skia2/tools/skpdiff/SkDifferentPixelsMetric_cpu.cpp
2013-11-12 18:29:17 +00:00

70 lines
2.2 KiB
C++

/*
* 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 "SkDifferentPixelsMetric.h"
#include "SkBitmap.h"
#include "skpdiff_util.h"
const char* SkDifferentPixelsMetric::getName() const {
return "different_pixels";
}
bool SkDifferentPixelsMetric::diff(SkBitmap* baseline, SkBitmap* test, bool computeMask,
Result* result) const {
double startTime = get_seconds();
// Ensure the images are comparable
if (baseline->width() != test->width() || baseline->height() != test->height() ||
baseline->width() <= 0 || baseline->height() <= 0 ||
baseline->config() != test->config()) {
return false;
}
int width = baseline->width();
int height = baseline->height();
// Prepare the POI alpha mask if needed
if (computeMask) {
result->poiAlphaMask.setConfig(SkBitmap::kA8_Config, width, height);
result->poiAlphaMask.allocPixels();
result->poiAlphaMask.lockPixels();
result->poiAlphaMask.eraseARGB(SK_AlphaOPAQUE, 0, 0, 0);
}
// Prepare the pixels for comparison
result->poiCount = 0;
baseline->lockPixels();
test->lockPixels();
for (int y = 0; y < height; y++) {
// Grab a row from each image for easy comparison
unsigned char* baselineRow = (unsigned char*)baseline->getAddr(0, y);
unsigned char* testRow = (unsigned char*)test->getAddr(0, y);
for (int x = 0; x < width; x++) {
// Compare one pixel at a time so each differing pixel can be noted
if (memcmp(&baselineRow[x * 4], &testRow[x * 4], 4) != 0) {
result->poiCount++;
if (computeMask) {
*result->poiAlphaMask.getAddr8(x,y) = SK_AlphaTRANSPARENT;
}
}
}
}
test->unlockPixels();
baseline->unlockPixels();
if (computeMask) {
result->poiAlphaMask.unlockPixels();
}
// Calculates the percentage of identical pixels
result->result = 1.0 - ((double)result->poiCount / (width * height));
result->timeElapsed = get_seconds() - startTime;
return true;
}