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[libpng16] Bookkeeping: Moved functions around (no changes). Moved transform

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function definitions before the place where they are called so that
they can be masde static. Move the intrapixel functions and the
grayscale palette builder out of the png?tran.c files. The latter
isn't a transform function and is no longer used internally, and the
former MNG specific functions are better placed in pngread/pngwrite.c
This commit is contained in:
John Bowler 2013-12-19 15:24:06 -06:00 committed by Glenn Randers-Pehrson
parent bff81bdddc
commit c10930a4fc
9 changed files with 549 additions and 543 deletions
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6
ANNOUNCE
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@ -27,6 +27,12 @@ Other information:
Changes since the last public release (1.6.8):
Version 1.6.9beta01 [December 19, 2013]
Bookkeeping: Moved functions around (no changes). Moved transform
function definitions before the place where they are called so that
they can be masde static. Move the intrapixel functions and the
grayscale palette builder out of the png?tran.c files. The latter
isn't a transform function and is no longer used internally, and the
former MNG specific functions are better placed in pngread/pngwrite.c
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

6
CHANGES
View File

@ -4751,6 +4751,12 @@ Version 1.6.8 [December 19, 2013]
No changes.
Version 1.6.9beta01 [December 19, 2013]
Bookkeeping: Moved functions around (no changes). Moved transform
function definitions before the place where they are called so that
they can be masde static. Move the intrapixel functions and the
grayscale palette builder out of the png?tran.c files. The latter
isn't a transform function and is no longer used internally, and the
former MNG specific functions are better placed in pngread/pngwrite.c
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

57
png.c
View File

@ -826,6 +826,63 @@ png_get_header_version(png_const_structrp png_ptr)
#endif
}
#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
/* NOTE: this routine is not used internally! */
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
* of code. This API is not used internally.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
{
int num_palette;
int color_inc;
int i;
int v;
png_debug(1, "in png_do_build_grayscale_palette");
if (palette == NULL)
return;
switch (bit_depth)
{
case 1:
num_palette = 2;
color_inc = 0xff;
break;
case 2:
num_palette = 4;
color_inc = 0x55;
break;
case 4:
num_palette = 16;
color_inc = 0x11;
break;
case 8:
num_palette = 256;
color_inc = 1;
break;
default:
num_palette = 0;
color_inc = 0;
break;
}
for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
{
palette[i].red = (png_byte)v;
palette[i].green = (png_byte)v;
palette[i].blue = (png_byte)v;
}
}
#endif
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
int PNGAPI
png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)

7
pngpriv.h
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@ -1556,13 +1556,6 @@ PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
PNG_INTERNAL_FUNCTION(void,png_do_read_intrapixel,(png_row_infop row_info,
png_bytep row),PNG_EMPTY);
PNG_INTERNAL_FUNCTION(void,png_do_write_intrapixel,(png_row_infop row_info,
png_bytep row),PNG_EMPTY);
#endif
/* Added at libpng version 1.6.0 */
#ifdef PNG_GAMMA_SUPPORTED
PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,

67
pngread.c
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@ -305,6 +305,72 @@ png_start_read_image(png_structrp png_ptr)
#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing,
* NOTE: this is apparently only supported in the 'sequential' reader.
*/
static void
png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_read_intrapixel");
if (
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
if (row_info->bit_depth == 8)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
*(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
}
}
else if (row_info->bit_depth == 16)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
*(rp + 5) = (png_byte)(blue & 0xff);
}
}
}
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */
void PNGAPI
png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
{
@ -489,7 +555,6 @@ png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
}
#endif
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
if (png_ptr->transformations)
png_do_read_transformations(png_ptr, &row_info);

692
pngrtran.c
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@ -2123,303 +2123,6 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
#endif
}
/* Transform the row. The order of transformations is significant,
* and is very touchy. If you add a transformation, take care to
* decide how it fits in with the other transformations here.
*/
void /* PRIVATE */
png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_read_transformations");
if (png_ptr->row_buf == NULL)
{
/* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
* error is incredibly rare and incredibly easy to debug without this
* information.
*/
png_error(png_ptr, "NULL row buffer");
}
/* The following is debugging; prior to 1.5.4 the code was never compiled in;
* in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
* PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
* all transformations, however in practice the ROW_INIT always gets done on
* demand, if necessary.
*/
if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
!(png_ptr->flags & PNG_FLAG_ROW_INIT))
{
/* Application has failed to call either png_read_start_image() or
* png_read_update_info() after setting transforms that expand pixels.
* This check added to libpng-1.2.19 (but not enabled until 1.5.4).
*/
png_error(png_ptr, "Uninitialized row");
}
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
{
png_do_expand_palette(row_info, png_ptr->row_buf + 1,
png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
}
else
{
if (png_ptr->num_trans &&
(png_ptr->transformations & PNG_EXPAND_tRNS))
png_do_expand(row_info, png_ptr->row_buf + 1,
&(png_ptr->trans_color));
else
png_do_expand(row_info, png_ptr->row_buf + 1,
NULL);
}
}
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
!(png_ptr->transformations & PNG_COMPOSE) &&
(row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
{
int rgb_error =
png_do_rgb_to_gray(png_ptr, row_info,
png_ptr->row_buf + 1);
if (rgb_error)
{
png_ptr->rgb_to_gray_status=1;
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_WARN)
png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_ERR)
png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
}
}
#endif
/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
*
* In most cases, the "simple transparency" should be done prior to doing
* gray-to-RGB, or you will have to test 3x as many bytes to check if a
* pixel is transparent. You would also need to make sure that the
* transparency information is upgraded to RGB.
*
* To summarize, the current flow is:
* - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
* with background "in place" if transparent,
* convert to RGB if necessary
* - Gray + alpha -> composite with gray background and remove alpha bytes,
* convert to RGB if necessary
*
* To support RGB backgrounds for gray images we need:
* - Gray + simple transparency -> convert to RGB + simple transparency,
* compare 3 or 6 bytes and composite with
* background "in place" if transparent
* (3x compare/pixel compared to doing
* composite with gray bkgrnd)
* - Gray + alpha -> convert to RGB + alpha, composite with background and
* remove alpha bytes (3x float
* operations/pixel compared with composite
* on gray background)
*
* Greg's change will do this. The reason it wasn't done before is for
* performance, as this increases the per-pixel operations. If we would check
* in advance if the background was gray or RGB, and position the gray-to-RGB
* transform appropriately, then it would save a lot of work/time.
*/
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* If gray -> RGB, do so now only if background is non-gray; else do later
* for performance reasons
*/
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
if (png_ptr->transformations & PNG_COMPOSE)
png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Because RGB_TO_GRAY does the gamma transform. */
!(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
/* Because PNG_COMPOSE does the gamma transform if there is something to
* do (if there is an alpha channel or transparency.)
*/
!((png_ptr->transformations & PNG_COMPOSE) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
/* Because png_init_read_transformations transforms the palette, unless
* RGB_TO_GRAY will do the transform.
*/
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
(png_ptr->transformations & PNG_COMPOSE) &&
(row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
(row_info->color_type & PNG_COLOR_MASK_ALPHA))
png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
if (png_ptr->transformations & PNG_SCALE_16_TO_8)
png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
/* There is no harm in doing both of these because only one has any effect,
* by putting the 'scale' option first if the app asks for scale (either by
* calling the API or in a TRANSFORM flag) this is what happens.
*/
if (png_ptr->transformations & PNG_16_TO_8)
png_do_chop(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
if (png_ptr->transformations & PNG_QUANTIZE)
{
png_do_quantize(row_info, png_ptr->row_buf + 1,
png_ptr->palette_lookup, png_ptr->quantize_index);
if (row_info->rowbytes == 0)
png_error(png_ptr, "png_do_quantize returned rowbytes=0");
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
#ifdef PNG_READ_EXPAND_16_SUPPORTED
/* Do the expansion now, after all the arithmetic has been done. Notice
* that previous transformations can handle the PNG_EXPAND_16 flag if this
* is efficient (particularly true in the case of gamma correction, where
* better accuracy results faster!)
*/
if (png_ptr->transformations & PNG_EXPAND_16)
png_do_expand_16(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* NOTE: moved here in 1.5.4 (from much later in this list.) */
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
png_do_unshift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_READ_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
png_do_unpack(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
/* Added at libpng-1.5.10 */
if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
png_ptr->num_palette_max >= 0)
png_do_check_palette_indexes(png_ptr, row_info);
#endif
#ifdef PNG_READ_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
png_do_read_filler(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->filler, png_ptr->flags);
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_16BIT_SUPPORTED
#ifdef PNG_READ_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#endif
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
if (png_ptr->read_user_transform_fn != NULL)
(*(png_ptr->read_user_transform_fn)) /* User read transform function */
(png_ptr, /* png_ptr */
row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
/* png_byte bit_depth; bit depth of samples */
/* png_byte channels; number of channels (1-4) */
/* png_byte pixel_depth; bits per pixel (depth*channels) */
png_ptr->row_buf + 1); /* start of pixel data for row */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
if (png_ptr->user_transform_depth)
row_info->bit_depth = png_ptr->user_transform_depth;
if (png_ptr->user_transform_channels)
row_info->channels = png_ptr->user_transform_channels;
#endif
row_info->pixel_depth = (png_byte)(row_info->bit_depth *
row_info->channels);
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
}
#endif
}
#ifdef PNG_READ_PACK_SUPPORTED
/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
* without changing the actual values. Thus, if you had a row with
@ -3469,66 +3172,7 @@ png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
return rgb_error;
}
#endif
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
* of code. This API is not used internally.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
{
int num_palette;
int color_inc;
int i;
int v;
png_debug(1, "in png_do_build_grayscale_palette");
if (palette == NULL)
return;
switch (bit_depth)
{
case 1:
num_palette = 2;
color_inc = 0xff;
break;
case 2:
num_palette = 4;
color_inc = 0x55;
break;
case 4:
num_palette = 16;
color_inc = 0x11;
break;
case 8:
num_palette = 256;
color_inc = 1;
break;
default:
num_palette = 0;
color_inc = 0;
break;
}
for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
{
palette[i].red = (png_byte)v;
palette[i].green = (png_byte)v;
palette[i].blue = (png_byte)v;
}
}
#endif
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
/* Replace any alpha or transparency with the supplied background color.
@ -5045,69 +4689,303 @@ png_do_quantize(png_row_infop row_info, png_bytep row,
}
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing */
/* Transform the row. The order of transformations is significant,
* and is very touchy. If you add a transformation, take care to
* decide how it fits in with the other transformations here.
*/
void /* PRIVATE */
png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_read_intrapixel");
png_debug(1, "in png_do_read_transformations");
if (
(row_info->color_type & PNG_COLOR_MASK_COLOR))
if (png_ptr->row_buf == NULL)
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
/* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
* error is incredibly rare and incredibly easy to debug without this
* information.
*/
png_error(png_ptr, "NULL row buffer");
}
if (row_info->bit_depth == 8)
/* The following is debugging; prior to 1.5.4 the code was never compiled in;
* in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
* PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
* all transformations, however in practice the ROW_INIT always gets done on
* demand, if necessary.
*/
if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
!(png_ptr->flags & PNG_FLAG_ROW_INIT))
{
/* Application has failed to call either png_read_start_image() or
* png_read_update_info() after setting transforms that expand pixels.
* This check added to libpng-1.2.19 (but not enabled until 1.5.4).
*/
png_error(png_ptr, "Uninitialized row");
}
#ifdef PNG_READ_EXPAND_SUPPORTED
if (png_ptr->transformations & PNG_EXPAND)
{
if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
*(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
}
png_do_expand_palette(row_info, png_ptr->row_buf + 1,
png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
}
else if (row_info->bit_depth == 16)
else
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
if (png_ptr->num_trans &&
(png_ptr->transformations & PNG_EXPAND_tRNS))
png_do_expand(row_info, png_ptr->row_buf + 1,
&(png_ptr->trans_color));
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
*(rp + 5) = (png_byte)(blue & 0xff);
}
png_do_expand(row_info, png_ptr->row_buf + 1,
NULL);
}
}
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
!(png_ptr->transformations & PNG_COMPOSE) &&
(row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
if (png_ptr->transformations & PNG_RGB_TO_GRAY)
{
int rgb_error =
png_do_rgb_to_gray(png_ptr, row_info,
png_ptr->row_buf + 1);
if (rgb_error)
{
png_ptr->rgb_to_gray_status=1;
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_WARN)
png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
PNG_RGB_TO_GRAY_ERR)
png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
}
}
#endif
/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
*
* In most cases, the "simple transparency" should be done prior to doing
* gray-to-RGB, or you will have to test 3x as many bytes to check if a
* pixel is transparent. You would also need to make sure that the
* transparency information is upgraded to RGB.
*
* To summarize, the current flow is:
* - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
* with background "in place" if transparent,
* convert to RGB if necessary
* - Gray + alpha -> composite with gray background and remove alpha bytes,
* convert to RGB if necessary
*
* To support RGB backgrounds for gray images we need:
* - Gray + simple transparency -> convert to RGB + simple transparency,
* compare 3 or 6 bytes and composite with
* background "in place" if transparent
* (3x compare/pixel compared to doing
* composite with gray bkgrnd)
* - Gray + alpha -> convert to RGB + alpha, composite with background and
* remove alpha bytes (3x float
* operations/pixel compared with composite
* on gray background)
*
* Greg's change will do this. The reason it wasn't done before is for
* performance, as this increases the per-pixel operations. If we would check
* in advance if the background was gray or RGB, and position the gray-to-RGB
* transform appropriately, then it would save a lot of work/time.
*/
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* If gray -> RGB, do so now only if background is non-gray; else do later
* for performance reasons
*/
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
if (png_ptr->transformations & PNG_COMPOSE)
png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Because RGB_TO_GRAY does the gamma transform. */
!(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
#endif
#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
defined(PNG_READ_ALPHA_MODE_SUPPORTED)
/* Because PNG_COMPOSE does the gamma transform if there is something to
* do (if there is an alpha channel or transparency.)
*/
!((png_ptr->transformations & PNG_COMPOSE) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
/* Because png_init_read_transformations transforms the palette, unless
* RGB_TO_GRAY will do the transform.
*/
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
if ((png_ptr->transformations & PNG_STRIP_ALPHA) &&
(png_ptr->transformations & PNG_COMPOSE) &&
(row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
0 /* at_start == false, because SWAP_ALPHA happens later */);
#endif
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
if ((png_ptr->transformations & PNG_ENCODE_ALPHA) &&
(row_info->color_type & PNG_COLOR_MASK_ALPHA))
png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
if (png_ptr->transformations & PNG_SCALE_16_TO_8)
png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
/* There is no harm in doing both of these because only one has any effect,
* by putting the 'scale' option first if the app asks for scale (either by
* calling the API or in a TRANSFORM flag) this is what happens.
*/
if (png_ptr->transformations & PNG_16_TO_8)
png_do_chop(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_QUANTIZE_SUPPORTED
if (png_ptr->transformations & PNG_QUANTIZE)
{
png_do_quantize(row_info, png_ptr->row_buf + 1,
png_ptr->palette_lookup, png_ptr->quantize_index);
if (row_info->rowbytes == 0)
png_error(png_ptr, "png_do_quantize returned rowbytes=0");
}
#endif /* PNG_READ_QUANTIZE_SUPPORTED */
#ifdef PNG_READ_EXPAND_16_SUPPORTED
/* Do the expansion now, after all the arithmetic has been done. Notice
* that previous transformations can handle the PNG_EXPAND_16 flag if this
* is efficient (particularly true in the case of gamma correction, where
* better accuracy results faster!)
*/
if (png_ptr->transformations & PNG_EXPAND_16)
png_do_expand_16(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
/* NOTE: moved here in 1.5.4 (from much later in this list.) */
if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
png_do_unshift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_READ_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
png_do_unpack(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
/* Added at libpng-1.5.10 */
if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
png_ptr->num_palette_max >= 0)
png_do_check_palette_indexes(png_ptr, row_info);
#endif
#ifdef PNG_READ_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
png_do_read_filler(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->filler, png_ptr->flags);
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_READ_16BIT_SUPPORTED
#ifdef PNG_READ_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#endif
#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
if (png_ptr->transformations & PNG_USER_TRANSFORM)
{
if (png_ptr->read_user_transform_fn != NULL)
(*(png_ptr->read_user_transform_fn)) /* User read transform function */
(png_ptr, /* png_ptr */
row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
/* png_byte bit_depth; bit depth of samples */
/* png_byte channels; number of channels (1-4) */
/* png_byte pixel_depth; bits per pixel (depth*channels) */
png_ptr->row_buf + 1); /* start of pixel data for row */
#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
if (png_ptr->user_transform_depth)
row_info->bit_depth = png_ptr->user_transform_depth;
if (png_ptr->user_transform_channels)
row_info->channels = png_ptr->user_transform_channels;
#endif
row_info->pixel_depth = (png_byte)(row_info->bit_depth *
row_info->channels);
row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
}
#endif
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
#endif /* PNG_READ_SUPPORTED */

65
pngwrite.c
View File

@ -607,6 +607,71 @@ png_write_image(png_structrp png_ptr, png_bytepp image)
}
}
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Performs intrapixel differencing */
static void
png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_write_intrapixel");
if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
if (row_info->bit_depth == 8)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((*rp - *(rp + 1)) & 0xff);
*(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
}
}
#ifdef PNG_WRITE_16BIT_SUPPORTED
else if (row_info->bit_depth == 16)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
*(rp + 5) = (png_byte)(blue & 0xff);
}
}
#endif /* PNG_WRITE_16BIT_SUPPORTED */
}
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */
/* Called by user to write a row of image data */
void PNGAPI
png_write_row(png_structrp png_ptr, png_const_bytep row)

191
pngwtran.c
View File

@ -14,83 +14,7 @@
#include "pngpriv.h"
#ifdef PNG_WRITE_SUPPORTED
#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
/* Transform the data according to the user's wishes. The order of
* transformations is significant.
*/
void /* PRIVATE */
png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_write_transformations");
if (png_ptr == NULL)
return;
#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
if (png_ptr->transformations & PNG_USER_TRANSFORM)
if (png_ptr->write_user_transform_fn != NULL)
(*(png_ptr->write_user_transform_fn)) /* User write transform
function */
(png_ptr, /* png_ptr */
row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
/* png_byte bit_depth; bit depth of samples */
/* png_byte channels; number of channels (1-4) */
/* png_byte pixel_depth; bits per pixel (depth*channels) */
png_ptr->row_buf + 1); /* start of pixel data for row */
#endif
#ifdef PNG_WRITE_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
!(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
#endif
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
png_do_pack(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->bit_depth);
#endif
#ifdef PNG_WRITE_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
png_do_shift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
}
#ifdef PNG_WRITE_PACK_SUPPORTED
/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
@ -568,70 +492,81 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
}
}
#endif
#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
#ifdef PNG_MNG_FEATURES_SUPPORTED
/* Undoes intrapixel differencing */
/* Transform the data according to the user's wishes. The order of
* transformations is significant.
*/
void /* PRIVATE */
png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
{
png_debug(1, "in png_do_write_intrapixel");
png_debug(1, "in png_do_write_transformations");
if ((row_info->color_type & PNG_COLOR_MASK_COLOR))
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
if (row_info->bit_depth == 8)
{
png_bytep rp;
png_uint_32 i;
if (png_ptr == NULL)
return;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
if (png_ptr->transformations & PNG_USER_TRANSFORM)
if (png_ptr->write_user_transform_fn != NULL)
(*(png_ptr->write_user_transform_fn)) /* User write transform
function */
(png_ptr, /* png_ptr */
row_info, /* row_info: */
/* png_uint_32 width; width of row */
/* png_size_t rowbytes; number of bytes in row */
/* png_byte color_type; color type of pixels */
/* png_byte bit_depth; bit depth of samples */
/* png_byte channels; number of channels (1-4) */
/* png_byte pixel_depth; bits per pixel (depth*channels) */
png_ptr->row_buf + 1); /* start of pixel data for row */
#endif
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
#ifdef PNG_WRITE_FILLER_SUPPORTED
if (png_ptr->transformations & PNG_FILLER)
png_do_strip_channel(row_info, png_ptr->row_buf + 1,
!(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
#endif
else
return;
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
if (png_ptr->transformations & PNG_PACKSWAP)
png_do_packswap(row_info, png_ptr->row_buf + 1);
#endif
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((*rp - *(rp + 1)) & 0xff);
*(rp + 2) = (png_byte)((*(rp + 2) - *(rp + 1)) & 0xff);
}
}
#ifdef PNG_WRITE_PACK_SUPPORTED
if (png_ptr->transformations & PNG_PACK)
png_do_pack(row_info, png_ptr->row_buf + 1,
(png_uint_32)png_ptr->bit_depth);
#endif
#ifdef PNG_WRITE_16BIT_SUPPORTED
else if (row_info->bit_depth == 16)
{
png_bytep rp;
png_uint_32 i;
#ifdef PNG_WRITE_SWAP_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_BYTES)
png_do_swap(row_info, png_ptr->row_buf + 1);
#endif
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
#ifdef PNG_WRITE_SHIFT_SUPPORTED
if (png_ptr->transformations & PNG_SHIFT)
png_do_shift(row_info, png_ptr->row_buf + 1,
&(png_ptr->shift));
#endif
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
#endif
else
return;
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
#endif
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
*(rp ) = (png_byte)((red >> 8) & 0xff);
*(rp + 1) = (png_byte)(red & 0xff);
*(rp + 4) = (png_byte)((blue >> 8) & 0xff);
*(rp + 5) = (png_byte)(blue & 0xff);
}
}
#endif /* PNG_WRITE_16BIT_SUPPORTED */
}
#ifdef PNG_WRITE_BGR_SUPPORTED
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(row_info, png_ptr->row_buf + 1);
#endif
#ifdef PNG_WRITE_INVERT_SUPPORTED
if (png_ptr->transformations & PNG_INVERT_MONO)
png_do_invert(row_info, png_ptr->row_buf + 1);
#endif
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */
#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
#endif /* PNG_WRITE_SUPPORTED */

1
scripts/pnglibconf.dfa
View File

@ -480,6 +480,7 @@ option INCH_CONVERSIONS
= INCH_CONVERSIONS INCH_CONVERSIONS
# API to build a grayscale palette
# NOTE: this is not used internally by libpng at present.
option BUILD_GRAYSCALE_PALETTE