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Imported from libpng-0.82.tar

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This commit is contained in:
Guy Schalnat
1995-11-28 11:22:13 -06:00
committed by Glenn Randers-Pehrson
parent 51f0eb4584
commit 0f71645dfe
16 changed files with 1233 additions and 475 deletions
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77
pngrtran.c
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@@ -572,7 +572,7 @@ png_init_read_transformations(png_struct *png_ptr)
}
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED)
#if defined(PNG_READ_SHIFT_SUPPORTED) && defined(PNG_READ_sBIT_SUPPORTED)
if ((png_ptr->transformations & PNG_SHIFT) &&
png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
@@ -876,19 +876,33 @@ png_do_unshift(png_row_info *row_info, png_bytef *row,
channels = 0;
if (row_info->color_type & PNG_COLOR_MASK_COLOR)
{
shift[channels++] = row_info->bit_depth - sig_bits->red;
shift[channels++] = row_info->bit_depth - sig_bits->green;
shift[channels++] = row_info->bit_depth - sig_bits->blue;
shift[channels++] = row_info->bit_depth - sig_bits->red < 0 ?
0 : row_info->bit_depth - sig_bits->red;
shift[channels++] = row_info->bit_depth - sig_bits->green < 0 ?
0 : row_info->bit_depth - sig_bits->green;
shift[channels++] = row_info->bit_depth - sig_bits->blue < 0 ?
0 : row_info->bit_depth - sig_bits->blue;
}
else
{
shift[channels++] = row_info->bit_depth - sig_bits->gray;
shift[channels++] = row_info->bit_depth - sig_bits->gray < 0 ?
0 : row_info->bit_depth - sig_bits->gray;
}
if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
{
shift[channels++] = row_info->bit_depth - sig_bits->alpha;
shift[channels++] = row_info->bit_depth - sig_bits->alpha < 0 ?
0 : row_info->bit_depth - sig_bits->alpha;
}
value = 1;
for (i = 0; i < channels; i++)
{
if (shift[i] != 0) value = 0;
}
if (value == 1) return;
switch (row_info->bit_depth)
{
case 2:
@@ -905,6 +919,7 @@ png_do_unshift(png_row_info *row_info, png_bytef *row,
case 4:
{
png_byte mask;
mask = (png_byte)(((int)0xf0 >> shift[0]) & (int)0xf0) |
((int)0xf >> shift[0]);
for (bp = row, i = 0;
@@ -957,17 +972,15 @@ png_do_unshift(png_row_info *row_info, png_bytef *row,
void
png_do_chop(png_row_info *row_info, png_bytef *row)
{
png_bytef *sp, *dp;
png_uint_32 i;
if (row && row_info && row_info->bit_depth == 16)
{
sp = row + 2;
dp = row + 1;
for (i = 1; i < row_info->width * row_info->channels; i++)
png_bytef *sp = row, *dp = row;
png_uint_32 i;
for (i = 0; i < row_info->width * row_info->channels; i++)
{
*dp = *sp;
sp += 2;
dp++;
*dp++ = ((((*sp << 8 | *(sp + 1)) - *sp) + 0x7F) >> 8) & 0xFF;
sp += 2;
}
row_info->bit_depth = 8;
row_info->pixel_depth = 8 * row_info->channels;
@@ -1147,6 +1160,7 @@ png_build_grayscale_palette(int bit_depth, png_color *palette)
break;
default:
num_palette = 0;
color_inc = 0;
break;
}
@@ -2002,7 +2016,7 @@ png_do_background(png_row_info *row_info, png_bytef *row,
you do this after you deal with the trasparency issue on grayscale
or rgb images. If your bit depth is 8, use gamma_table, if it is 16,
use gamma_16_table and gamma_shift. Build these with
build_gamma_table(). If your bit depth < 8, gamma correct a
build_gamma_table(). If your bit depth <= 8, gamma correct a
palette, not the data. */
void
png_do_gamma(png_row_info *row_info, png_bytef *row,
@@ -2623,8 +2637,9 @@ png_build_gamma_table(png_struct *png_ptr)
{
double g;
int i, j, shift, num;
int sig_bit;
png_uint_32 ig;
#if defined(PNG_READ_sBIT_SUPPORTED)
int sig_bit;
if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
{
@@ -2642,6 +2657,7 @@ png_build_gamma_table(png_struct *png_ptr)
if (sig_bit > 0)
shift = 16 - sig_bit;
else
#endif /* PNG_READ_sBIT_SUPPORTED */
shift = 0;
if (png_ptr->transformations & PNG_16_TO_8)
@@ -2677,26 +2693,25 @@ png_build_gamma_table(png_struct *png_ptr)
}
g = 1.0 / g;
last = 0;
for (i = 0; i < 256; i++)
last = 0;
for (i = 0; i < 256; i++)
{
fout = ((double)i + 0.5) / 256.0;
fin = pow(fout, g);
max = (png_uint_32)(fin * (double)(num << 8));
while (last <= max)
fout = ((double)i + 0.5) / 256.0;
fin = pow(fout, g);
max = (png_uint_32)(fin * (double)(num << 8));
while (last <= max)
{
png_ptr->gamma_16_table[(int)(last >> 8)]
[(int)(last & 0xff)] =
png_ptr->gamma_16_table[(int)(last >> 8)][(int)(last & 0xff)] =
(png_uint_16)i | ((png_uint_16)i << 8);
last++;
}
}
while (last < (num << 8))
{
png_ptr->gamma_16_table[(int)(last >> 8)][(int)(last & 0xff)] =
(png_uint_16)65535L;
last++;
}
}
while (last < (num << 8))
{
png_ptr->gamma_16_table[(int)(last >> 8)][(int)(last & 0xff)] =
(png_uint_16)65535L;
last++;
}
}
else
{