add diff recording and output code
R=bsalomon@google.com
Review URL: https://codereview.chromium.org/18348011
git-svn-id: http://skia.googlecode.com/svn/trunk@9875 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/skpdiff/SkDiffContext.h b/experimental/skpdiff/SkDiffContext.h
new file mode 100644
index 0000000..545b515
--- /dev/null
+++ b/experimental/skpdiff/SkDiffContext.h
@@ -0,0 +1,115 @@
+/*
+ * 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
+
+#include "SkString.h"
+#include "SkTArray.h"
+#include "SkTDArray.h"
+
+class SkWStream;
+class SkImageDiffer;
+
+/**
+ * Collects records of diffs and outputs them as JSON.
+ */
+class SkDiffContext {
+public:
+ SkDiffContext();
+ ~SkDiffContext();
+
+ /**
+ * 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);
+
+ /**
+ * Compares two directories of images with the given differ
+ * @param baselinePath The baseline directory's path
+ * @param testPath The test directory's path
+ */
+ void diffDirectories(const char baselinePath[], const char testPath[]);
+
+ /**
+ * Compares two sets of images identified by glob style patterns with the given differ
+ * @param baselinePattern A pattern for baseline files
+ * @param testPattern A pattern for test files that matches each file of the baseline file
+ */
+ void diffPatterns(const char baselinePattern[], const char testPattern[]);
+
+ /**
+ * Compares the images at the given paths
+ * @param baselinePath The baseline file path
+ * @param testPath The matching test file path
+ */
+ void addDiff(const char* baselinePath, const char* testPath);
+
+ /**
+ * Output the records of each diff in JSON.
+ *
+ * The format of the JSON document is one top level array named "records".
+ * Each record in the array is an object with both a "baselinePath" and "testPath" string field.
+ * 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
+ * "pointsOfInterest" : an array of coordinates (stored as a 2-array of ints) of interesting
+ * points
+ *
+ * Here is an example:
+ *
+ * {
+ * "records": [
+ * {
+ * "baselinePath": "queue.png",
+ * "testPath": "queue.png",
+ * "diffs": [
+ * {
+ * "differName": "different_pixels",
+ * "result": 1,
+ * "pointsOfInterest": [
+ * [285,279],
+ * ]
+ * }
+ * ]
+ * }
+ * ]
+ * }
+ *
+ * @param stream The stream to output the diff to
+ */
+ void outputRecords(SkWStream& stream);
+
+private:
+ struct DiffData {
+ const char* fDiffName;
+ double fResult;
+ SkTDArray<SkIPoint> fPointsOfInterest;
+ };
+
+ struct DiffRecord {
+ SkString fBaselinePath;
+ SkString fTestPath;
+ SkTArray<DiffData> fDiffs;
+ DiffRecord* fNext;
+ };
+
+ // 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.
+ DiffRecord * fRecords;
+
+ SkImageDiffer** fDiffers;
+ int fDifferCount;
+};
+
+#endif