add readPixels to SkImage

src/image/SkReadPixelsRec.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkReadPixelsRec_DEFINED
+#define SkReadPixelsRec_DEFINED
+
+#include "SkImageInfo.h"
+

[robertphillips, 2014/12/10 15:26:57]

// A helper class to abstract away some of the computation involved when
converting readPixels' parameters to actual pixels

?

[reed1, 2014/12/10 15:35:20]

Done.

+struct SkReadPixelsRec {
+    SkReadPixelsRec(const SkImageInfo& info, void* pixels, size_t rowBytes, int x, int y)
+        : fPixels(pixels)
+        , fRowBytes(rowBytes)
+        , fInfo(info)
+        , fX(x)
+        , fY(y)
+    {}
+
+    void*       fPixels;
+    size_t      fRowBytes;
+    SkImageInfo fInfo;
+    int         fX;
+    int         fY;
+    
+    bool trim(int srcWidth, int srcHeight);
+};
+
+#endif