new scanconversion technique

This technique geometrically clips all segments against the clip bounds,
ensuring that we never send a value to the edgelist that might overflow in
fixedpoint.

Current disabled in SkScan_Path.cpp by a #define. There are a few minor pixel
differences between this and the old technique, as found by the gm tool, so
at the moment this new code is off by default.



git-svn-id: http://skia.googlecode.com/svn/trunk@432 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 31 insertions, 0 deletions

diff --git a/src/core/SkEdgeBuilder.h b/src/core/SkEdgeBuilder.h
new file mode 100644
index 0000000000..e9ed51963b
--- /dev/null
+++ b/src/core/SkEdgeBuilder.h
@@ -0,0 +1,31 @@
+#ifndef SkEdgeBuilder_DEFINED
+#define SkEdgeBuilder_DEFINED
+
+#include "SkChunkAlloc.h"
+#include "SkRect.h"
+#include "SkTDArray.h"
+
+class SkEdge;
+class SkEdgeClipper;
+class SkPath;
+
+class SkEdgeBuilder {
+public:
+    SkEdgeBuilder();
+    
+    int build(const SkPath& path, const SkIRect* clip, int shiftUp);
+
+    SkEdge** edgeList() { return fList.begin(); }
+
+private:
+    SkChunkAlloc        fAlloc;
+    SkTDArray<SkEdge*>  fList;
+    int                 fShiftUp;
+
+    void addLine(const SkPoint pts[]);
+    void addQuad(const SkPoint pts[]);
+    void addCubic(const SkPoint pts[]);
+    void addClipper(SkEdgeClipper*);
+};
+
+#endif