rdos/bmp2font.c
2020-03-16 17:24:16 +00:00

56 lines
1.4 KiB
C

/* This script os meant to convert a 256x256 pixel bitmap into an bitmap of
* 8x8 pixel characters. When deciding upon the output format, i had the
* video output of scanlines in mind. So there are 8 sections for each row
* of pixels for a character cell, each secton containing the the pixel line
* data of all 256 character codes. If you align this blob to 256-bytes, you
* quickly fetch the data by pointing bx to the begin of the section for the
* pixel line you are currently drawing, then set bl to the character value
* you want to print and dereference [bx].
*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
FILE* in;
FILE* out;
void *addr;
void copyline(int c) {
uint8_t *ptr = addr + 0x82 + (128/8)*(127 - c);
int i;
for (i=0; i<16; i++) {
fputc(*ptr++, out);
}
}
int main(int argc, char** argv) {
struct stat sbuf;
in = fopen(argv[1], "r+");
out = fopen(argv[2], "w");
fstat(fileno(in), &sbuf);
if (sbuf.st_size != 2178) {
printf("File must be a 128x128 pixel 1 bit monochrome bmp\n");
exit(1);
}
addr = mmap(NULL, sbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(in), 0);
int i, j;
for(j=0; j<8; j++) {
for(i=0; i<16; i++) {
copyline(j+i*8);
}
}
}