make dev_bbox take clips into account

Currently, dev_bbox creates a union of all bounding boxes of paths,
text and images. If any of these are however clipped away or inside
a tile, they should be ignored.

1 files changed, 163 insertions, 16 deletions

diff --git a/fitz/dev_bbox.c b/fitz/dev_bbox.c
index 94c88144..7f083525 100644
--- a/fitz/dev_bbox.c
+++ b/fitz/dev_bbox.c
@@ -1,66 +1,191 @@
 #include "fitz-internal.h"
 
-/* TODO: add clip stack and use to intersect bboxes */
+#define STACK_SIZE 96
+
+typedef struct fz_bbox_data_s
+{
+	fz_rect *result;
+	int top;
+	fz_rect stack[STACK_SIZE];
+	/* mask content and tiles are ignored */
+	int ignore;
+} fz_bbox_data;
+
+static void
+fz_bbox_add_rect(fz_device *dev, const fz_rect *rect, int clip)
+{
+	fz_bbox_data *data = dev->user;
+	fz_rect r = *rect;
+
+	if (0 < data->top && data->top <= STACK_SIZE)
+	{
+		fz_intersect_rect(&r, &data->stack[data->top-1]);
+	}
+	if (!clip && data->top <= STACK_SIZE && !data->ignore)
+	{
+		fz_union_rect(data->result, &r);
+	}
+	if (clip && ++data->top <= STACK_SIZE)
+	{
+		data->stack[data->top-1] = r;
+	}
+}
 
 static void
 fz_bbox_fill_path(fz_device *dev, fz_path *path, int even_odd, const fz_matrix *ctm,
 	fz_colorspace *colorspace, float *color, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r;
-	fz_union_rect(result, fz_bound_path(dev->ctx, path, NULL, ctm, &r));
+	fz_bbox_add_rect(dev, fz_bound_path(dev->ctx, path, NULL, ctm, &r), 0);
 }
 
 static void
 fz_bbox_stroke_path(fz_device *dev, fz_path *path, fz_stroke_state *stroke,
 	const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r;
-	fz_union_rect(result, fz_bound_path(dev->ctx, path, stroke, ctm, &r));
+	fz_bbox_add_rect(dev, fz_bound_path(dev->ctx, path, stroke, ctm, &r), 0);
 }
 
 static void
 fz_bbox_fill_text(fz_device *dev, fz_text *text, const fz_matrix *ctm,
 	fz_colorspace *colorspace, float *color, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r;
-	fz_union_rect(result, fz_bound_text(dev->ctx, text, NULL, ctm, &r));
+	fz_bbox_add_rect(dev, fz_bound_text(dev->ctx, text, NULL, ctm, &r), 0);
 }
 
 static void
 fz_bbox_stroke_text(fz_device *dev, fz_text *text, fz_stroke_state *stroke,
 	const fz_matrix *ctm, fz_colorspace *colorspace, float *color, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r;
-	fz_union_rect(result, fz_bound_text(dev->ctx, text, stroke, ctm, &r));
+	fz_bbox_add_rect(dev, fz_bound_text(dev->ctx, text, stroke, ctm, &r), 0);
 }
 
 static void
 fz_bbox_fill_shade(fz_device *dev, fz_shade *shade, const fz_matrix *ctm, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r;
-	fz_union_rect(result, fz_bound_shade(dev->ctx, shade, ctm, &r));
+	fz_bbox_add_rect(dev, fz_bound_shade(dev->ctx, shade, ctm, &r), 0);
 }
 
 static void
 fz_bbox_fill_image(fz_device *dev, fz_image *image, const fz_matrix *ctm, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r = fz_unit_rect;
-	fz_union_rect(result, fz_transform_rect(&r, ctm));
+	fz_bbox_add_rect(dev, fz_transform_rect(&r, ctm), 0);
 }
 
 static void
 fz_bbox_fill_image_mask(fz_device *dev, fz_image *image, const fz_matrix *ctm,
 	fz_colorspace *colorspace, float *color, float alpha)
 {
-	fz_rect *result = dev->user;
 	fz_rect r = fz_unit_rect;
-	fz_union_rect(result, fz_transform_rect(&r, ctm));
+	fz_bbox_add_rect(dev, fz_transform_rect(&r, ctm), 0);
+}
+
+static void
+fz_bbox_clip_path(fz_device *dev, fz_path *path, const fz_rect *rect, int even_odd, const fz_matrix *ctm)
+{
+	fz_rect r;
+	fz_bbox_add_rect(dev, fz_bound_path(dev->ctx, path, NULL, ctm, &r), 1);
+}
+
+static void
+fz_bbox_clip_stroke_path(fz_device *dev, fz_path *path, const fz_rect *rect, fz_stroke_state *stroke, const fz_matrix *ctm)
+{
+	fz_rect r;
+	fz_bbox_add_rect(dev, fz_bound_path(dev->ctx, path, stroke, ctm, &r), 1);
+}
+
+static void
+fz_bbox_clip_text(fz_device *dev, fz_text *text, const fz_matrix *ctm, int accumulate)
+{
+	fz_rect r = fz_infinite_rect;
+	if (accumulate)
+		fz_bbox_add_rect(dev, &r, accumulate != 2);
+	else
+		fz_bbox_add_rect(dev, fz_bound_text(dev->ctx, text, NULL, ctm, &r), 1);
+}
+
+static void
+fz_bbox_clip_stroke_text(fz_device *dev, fz_text *text, fz_stroke_state *stroke, const fz_matrix *ctm)
+{
+	fz_rect r;
+	fz_bbox_add_rect(dev, fz_bound_text(dev->ctx, text, stroke, ctm, &r), 1);
+}
+
+static void
+fz_bbox_clip_image_mask(fz_device *dev, fz_image *image, const fz_rect *rect, const fz_matrix *ctm)
+{
+	fz_rect r = *rect;
+	fz_bbox_add_rect(dev, fz_transform_rect(&r, ctm), 1);
+}
+
+static void
+fz_bbox_pop_clip(fz_device *dev)
+{
+	fz_bbox_data *data = dev->user;
+	if (data->top > 0)
+		data->top--;
+	else
+		fz_warn(dev->ctx, "unexpected pop clip");
+}
+
+static void
+fz_bbox_begin_mask(fz_device *dev, const fz_rect *rect, int luminosity, fz_colorspace *colorspace, float *color)
+{
+	fz_bbox_data *data = dev->user;
+	fz_bbox_add_rect(dev, rect, 1);
+	data->ignore++;
+}
+
+static void
+fz_bbox_end_mask(fz_device *dev)
+{
+	fz_bbox_data *data = dev->user;
+	assert(data->ignore > 0);
+	data->ignore--;
+}
+
+static void
+fz_bbox_begin_group(fz_device *dev, const fz_rect *rect, int isolated, int knockout, int blendmode, float alpha)
+{
+	fz_bbox_add_rect(dev, rect, 1);
+}
+
+static void
+fz_bbox_end_group(fz_device *dev)
+{
+	fz_bbox_pop_clip(dev);
+}
+
+static int
+fz_bbox_begin_tile(fz_device *dev, const fz_rect *area, const fz_rect *view, float xstep, float ystep, const fz_matrix *ctm, int id)
+{
+	fz_bbox_data *data = dev->user;
+	fz_rect r = *area;
+	fz_bbox_add_rect(dev, fz_transform_rect(&r, ctm), 0);
+	data->ignore++;
+	return 0;
+}
+
+static void
+fz_bbox_end_tile(fz_device *dev)
+{
+	fz_bbox_data *data = dev->user;
+	assert(data->ignore > 0);
+	data->ignore--;
+}
+
+static void
+fz_bbox_free_user(fz_device *dev)
+{
+	fz_bbox_data *data = dev->user;
+	if (data->top > 0)
+		fz_warn(dev->ctx, "items left on stack in bbox device: %d", data->top);
+	fz_free(dev->ctx, dev->user);
 }
 
 fz_device *
@@ -68,15 +193,37 @@ fz_new_bbox_device(fz_context *ctx, fz_rect *result)
 {
 	fz_device *dev;
 
-	dev = fz_new_device(ctx, result);
+	fz_bbox_data *user = fz_malloc_struct(ctx, fz_bbox_data);
+	user->result = result;
+	user->top = 0;
+	user->ignore = 0;
+	dev = fz_new_device(ctx, user);
+	dev->free_user = fz_bbox_free_user;
 
 	dev->fill_path = fz_bbox_fill_path;
 	dev->stroke_path = fz_bbox_stroke_path;
+	dev->clip_path = fz_bbox_clip_path;
+	dev->clip_stroke_path = fz_bbox_clip_stroke_path;
+
 	dev->fill_text = fz_bbox_fill_text;
 	dev->stroke_text = fz_bbox_stroke_text;
+	dev->clip_text = fz_bbox_clip_text;
+	dev->clip_stroke_text = fz_bbox_clip_stroke_text;
+
 	dev->fill_shade = fz_bbox_fill_shade;
 	dev->fill_image = fz_bbox_fill_image;
 	dev->fill_image_mask = fz_bbox_fill_image_mask;
+	dev->clip_image_mask = fz_bbox_clip_image_mask;
+
+	dev->pop_clip = fz_bbox_pop_clip;
+
+	dev->begin_mask = fz_bbox_begin_mask;
+	dev->end_mask = fz_bbox_end_mask;
+	dev->begin_group = fz_bbox_begin_group;
+	dev->end_group = fz_bbox_end_group;
+
+	dev->begin_tile = fz_bbox_begin_tile;
+	dev->end_tile = fz_bbox_end_tile;
 
 	*result = fz_empty_rect;