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/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at http://www.graphviz.org/
*************************************************************************/
/*
* This program generates an image where each pixel is the
* difference between the corresponding pixel in each of the
* two source images. Thus, if the source images are the same
* the resulting image will be black, otherwise it will have
* regions of non-black where the images differ.
*
* Currently supports: .png, .gif, .jpg, and .ps by using ghostscript
*
* John Ellson <ellson@research.att.com>
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifdef _WIN32
#define EX_USAGE 64
#define EX_DATAERR 65
#define EX_NOINPUT 66
#define EX_UNAVAILABLE 69
#define EX_OSERR 71
#else
#include <sysexits.h>
#endif
#include <gd.h>
#include <stdbool.h>
#include <util/agxbuf.h>
#include <util/alloc.h>
#include <util/exit.h>
static const char pstopng[] =
"gs -dNOPAUSE -sDEVICE=pngalpha -sOutputFile=- -q -";
static gdImagePtr imageLoad(const char *filename) {
FILE *f;
const char *ext = strrchr(filename, '.');
if (!ext) {
fprintf(stderr, "Filename \"%s\" has no file extension.\n", filename);
graphviz_exit(EX_USAGE);
}
int rc = stat(filename, &(struct stat){0});
if (rc) {
fprintf(stderr, "Failed to stat \"%s\"\n", filename);
graphviz_exit(EX_NOINPUT);
}
if (strcasecmp(ext, ".ps") == 0) {
ext = ".png";
agxbuf fname = {0};
agxbprint(&fname, "%s%s", filename, ext);
const char *tmp = agxbuse(&fname);
agxbuf cmd = {0};
agxbprint(&cmd, "%s <%s >%s", pstopng, filename, tmp);
rc = system(agxbuse(&cmd));
agxbfree(&cmd);
if (rc) {
agxbfree(&fname);
fprintf(stderr, "Failed to convert \"%s%s\"\n", filename, ext);
graphviz_exit(EX_USAGE);
}
f = fopen(tmp, "rb");
agxbfree(&fname);
if (!f) {
fprintf(stderr, "Failed to open converted \"%s%s\"\n", filename, ext);
graphviz_exit(EX_NOINPUT);
}
} else {
f = fopen(filename, "rb");
if (!f) {
fprintf(stderr, "Failed to open \"%s\"\n", filename);
graphviz_exit(EX_NOINPUT);
}
}
gdImagePtr im = NULL;
if (strcasecmp(ext, ".png") == 0) {
#ifdef HAVE_GD_PNG
im = gdImageCreateFromPng(f);
#else
fprintf(stderr, "PNG support is not available\n");
graphviz_exit(EX_UNAVAILABLE);
#endif
} else if (strcasecmp(ext, ".gif") == 0) {
#ifdef HAVE_GD_GIF
im = gdImageCreateFromGif(f);
#else
fprintf(stderr, "GIF support is not available\n");
graphviz_exit(EX_UNAVAILABLE);
#endif
} else if (strcasecmp(ext, ".jpg") == 0) {
#ifdef HAVE_GD_JPEG
im = gdImageCreateFromJpeg(f);
#else
fprintf(stderr, "JPEG support is not available\n");
graphviz_exit(EX_UNAVAILABLE);
#endif
}
fclose(f);
if (!im) {
fprintf(stderr, "Loading image from file \"%s\" failed!\n", filename);
graphviz_exit(EX_DATAERR);
}
return im;
}
static bool imageDiff(gdImagePtr A, gdImagePtr B, gdImagePtr C, int w, int h,
int black, int white) {
bool rc = false;
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
const bool d = (bool)(gdImageGetTrueColorPixel(B, x, y) -
gdImageGetTrueColorPixel(A, x, y));
gdImageSetPixel(C, x, y, d ? white : black);
rc |= d;
}
}
return rc;
}
int main(int argc, char **argv) {
#ifdef HAVE_GD_PNG
FILE *f;
#endif
if (argc == 2 && strcmp(argv[1], "-?") == 0) {
fprintf(stderr, "Usage: diffimg image1 image2 [outimage]\n");
graphviz_exit(0);
}
if (argc < 3) {
fprintf(stderr, "Usage: diffimg image1 image2 [outimage]\n");
graphviz_exit(EX_USAGE);
}
gdImagePtr A = imageLoad(argv[1]);
gdImagePtr B = imageLoad(argv[2]);
const int minSX = (gdImageSX(A) < gdImageSX(B)) ? gdImageSX(A) : gdImageSX(B);
const int minSY = (gdImageSY(A) < gdImageSY(B)) ? gdImageSY(A) : gdImageSY(B);
const int maxSX = (gdImageSX(A) > gdImageSX(B)) ? gdImageSX(A) : gdImageSX(B);
const int maxSY = (gdImageSY(A) > gdImageSY(B)) ? gdImageSY(A) : gdImageSY(B);
gdImagePtr C = gdImageCreatePalette(maxSX, maxSY);
const int white = gdImageColorAllocate(C, gdRedMax, gdGreenMax, gdBlueMax);
const int black = gdImageColorAllocate(C, 0, 0, 0);
if (maxSX > minSX && maxSY > minSY)
gdImageFilledRectangle(C, minSX, minSY, maxSX - 1, maxSY - 1, black);
const bool rc = imageDiff(A, B, C, minSX, minSY, black, white);
#ifdef HAVE_GD_PNG
if (argc > 3 && (f = fopen(argv[3], "wb"))) {
gdImagePng(C, f);
fclose(f);
} else
gdImagePng(C, stdout);
#else
fprintf(stderr, "PNG output support is not available\n");
#endif
gdImageDestroy(A);
gdImageDestroy(B);
gdImageDestroy(C);
graphviz_exit(rc ? EXIT_FAILURE : EXIT_SUCCESS);
}
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