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