Adding direct access to SkMipMap levels.

src/core/SkMipMap.h

Index: src/core/SkMipMap.h
diff --git a/src/core/SkMipMap.h b/src/core/SkMipMap.h
index bc6d154939a44c58cd4f0d3b8aa625f18ccfc5b8..51ceda5feb1c7c5f1de468384832efbbd4fd58ee 100644
--- a/src/core/SkMipMap.h
+++ b/src/core/SkMipMap.h
@@ -23,12 +23,18 @@ public:
     static SkMipMap* Build(const SkPixmap& src, SkDiscardableFactoryProc);
     static SkMipMap* Build(const SkBitmap& src, SkDiscardableFactoryProc);
 
+    // This function lets you determine how many levels a mipmap will have without
+    // creating that mipmap.
+    static int ComputeLevelCount(int baseWidth, int baseHeight);

[reed1, 2016/02/05 22:37:11]

Its odd that this returns a different value (+1) from countLevels(). Can we make
them the same?

[cblume, 2016/02/06 13:38:16]

Done.

+
     struct Level {
         SkPixmap    fPixmap;
         SkSize      fScale; // < 1.0
     };
 
     bool extractLevel(SkScalar scale, Level*) const;
+    int countLevels() const;
+    void getLevel(int index, Level*) const;
 
 protected:
     void onDataChange(void* oldData, void* newData) override {