diff options
Diffstat (limited to 'rd/read-png.c')
| -rw-r--r-- | rd/read-png.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/rd/read-png.c b/rd/read-png.c new file mode 100644 index 0000000..c4f82d2 --- /dev/null +++ b/rd/read-png.c @@ -0,0 +1,164 @@ +#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); +} |