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Unfinished tool for examining GIF files. May prove useful.

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git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1694 416bcca6-2ee7-4201-b75f-2eb2f807beb1
This commit is contained in:
Adrien Destugues 2011-01-23 17:00:07 +00:00
parent e7842861f7
commit 2373a19c62
1 changed files with 97 additions and 0 deletions
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tools/gifanalyzer/gifanalyzer.c Normal file
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/* vim:expandtab:ts=2 sw=2:
*/
/* Grafx2 - The Ultimate 256-color bitmap paint program
* Gif Analyzer tool
Copyright 2010 Adrien Destugues
Grafx2 is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; version 2
of the License.
Grafx2 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Grafx2; if not, see <http://www.gnu.org/licenses/>
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
int main(int argc, char* argv[])
{
FILE* theFile;
if(argc != 2)
{
printf("%s file.gif\n",argv[0]);
exit(-1);
}
theFile = fopen(argv[1], "r");
uint8_t buffer[256];
fread(buffer, 1, 6, theFile);
buffer[6] = 0;
printf("Signature: %6s\n", buffer);
uint16_t w,h;
fread(&w,2,1,theFile);
fread(&h,2,1,theFile);
printf("Resolution: %dx%d\n",w,h);
fread(buffer,1,3,theFile);
int colors = ((buffer[0]&0b01110000)>>4)+1;
colors = pow(2,colors);
int bpp = (buffer[0]&0xF) +1;
printf("Color palette: %#02.2x\n",buffer[0]&0xFF);
if (buffer[0] & 0b10000000)
printf("\tGlobal palette\n");
printf("\tColor count: %d\n", colors);
printf("\tBits per pixel: %d\n",bpp);
printf("Index of background color: %d\n",buffer[1]);
printf("(reserved byte: %d)\n",buffer[2]);
printf("Color palette:\n");
for (int i = 0; i < pow(2,bpp); i++)
{
fread(buffer,1,3,theFile);
printf("\t%d: %u %u %u\t",i,buffer[0], buffer[1], buffer[2]);
if ((i+1)%4 ==0)puts("");
}
int i = 0;
do {
fread(buffer,1,1,theFile);
i++;
} while (i != ',');
if (i > 1);
printf("Skipped %d meaningless bytes before image descriptor\n",i);
uint16_t x,y;
fread(&x,2,1,theFile);
fread(&y,2,1,theFile);
fread(&w,2,1,theFile);
fread(&h,2,1,theFile);
printf("Image descriptor\n");
printf("\tx=%d y=%d w=%d h=%d\n",x,y,w,h);
fclose(theFile);
}