Allow stroke states to be kept on the stack.

Add a function to clone stroke states, a magic number to keep in the
reference count to signal that a stroke state is stack-stored, and
automatically clone stack stored stroke states in the keep function.

Use fz_default_stroke_state to initialise stack stored stroke states.

2 files changed, 26 insertions, 0 deletions

diff --git a/include/mupdf/fitz/path.h b/include/mupdf/fitz/path.h
index a4a74aea..9b32b8d3 100644
--- a/include/mupdf/fitz/path.h
+++ b/include/mupdf/fitz/path.h
@@ -81,12 +81,15 @@ fz_path *fz_clone_path(fz_context *ctx, fz_path *old);
 fz_rect *fz_bound_path(fz_context *ctx, fz_path *path, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r);
 fz_rect *fz_adjust_rect_for_stroke(fz_rect *r, const fz_stroke_state *stroke, const fz_matrix *ctm);
 
+extern const fz_stroke_state fz_default_stroke_state;
+
 fz_stroke_state *fz_new_stroke_state(fz_context *ctx);
 fz_stroke_state *fz_new_stroke_state_with_dash_len(fz_context *ctx, int len);
 fz_stroke_state *fz_keep_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
 void fz_drop_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
 fz_stroke_state *fz_unshare_stroke_state(fz_context *ctx, fz_stroke_state *shared);
 fz_stroke_state *fz_unshare_stroke_state_with_dash_len(fz_context *ctx, fz_stroke_state *shared, int len);
+fz_stroke_state *fz_clone_stroke_state(fz_context *ctx, fz_stroke_state *stroke);
 
 #ifndef NDEBUG
 void fz_print_path(fz_context *ctx, FILE *out, fz_path *, int indent);
diff --git a/source/fitz/path.c b/source/fitz/path.c
index 811db282..04a3a7bc 100644
--- a/source/fitz/path.c
+++ b/source/fitz/path.c
@@ -364,12 +364,24 @@ fz_print_path(fz_context *ctx, FILE *out, fz_path *path, int indent)
 }
 #endif
 
+const fz_stroke_state fz_default_stroke_state = {
+	-2, /* -2 is the magic number we use when we have stroke states stored on the stack */
+	FZ_LINECAP_BUTT, FZ_LINECAP_BUTT, FZ_LINECAP_BUTT,
+	FZ_LINEJOIN_MITER,
+	1, 10,
+	0, 0, { 0 }
+};
+
 fz_stroke_state *
 fz_keep_stroke_state(fz_context *ctx, fz_stroke_state *stroke)
 {
 	if (!stroke)
 		return NULL;
 
+	/* -2 is the magic number we use when we have stroke states stored on the stack */
+	if (stroke->refs == -2)
+		return fz_clone_stroke_state(ctx, stroke);
+
 	fz_lock(ctx, FZ_LOCK_ALLOC);
 	if (stroke->refs > 0)
 		stroke->refs++;
@@ -423,6 +435,17 @@ fz_new_stroke_state(fz_context *ctx)
 }
 
 fz_stroke_state *
+fz_clone_stroke_state(fz_context *ctx, fz_stroke_state *stroke)
+{
+	fz_stroke_state *clone = fz_new_stroke_state_with_dash_len(ctx, stroke->dash_len);
+	int extra = stroke->dash_len - nelem(stroke->dash_list);
+	int size = sizeof(*stroke) + sizeof(stroke->dash_list[0]) * extra;
+	memcpy(clone, stroke, size);
+	clone->refs = 1;
+	return clone;
+}
+
+fz_stroke_state *
 fz_unshare_stroke_state_with_dash_len(fz_context *ctx, fz_stroke_state *shared, int len)
 {
 	int single, unsize, shsize, shlen, drop;