rebaseline_server: use just skpdiff, not Python Image Library

tools/skpdiff/SkDiffContext.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 SkDiffContext_DEFINED
 #define SkDiffContext_DEFINED
 
@@ skipping 10 matching lines @@
  * Collects records of diffs and outputs them as JSON.
  */
 class SkDiffContext {
 public:
     SkDiffContext();
     ~SkDiffContext();
 
     void setThreadCount(int threadCount) { fThreadCount = threadCount; }
 
     /**
-     * Creates the directory if it does not exist and uses it to store differences
-     * between images.
+     * Sets the directory within which to store alphaMasks (images that
+     * are transparent for each pixel that differs between baseline and test).
+     *
+     * If the directory does not exist yet, it will be created.
      */
-    void setDifferenceDir(const SkString& directory);
+    void setAlphaMaskDir(const SkString& directory);
+
+    /**
+     * Sets the directory within which to store rgbDiffs (images showing the
+     * per-channel difference between baseline and test at each pixel).
+     *
+     * If the directory does not exist yet, it will be created.
+     */
+    void setRgbDiffDir(const SkString& directory);
+
+    /**
+     * Sets the directory within which to store whiteDiffs (images showing white
+     * for each pixel that differs between baseline and test).
+     *
+     * If the directory does not exist yet, it will be created.
+     */
+    void setWhiteDiffDir(const SkString& directory);
 
     /**
      * Sets the differs to be used in each diff. Already started diffs will not retroactively use
      * these.
      * @param differs An array of differs to use. The array is copied, but not the differs
      *                themselves.
      */
     void setDiffers(const SkTDArray<SkImageDiffer*>& differs);
 
     /**
@@ skipping 22 matching lines @@
      *
      * The format of the JSON document is one top level array named "records".
      * Each record in the array is an object with the following values:
      *    "commonName"     : string containing the common prefix of the baselinePath
      *                       and testPath filenames
      *    "baselinePath"   : string containing the path to the baseline image
      *    "testPath"       : string containing the path to the test image
      *    "differencePath" : (optional) string containing the path to an alpha
      *                       mask of the pixel difference between the baseline
      *                       and test images
+     *                       TODO(epoger): consider renaming this "alphaMaskPath"
+     *                       to distinguish from other difference types?
+     *    "rgbDiffPath"    : (optional) string containing the path to a bitmap
+     *                       showing per-channel differences between the
+     *                       baseline and test images at each pixel
+     *    "whiteDiffPath"  : (optional) string containing the path to a bitmap
+     *                       showing every pixel that differs between the
+     *                       baseline and test images as white
      *
      * They also have an array named "diffs" with each element being one diff record for the two
      * images indicated in the above field.
      * A diff record includes:
      *    "differName"       : string name of the diff metric used
      *    "result"           : numerical result of the diff
      *
      * Here is an example:
      *
      * {
@@ skipping 23 matching lines @@
     void outputCsv(SkWStream& stream);
 
 
 private:
     struct DiffData {
         const char* fDiffName;
         SkImageDiffer::Result fResult;
     };
 
     struct DiffRecord {
+        // TODO(djsollen): Some of these fields are required, while others are optional
+        // (e.g., fRgbDiffPath is only filled in if SkDifferentPixelsMetric
+        // was run).  Figure out a way to note that.  See http://skbug.com/2712
+        // ('allow skpdiff to report different sets of result fields for
+        // different comparison algorithms')
         SkString           fCommonName;
-        SkString           fDifferencePath;
+        SkString           fAlphaMaskPath;
+        SkString           fRgbDiffPath;
+        SkString           fWhiteDiffPath;
         SkString           fBaselinePath;
         SkString               fTestPath;
+        SkISize                    fSize;
+        int                  fMaxRedDiff;
+        int                fMaxGreenDiff;
+        int                 fMaxBlueDiff;
         SkTArray<DiffData>        fDiffs;
     };
 
     // Used to protect access to fRecords and ensure only one thread is
     // adding new entries at a time.
     SkMutex fRecordMutex;
 
     // We use linked list for the records so that their pointers remain stable. A resizable array
     // might change its pointers, which would make it harder for async diffs to record their
     // results.
     SkTLList<DiffRecord> fRecords;
 
     SkImageDiffer** fDiffers;
     int fDifferCount;
     int fThreadCount;
 
-    SkString fDifferenceDir;
+    SkString fAlphaMaskDir;
+    SkString fRgbDiffDir;
+    SkString fWhiteDiffDir;
 };
 
 #endif