add --readJsonSummaryPath to render_pictures

tools/image_expectations.h

Index: tools/image_expectations.h
diff --git a/tools/image_expectations.h b/tools/image_expectations.h
new file mode 100644
index 0000000000000000000000000000000000000000..74964e9ea5be1bf6c829dfb1ce0287c07d6d39e6
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+++ b/tools/image_expectations.h
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+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Information about the images we actually generated, and the images we expected to see.
+ *
+ * TODO(epoger): Combine this with gm/gm_expectations.h, or eliminate one of the two.
+ */
+#ifndef image_expectations_DEFINED
+#define image_expectations_DEFINED
+
+#include "SkBitmap.h"
+#include "SkJSONCPP.h"
+
+// EPOGER: Before committing, add unittests for all of these things
+
+namespace sk_tools {
+
+    /**
+     * The digest of an image (either an image we have generated locally, or an image expectation).
+     *
+     * Currently, this is always a uint64_t hash digest of an SkBitmap.
+     */
+    class ImageDigest {
+    public:
+        /**
+         * Create an ImageDigest of a bitmap.
+         *
+         * Note that this is an expensive operation, because it has to examine all pixels in
+         * the bitmap.  You may wish to consider using the BitmapAndDigest class, which will
+         * compute the ImageDigest lazily.
+         *
+         * @param bitmap image to get the digest of
+         */
+        explicit ImageDigest(const SkBitmap &bitmap);
+
+        /**
+         * Create an ImageDigest using a hashType/hashValue pair.
+         *
+         * @param hashType the algorithm used to generate the hash; for now, only
+         *     kJsonValue_Image_ChecksumAlgorithm_Bitmap64bitMD5 is allowed.
+         * @param hashValue the value generated by the hash algorithm for a particular image.
+         */
+        explicit ImageDigest(const SkString &hashType, uint64_t hashValue);
+
+        /**
+         * Returns the hash digest type as an SkString.
+         *
+         * For now, this always returns kJsonValue_Image_ChecksumAlgorithm_Bitmap64bitMD5 .
+         */
+        SkString getHashType() const;
+
+        /**
+         * Returns the hash digest value as a uint64_t.
+         */
+        uint64_t getHashValue() const;
+
+    private:
+        uint64_t fHashValue;
+    };
+
+    /**
+     * Container that holds a reference to an SkBitmap and computes its ImageDigest lazily.
+     */
+    class BitmapAndDigest {
+    public:
+        explicit BitmapAndDigest(const SkBitmap &bitmap);
+
+        const ImageDigest *getImageDigestPtr();
+        const SkBitmap *getBitmapPtr() const;
+    private:
+        const SkBitmap fBitmap;
+        // EPOGER: before committing, implement this properly so that digest is computed lazily
+        ImageDigest fEPOGERImageDigest;
+    };
+
+    /**
+     * Collects ImageDigests of actually rendered images, perhaps comparing to expectations.
+     */
+    class ImageResultsSummary {
+    public:
+        /**
+         * Adds expectations from a JSON file, returning true if successful.
+         */
+        bool readExpectationsFile(const char *jsonPath);
+
+        /**
+         * Adds this image to the summary of results.
+         *
+         * @param sourceName name of the source file that generated this result
+         * @param fileName relative path to the image output file on local disk
+         * @param digest description of the image's contents
+         * @param tileNumber if not NULL, ptr to tile number
+         */
+        void add(const char *sourceName, const char *fileName, const ImageDigest &digest,
+                 const int *tileNumber=NULL);
+
+        /**
+         * Writes the summary (as constructed so far) to a file.
+         *
+         * @param filename path to write the summary to
+         */
+        void writeToFile(const char *filename) const;
+
+    private:
+
+        /**
+         * Read the file contents from jsonPath and parse them into jsonRoot.
+         *
+         * Returns true if successful.
+         */
+        static bool Parse(const char *jsonPath, Json::Value *jsonRoot);
+
+        Json::Value fActualResults;
+        Json::Value fExpectedJsonRoot;
+        Json::Value fExpectedResults;
+    };
+
+
+} // namespace sk_tools
+#endif // image_expectations_DEFINED