Initial revision

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);
+}