/*
* Copyright (C) 2009 Zan Dobersek <zandobersek@gmail.com>
* Copyright (C) 2010 Igalia S.L.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <gdk/gdk.h>
using namespace std;
static double tolerance = 0;
static GOptionEntry commandLineOptionEntries[] =
{
{ "tolerance", 0, 0, G_OPTION_ARG_DOUBLE, &tolerance, "Percentage difference between images before considering them different", "T" },
{ 0, 0, 0, G_OPTION_ARG_NONE, 0, 0, 0 },
};
GdkPixbuf* readPixbufFromStdin(long imageSize)
{
unsigned char imageBuffer[2048];
GdkPixbufLoader* loader = gdk_pixbuf_loader_new_with_type("png", 0);
GError* error = 0;
while (imageSize > 0) {
size_t bytesToRead = min<int>(imageSize, 2048);
size_t bytesRead = fread(imageBuffer, 1, bytesToRead, stdin);
if (!gdk_pixbuf_loader_write(loader, reinterpret_cast<const guchar*>(imageBuffer), bytesRead, &error)) {
g_error_free(error);
gdk_pixbuf_loader_close(loader, 0);
g_object_unref(loader);
return 0;
}
imageSize -= static_cast<int>(bytesRead);
}
gdk_pixbuf_loader_close(loader, 0);
GdkPixbuf* decodedImage = gdk_pixbuf_loader_get_pixbuf(loader);
g_object_ref(decodedImage);
return decodedImage;
}
GdkPixbuf* differenceImageFromDifferenceBuffer(unsigned char* buffer, int width, int height)
{
GdkPixbuf* image = gdk_pixbuf_new(GDK_COLORSPACE_RGB, FALSE, 8, width, height);
if (!image)
return image;
int rowStride = gdk_pixbuf_get_rowstride(image);
unsigned char* diffPixels = gdk_pixbuf_get_pixels(image);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
unsigned char* diffPixel = diffPixels + (y * rowStride) + (x * 3);
diffPixel[0] = diffPixel[1] = diffPixel[2] = *buffer++;
}
}
return image;
}
float calculateDifference(GdkPixbuf* baselineImage, GdkPixbuf* actualImage, GdkPixbuf** differenceImage)
{
int width = gdk_pixbuf_get_width(actualImage);
int height = gdk_pixbuf_get_height(actualImage);
int numberOfChannels = gdk_pixbuf_get_n_channels(actualImage);
if ((width != gdk_pixbuf_get_width(baselineImage))
|| (height != gdk_pixbuf_get_height(baselineImage))
|| (numberOfChannels != gdk_pixbuf_get_n_channels(baselineImage))
|| (gdk_pixbuf_get_has_alpha(actualImage) != gdk_pixbuf_get_has_alpha(baselineImage))) {
fprintf(stderr, "Error, test and reference image have different properties.\n");
return 100; // Completely different.
}
unsigned char* diffBuffer = static_cast<unsigned char*>(malloc(width * height));
float count = 0;
float sum = 0;
float maxDistance = 0;
int actualRowStride = gdk_pixbuf_get_rowstride(actualImage);
int baseRowStride = gdk_pixbuf_get_rowstride(baselineImage);
unsigned char* actualPixels = gdk_pixbuf_get_pixels(actualImage);
unsigned char* basePixels = gdk_pixbuf_get_pixels(baselineImage);
unsigned char* currentDiffPixel = diffBuffer;
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
unsigned char* actualPixel = actualPixels + (y * actualRowStride) + (x * numberOfChannels);
unsigned char* basePixel = basePixels + (y * baseRowStride) + (x * numberOfChannels);
float red = (actualPixel[0] - basePixel[0]) / max<float>(255 - basePixel[0], basePixel[0]);
float green = (actualPixel[1] - basePixel[1]) / max<float>(255 - basePixel[1], basePixel[1]);
float blue = (actualPixel[2] - basePixel[2]) / max<float>(255 - basePixel[2], basePixel[2]);
float alpha = (actualPixel[3] - basePixel[3]) / max<float>(255 - basePixel[3], basePixel[3]);
float distance = sqrtf(red * red + green * green + blue * blue + alpha * alpha) / 2.0f;
*currentDiffPixel++ = (unsigned char)(distance * 255.0f);
if (distance >= 1.0f / 255.0f) {
count += 1.0f;
sum += distance;
maxDistance = max<float>(maxDistance, distance);
}
}
}
// Compute the difference as a percentage combining both the number of
// different pixels and their difference amount i.e. the average distance
// over the entire image
float difference = 0;
if (count > 0.0f)
difference = 100.0f * sum / (height * width);
if (difference <= tolerance)
difference = 0;
else {
difference = roundf(difference * 100.0f) / 100.0f;
difference = max(difference, 0.01f); // round to 2 decimal places
*differenceImage = differenceImageFromDifferenceBuffer(diffBuffer, width, height);
}
free(diffBuffer);
return difference;
}
void printImage(GdkPixbuf* image)
{
char* buffer;
gsize bufferSize;
GError* error = 0;
if (!gdk_pixbuf_save_to_buffer(image, &buffer, &bufferSize, "png", &error, NULL)) {
g_error_free(error);
return; // Don't bail out, as we can still use the percentage output.
}
printf("Content-Length: %"G_GSIZE_FORMAT"\n", bufferSize);
fwrite(buffer, 1, bufferSize, stdout);
}
void printImageDifferences(GdkPixbuf* baselineImage, GdkPixbuf* actualImage)
{
GdkPixbuf* differenceImage = 0;
float difference = calculateDifference(baselineImage, actualImage, &differenceImage);
if (difference > 0.0f) {
if (differenceImage) {
printImage(differenceImage);
g_object_unref(differenceImage);
}
printf("diff: %01.2f%% failed\n", difference);
} else {
printf("diff: %01.2f%% passed\n", difference);
}
}
int main(int argc, char* argv[])
{
gdk_init(&argc, &argv);
GError* error = 0;
GOptionContext* context = g_option_context_new("- compare two image files, printing their percentage difference and the difference image to stdout");
g_option_context_add_main_entries(context, commandLineOptionEntries, 0);
if (!g_option_context_parse(context, &argc, &argv, &error)) {
printf("Option parsing failed: %s\n", error->message);
g_error_free(error);
return 1;
}
GdkPixbuf* actualImage = 0;
GdkPixbuf* baselineImage = 0;
char buffer[2048];
while (fgets(buffer, sizeof(buffer), stdin)) {
// Convert the first newline into a NUL character so that strtok doesn't produce it.
char* newLineCharacter = strchr(buffer, '\n');
if (newLineCharacter)
*newLineCharacter = '\0';
if (!strncmp("Content-Length: ", buffer, 16)) {
gchar** tokens = g_strsplit(buffer, " ", 0);
if (!tokens[1]) {
g_strfreev(tokens);
printf("Error, image size must be specified..\n");
return 1;
}
long imageSize = strtol(tokens[1], 0, 10);
g_strfreev(tokens);
if (imageSize > 0 && !actualImage) {
if (!(actualImage = readPixbufFromStdin(imageSize))) {
printf("Error, could not read actual image.\n");
return 1;
}
} else if (imageSize > 0 && !baselineImage) {
if (!(baselineImage = readPixbufFromStdin(imageSize))) {
printf("Error, could not read baseline image.\n");
return 1;
}
} else {
printf("Error, image size must be specified..\n");
return 1;
}
}
if (actualImage && baselineImage) {
printImageDifferences(baselineImage, actualImage);
g_object_unref(actualImage);
g_object_unref(baselineImage);
actualImage = 0;
baselineImage = 0;
}
fflush(stdout);
}
return 0;
}