SVG: Add simple smask support.

The luminosity flag and background color are currently ignored.

The clip stack optionally held in the null device is updated here to
be a container stack, together with a flags word (currently just used
to indicate the type of the container at the current place in the
stack), and a user value (used by the SVG device to stash the id for
the mask it's generating).

2 files changed, 71 insertions, 41 deletions

diff --git a/source/fitz/device.c b/source/fitz/device.c
index 2d042ade..79f2f42a 100644
--- a/source/fitz/device.c
+++ b/source/fitz/device.c
@@ -19,7 +19,7 @@ fz_free_device(fz_device *dev)
 		return;
 	if (dev->free_user)
 		dev->free_user(dev);
-	fz_free(dev->ctx, dev->scissor);
+	fz_free(dev->ctx, dev->container);
 	fz_free(dev->ctx, dev);
 }
 
@@ -50,24 +50,26 @@ fz_end_page(fz_device *dev)
 }
 
 static void
-push_clip_stack(fz_device *dev, const fz_rect *rect)
+push_clip_stack(fz_device *dev, const fz_rect *rect, int flags)
 {
-	if (dev->scissor_len == dev->scissor_cap)
+	if (dev->container_len == dev->container_cap)
 	{
-		int newmax = dev->scissor_cap * 2;
+		int newmax = dev->container_cap * 2;
 		if (newmax == 0)
 			newmax = 4;
-		dev->scissor = fz_resize_array(dev->ctx, dev->scissor, newmax, sizeof(*dev->scissor));
-		dev->scissor_cap = newmax;
+		dev->container = fz_resize_array(dev->ctx, dev->container, newmax, sizeof(*dev->container));
+		dev->container_cap = newmax;
 	}
-	if (dev->scissor_len == 0)
-		dev->scissor[0] = *rect;
+	if (dev->container_len == 0)
+		dev->container[0].scissor = *rect;
 	else
 	{
-		dev->scissor[dev->scissor_len] = dev->scissor[dev->scissor_len-1];
-		fz_intersect_rect(&dev->scissor[dev->scissor_len], rect);
+		dev->container[dev->container_len].scissor = dev->container[dev->container_len-1].scissor;
+		fz_intersect_rect(&dev->container[dev->container_len].scissor, rect);
 	}
-	dev->scissor_len++;
+	dev->container[dev->container_len].flags = flags;
+	dev->container[dev->container_len].user = 0;
+	dev->container_len++;
 }
 
 static void
@@ -76,31 +78,33 @@ push_clip_stack_accumulate(fz_device *dev, const fz_rect *rect, int accumulate)
 	if (accumulate <= 1)
 	{
 		dev->scissor_accumulator = *rect;
-		if (dev->scissor_len == dev->scissor_cap)
+		if (dev->container_len == dev->container_cap)
 		{
-			int newmax = dev->scissor_cap * 2;
+			int newmax = dev->container_cap * 2;
 			if (newmax == 0)
 				newmax = 4;
-			dev->scissor = fz_resize_array(dev->ctx, dev->scissor, newmax, sizeof(*dev->scissor));
-			dev->scissor_cap = newmax;
+			dev->container = fz_resize_array(dev->ctx, dev->container, newmax, sizeof(*dev->container));
+			dev->container_cap = newmax;
 		}
-		fz_intersect_rect(&dev->scissor[dev->scissor_len], rect);
-		dev->scissor_len++;
+		fz_intersect_rect(&dev->container[dev->container_len].scissor, rect);
+		dev->container[dev->container_len].flags = fz_device_container_stack_is_clip_text;
+		dev->container[dev->container_len].user = 0;
+		dev->container_len++;
 	}
 	else
 	{
-		if (dev->scissor_len <= 0)
+		if (dev->container_len <= 0)
 			return;
 		fz_union_rect(&dev->scissor_accumulator, rect);
-		fz_intersect_rect(&dev->scissor[dev->scissor_len-1], &dev->scissor_accumulator);
+		fz_intersect_rect(&dev->container[dev->container_len-1].scissor, &dev->scissor_accumulator);
 	}
 }
 
 static void
 pop_clip_stack(fz_device *dev)
 {
-	if (dev->scissor_len > 0)
-		dev->scissor_len--;
+	if (dev->container_len > 0)
+		dev->container_len--;
 }
 
 void
@@ -136,16 +140,16 @@ fz_clip_path(fz_device *dev, fz_path *path, const fz_rect *rect, int even_odd, c
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		{
 			if (rect == NULL)
 			{
 				fz_rect bbox;
 				fz_bound_path(ctx, path, NULL, ctm, &bbox);
-				push_clip_stack(dev, &bbox);
+				push_clip_stack(dev, &bbox, fz_device_container_stack_is_clip_path);
 			}
 			else
-				push_clip_stack(dev, rect);
+				push_clip_stack(dev, rect, fz_device_container_stack_is_clip_path);
 		}
 		if (dev->clip_path)
 			dev->clip_path(dev, path, rect, even_odd, ctm);
@@ -171,16 +175,16 @@ fz_clip_stroke_path(fz_device *dev, fz_path *path, const fz_rect *rect, fz_strok
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		{
 			if (rect == NULL)
 			{
 				fz_rect bbox;
 				fz_bound_path(ctx, path, stroke, ctm, &bbox);
-				push_clip_stack(dev, &bbox);
+				push_clip_stack(dev, &bbox, fz_device_container_stack_is_clip_stroke_path);
 			}
 			else
-				push_clip_stack(dev, rect);
+				push_clip_stack(dev, rect, fz_device_container_stack_is_clip_stroke_path);
 		}
 		if (dev->clip_stroke_path)
 			dev->clip_stroke_path(dev, path, rect, stroke, ctm);
@@ -227,7 +231,7 @@ fz_clip_text(fz_device *dev, fz_text *text, const fz_matrix *ctm, int accumulate
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		{
 			fz_rect bbox;
 			fz_bound_text(ctx, text, NULL, ctm, &bbox);
@@ -259,11 +263,11 @@ fz_clip_stroke_text(fz_device *dev, fz_text *text, fz_stroke_state *stroke, cons
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		{
 			fz_rect bbox;
 			fz_bound_text(ctx, text, stroke, ctm, &bbox);
-			push_clip_stack_accumulate(dev, &bbox, 0);
+			push_clip_stack(dev, &bbox, fz_device_container_stack_is_clip_stroke_text);
 		}
 		if (dev->clip_stroke_text)
 			dev->clip_stroke_text(dev, text, stroke, ctm);
@@ -295,7 +299,7 @@ fz_pop_clip(fz_device *dev)
 			fz_throw(dev->ctx, FZ_ERROR_GENERIC, "%s", dev->errmess);
 		return;
 	}
-	if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+	if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		pop_clip_stack(dev);
 	if (dev->pop_clip)
 		dev->pop_clip(dev);
@@ -342,8 +346,8 @@ fz_clip_image_mask(fz_device *dev, fz_image *image, const fz_rect *rect, const f
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
-			push_clip_stack(dev, rect);
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
+			push_clip_stack(dev, rect, fz_device_container_stack_is_clip_image_mask);
 		if (dev->clip_image_mask)
 			dev->clip_image_mask(dev, image, rect, ctm);
 	}
@@ -368,8 +372,8 @@ fz_begin_mask(fz_device *dev, const fz_rect *area, int luminosity, fz_colorspace
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
-			push_clip_stack(dev, area);
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
+			push_clip_stack(dev, area, fz_device_container_stack_in_mask);
 		if (dev->begin_mask)
 			dev->begin_mask(dev, area, luminosity, colorspace, bc);
 	}
@@ -389,6 +393,11 @@ fz_end_mask(fz_device *dev)
 		/* Converts from mask to clip, so no change in stack depth */
 		return;
 	}
+	if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
+	{
+		dev->container[dev->container_len-1].flags &= ~fz_device_container_stack_in_mask;
+		dev->container[dev->container_len-1].flags |= fz_device_container_stack_is_mask;
+	}
 	if (dev->end_mask)
 		dev->end_mask(dev);
 }
@@ -406,8 +415,8 @@ fz_begin_group(fz_device *dev, const fz_rect *area, int isolated, int knockout,
 
 	fz_try(ctx)
 	{
-		if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
-			push_clip_stack(dev, area);
+		if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
+			push_clip_stack(dev, area, fz_device_container_stack_is_group);
 		if (dev->begin_group)
 			dev->begin_group(dev, area, isolated, knockout, blendmode, alpha);
 	}
@@ -431,7 +440,7 @@ fz_end_group(fz_device *dev)
 	}
 	if (dev->end_group)
 		dev->end_group(dev);
-	if (dev->hints & FZ_MAINTAIN_SCISSOR_STACK)
+	if (dev->hints & FZ_MAINTAIN_CONTAINER_STACK)
 		pop_clip_stack(dev);
 }
 
diff --git a/source/fitz/svg-device.c b/source/fitz/svg-device.c
index 77eeb072..ddf4031c 100644
--- a/source/fitz/svg-device.c
+++ b/source/fitz/svg-device.c
@@ -723,10 +723,10 @@ svg_dev_fill_shade(fz_device *dev, fz_shade *shade, const fz_matrix *ctm, float
 
 	fz_var(buf);
 
-	if (dev->scissor_len == 0)
+	if (dev->container_len == 0)
 		return;
 
-	fz_round_rect(&bbox, fz_intersect_rect(fz_bound_shade(ctx, shade, ctm, &rect), &dev->scissor[dev->scissor_len-1]));
+	fz_round_rect(&bbox, fz_intersect_rect(fz_bound_shade(ctx, shade, ctm, &rect), &dev->container[dev->container_len-1].scissor));
 	if (fz_is_empty_irect(&bbox))
 		return;
 	pix = fz_new_pixmap_with_bbox(ctx, fz_device_rgb(ctx), &bbox);
@@ -847,11 +847,32 @@ svg_dev_pop_clip(fz_device *dev)
 static void
 svg_dev_begin_mask(fz_device *dev, const fz_rect *bbox, int luminosity, fz_colorspace *colorspace, float *color)
 {
+	svg_device *sdev = (svg_device *)dev->user;
+	fz_context *ctx = dev->ctx;
+	fz_output *out;
+	int mask = sdev->id++;
+
+	out = start_def(sdev);
+	fz_printf(out, "<mask id=\"ma%d\">", mask);
+
+	if (dev->container_len > 0)
+		dev->container[dev->container_len-1].user = mask;
 }
 
 static void
 svg_dev_end_mask(fz_device *dev)
 {
+	svg_device *sdev = (svg_device *)dev->user;
+	fz_context *ctx = dev->ctx;
+	fz_output *out = sdev->out;
+	int mask = 0;
+
+	if (dev->container_len > 0)
+		mask = (int)dev->container[dev->container_len-1].user;
+
+	fz_printf(out, "\"/></mask>\n");
+	out = end_def(sdev);
+	fz_printf(out, "<g mask=\"url(#ma%d)\">\n", mask);
 
 }
 
@@ -1050,7 +1071,7 @@ fz_device *fz_new_svg_device(fz_context *ctx, fz_output *out, float page_width,
 	dev->begin_tile = svg_dev_begin_tile;
 	dev->end_tile = svg_dev_end_tile;
 
-	dev->hints |= FZ_MAINTAIN_SCISSOR_STACK;
+	dev->hints |= FZ_MAINTAIN_CONTAINER_STACK;
 
 	fz_printf(out, "<?xml version=\"1.0\" standalone=\"no\"?>\n");
 	fz_printf(out, "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n");