-/**************************************************************************
- *
- * Copyright 2011 Jose Fonseca
- * Copyright 2008-2010 VMware, Inc.
- * All Rights Reserved.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- *
- **************************************************************************/
-
-
-#include <assert.h>
-#include <math.h>
-
-#include <algorithm>
-
-#include "image.hpp"
-
-
-namespace image {
-
-
-double Image::compare(Image &ref)
-{
- if (width != ref.width ||
- height != ref.height ||
- channels < 3 ||
- ref.channels < 3) {
- return 0.0;
- }
-
- // Ignore missing alpha when comparing RGB w/ RGBA, but enforce an equal
- // number of channels otherwise.
- unsigned minChannels = std::min(channels, ref.channels);
- if (channels != ref.channels && minChannels < 3) {
- return 0.0;
- }
-
- const unsigned char *pSrc = start();
- const unsigned char *pRef = ref.start();
-
- unsigned long long error = 0;
- for (unsigned y = 0; y < height; ++y) {
- for (unsigned x = 0; x < width; ++x) {
- // FIXME: Ignore alpha channel until we are able to pick a visual
- // that matches the traces
- for (unsigned c = 0; c < minChannels; ++c) {
- int delta = pSrc[x*channels + c] - pRef[x*ref.channels + c];
- error += delta*delta;
- }
- }
-
- pSrc += stride();
- pRef += ref.stride();
- }
-
- double numerator = error*2 + 1;
- double denominator = height*width*minChannels*255ULL*255ULL*2;
- double quotient = numerator/denominator;
-
- // Precision in bits
- double precision = -log(quotient)/log(2.0);
-
- return precision;
-}
-
-
-} /* namespace image */