1 /*****************************************************************************
2 * RRDtool 1.2.30 Copyright by Tobi Oetiker, 1997-2009
3 *****************************************************************************
4 * pngsize.c determine the size of a PNG image
5 *****************************************************************************/
6
7 #include <png.h>
8 #include "rrd_tool.h"
9
10 int
PngSize(FILE * fd,long * width,long * height)11 PngSize(FILE *fd, long *width, long *height)
12 {
13 png_structp png_read_ptr =
14 png_create_read_struct(PNG_LIBPNG_VER_STRING,
15 (png_voidp)NULL,
16 /* we would need to point to error handlers
17 here to do it properly */
18 (png_error_ptr)NULL, (png_error_ptr)NULL);
19
20 png_infop info_ptr = png_create_info_struct(png_read_ptr);
21
22 (*width)=0;
23 (*height)=0;
24
25 /* this is to make compile on aix work since they seem to define jmpbuf
26 to be _jmpbuf which breaks compilation */
27
28
29 #ifndef png_jmpbuf
30 #ifdef PNG_SETJMP_SUPPORTED
31 # define png_jmpbuf(png_ptr) ((png_ptr)->PNG_jmpbuf)
32 #else
33 #ifdef jmpbuf
34 #undef jmpbuf
35 #endif
36 # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
37 #endif
38 #endif
39
40 if (setjmp(png_jmpbuf(png_read_ptr))){
41 png_destroy_read_struct(&png_read_ptr, &info_ptr, (png_infopp)NULL);
42 return 0;
43 }
44
45 png_init_io(png_read_ptr,fd);
46 png_read_info(png_read_ptr, info_ptr);
47 (*width)=png_get_image_width(png_read_ptr, info_ptr);
48 (*height)=png_get_image_height(png_read_ptr, info_ptr);
49
50 png_destroy_read_struct(&png_read_ptr, &info_ptr, NULL);
51 if (*width >0 && *height >0)
52 return 1;
53 else
54 return 0;
55 }
56
57
58
59