1 files changed, 69 insertions, 0 deletions
diff --git a/gfx/skia/skia/include/core/SkRSXform.h b/gfx/skia/skia/include/core/SkRSXform.h
new file mode 100644
index 0000000000..5fcfff2922
--- /dev/null
+++ b/gfx/skia/skia/include/core/SkRSXform.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkRSXform_DEFINED
+#define SkRSXform_DEFINED
+
+#include "include/core/SkPoint.h"
+#include "include/core/SkSize.h"
+
+/**
+ *  A compressed form of a rotation+scale matrix.
+ *
+ *  [ fSCos     -fSSin    fTx ]
+ *  [ fSSin      fSCos    fTy ]
+ *  [     0          0      1 ]
+ */
+struct SK_API SkRSXform {
+    static SkRSXform Make(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
+        SkRSXform xform = { scos, ssin, tx, ty };
+        return xform;
+    }
+
+    /*
+     *  Initialize a new xform based on the scale, rotation (in radians), final tx,ty location
+     *  and anchor-point ax,ay within the src quad.
+     *
+     *  Note: the anchor point is not normalized (e.g. 0...1) but is in pixels of the src image.
+     */
+    static SkRSXform MakeFromRadians(SkScalar scale, SkScalar radians, SkScalar tx, SkScalar ty,
+                                     SkScalar ax, SkScalar ay) {
+        const SkScalar s = SkScalarSin(radians) * scale;
+        const SkScalar c = SkScalarCos(radians) * scale;
+        return Make(c, s, tx + -c * ax + s * ay, ty + -s * ax - c * ay);
+    }
+
+    SkScalar fSCos;
+    SkScalar fSSin;
+    SkScalar fTx;
+    SkScalar fTy;
+
+    bool rectStaysRect() const {
+        return 0 == fSCos || 0 == fSSin;
+    }
+
+    void setIdentity() {
+        fSCos = 1;
+        fSSin = fTx = fTy = 0;
+    }
+
+    void set(SkScalar scos, SkScalar ssin, SkScalar tx, SkScalar ty) {
+        fSCos = scos;
+        fSSin = ssin;
+        fTx = tx;
+        fTy = ty;
+    }
+
+    void toQuad(SkScalar width, SkScalar height, SkPoint quad[4]) const;
+    void toQuad(const SkSize& size, SkPoint quad[4]) const {
+        this->toQuad(size.width(), size.height(), quad);
+    }
+    void toTriStrip(SkScalar width, SkScalar height, SkPoint strip[4]) const;
+};
+
+#endif
+