Analytic AntiAlias for Convex Shapes

src/core/SkScan.h

Index: src/core/SkScan.h
diff --git a/src/core/SkScan.h b/src/core/SkScan.h
index 4aa8e443990ecf05b5d3918d5b2fe29047b1a588..1e3d60a290406b2288216f416328494a468bf359 100644
--- a/src/core/SkScan.h
+++ b/src/core/SkScan.h
@@ -22,6 +22,24 @@ class SkPath;
 */
 typedef SkIRect SkXRect;
 
+class GlobalAAConfig {
+private:
+    GlobalAAConfig() {}
+
+public:
+    bool fUseAnalyticAA = false;
+
+    GlobalAAConfig(const GlobalAAConfig&) = delete;
+    void operator=(const GlobalAAConfig&) = delete;
+
+    static GlobalAAConfig& getInstance() {
+        static GlobalAAConfig instance;
+        return instance;
+    }
+};
+
+class AdditiveBlitter;
+
 class SkScan {
 public:
     /*
@@ -45,6 +63,7 @@ public:
     static void AntiFillXRect(const SkXRect&, const SkRasterClip&, SkBlitter*);
     static void FillPath(const SkPath&, const SkRasterClip&, SkBlitter*);
     static void AntiFillPath(const SkPath&, const SkRasterClip&, SkBlitter*);
+    static void AAAFillPath(const SkPath&, const SkRasterClip&, SkBlitter*);
     static void FrameRect(const SkRect&, const SkPoint& strokeSize,
                           const SkRasterClip&, SkBlitter*);
     static void AntiFrameRect(const SkRect&, const SkPoint& strokeSize,
@@ -79,6 +98,9 @@ private:
                               const SkRegion*, SkBlitter*);
     static void HairLineRgn(const SkPoint[], int count, const SkRegion*, SkBlitter*);
     static void AntiHairLineRgn(const SkPoint[], int count, const SkRegion*, SkBlitter*);
+    static void AAAFillPath(const SkPath& path, const SkRegion& origClip, SkBlitter* blitter);
+    static void aaa_fill_path(const SkPath& path, const SkIRect* clipRect, AdditiveBlitter*,

[reed1, 2016/10/03 17:33:35]

who calls this method? (aaa...) Does it need to be in this header?

[liyuqian, 2016/10/03 17:55:42]

Only AAAFillPath is using aaa_fill_path.

However, aaa_fill_path now calls SkScan::AntiFillPath to fill non-convex paths
because we haven't implemented that yet. Since AntiFillPath is private in
SkScan, I have to also make aaa_fill_path as a member of SkScan. (If
AntiFillPath is not called in the future, I could just make aaa_fill_path a
static void function in SkScan_AAAPath.cpp.)

+                   int start_y, int stop_y, const SkRegion& clipRgn, bool isUsingMask);
 };
 
 /** Assign an SkXRect from a SkIRect, by promoting the src rect's coordinates