathtogel(gc->gel, path, ctm);
+	if (error)
+		return error;
+
+	fz_sortgel(gc->gel);
+
+	error = fz_newpixmap(&gc->tmp, nil, gc->x, gc->y, gc->w, gc->h, 0, 1);
+	if (error)
+		return error;
+
+	fz_clearpixmap(gc->tmp);
+
+	fz_scanconvert(gc->gel, gc->ael,
+		path->paint == FZ_EOFILL,
+		gc->y, gc->y + gc->h,
+		blitalphaspan, gc->tmp);
+
+	return nil;
+}
+