mewin/libpng
1
0
Fork 0
mirror of https://git.code.sf.net/p/libpng/code.git synced 2025-07-10 18:04:09 +02:00
Code Issues Projects Releases Wiki Activity

pngminus: Fix and improve the PNM processing

Browse Source 
Improve png2pnm.c:

 * Add support for writing 16-bit raw PNM image files.

Fix and improve pnm2png.c:

 * Add support for reading 16-bit raw PNM image files.

 * Fix the parsing of arbitrarily long numeric strings.
   In the parsing of PNM tokens, we can and we should avoid storing
   more than one leading '0' in the token buffer. All valid (in-range)
   numeric strings must fit in this limited-size buffer, regardless of
   their actual length in the input file.

 * Refactor the PNM parsing in order to make it more capable to handle
   various kinds of input file errors.

 * Remove the volatile qualifiers from all variable declarations.
   Their original purpose was to appease old (and incorrect) warnings
   issued by ancient optimizing compilers.

 * Print a note about the program's lack of support for the PAM ("P7")
   file format when the input is in this format.

 * Add FIXME notes about the need to signal incorrect or incomplete
   input files. (For png2pnm, this is done inside libpng.)
This commit is contained in:
Cosmin Truta
2024-01-08 14:14:33 +02:00
parent c993ae4c67
commit abb8d4a71f
2 changed files with 211 additions and 160 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
contrib/pngminus/png2pnm.c
View File

@@ -14,10 +14,10 @@
#define BOOL unsigned char
#endif
#ifndef TRUE
#define TRUE (BOOL) 1
#define TRUE ((BOOL) 1)
#endif
#ifndef FALSE
#define FALSE (BOOL) 0
#define FALSE ((BOOL) 0)
#endif
/* make png2pnm verbose so we can find problems (needs to be before png.h) */
@@ -256,15 +256,6 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
NULL, NULL, NULL);
/* check for 16-bit files */
if (bit_depth == 16)
{
raw = FALSE;
#if defined(O_BINARY) && (O_BINARY != 0)
setmode (fileno (pnm_file), O_BINARY);
#endif
}
/* calculate new number of channels and store alpha-presence */
if (color_type == PNG_COLOR_TYPE_GRAY)
channels = 1;
@@ -364,13 +355,16 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
if (raw)
{
fputc ((int) *pix_ptr++, pnm_file);
if (bit_depth == 16)
fputc ((int) *pix_ptr++, pnm_file);
}
else
{
if (bit_depth == 16)
{
dep_16 = (long) *pix_ptr++;
fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
dep_16 = ((long) *pix_ptr++) << 8;
dep_16 += ((long) *pix_ptr++);
fprintf (pnm_file, "%ld ", dep_16);
}
else
{
@@ -382,22 +376,27 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
{
if (!alpha)
{
pix_ptr++; /* alpha */
/* skip the alpha-channel */
pix_ptr++;
if (bit_depth == 16)
pix_ptr++;
}
else /* output alpha-channel as pgm file */
else
{
/* output the alpha-channel as pgm file */
if (raw)
{
fputc ((int) *pix_ptr++, alpha_file);
if (bit_depth == 16)
fputc ((int) *pix_ptr++, alpha_file);
}
else
{
if (bit_depth == 16)
{
dep_16 = (long) *pix_ptr++;
fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
dep_16 = ((long) *pix_ptr++) << 8;
dep_16 += ((long) *pix_ptr++);
fprintf (alpha_file, "%ld ", dep_16);
}
else
{
@@ -423,5 +422,4 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file,
free (png_pixels);
return TRUE;
} /* end of source */