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https://github.com/webmproject/libwebp.git
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simple WebP viewer, based on OpenGL
Quite handy and simple (for now). It's not yet incorporated within the build system (autotools or makefile.unix), because it gets complicated with OpenGL. TODO(later). For now, there's some ready-to-use command line for compiling on Linux or Mac in the header of vwebp.c Later, this tool will be supplemented with support for animation, tiling, zooming, etc. Change-Id: I292972cea4862536afbe8c9ec444c590d152f086
This commit is contained in:
Pascal Massimino
parent
6aac1df17b
commit
7937b409e7
12
README
12
README
@ -228,6 +228,18 @@ Use following options to convert into alternate image formats:
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-v ....... verbose (e.g. print encoding/decoding times)
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-noasm ....... disable all assembly optimizations.
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Visualization tool:
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===================
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There's a little self-serve visualization tool called 'vwebp' under the
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examples/ directory. It uses OpenGL to open a simple drawing window and show
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a decoded WebP file. It's not yet integrated in the automake or makefile.unix
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build system, but you can try to manually compile it using the recommendations
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at the top of the source file.
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Usage: 'vwebp my_picture.webp'
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Encoding API:
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=============
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248
examples/vwebp.c
Normal file
248
examples/vwebp.c
Normal file
@ -0,0 +1,248 @@
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// Copyright 2011 Google Inc.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Simple WebP file viewer.
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//
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// Compiling on linux:
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// sudo apt-get install libglut3-dev mesa-common-dev
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// gcc -o vwebp vwebp.c -O3 -lwebp -lglut -lGL
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// Compiling on Mac + XCode:
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// gcc -o vwebp vwebp.c -lwebp -framework GLUT -framework OpenGL
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "webp/decode.h"
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#ifdef __APPLE__
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#include <GLUT/glut.h>
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#else
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#include <GL/glut.h>
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#ifdef FREEGLUT
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#include <GL/freeglut.h>
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#endif
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#endif
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// Unfortunate global variables
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static const WebPDecBuffer* kPic = NULL;
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static const char* file_name = NULL;
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static int print_info = 0;
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//------------------------------------------------------------------------------
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// Callbacks
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static void HandleKey(unsigned char key, int pos_x, int pos_y) {
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(void)pos_x;
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(void)pos_y;
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if (key == 'q' || key == 'Q' || key == 27 /* Esc */) {
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#ifdef FREEGLUT
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glutLeaveMainLoop();
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#else
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WebPFreeDecBuffer((WebPDecBuffer*)kPic);
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kPic = NULL;
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exit(0);
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#endif
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} else if (key == 'i') {
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print_info = 1 - print_info;
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glutPostRedisplay();
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}
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}
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static void HandleReshape(int width, int height) {
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// TODO(skal): proper handling of resize, esp. for large pictures.
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// + key control of the zoom.
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glViewport(0, 0, width, height);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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}
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static void PrintString(const char* const text) {
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void* const font = GLUT_BITMAP_9_BY_15;
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int i;
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for (i = 0; text[i]; ++i) {
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glutBitmapCharacter(font, text[i]);
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}
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}
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static void HandleDisplay(void) {
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if (kPic == NULL) return;
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glClear(GL_COLOR_BUFFER_BIT);
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glPushMatrix();
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glPixelZoom(1, -1);
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glRasterPos2f(-1, 1);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glPixelStorei(GL_UNPACK_ROW_LENGTH, kPic->u.RGBA.stride / 4);
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glDrawPixels(kPic->width, kPic->height, GL_RGBA, GL_UNSIGNED_BYTE,
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(GLvoid*)kPic->u.RGBA.rgba);
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if (print_info) {
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char tmp[32];
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glColor4f(0.0, 0.0, 0.0, 0.0);
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glRasterPos2f(-0.95, 0.90);
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PrintString(file_name);
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snprintf(tmp, sizeof(tmp), "Dimension:%d x %d", kPic->width, kPic->height);
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glColor4f(0.0, 0.0, 0.0, 0.0);
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glRasterPos2f(-0.95, 0.80);
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PrintString(tmp);
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}
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glFlush();
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}
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static void Show(const WebPDecBuffer* const pic) {
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glutInitDisplayMode(GLUT_RGBA);
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glutInitWindowSize(pic->width, pic->height);
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glutCreateWindow("WebP viewer");
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glutReshapeFunc(HandleReshape);
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glutDisplayFunc(HandleDisplay);
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glutIdleFunc(NULL);
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glutKeyboardFunc(HandleKey);
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glClearColor(0.0, 0.0, 0.0, 0.0);
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HandleReshape(pic->width, pic->height);
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glutMainLoop();
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}
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//------------------------------------------------------------------------------
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// File decoding
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static const char* const kStatusMessages[] = {
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"OK", "OUT_OF_MEMORY", "INVALID_PARAM", "BITSTREAM_ERROR",
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"UNSUPPORTED_FEATURE", "SUSPENDED", "USER_ABORT", "NOT_ENOUGH_DATA"
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};
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static int Decode(const char* const in_file, WebPDecoderConfig* const config) {
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WebPDecBuffer* const output_buffer = &config->output;
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WebPBitstreamFeatures* const bitstream = &config->input;
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VP8StatusCode status = VP8_STATUS_OK;
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int ok;
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size_t data_size = 0;
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void* data = NULL;
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FILE* const in = fopen(in_file, "rb");
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if (!in) {
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fprintf(stderr, "cannot open input file '%s'\n", in_file);
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return 0;
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}
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fseek(in, 0, SEEK_END);
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data_size = ftell(in);
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fseek(in, 0, SEEK_SET);
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data = malloc(data_size);
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if (data == NULL) return 0;
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ok = (fread(data, data_size, 1, in) == 1);
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fclose(in);
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if (!ok) {
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fprintf(stderr, "Could not read %zu bytes of data from file %s\n",
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data_size, in_file);
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free(data);
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return 0;
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}
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status = WebPGetFeatures((const uint8_t*)data, data_size, bitstream);
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if (status != VP8_STATUS_OK) {
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goto end;
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}
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output_buffer->colorspace = MODE_RGBA;
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status = WebPDecode((const uint8_t*)data, data_size, config);
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end:
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free(data);
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ok = (status == VP8_STATUS_OK);
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if (!ok) {
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fprintf(stderr, "Decoding of %s failed.\n", in_file);
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fprintf(stderr, "Status: %d (%s)\n", status, kStatusMessages[status]);
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}
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return ok;
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}
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//------------------------------------------------------------------------------
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// Main
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static void Help(void) {
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printf("Usage: vwebp in_file [options]\n\n"
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"Decodes the WebP image file and visualize it using OpenGL\n"
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"Options are:\n"
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" -version .... print version number and exit.\n"
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" -nofancy ..... don't use the fancy YUV420 upscaler.\n"
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" -nofilter .... disable in-loop filtering.\n"
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" -mt .......... use multi-threading\n"
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" -crop <x> <y> <w> <h> ... crop output with the given rectangle\n"
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" -scale <w> <h> .......... scale the output (*after* any cropping)\n"
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" -h ....... this help message.\n"
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);
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}
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int main(int argc, char *argv[]) {
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WebPDecoderConfig config;
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int c;
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if (!WebPInitDecoderConfig(&config)) {
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fprintf(stderr, "Library version mismatch!\n");
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return -1;
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}
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for (c = 1; c < argc; ++c) {
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if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
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Help();
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return 0;
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} else if (!strcmp(argv[c], "-nofancy")) {
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config.options.no_fancy_upsampling = 1;
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} else if (!strcmp(argv[c], "-nofilter")) {
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config.options.bypass_filtering = 1;
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} else if (!strcmp(argv[c], "-version")) {
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const int version = WebPGetDecoderVersion();
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printf("%d.%d.%d\n",
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(version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
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return 0;
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} else if (!strcmp(argv[c], "-mt")) {
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config.options.use_threads = 1;
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} else if (!strcmp(argv[c], "-crop") && c < argc - 4) {
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config.options.use_cropping = 1;
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config.options.crop_left = strtol(argv[++c], NULL, 0);
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config.options.crop_top = strtol(argv[++c], NULL, 0);
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config.options.crop_width = strtol(argv[++c], NULL, 0);
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config.options.crop_height = strtol(argv[++c], NULL, 0);
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} else if (!strcmp(argv[c], "-scale") && c < argc - 2) {
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config.options.use_scaling = 1;
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config.options.scaled_width = strtol(argv[++c], NULL, 0);
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config.options.scaled_height = strtol(argv[++c], NULL, 0);
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} else if (argv[c][0] == '-') {
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printf("Unknown option '%s'\n", argv[c]);
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Help();
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return -1;
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} else {
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file_name = argv[c];
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}
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}
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if (file_name == NULL) {
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printf("missing input file!!\n");
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Help();
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return -1;
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}
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if (!Decode(file_name, &config)) {
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return -1;
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}
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kPic = &config.output;
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printf("Displaying [%s]: %d x %d. Press Esc to exit, 'i' for info.\n",
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file_name, kPic->width, kPic->height);
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glutInit(&argc, argv);
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Show(kPic);
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// Should only be reached when using FREEGLUT:
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WebPFreeDecBuffer(&config.output);
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return 0;
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}
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//------------------------------------------------------------------------------
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