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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <png.h>
#include "readers.h"
static const char *ct[] = {
"gray", "X1", "rgb", "palette",
"graya", "X5", "rgba", "X7",
};
struct png_state {
FILE *infile;
png_structp png;
png_infop info;
png_bytep image;
png_uint_32 w,h;
int color_type;
};
static void*
png_init(FILE *fp, char *filename, unsigned int page,
struct ida_image_info *i, int thumbnail)
{
struct png_state *h;
int bit_depth, interlace_type;
int pass, number_passes;
unsigned int y;
png_uint_32 resx, resy;
png_color_16 *file_bg, my_bg = {
.red = 192,
.green = 192,
.blue = 192,
.gray = 192,
};
int unit;
h = malloc(sizeof(*h));
memset(h,0,sizeof(*h));
h->infile = fp;
h->png = png_create_read_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (NULL == h->png)
goto oops;
h->info = png_create_info_struct(h->png);
if (NULL == h->info)
goto oops;
png_init_io(h->png, h->infile);
png_read_info(h->png, h->info);
png_get_IHDR(h->png, h->info, &h->w, &h->h,
&bit_depth,&h->color_type,&interlace_type, NULL,NULL);
png_get_pHYs(h->png, h->info, &resx, &resy, &unit);
i->width = h->w;
i->height = h->h;
if (PNG_RESOLUTION_METER == unit)
i->dpi = res_m_to_inch(resx);
if (debug)
fprintf(stderr,"png: color_type=%s #1\n",ct[h->color_type]);
i->npages = 1;
png_set_packing(h->png);
if (bit_depth == 16)
png_set_strip_16(h->png);
if (h->color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb(h->png);
if (h->color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
png_set_gray_1_2_4_to_8(h->png);
if (png_get_bKGD(h->png, h->info, &file_bg)) {
png_set_background(h->png,file_bg,PNG_BACKGROUND_GAMMA_FILE,1,1.0);
} else {
png_set_background(h->png,&my_bg,PNG_BACKGROUND_GAMMA_SCREEN,0,1.0);
}
number_passes = png_set_interlace_handling(h->png);
png_read_update_info(h->png, h->info);
h->color_type = png_get_color_type(h->png, h->info);
if (debug)
fprintf(stderr,"png: color_type=%s #2\n",ct[h->color_type]);
h->image = malloc(i->width * i->height * 4);
for (pass = 0; pass < number_passes-1; pass++) {
if (debug)
fprintf(stderr,"png: pass #%d\n",pass);
for (y = 0; y < i->height; y++) {
png_bytep row = h->image + y * i->width * 4;
png_read_rows(h->png, &row, NULL, 1);
}
}
return h;
oops:
if (h->image)
free(h->image);
if (h->png)
png_destroy_read_struct(&h->png, NULL, NULL);
fclose(h->infile);
free(h);
return NULL;
}
static void
png_read(unsigned char *dst, unsigned int line, void *data)
{
struct png_state *h = data;
png_bytep row = h->image + line * h->w * 4;
switch (h->color_type) {
case PNG_COLOR_TYPE_GRAY:
png_read_rows(h->png, &row, NULL, 1);
load_gray(dst,row,h->w);
break;
case PNG_COLOR_TYPE_RGB:
png_read_rows(h->png, &row, NULL, 1);
memcpy(dst,row,3*h->w);
break;
case PNG_COLOR_TYPE_RGB_ALPHA:
png_read_rows(h->png, &row, NULL, 1);
load_rgba(dst,row,h->w);
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
png_read_rows(h->png, &row, NULL, 1);
load_graya(dst,row,h->w);
break;
default:
/* shouldn't happen */
fprintf(stderr,"Oops: %s:%d\n",__FILE__,__LINE__);
exit(1);
}
}
static void
png_done(void *data)
{
struct png_state *h = data;
free(h->image);
png_destroy_read_struct(&h->png, &h->info, NULL);
fclose(h->infile);
free(h);
}
static struct ida_loader png_loader = {
magic: "\x89PNG",
moff: 0,
mlen: 4,
name: "libpng",
init: png_init,
read: png_read,
done: png_done,
};
static void __init init_rd(void)
{
load_register(&png_loader);
}
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