tools/skpdiff/SkDiffContext.cpp - platform/external/skqp - Gitiles

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "SkBitmap.h"
 #include "SkImageDecoder.h"
 #include "SkOSFile.h"
 #include "SkRunnable.h"
 #include "SkSize.h"
 #include "SkStream.h"
 #include "SkTDict.h"
 #include "SkThreadPool.h"

 // from the tools directory for replace_char(...)
 #include "picture_utils.h"

 #include "SkDiffContext.h"
 #include "SkImageDiffer.h"
 #include "skpdiff_util.h"

 SkDiffContext::SkDiffContext() {
     fDiffers = NULL;
     fDifferCount = 0;
     fThreadCount = SkThreadPool::kThreadPerCore;
 }

 SkDiffContext::~SkDiffContext() {
     if (NULL != fDiffers) {
         SkDELETE_ARRAY(fDiffers);
     }
 }

 void SkDiffContext::setAlphaMaskDir(const SkString& path) {
     if (!path.isEmpty() && sk_mkdir(path.c_str())) {
         fAlphaMaskDir = path;
     }
 }

 void SkDiffContext::setRgbDiffDir(const SkString& path) {
     if (!path.isEmpty() && sk_mkdir(path.c_str())) {
         fRgbDiffDir = path;
     }
 }

 void SkDiffContext::setWhiteDiffDir(const SkString& path) {
     if (!path.isEmpty() && sk_mkdir(path.c_str())) {
         fWhiteDiffDir = path;
     }
 }

 void SkDiffContext::setLongNames(const bool useLongNames) {
     longNames = useLongNames;
 }

 void SkDiffContext::setDiffers(const SkTDArray<SkImageDiffer*>& differs) {
     // Delete whatever the last array of differs was
     if (NULL != fDiffers) {
         SkDELETE_ARRAY(fDiffers);
         fDiffers = NULL;
         fDifferCount = 0;
     }

     // Copy over the new differs
     fDifferCount = differs.count();
     fDiffers = SkNEW_ARRAY(SkImageDiffer*, fDifferCount);
     differs.copy(fDiffers);
 }

 static SkString get_common_prefix(const SkString& a, const SkString& b) {
     const size_t maxPrefixLength = SkTMin(a.size(), b.size());
     SkASSERT(maxPrefixLength > 0);
     for (size_t x = 0; x < maxPrefixLength; ++x) {
         if (a[x] != b[x]) {
             SkString result;
             result.set(a.c_str(), x);
             return result;
         }
     }
     if (a.size() > b.size()) {
         return b;
     } else {
         return a;
     }
 }

 static SkString get_combined_name(const SkString& a, const SkString& b) {
     // Note (stephana): We must keep this function in sync with
     // getImageDiffRelativeUrl() in static/loader.js (under rebaseline_server).
     SkString result = a;
     result.append("-vs-");
     result.append(b);
     sk_tools::replace_char(&result, '.', '_');
     return result;
 }

 void SkDiffContext::addDiff(const char* baselinePath, const char* testPath) {
     // Load the images at the paths
     SkBitmap baselineBitmap;
     SkBitmap testBitmap;
     if (!SkImageDecoder::DecodeFile(baselinePath, &baselineBitmap)) {
         SkDebugf("Failed to load bitmap \"%s\"\n", baselinePath);
         return;
     }
     if (!SkImageDecoder::DecodeFile(testPath, &testBitmap)) {
         SkDebugf("Failed to load bitmap \"%s\"\n", testPath);
         return;
     }

     // Setup a record for this diff
     fRecordMutex.acquire();
     DiffRecord* newRecord = fRecords.addToHead(DiffRecord());
     fRecordMutex.release();

     // compute the common name
     SkString baseName = SkOSPath::Basename(baselinePath);
     SkString testName = SkOSPath::Basename(testPath);

     if (longNames) {
         newRecord->fCommonName = get_combined_name(baseName, testName);
     } else {
         newRecord->fCommonName = get_common_prefix(baseName, testName);
     }
     newRecord->fCommonName.append(".png");

     newRecord->fBaselinePath = baselinePath;
     newRecord->fTestPath = testPath;
     newRecord->fSize = SkISize::Make(baselineBitmap.width(), baselineBitmap.height());

     // only generate diff images if we have a place to store them
     SkImageDiffer::BitmapsToCreate bitmapsToCreate;
     bitmapsToCreate.alphaMask = !fAlphaMaskDir.isEmpty();
     bitmapsToCreate.rgbDiff = !fRgbDiffDir.isEmpty();
     bitmapsToCreate.whiteDiff = !fWhiteDiffDir.isEmpty();

     // Perform each diff
     for (int differIndex = 0; differIndex < fDifferCount; differIndex++) {
         SkImageDiffer* differ = fDiffers[differIndex];

         // Copy the results into data for this record
         DiffData& diffData = newRecord->fDiffs.push_back();
         diffData.fDiffName = differ->getName();

         if (!differ->diff(&baselineBitmap, &testBitmap, bitmapsToCreate, &diffData.fResult)) {
             // if the diff failed, record -1 as the result
             // TODO(djsollen): Record more detailed information about exactly what failed.
             // (Image dimension mismatch? etc.)  See http://skbug.com/2710 ('make skpdiff
             // report more detail when it fails to compare two images')
             diffData.fResult.result = -1;
             continue;
         }

         if (bitmapsToCreate.alphaMask
                 && SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
                 && !diffData.fResult.poiAlphaMask.empty()
                 && !newRecord->fCommonName.isEmpty()) {

             newRecord->fAlphaMaskPath = SkOSPath::Join(fAlphaMaskDir.c_str(),
                                                        newRecord->fCommonName.c_str());

             // compute the image diff and output it
             SkBitmap copy;
             diffData.fResult.poiAlphaMask.copyTo(&copy, kN32_SkColorType);
             SkImageEncoder::EncodeFile(newRecord->fAlphaMaskPath.c_str(), copy,
                                        SkImageEncoder::kPNG_Type, 100);

             // cleanup the existing bitmap to free up resources;
             diffData.fResult.poiAlphaMask.reset();

             bitmapsToCreate.alphaMask = false;
         }

         if (bitmapsToCreate.rgbDiff
                 && SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
                 && !diffData.fResult.rgbDiffBitmap.empty()
                 && !newRecord->fCommonName.isEmpty()) {
             // TODO(djsollen): Rather than taking the max r/g/b diffs that come back from
             // a particular differ and storing them as toplevel fields within
             // newRecord, we should extend outputRecords() to report optional
             // fields for each differ (not just "result" and "pointsOfInterest").
             // See http://skbug.com/2712 ('allow skpdiff to report different sets
             // of result fields for different comparison algorithms')
             newRecord->fMaxRedDiff = diffData.fResult.maxRedDiff;
             newRecord->fMaxGreenDiff = diffData.fResult.maxGreenDiff;
             newRecord->fMaxBlueDiff = diffData.fResult.maxBlueDiff;

             newRecord->fRgbDiffPath = SkOSPath::Join(fRgbDiffDir.c_str(),
                                                      newRecord->fCommonName.c_str());
             SkImageEncoder::EncodeFile(newRecord->fRgbDiffPath.c_str(),
                                        diffData.fResult.rgbDiffBitmap,
                                        SkImageEncoder::kPNG_Type, 100);
             diffData.fResult.rgbDiffBitmap.reset();
             bitmapsToCreate.rgbDiff = false;
         }

         if (bitmapsToCreate.whiteDiff
                 && SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
                 && !diffData.fResult.whiteDiffBitmap.empty()
                 && !newRecord->fCommonName.isEmpty()) {
             newRecord->fWhiteDiffPath = SkOSPath::Join(fWhiteDiffDir.c_str(),
                                                        newRecord->fCommonName.c_str());
             SkImageEncoder::EncodeFile(newRecord->fWhiteDiffPath.c_str(),
                                        diffData.fResult.whiteDiffBitmap,
                                        SkImageEncoder::kPNG_Type, 100);
             diffData.fResult.whiteDiffBitmap.reset();
             bitmapsToCreate.whiteDiff = false;
         }
     }
 }

 class SkThreadedDiff : public SkRunnable {
 public:
     SkThreadedDiff() : fDiffContext(NULL) { }

     void setup(SkDiffContext* diffContext, const SkString& baselinePath, const SkString& testPath) {
         fDiffContext = diffContext;
         fBaselinePath = baselinePath;
         fTestPath = testPath;
     }

     virtual void run() SK_OVERRIDE {
         fDiffContext->addDiff(fBaselinePath.c_str(), fTestPath.c_str());
     }

 private:
     SkDiffContext* fDiffContext;
     SkString fBaselinePath;
     SkString fTestPath;
 };

 void SkDiffContext::diffDirectories(const char baselinePath[], const char testPath[]) {
     // Get the files in the baseline, we will then look for those inside the test path
     SkTArray<SkString> baselineEntries;
     if (!get_directory(baselinePath, &baselineEntries)) {
         SkDebugf("Unable to open path \"%s\"\n", baselinePath);
         return;
     }

     SkThreadPool threadPool(fThreadCount);
     SkTArray<SkThreadedDiff> runnableDiffs;
     runnableDiffs.reset(baselineEntries.count());

     for (int x = 0; x < baselineEntries.count(); x++) {
         const char* baseFilename = baselineEntries[x].c_str();

         // Find the real location of each file to compare
         SkString baselineFile = SkOSPath::Join(baselinePath, baseFilename);
         SkString testFile = SkOSPath::Join(testPath, baseFilename);

         // Check that the test file exists and is a file
         if (sk_exists(testFile.c_str()) && !sk_isdir(testFile.c_str())) {
             // Queue up the comparison with the differ
             runnableDiffs[x].setup(this, baselineFile, testFile);
             threadPool.add(&runnableDiffs[x]);
         } else {
             SkDebugf("Baseline file \"%s\" has no corresponding test file\n", baselineFile.c_str());
         }
     }

     threadPool.wait();
 }


 void SkDiffContext::diffPatterns(const char baselinePattern[], const char testPattern[]) {
     // Get the files in the baseline and test patterns. Because they are in sorted order, it's easy
     // to find corresponding images by matching entry indices.

     SkTArray<SkString> baselineEntries;
     if (!glob_files(baselinePattern, &baselineEntries)) {
         SkDebugf("Unable to get pattern \"%s\"\n", baselinePattern);
         return;
     }

     SkTArray<SkString> testEntries;
     if (!glob_files(testPattern, &testEntries)) {
         SkDebugf("Unable to get pattern \"%s\"\n", testPattern);
         return;
     }

     if (baselineEntries.count() != testEntries.count()) {
         SkDebugf("Baseline and test patterns do not yield corresponding number of files\n");
         return;
     }

     SkThreadPool threadPool(fThreadCount);
     SkTArray<SkThreadedDiff> runnableDiffs;
     runnableDiffs.reset(baselineEntries.count());

     for (int x = 0; x < baselineEntries.count(); x++) {
         runnableDiffs[x].setup(this, baselineEntries[x], testEntries[x]);
         threadPool.add(&runnableDiffs[x]);
     }

     threadPool.wait();
 }

 void SkDiffContext::outputRecords(SkWStream& stream, bool useJSONP) {
     SkTLList<DiffRecord>::Iter iter(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
     DiffRecord* currentRecord = iter.get();

     if (useJSONP) {
         stream.writeText("var SkPDiffRecords = {\n");
     } else {
         stream.writeText("{\n");
     }

     // TODO(djsollen): Would it be better to use the jsoncpp library to write out the JSON?
     // This manual approach is probably more efficient, but it sure is ugly.
     // See http://skbug.com/2713 ('make skpdiff use jsoncpp library to write out
     // JSON output, instead of manual writeText() calls?')
     stream.writeText("    \"records\": [\n");
     while (NULL != currentRecord) {
         stream.writeText("        {\n");

             SkString baselineAbsPath = get_absolute_path(currentRecord->fBaselinePath);
             SkString testAbsPath = get_absolute_path(currentRecord->fTestPath);

             stream.writeText("            \"commonName\": \"");
             stream.writeText(currentRecord->fCommonName.c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"differencePath\": \"");
             stream.writeText(get_absolute_path(currentRecord->fAlphaMaskPath).c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"rgbDiffPath\": \"");
             stream.writeText(get_absolute_path(currentRecord->fRgbDiffPath).c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"whiteDiffPath\": \"");
             stream.writeText(get_absolute_path(currentRecord->fWhiteDiffPath).c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"baselinePath\": \"");
             stream.writeText(baselineAbsPath.c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"testPath\": \"");
             stream.writeText(testAbsPath.c_str());
             stream.writeText("\",\n");

             stream.writeText("            \"width\": ");
             stream.writeDecAsText(currentRecord->fSize.width());
             stream.writeText(",\n");
             stream.writeText("            \"height\": ");
             stream.writeDecAsText(currentRecord->fSize.height());
             stream.writeText(",\n");

             stream.writeText("            \"maxRedDiff\": ");
             stream.writeDecAsText(currentRecord->fMaxRedDiff);
             stream.writeText(",\n");
             stream.writeText("            \"maxGreenDiff\": ");
             stream.writeDecAsText(currentRecord->fMaxGreenDiff);
             stream.writeText(",\n");
             stream.writeText("            \"maxBlueDiff\": ");
             stream.writeDecAsText(currentRecord->fMaxBlueDiff);
             stream.writeText(",\n");

             stream.writeText("            \"diffs\": [\n");
             for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
                 DiffData& data = currentRecord->fDiffs[diffIndex];
                 stream.writeText("                {\n");

                     stream.writeText("                    \"differName\": \"");
                     stream.writeText(data.fDiffName);
                     stream.writeText("\",\n");

                     stream.writeText("                    \"result\": ");
                     stream.writeScalarAsText((SkScalar)data.fResult.result);
                     stream.writeText(",\n");

                     stream.writeText("                    \"pointsOfInterest\": ");
                     stream.writeDecAsText(data.fResult.poiCount);
                     stream.writeText("\n");

                 stream.writeText("                }");

                 // JSON does not allow trailing commas
                 if (diffIndex + 1 < currentRecord->fDiffs.count()) {
                     stream.writeText(",");
                 }
                 stream.writeText("                \n");
             }
             stream.writeText("            ]\n");

         stream.writeText("        }");

         currentRecord = iter.next();

         // JSON does not allow trailing commas
         if (NULL != currentRecord) {
             stream.writeText(",");
         }
         stream.writeText("\n");
     }
     stream.writeText("    ]\n");
     if (useJSONP) {
         stream.writeText("};\n");
     } else {
         stream.writeText("}\n");
     }
 }

 void SkDiffContext::outputCsv(SkWStream& stream) {
     SkTDict<int> columns(2);
     int cntColumns = 0;

     stream.writeText("key");

     SkTLList<DiffRecord>::Iter iter(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
     DiffRecord* currentRecord = iter.get();

     // Write CSV header and create a dictionary of all columns.
     while (NULL != currentRecord) {
         for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
             DiffData& data = currentRecord->fDiffs[diffIndex];
             if (!columns.find(data.fDiffName)) {
                 columns.set(data.fDiffName, cntColumns);
                 stream.writeText(", ");
                 stream.writeText(data.fDiffName);
                 cntColumns++;
             }
         }
         currentRecord = iter.next();
     }
     stream.writeText("\n");

     double values[100];
     SkASSERT(cntColumns < 100);  // Make the array larger, if we ever have so many diff types.

     SkTLList<DiffRecord>::Iter iter2(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
     currentRecord = iter2.get();
     while (NULL != currentRecord) {
         for (int i = 0; i < cntColumns; i++) {
             values[i] = -1;
         }

         for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
             DiffData& data = currentRecord->fDiffs[diffIndex];
             int index = -1;
             SkAssertResult(columns.find(data.fDiffName, &index));
             SkASSERT(index >= 0 && index < cntColumns);
             values[index] = data.fResult.result;
         }

         const char* filename = currentRecord->fBaselinePath.c_str() +
                 strlen(currentRecord->fBaselinePath.c_str()) - 1;
         while (filename > currentRecord->fBaselinePath.c_str() && *(filename - 1) != '/') {
             filename--;
         }

         stream.writeText(filename);

         for (int i = 0; i < cntColumns; i++) {
             SkString str;
             str.printf(", %f", values[i]);
             stream.writeText(str.c_str());
         }
         stream.writeText("\n");

         currentRecord = iter2.next();
     }
 }
	/*
	* Copyright 2013 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "SkBitmap.h"
	#include "SkImageDecoder.h"
	#include "SkOSFile.h"
	#include "SkRunnable.h"
	#include "SkSize.h"
	#include "SkStream.h"
	#include "SkTDict.h"
	#include "SkThreadPool.h"

	// from the tools directory for replace_char(...)
	#include "picture_utils.h"

	#include "SkDiffContext.h"
	#include "SkImageDiffer.h"
	#include "skpdiff_util.h"

	SkDiffContext::SkDiffContext() {
	fDiffers = NULL;
	fDifferCount = 0;
	fThreadCount = SkThreadPool::kThreadPerCore;
	}

	SkDiffContext::~SkDiffContext() {
	if (NULL != fDiffers) {
	SkDELETE_ARRAY(fDiffers);
	}
	}

	void SkDiffContext::setAlphaMaskDir(const SkString& path) {
	if (!path.isEmpty() && sk_mkdir(path.c_str())) {
	fAlphaMaskDir = path;
	}
	}

	void SkDiffContext::setRgbDiffDir(const SkString& path) {
	if (!path.isEmpty() && sk_mkdir(path.c_str())) {
	fRgbDiffDir = path;
	}
	}

	void SkDiffContext::setWhiteDiffDir(const SkString& path) {
	if (!path.isEmpty() && sk_mkdir(path.c_str())) {
	fWhiteDiffDir = path;
	}
	}

	void SkDiffContext::setLongNames(const bool useLongNames) {
	longNames = useLongNames;
	}

	void SkDiffContext::setDiffers(const SkTDArray<SkImageDiffer*>& differs) {
	// Delete whatever the last array of differs was
	if (NULL != fDiffers) {
	SkDELETE_ARRAY(fDiffers);
	fDiffers = NULL;
	fDifferCount = 0;
	}

	// Copy over the new differs
	fDifferCount = differs.count();
	fDiffers = SkNEW_ARRAY(SkImageDiffer*, fDifferCount);
	differs.copy(fDiffers);
	}

	static SkString get_common_prefix(const SkString& a, const SkString& b) {
	const size_t maxPrefixLength = SkTMin(a.size(), b.size());
	SkASSERT(maxPrefixLength > 0);
	for (size_t x = 0; x < maxPrefixLength; ++x) {
	if (a[x] != b[x]) {
	SkString result;
	result.set(a.c_str(), x);
	return result;
	}
	}
	if (a.size() > b.size()) {
	return b;
	} else {
	return a;
	}
	}

	static SkString get_combined_name(const SkString& a, const SkString& b) {
	// Note (stephana): We must keep this function in sync with
	// getImageDiffRelativeUrl() in static/loader.js (under rebaseline_server).
	SkString result = a;
	result.append("-vs-");
	result.append(b);
	sk_tools::replace_char(&result, '.', '_');
	return result;
	}

	void SkDiffContext::addDiff(const char* baselinePath, const char* testPath) {
	// Load the images at the paths
	SkBitmap baselineBitmap;
	SkBitmap testBitmap;
	if (!SkImageDecoder::DecodeFile(baselinePath, &baselineBitmap)) {
	SkDebugf("Failed to load bitmap \"%s\"\n", baselinePath);
	return;
	}
	if (!SkImageDecoder::DecodeFile(testPath, &testBitmap)) {
	SkDebugf("Failed to load bitmap \"%s\"\n", testPath);
	return;
	}

	// Setup a record for this diff
	fRecordMutex.acquire();
	DiffRecord* newRecord = fRecords.addToHead(DiffRecord());
	fRecordMutex.release();

	// compute the common name
	SkString baseName = SkOSPath::Basename(baselinePath);
	SkString testName = SkOSPath::Basename(testPath);

	if (longNames) {
	newRecord->fCommonName = get_combined_name(baseName, testName);
	} else {
	newRecord->fCommonName = get_common_prefix(baseName, testName);
	}
	newRecord->fCommonName.append(".png");

	newRecord->fBaselinePath = baselinePath;
	newRecord->fTestPath = testPath;
	newRecord->fSize = SkISize::Make(baselineBitmap.width(), baselineBitmap.height());

	// only generate diff images if we have a place to store them
	SkImageDiffer::BitmapsToCreate bitmapsToCreate;
	bitmapsToCreate.alphaMask = !fAlphaMaskDir.isEmpty();
	bitmapsToCreate.rgbDiff = !fRgbDiffDir.isEmpty();
	bitmapsToCreate.whiteDiff = !fWhiteDiffDir.isEmpty();

	// Perform each diff
	for (int differIndex = 0; differIndex < fDifferCount; differIndex++) {
	SkImageDiffer* differ = fDiffers[differIndex];

	// Copy the results into data for this record
	DiffData& diffData = newRecord->fDiffs.push_back();
	diffData.fDiffName = differ->getName();

	if (!differ->diff(&baselineBitmap, &testBitmap, bitmapsToCreate, &diffData.fResult)) {
	// if the diff failed, record -1 as the result
	// TODO(djsollen): Record more detailed information about exactly what failed.
	// (Image dimension mismatch? etc.) See http://skbug.com/2710 ('make skpdiff
	// report more detail when it fails to compare two images')
	diffData.fResult.result = -1;
	continue;
	}

	if (bitmapsToCreate.alphaMask
	&& SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
	&& !diffData.fResult.poiAlphaMask.empty()
	&& !newRecord->fCommonName.isEmpty()) {

	newRecord->fAlphaMaskPath = SkOSPath::Join(fAlphaMaskDir.c_str(),
	newRecord->fCommonName.c_str());

	// compute the image diff and output it
	SkBitmap copy;
	diffData.fResult.poiAlphaMask.copyTo(&copy, kN32_SkColorType);
	SkImageEncoder::EncodeFile(newRecord->fAlphaMaskPath.c_str(), copy,
	SkImageEncoder::kPNG_Type, 100);

	// cleanup the existing bitmap to free up resources;
	diffData.fResult.poiAlphaMask.reset();

	bitmapsToCreate.alphaMask = false;
	}

	if (bitmapsToCreate.rgbDiff
	&& SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
	&& !diffData.fResult.rgbDiffBitmap.empty()
	&& !newRecord->fCommonName.isEmpty()) {
	// TODO(djsollen): Rather than taking the max r/g/b diffs that come back from
	// a particular differ and storing them as toplevel fields within
	// newRecord, we should extend outputRecords() to report optional
	// fields for each differ (not just "result" and "pointsOfInterest").
	// See http://skbug.com/2712 ('allow skpdiff to report different sets
	// of result fields for different comparison algorithms')
	newRecord->fMaxRedDiff = diffData.fResult.maxRedDiff;
	newRecord->fMaxGreenDiff = diffData.fResult.maxGreenDiff;
	newRecord->fMaxBlueDiff = diffData.fResult.maxBlueDiff;

	newRecord->fRgbDiffPath = SkOSPath::Join(fRgbDiffDir.c_str(),
	newRecord->fCommonName.c_str());
	SkImageEncoder::EncodeFile(newRecord->fRgbDiffPath.c_str(),
	diffData.fResult.rgbDiffBitmap,
	SkImageEncoder::kPNG_Type, 100);
	diffData.fResult.rgbDiffBitmap.reset();
	bitmapsToCreate.rgbDiff = false;
	}

	if (bitmapsToCreate.whiteDiff
	&& SkImageDiffer::RESULT_CORRECT != diffData.fResult.result
	&& !diffData.fResult.whiteDiffBitmap.empty()
	&& !newRecord->fCommonName.isEmpty()) {
	newRecord->fWhiteDiffPath = SkOSPath::Join(fWhiteDiffDir.c_str(),
	newRecord->fCommonName.c_str());
	SkImageEncoder::EncodeFile(newRecord->fWhiteDiffPath.c_str(),
	diffData.fResult.whiteDiffBitmap,
	SkImageEncoder::kPNG_Type, 100);
	diffData.fResult.whiteDiffBitmap.reset();
	bitmapsToCreate.whiteDiff = false;
	}
	}
	}

	class SkThreadedDiff : public SkRunnable {
	public:
	SkThreadedDiff() : fDiffContext(NULL) { }

	void setup(SkDiffContext* diffContext, const SkString& baselinePath, const SkString& testPath) {
	fDiffContext = diffContext;
	fBaselinePath = baselinePath;
	fTestPath = testPath;
	}

	virtual void run() SK_OVERRIDE {
	fDiffContext->addDiff(fBaselinePath.c_str(), fTestPath.c_str());
	}

	private:
	SkDiffContext* fDiffContext;
	SkString fBaselinePath;
	SkString fTestPath;
	};

	void SkDiffContext::diffDirectories(const char baselinePath[], const char testPath[]) {
	// Get the files in the baseline, we will then look for those inside the test path
	SkTArray<SkString> baselineEntries;
	if (!get_directory(baselinePath, &baselineEntries)) {
	SkDebugf("Unable to open path \"%s\"\n", baselinePath);
	return;
	}

	SkThreadPool threadPool(fThreadCount);
	SkTArray<SkThreadedDiff> runnableDiffs;
	runnableDiffs.reset(baselineEntries.count());

	for (int x = 0; x < baselineEntries.count(); x++) {
	const char* baseFilename = baselineEntries[x].c_str();

	// Find the real location of each file to compare
	SkString baselineFile = SkOSPath::Join(baselinePath, baseFilename);
	SkString testFile = SkOSPath::Join(testPath, baseFilename);

	// Check that the test file exists and is a file
	if (sk_exists(testFile.c_str()) && !sk_isdir(testFile.c_str())) {
	// Queue up the comparison with the differ
	runnableDiffs[x].setup(this, baselineFile, testFile);
	threadPool.add(&runnableDiffs[x]);
	} else {
	SkDebugf("Baseline file \"%s\" has no corresponding test file\n", baselineFile.c_str());
	}
	}

	threadPool.wait();
	}


	void SkDiffContext::diffPatterns(const char baselinePattern[], const char testPattern[]) {
	// Get the files in the baseline and test patterns. Because they are in sorted order, it's easy
	// to find corresponding images by matching entry indices.

	SkTArray<SkString> baselineEntries;
	if (!glob_files(baselinePattern, &baselineEntries)) {
	SkDebugf("Unable to get pattern \"%s\"\n", baselinePattern);
	return;
	}

	SkTArray<SkString> testEntries;
	if (!glob_files(testPattern, &testEntries)) {
	SkDebugf("Unable to get pattern \"%s\"\n", testPattern);
	return;
	}

	if (baselineEntries.count() != testEntries.count()) {
	SkDebugf("Baseline and test patterns do not yield corresponding number of files\n");
	return;
	}

	SkThreadPool threadPool(fThreadCount);
	SkTArray<SkThreadedDiff> runnableDiffs;
	runnableDiffs.reset(baselineEntries.count());

	for (int x = 0; x < baselineEntries.count(); x++) {
	runnableDiffs[x].setup(this, baselineEntries[x], testEntries[x]);
	threadPool.add(&runnableDiffs[x]);
	}

	threadPool.wait();
	}

	void SkDiffContext::outputRecords(SkWStream& stream, bool useJSONP) {
	SkTLList<DiffRecord>::Iter iter(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
	DiffRecord* currentRecord = iter.get();

	if (useJSONP) {
	stream.writeText("var SkPDiffRecords = {\n");
	} else {
	stream.writeText("{\n");
	}

	// TODO(djsollen): Would it be better to use the jsoncpp library to write out the JSON?
	// This manual approach is probably more efficient, but it sure is ugly.
	// See http://skbug.com/2713 ('make skpdiff use jsoncpp library to write out
	// JSON output, instead of manual writeText() calls?')
	stream.writeText(" \"records\": [\n");
	while (NULL != currentRecord) {
	stream.writeText(" {\n");

	SkString baselineAbsPath = get_absolute_path(currentRecord->fBaselinePath);
	SkString testAbsPath = get_absolute_path(currentRecord->fTestPath);

	stream.writeText(" \"commonName\": \"");
	stream.writeText(currentRecord->fCommonName.c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"differencePath\": \"");
	stream.writeText(get_absolute_path(currentRecord->fAlphaMaskPath).c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"rgbDiffPath\": \"");
	stream.writeText(get_absolute_path(currentRecord->fRgbDiffPath).c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"whiteDiffPath\": \"");
	stream.writeText(get_absolute_path(currentRecord->fWhiteDiffPath).c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"baselinePath\": \"");
	stream.writeText(baselineAbsPath.c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"testPath\": \"");
	stream.writeText(testAbsPath.c_str());
	stream.writeText("\",\n");

	stream.writeText(" \"width\": ");
	stream.writeDecAsText(currentRecord->fSize.width());
	stream.writeText(",\n");
	stream.writeText(" \"height\": ");
	stream.writeDecAsText(currentRecord->fSize.height());
	stream.writeText(",\n");

	stream.writeText(" \"maxRedDiff\": ");
	stream.writeDecAsText(currentRecord->fMaxRedDiff);
	stream.writeText(",\n");
	stream.writeText(" \"maxGreenDiff\": ");
	stream.writeDecAsText(currentRecord->fMaxGreenDiff);
	stream.writeText(",\n");
	stream.writeText(" \"maxBlueDiff\": ");
	stream.writeDecAsText(currentRecord->fMaxBlueDiff);
	stream.writeText(",\n");

	stream.writeText(" \"diffs\": [\n");
	for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
	DiffData& data = currentRecord->fDiffs[diffIndex];
	stream.writeText(" {\n");

	stream.writeText(" \"differName\": \"");
	stream.writeText(data.fDiffName);
	stream.writeText("\",\n");

	stream.writeText(" \"result\": ");
	stream.writeScalarAsText((SkScalar)data.fResult.result);
	stream.writeText(",\n");

	stream.writeText(" \"pointsOfInterest\": ");
	stream.writeDecAsText(data.fResult.poiCount);
	stream.writeText("\n");

	stream.writeText(" }");

	// JSON does not allow trailing commas
	if (diffIndex + 1 < currentRecord->fDiffs.count()) {
	stream.writeText(",");
	}
	stream.writeText(" \n");
	}
	stream.writeText(" ]\n");

	stream.writeText(" }");

	currentRecord = iter.next();

	// JSON does not allow trailing commas
	if (NULL != currentRecord) {
	stream.writeText(",");
	}
	stream.writeText("\n");
	}
	stream.writeText(" ]\n");
	if (useJSONP) {
	stream.writeText("};\n");
	} else {
	stream.writeText("}\n");
	}
	}

	void SkDiffContext::outputCsv(SkWStream& stream) {
	SkTDict<int> columns(2);
	int cntColumns = 0;

	stream.writeText("key");

	SkTLList<DiffRecord>::Iter iter(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
	DiffRecord* currentRecord = iter.get();

	// Write CSV header and create a dictionary of all columns.
	while (NULL != currentRecord) {
	for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
	DiffData& data = currentRecord->fDiffs[diffIndex];
	if (!columns.find(data.fDiffName)) {
	columns.set(data.fDiffName, cntColumns);
	stream.writeText(", ");
	stream.writeText(data.fDiffName);
	cntColumns++;
	}
	}
	currentRecord = iter.next();
	}
	stream.writeText("\n");

	double values[100];
	SkASSERT(cntColumns < 100); // Make the array larger, if we ever have so many diff types.

	SkTLList<DiffRecord>::Iter iter2(fRecords, SkTLList<DiffRecord>::Iter::kHead_IterStart);
	currentRecord = iter2.get();
	while (NULL != currentRecord) {
	for (int i = 0; i < cntColumns; i++) {
	values[i] = -1;
	}

	for (int diffIndex = 0; diffIndex < currentRecord->fDiffs.count(); diffIndex++) {
	DiffData& data = currentRecord->fDiffs[diffIndex];
	int index = -1;
	SkAssertResult(columns.find(data.fDiffName, &index));
	SkASSERT(index >= 0 && index < cntColumns);
	values[index] = data.fResult.result;
	}

	const char* filename = currentRecord->fBaselinePath.c_str() +
	strlen(currentRecord->fBaselinePath.c_str()) - 1;
	while (filename > currentRecord->fBaselinePath.c_str() && *(filename - 1) != '/') {
	filename--;
	}

	stream.writeText(filename);

	for (int i = 0; i < cntColumns; i++) {
	SkString str;
	str.printf(", %f", values[i]);
	stream.writeText(str.c_str());
	}
	stream.writeText("\n");

	currentRecord = iter2.next();
	}
	}