109 lines
3.0 KiB
C
109 lines
3.0 KiB
C
// x-run: make test-cpi2png
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#include <assert.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stb/stb_image.h>
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#include <stb/stb_image_write.h>
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#include <string.h>
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#include "cc-common.h"
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bool read_varint(FILE *fp, unsigned int *out);
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int main(int argc, char **argv) {
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if (argc < 3) {
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fprintf(stderr, "Usage: %s [input.cpi] [output.png]\n", argv[0]);
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}
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FILE *fp_in = fopen(argv[1], "rb");
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assert(fp_in != NULL && "Failed to open input file");
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unsigned char header[4];
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unsigned char version = 0;
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assert(fread(header, 1, 4, fp_in) == 4 && "Failed to read header: not enough bytes");
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if (0 == memcmp(header, "CCPI", 4)) { // Original CCPI (CPIv0)
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printf("CPIv0 (old header)\n");
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} else if (0 == memcmp(header, "CPI", 3)) { // Newer CCPI (CPIvX)
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version = header[3];
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} else {
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assert(false && "Not a CPI/CCPI image: invalid header");
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}
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if (version & 0x80) {
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fprintf(stderr, "Draft version: 0x%02x may not be supported properly! Here be dragons!\n", version);
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}
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unsigned int width = 0, height = 0;
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if (version == 0) {
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width = fgetc(fp_in);
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height = fgetc(fp_in);
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(void)fgetc(fp_in); // XXX: ignore scale
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} else if (version == 1) {
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assert(read_varint(fp_in, &width) && "Failed to read width varint");
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assert(read_varint(fp_in, &height) && "Failed to read height varint");
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} else {
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assert(false && "Failed to read size: unsupported version");
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}
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union color *canvas = malloc(width * height * 8 * 11 * sizeof(union color));
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// XXX: may change in future when we introduce variable-size palettes
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// though, it may never change, if I'm being honest. Why would I choose
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// worse image quality with less colors when I can use all of them?
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union color *colors = calloc(16, sizeof(union color));
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// NOTE: our `union color` type is 4 bytes long, while palette stored in the
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// file itself uses 3 bytes per color, so we can't just `fread` them at once,
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// sadly.
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for (int i = 0; i < 16; i++) {
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colors[i].rgba.r = fgetc(fp_in);
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colors[i].rgba.g = fgetc(fp_in);
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colors[i].rgba.b = fgetc(fp_in);
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colors[i].rgba.a = 0xff;
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}
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for (int y = 0; y < height; y++) {
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for (int x = 0; x < width; x++) {
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unsigned char sym = fgetc(fp_in);
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unsigned char color = fgetc(fp_in);
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union color background = colors[color & 0xF];
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union color foreground = colors[color >> 4];
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for (int oy = 0; oy < 11; oy++) {
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for (int ox = 0; ox < 8; ox++) {
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union color pix = ((0x80 >> ox) & cc_font_atlas[sym][oy]) ? foreground : background;
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canvas[ox + (x + (y * 11 + oy) * width) * 8] = pix;
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}
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}
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}
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}
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stbi_write_png(argv[2], width * 8, height * 11, 4, canvas, 0);
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free(colors);
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free(canvas);
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fclose(fp_in);
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return EXIT_SUCCESS;
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}
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bool read_varint(FILE *fp, unsigned int *out) {
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int position = 0;
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while (true) {
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unsigned char curr = fgetc(fp);
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*out |= (curr & 0x7F) << position;
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if ((curr & 0x80) == 0) break;
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position += 7;
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if (position >= 32) return false;
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}
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return true;
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}
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