Expose Cairo path copy/append functions through Thebes - bug 445616 r=vlad

gfx/thebes/public/gfxContext.h

@@ -140,6 +140,16 @@ public:
      */
     void ClosePath();
 
+    /**
+     * Copies the current path and returns the copy.
+     */
+    already_AddRefed<gfxPath> CopyPath();
+
+    /**
+     * Appends the given path to the current path.
+     */
+    void AppendPath(gfxPath* path);
+
     /**
      * Moves the pen to a new point without drawing a line.
      */

gfx/thebes/public/gfxPath.h

@@ -39,15 +39,41 @@
 
 #include "gfxTypes.h"
 
+class gfxContext;
 struct gfxPoint;
 typedef struct cairo_path cairo_path_t;
 
-class THEBES_API gfxFlattenedPath {
+/**
+ * Class representing a path. Can be created by copying the current path
+ * of a gfxContext.
+ */
+class THEBES_API gfxPath {
     THEBES_INLINE_DECL_REFCOUNTING(gfxPath)
 
+    friend class gfxContext;
+
+protected:
+    gfxPath(cairo_path_t* aPath);
+
 public:
-    gfxFlattenedPath(cairo_path_t *aPath);
-    ~gfxFlattenedPath();
+    virtual ~gfxPath();
+
+protected:
+    cairo_path_t* mPath;
+};
+
+/**
+ * Specialization of a path that only contains linear pieces. Can be created
+ * from the existing path of a gfxContext.
+ */
+class THEBES_API gfxFlattenedPath : public gfxPath {
+    friend class gfxContext;
+
+protected:
+    gfxFlattenedPath(cairo_path_t* aPath);
+
+public:
+    virtual ~gfxFlattenedPath();
 
     /**
      * Returns calculated total length of path
@@ -62,10 +88,7 @@ public:
      * @param aAngle optional - output tangent
      */
     gfxPoint FindPoint(gfxPoint aOffset,
-                       gfxFloat *aAngle = nsnull);
-
-protected:
-    cairo_path_t *mPath;
+                       gfxFloat* aAngle = nsnull);
 };
 
 #endif

gfx/thebes/src/gfxContext.cpp

@@ -116,6 +116,18 @@ gfxContext::ClosePath()
     cairo_close_path(mCairo);
 }
 
+already_AddRefed<gfxPath> gfxContext::CopyPath()
+{
+    nsRefPtr<gfxPath> path = new gfxPath(cairo_copy_path(mCairo));
+    return path.forget();
+}
+
+void gfxContext::AppendPath(gfxPath* path)
+{
+    if (path->mPath->status == CAIRO_STATUS_SUCCESS && path->mPath->num_data != 0)
+        cairo_append_path(mCairo, path->mPath);
+}
+
 gfxPoint
 gfxContext::CurrentPoint() const
 {

gfx/thebes/src/gfxPath.cpp

@@ -39,13 +39,21 @@
 
 #include "cairo.h"
 
-gfxFlattenedPath::gfxFlattenedPath(cairo_path_t *aPath) : mPath(aPath)
+gfxPath::gfxPath(cairo_path_t* aPath) : mPath(aPath)
+{
+}
+
+gfxPath::~gfxPath()
+{
+    cairo_path_destroy(mPath);
+}
+
+gfxFlattenedPath::gfxFlattenedPath(cairo_path_t* aPath) : gfxPath(aPath)
 {
 }
 
 gfxFlattenedPath::~gfxFlattenedPath()
 {
-    cairo_path_destroy(mPath);
 }
 
 static gfxFloat