update skpdiff visualization (image magnification with alpha mask)

tools/skpdiff/SkImageDiffer.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageDiffer_DEFINED
 #define SkImageDiffer_DEFINED
 
@@ skipping 19 matching lines @@
      * @return True if this differ can be used, false otherwise
      */
     bool isGood() { return fIsGood; }
 
     /**
      * Gets if this differ needs to be initialized with and OpenCL device and context.
      */
     virtual bool requiresOpenCL() { return false; }
 
     /**
+     *
+     */
+    virtual void enablePOIAlphaMask() { fPOIAlphaMask = true; }

[epoger, 2013/10/21 15:02:53]

Related to my comments above about fPOIAlphaMask: maybe instead, match
getPointsOfInterestAlphaMask below:

virtual void enablePOIAlphaMask() { /* do nothing */ }

and override enablePOIAlphaMask() in SkDifferentPixelsMetric class

[djsollen, 2013/11/06 16:02:30]

Done.

+
+    /**
      * Wraps a call to queueDiff by loading the given filenames into SkBitmaps
      * @param  baseline The file path of the baseline image
      * @param  test     The file path of the test image
      * @return          The results of queueDiff with the loaded bitmaps
      */
     int queueDiffOfFile(const char baseline[], const char test[]);
 
     /**
      * Queues a diff on a pair of bitmaps to be done at some future time.
      * @param  baseline The correct bitmap
@@ skipping 30 matching lines @@
      */
     virtual int getPointsOfInterestCount(int id) = 0;
 
     /**
      * Gets an array of the points of interest for the diff of the given id. The results are only
      * meaningful after the queued diff has finished.
      * @param  id The id of the queued diff to query
      */
     virtual SkIPoint* getPointsOfInterest(int id) = 0;
 
+    /*
+     *
+     */
+    virtual SkBitmap* getPointsOfInterestAlphaMask(int id) { return NULL; }
 
 
 protected:
     bool fIsGood;
+    bool fPOIAlphaMask;
 };
 
 
 #endif