54 lines
1.4 KiB
C
54 lines
1.4 KiB
C
|
#include <stdio.h>
|
||
|
|
#include <sys/types.h>
|
||
|
|
|
||
|
|
#include "bmp.h"
|
||
|
|
#include "vesa.h"
|
||
|
|
|
||
|
|
int readBMPHeader(FILE *fh, struct BMPImage *info) {
|
||
|
|
int sizeOfHeader;
|
||
|
|
char value;
|
||
|
|
unsigned int numberOfUsedColors;
|
||
|
|
|
||
|
|
if ((fgetc(fh) != 'B') || (fgetc(fh) != 'M')) {
|
||
|
|
printf("Not a BMP file\n");
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
fseek(fh, 12, SEEK_CUR);
|
||
|
|
|
||
|
|
fread(&sizeOfHeader, sizeof(int), 1, fh);
|
||
|
|
fread(&info->width, sizeof(int), 1, fh);
|
||
|
|
fread(&info->height, sizeof(int), 1, fh);
|
||
|
|
fseek(fh, 2, SEEK_CUR);
|
||
|
|
fread(&info->bpp, sizeof(int), 1, fh);
|
||
|
|
|
||
|
|
// for gimp, you need to add colors to the color map until it hits
|
||
|
|
// 16 colors, then the image will be a 256 color, 8 bpp image
|
||
|
|
//
|
||
|
|
// https://www.gimp-forum.net/Thread-indexing-into-8-bit?pid=13233#pid13233
|
||
|
|
if (info->bpp != 8) return 1;
|
||
|
|
|
||
|
|
fseek(fh, 18, SEEK_CUR);
|
||
|
|
fread(&numberOfUsedColors, sizeof(unsigned int), 1, fh);
|
||
|
|
printf("used colors: %d\n",numberOfUsedColors);
|
||
|
|
if (numberOfUsedColors > 256) return 1;
|
||
|
|
|
||
|
|
|
||
|
|
// get down to color data
|
||
|
|
fseek(fh, 14 + sizeOfHeader, SEEK_SET);
|
||
|
|
|
||
|
|
fread(info->colors, sizeof(struct BMPColor), numberOfUsedColors, fh);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
void bmp256ColorPaletteToVESAColorPalette(struct BMPImage* bmpImage, struct VESAColor colors[]) {
|
||
|
|
int i;
|
||
|
|
|
||
|
|
for (i = 0; i < 256; ++i) {
|
||
|
|
colors[i].red = bmpImage->colors[i].red >> 2;
|
||
|
|
colors[i].green = bmpImage->colors[i].green >> 2;
|
||
|
|
colors[i].blue = bmpImage->colors[i].blue >> 2;
|
||
|
|
}
|
||
|
|
}
|