/* pngwutil.c - utilities to write a PNG file
*
- * libpng 1.0.1
+ * libpng 1.0.3 - January 14, 1999
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1996, 1997 Andreas Dilger
- * Copyright (c) 1998, Glenn Randers-Pehrson
- * March 15, 1998
+ * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
*/
#define PNG_INTERNAL
-#include "../png/png.h"
+#include "png.h"
/* Place a 32-bit number into a buffer in PNG byte order. We work
* with unsigned numbers for convenience, although one supported
}
/* write the palette. We are careful not to trust png_color to be in the
- * correct order for PNG, so people can redefine it to any convient
+ * correct order for PNG, so people can redefine it to any convenient
* structure.
*/
void
{
png_byte maxbits;
- maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8:png_ptr->usr_bit_depth;
- if (sbit->red == 0 || sbit->red > maxbits ||
- sbit->green == 0 || sbit->green > maxbits ||
+ maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8 : png_ptr->usr_bit_depth;
+ if (sbit->red == 0 || sbit->red > maxbits ||
+ sbit->green == 0 || sbit->green > maxbits ||
sbit->blue == 0 || sbit->blue > maxbits)
{
png_warning(png_ptr, "Invalid sBIT depth specified");
}
#endif
-#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
+#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED) || \
+ defined(PNG_WRITE_pCAL_SUPPORTED)
/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
* and if invalid, correct the keyword rather than discarding the entire
* chunk. The PNG 1.0 specification requires keywords 1-79 characters in
}
/* We can't write the chunk until we find out how much data we have,
- * which means we need to run the compressor first, and save the
+ * which means we need to run the compressor first and save the
* output. This shouldn't be a problem, as the vast majority of
* comments should be reasonable, but we will set up an array of
* malloc'd pointers to be sure.
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
png_ptr->zstream.next_out = png_ptr->zbuf;
}
- /* continue until we don't have anymore to compress */
+ /* continue until we don't have any more to compress */
} while (png_ptr->zstream.avail_in);
/* finish the compression */
png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
{
- png_size_t purpose_len, units_len, total_len;
+ png_size_t purpose_len, units_len, total_len;
png_uint_32p params_len;
png_byte buf[10];
png_charp new_purpose;
if (png_ptr->pass < 7)
{
if (png_ptr->prev_row != NULL)
- png_memset(png_ptr->prev_row, 0,
+ png_memset(png_ptr->prev_row, 0,
(png_size_t) (((png_uint_32)png_ptr->usr_channels *
(png_uint_32)png_ptr->usr_bit_depth *
png_ptr->width + 7) >> 3) + 1);
if (pass < 6)
#endif
{
- /* each pixel depth is handled seperately */
+ /* each pixel depth is handled separately */
switch (row_info->pixel_depth)
{
case 1:
int d;
int value;
png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
d = 0;
shift = 7;
- for (i = png_pass_start[pass]; i < row_info->width;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 3);
int d;
int value;
png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
shift = 6;
d = 0;
- for (i = png_pass_start[pass]; i < row_info->width;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 2);
int d;
int value;
png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
dp = row;
shift = 4;
d = 0;
- for (i = png_pass_start[pass]; i < row_info->width;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
sp = row + (png_size_t)(i >> 1);
png_bytep sp;
png_bytep dp;
png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
png_size_t pixel_bytes;
/* start at the beginning */
pixel_bytes = (row_info->pixel_depth >> 3);
/* loop through the row, only looking at the pixels that
matter */
- for (i = png_pass_start[pass]; i < row_info->width;
+ for (i = png_pass_start[pass]; i < row_width;
i += png_pass_inc[pass])
{
/* find out where the original pixel is */
{
png_bytep prev_row, best_row, row_buf;
png_uint_32 mins, bpp;
+ png_byte filter_to_do = png_ptr->do_filter;
+ png_uint_32 row_bytes = row_info->rowbytes;
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+ int num_p_filters = (int)png_ptr->num_prev_filters;
+#endif
png_debug(1, "in png_write_find_filter\n");
/* find out how many bytes offset each pixel is */
/* The prediction method we use is to find which method provides the
* smallest value when summing the absolute values of the distances
- * from zero using anything >= 128 as negative numbers. This is known
+ * from zero, using anything >= 128 as negative numbers. This is known
* as the "minimum sum of absolute differences" heuristic. Other
- * heuristics are the "weighted minumum sum of absolute differences"
+ * heuristics are the "weighted minimum sum of absolute differences"
* (experimental and can in theory improve compression), and the "zlib
- * predictive" method (not implemented in libpng 0.95), which does test
- * compressions of lines using different filter methods, and then chooses
- * the (series of) filter(s) which give minimum compressed data size (VERY
+ * predictive" method (not implemented yet), which does test compressions
+ * of lines using different filter methods, and then chooses the
+ * (series of) filter(s) that give minimum compressed data size (VERY
* computationally expensive).
+ *
+ * GRR 980525: consider also
+ * (1) minimum sum of absolute differences from running average (i.e.,
+ * keep running sum of non-absolute differences & count of bytes)
+ * [track dispersion, too? restart average if dispersion too large?]
+ * (1b) minimum sum of absolute differences from sliding average, probably
+ * with window size <= deflate window (usually 32K)
+ * (2) minimum sum of squared differences from zero or running average
+ * (i.e., ~ root-mean-square approach)
*/
+
/* We don't need to test the 'no filter' case if this is the only filter
* that has been chosen, as it doesn't actually do anything to the data.
*/
- if (png_ptr->do_filter & PNG_FILTER_NONE &&
- png_ptr->do_filter != PNG_FILTER_NONE)
+ if (filter_to_do & PNG_FILTER_NONE &&
+ filter_to_do != PNG_FILTER_NONE)
{
png_bytep rp;
png_uint_32 sum = 0;
png_uint_32 i;
int v;
- for (i = 0, rp = row_buf + 1; i < row_info->rowbytes; i++, rp++)
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
{
v = *rp;
sum += (v < 128) ? v : 256 - v;
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
png_uint_32 sumhi, sumlo;
+ int j;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
/* Reduce the sum if we match any of the previous rows */
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_NONE)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
}
/* sub filter */
- if (png_ptr->do_filter & PNG_FILTER_SUB)
+ if (filter_to_do == PNG_FILTER_SUB)
+ /* it's the only filter so no testing is needed */
+ {
+ png_bytep rp, lp, dp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ *dp = *rp;
+ }
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+ }
+ best_row = png_ptr->sub_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_SUB)
{
png_bytep rp, dp, lp;
png_uint_32 sum = 0, lmins = mins;
int v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
- /* We temporarily increase the "minumum sum" by the factor we
+ /* We temporarily increase the "minimum sum" by the factor we
* would reduce the sum of this filter, so that we can do the
* early exit comparison without scaling the sum each time.
*/
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_SUB)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_SUB)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
{
- sumlo = (sumlo * png_ptr->inv_filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->inv_filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
}
/* up filter */
- if (png_ptr->do_filter & PNG_FILTER_UP)
+ if (filter_to_do == PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ }
+ best_row = png_ptr->up_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_UP)
{
png_bytep rp, dp, pp;
png_uint_32 sum = 0, lmins = mins;
png_uint_32 i;
int v;
+
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_UP)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
- pp = prev_row + 1; i < row_info->rowbytes;
- i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < row_bytes; i++)
{
- v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
sum += (v < 128) ? v : 256 - v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_UP)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
}
/* avg filter */
- if (png_ptr->do_filter & PNG_FILTER_AVG)
+ if (filter_to_do == PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+ }
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+ & 0xff);
+ }
+ best_row = png_ptr->avg_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_AVG)
{
png_bytep rp, dp, pp, lp;
png_uint_32 sum = 0, lmins = mins;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < (png_uint_32)png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_AVG)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
- pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- v = *dp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
sum += (v < 128) ? v : 256 - v;
}
- for (lp = row_buf + 1; i < row_info->rowbytes;
- i++, rp++, pp++, lp++, dp++)
+ for (lp = row_buf + 1; i < row_bytes; i++)
{
- v = *dp = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
+ v = *dp++ =
+ (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
sum += (v < 128) ? v : 256 - v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_NONE)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
}
/* Paeth filter */
- if (png_ptr->do_filter & PNG_FILTER_PAETH)
+ if (filter_to_do == PNG_FILTER_PAETH)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_uint_32 i;
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+ p = b - c;
+ pc = a - c;
+
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+ *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+ }
+ best_row = png_ptr->paeth_row;
+ }
+
+ else if (filter_to_do & PNG_FILTER_PAETH)
{
png_bytep rp, dp, pp, cp, lp;
png_uint_32 sum = 0, lmins = mins;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 lmhi, lmlo;
lmlo = lmins & PNG_LOMASK;
lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_VALUE_PAETH)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
- lmlo = (lmlo * png_ptr->inv_filter_weights[i]) >>
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- lmhi = (lmhi * png_ptr->inv_filter_weights[i]) >>
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
#endif
for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
- pp = prev_row + 1; (unsigned)i < bpp; i++, rp++, pp++, dp++)
+ pp = prev_row + 1; i < bpp; i++)
{
- v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
sum += (v < 128) ? v : 256 - v;
}
- for (lp = row_buf + 1, cp = prev_row + 1; i < row_info->rowbytes;
- i++, rp++, pp++, lp++, dp++, cp++)
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
{
int a, b, c, pa, pb, pc, p;
- b = *pp;
- c = *cp;
- a = *lp;
-
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+#ifndef PNG_SLOW_PAETH
+ p = b - c;
+ pc = a - c;
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+#else /* PNG_SLOW_PAETH */
p = a + b - c;
pa = abs(p - a);
pb = abs(p - b);
pc = abs(p - c);
-
if (pa <= pb && pa <= pc)
p = a;
else if (pb <= pc)
p = b;
else
p = c;
+#endif /* PNG_SLOW_PAETH */
- v = *dp = (png_byte)(((int)*rp - p) & 0xff);
+ v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
sum += (v < 128) ? v : 256 - v;
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
{
+ int j;
png_uint_32 sumhi, sumlo;
sumlo = sum & PNG_LOMASK;
sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
- for (i = 0; i < png_ptr->num_prev_filters; i++)
+ for (j = 0; j < num_p_filters; j++)
{
- if (png_ptr->prev_filters[i] == PNG_FILTER_PAETH)
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
{
- sumlo = (sumlo * png_ptr->filter_weights[i]) >>
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
- sumhi = (sumhi * png_ptr->filter_weights[i]) >>
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
PNG_WEIGHT_SHIFT;
}
}
}
/* Do the actual writing of the filtered row data from the chosen filter. */
+
png_write_filtered_row(png_ptr, best_row);
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
/* Save the type of filter we picked this time for future calculations */
if (png_ptr->num_prev_filters > 0)
{
- int i;
-
- for (i = 1; i < (int)png_ptr->num_prev_filters; i++)
+ int j;
+ for (j = 1; j < num_p_filters; j++)
{
- png_ptr->prev_filters[i] = png_ptr->prev_filters[i - 1];
+ png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
}
- png_ptr->prev_filters[i] = best_row[0];
+ png_ptr->prev_filters[j] = best_row[0];
}
#endif
}
projects / wxWidgets.git / blobdiff