void tga::print_header(FILE* fp, const dimension& dim, const ColorTable& ct)
{
const char BITS_PER_COLOR = 24;
const char BIT_PER_PIXEL = 8; // GIMP does not allow 16
// 0-0: no image id field
// 1-1: color map? yes
// 2-2: image type: color mapped
fwrite("\x00\x01\x01", 1, 3, fp);
// color map:
// 0-1: index of first entry (=0)
// 2-3: number of entries
// 4-4: bpp to describe each color
fwrite("\x00\x00", 1, 2, fp);
const short number_of_colors = ct.num_colors();
fwrite(&number_of_colors, 1, 2, fp);
fwrite(&BITS_PER_COLOR, 1, 1, fp);
// 0-1: x-origin (=0)
// 2-3: y-origin (=0)
fwrite("\x00\x00\x00\x00", 1, 4, fp);
const short width = dim.width() - 2;
fwrite(&width, 2, 1, fp);
const short height = dim.height() - 2;
fwrite(&height, 2, 1, fp);
// 0: pixel depth (=BPP)
// 1: bits 3-0: attributes per pixel (=alpha?) =0
// 1: bits 4-5: left-right => set bit 4
// 1: bits 6-7: reserved to be 0
fwrite(&BIT_PER_PIXEL, 1, 1, fp);
fwrite("\x20", 1, 1, fp);
}
