dos33fsprogs/gr-utils/loadpng.c
Vince Weaver e17f3b6c02 png2rle: actually fix png2rle 4-bit mode
forgot to mask colors
2019-07-11 14:04:32 -04:00

231 lines
5.0 KiB
C

/* Loads a 80x48 PNG image into a 40x48 Apple II layout */
/* It's not interleaved like an actual Apple II */
/* But the top/bottom are pre-packed into a naive 40x24 array */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <png.h>
static int convert_color(int color) {
int c=0;
switch(color) {
case 0x000000: c=0; break; /* black */
case 0xe31e60: c=1; break; /* magenta */
case 0x604ebd: c=2; break; /* dark blue */
case 0xff44fd: c=3; break; /* purple */
case 0x00a360: c=4; break; /* dark green */
case 0x9c9c9c: c=5; break; /* grey 1 */
case 0x14cffd: c=6; break; /* medium blue */
case 0xd0c3ff: c=7; break; /* light blue */
case 0x607203: c=8; break; /* brown */
case 0xff6a3c: c=9; break; /* orange */
case 0x9d9d9d: c=10; break; /* grey 2 */
case 0xffa0d0: c=11; break; /* pink */
case 0x14f53c: c=12; break; /* bright green */
case 0xd0dd8d: c=13; break; /* yellow */
case 0x72ffd0: c=14; break; /* aqua */
case 0xffffff: c=15; break; /* white */
default:
printf("Unknown color %x\n",color);
break;
}
return c;
}
/* expects a PNG where the xsize is *2 */
int loadpng(char *filename, unsigned char **image_ptr, int *xsize, int *ysize) {
int x,y;
int color;
FILE *infile;
int debug=0;
unsigned char *image,*out_ptr;
int width, height;
int a2_color;
png_byte bit_depth;
png_structp png_ptr;
png_infop info_ptr;
png_bytep *row_pointers;
png_byte color_type;
// int number_of_passes;
unsigned char header[8];
/* open file and test for it being a png */
infile = fopen(filename, "rb");
if (infile==NULL) {
fprintf(stderr,"Error! Could not open %s\n",filename);
return -1;
}
/* Check the header */
fread(header, 1, 8, infile);
if (png_sig_cmp(header, 0, 8)) {
fprintf(stderr,"Error! %s is not a PNG file\n",filename);
return -1;
}
/* initialize stuff */
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr) {
fprintf(stderr,"Error create_read_struct\n");
exit(-1);
}
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
fprintf(stderr,"Error png_create_info_struct\n");
exit(-1);
}
png_init_io(png_ptr, infile);
png_set_sig_bytes(png_ptr, 8);
png_read_info(png_ptr, info_ptr);
width = png_get_image_width(png_ptr, info_ptr);
height = png_get_image_height(png_ptr, info_ptr);
*xsize=width/2;
*ysize=height;
color_type = png_get_color_type(png_ptr, info_ptr);
bit_depth = png_get_bit_depth(png_ptr, info_ptr);
if (debug) {
printf("PNG: width=%d height=%d depth=%d\n",width,height,bit_depth);
if (color_type==PNG_COLOR_TYPE_RGB) printf("Type RGB\n");
else if (color_type==PNG_COLOR_TYPE_RGB_ALPHA) printf("Type RGBA\n");
else if (color_type==PNG_COLOR_TYPE_PALETTE) printf("Type palette\n");
}
// number_of_passes = png_set_interlace_handling(png_ptr);
png_read_update_info(png_ptr, info_ptr);
row_pointers = (png_bytep*) malloc(sizeof(png_bytep) * height);
for (y=0; y<height; y++) {
row_pointers[y] = (png_byte*) malloc(png_get_rowbytes(png_ptr,info_ptr));
}
png_read_image(png_ptr, row_pointers);
fclose(infile);
image=calloc(width*height/2,sizeof(unsigned char));
if (image==NULL) {
fprintf(stderr,"Memory error!\n");
return -1;
}
out_ptr=image;
if (color_type==PNG_COLOR_TYPE_RGB_ALPHA) {
for(y=0;y<height;y+=2) {
for(x=0;x<width/2;x++) {
/* top color */
color= (row_pointers[y][x*2*4]<<16)+
(row_pointers[y][x*2*4+1]<<8)+
(row_pointers[y][x*2*4+2]);
if (debug) {
printf("%x ",color);
}
a2_color=convert_color(color);
/* bottom color */
color= (row_pointers[y+1][x*2*4]<<16)+
(row_pointers[y+1][x*2*4+1]<<8)+
(row_pointers[y+1][x*2*4+2]);
if (debug) {
printf("%x ",color);
}
a2_color|=(convert_color(color)<<4);
*out_ptr=a2_color;
out_ptr++;
}
if (debug) printf("\n");
}
}
else if (color_type==PNG_COLOR_TYPE_PALETTE) {
for(y=0;y<height;y+=2) {
for(x=0;x<width/2;x++) {
if (bit_depth==8) {
/* top color */
a2_color=row_pointers[y][x*2];
/* bottom color */
color=row_pointers[y+1][x*2];
a2_color|=(color<<4);
if (debug) {
printf("%x ",a2_color);
}
*out_ptr=a2_color;
out_ptr++;
}
else if (bit_depth==4) {
/* top color */
a2_color=(row_pointers[y][x])&0xf;
/* bottom color */
color=(row_pointers[y+1][x])&0xf;
a2_color|=(color<<4);
if (debug) {
printf("%x ",a2_color);
}
*out_ptr=a2_color;
out_ptr++;
}
}
if (debug) printf("\n");
}
}
else {
printf("Unknown color type\n");
}
/* Stripe test image */
// for(x=0;x<40;x++) for(y=0;y<40;y++) image[(y*width)+x]=y%16;
/*
Addr Row /80 %40
$400 0 0 0 0
$428 28 16 0
$450 50 32 0
$480 80 2 1
$4A8 a8 18 1
$4D0 d0 34 1
$500 100 3 2
0,0 0,1 0,2....0,39 16,0 16,1 ....16,39 32,0..32,39, X X X X X X X X
*/
*image_ptr=image;
return 0;
}