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-rw-r--r--libpng/pngtrans.c243
1 files changed, 146 insertions, 97 deletions
diff --git a/libpng/pngtrans.c b/libpng/pngtrans.c
index cf7622c..137f555 100644
--- a/libpng/pngtrans.c
+++ b/libpng/pngtrans.c
@@ -1,7 +1,7 @@
/* pngtrans.c - transforms the data in a row (used by both readers and writers)
*
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.1 [February 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -424,115 +424,170 @@ png_do_packswap(png_row_infop row_info, png_bytep row)
#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
- * somewhat weird combination of flags to determine what to do. All the calls
- * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
- * correct arguments.
- *
- * The routine isn't general - the channel must be the channel at the start or
- * end (not in the middle) of each pixel.
- */
+/* Remove filler or alpha byte(s) */
void /* PRIVATE */
-png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
+png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
{
- png_bytep sp = row; /* source pointer */
- png_bytep dp = row; /* destination pointer */
- png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
-
- /* At the start sp will point to the first byte to copy and dp to where
- * it is copied to. ep always points just beyond the end of the row, so
- * the loop simply copies (channels-1) channels until sp reaches ep.
- */
- /* GA, GX, XG cases */
- if (row_info->channels == 2)
- {
- if (row_info->bit_depth == 8)
- {
- if (at_start) /* Skip initial filler */
- ++sp;
- else /* Skip initial channels and, for sp, the filler */
- sp += 2, ++dp;
-
- /* For a 1 pixel wide image there is nothing to do */
- while (sp < ep)
- *dp++ = *sp, sp += 2;
+ png_debug(1, "in png_do_strip_filler");
- row_info->pixel_depth = 8;
- }
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 row_width = row_info->width;
+ png_uint_32 i;
- else if (row_info->bit_depth == 16)
+ if ((row_info->color_type == PNG_COLOR_TYPE_RGB ||
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+ (flags & PNG_FLAG_STRIP_ALPHA))) &&
+ row_info->channels == 4)
{
- if (at_start)
- sp += 2;
- else
- sp += 4, dp += 2;
-
- while (sp < ep)
- *dp++ = *sp++, *dp++ = *sp, sp += 3;
-
- row_info->pixel_depth = 16;
- }
-
- else
- return; /* bad bit depth */
-
- row_info->channels = 1;
+ if (row_info->bit_depth == 8)
+ {
+ /* This converts from RGBX or RGBA to RGB */
+ if (flags & PNG_FLAG_FILLER_AFTER)
+ {
+ dp += 3; sp += 4;
+ for (i = 1; i < row_width; i++)
+ {
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ sp++;
+ }
+ }
- /* Finally fix the color type if it records an alpha channel */
- if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- row_info->color_type = PNG_COLOR_TYPE_GRAY;
- }
+ /* This converts from XRGB or ARGB to RGB */
+ else
+ {
+ for (i = 0; i < row_width; i++)
+ {
+ sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ }
+ }
+ row_info->pixel_depth = 24;
+ row_info->rowbytes = row_width * 3;
+ }
- /* RGBA, RGBX, XRGB cases */
- else if (row_info->channels == 4)
- {
- if (row_info->bit_depth == 8)
- {
- if (at_start) /* Skip initial filler */
- ++sp;
- else /* Skip initial channels and, for sp, the filler */
- sp += 4, dp += 3;
+ else /* if (row_info->bit_depth == 16) */
+ {
+ if (flags & PNG_FLAG_FILLER_AFTER)
+ {
+ /* This converts from RRGGBBXX or RRGGBBAA to RRGGBB */
+ sp += 8; dp += 6;
+ for (i = 1; i < row_width; i++)
+ {
+ /* This could be (although png_memcpy is probably slower):
+ png_memcpy(dp, sp, 6);
+ sp += 8;
+ dp += 6;
+ */
+
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ sp += 2;
+ }
+ }
- /* Note that the loop adds 3 to dp and 4 to sp each time. */
- while (sp < ep)
- *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;
+ else
+ {
+ /* This converts from XXRRGGBB or AARRGGBB to RRGGBB */
+ for (i = 0; i < row_width; i++)
+ {
+ /* This could be (although png_memcpy is probably slower):
+ png_memcpy(dp, sp, 6);
+ sp += 8;
+ dp += 6;
+ */
+
+ sp += 2;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ }
+ }
- row_info->pixel_depth = 24;
+ row_info->pixel_depth = 48;
+ row_info->rowbytes = row_width * 6;
+ }
+ row_info->channels = 3;
}
- else if (row_info->bit_depth == 16)
+ else if ((row_info->color_type == PNG_COLOR_TYPE_GRAY ||
+ (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ (flags & PNG_FLAG_STRIP_ALPHA))) &&
+ row_info->channels == 2)
{
- if (at_start)
- sp += 2;
- else
- sp += 8, dp += 6;
-
- while (sp < ep)
+ if (row_info->bit_depth == 8)
{
- /* Copy 6 bytes, skip 2 */
- *dp++ = *sp++, *dp++ = *sp++;
- *dp++ = *sp++, *dp++ = *sp++;
- *dp++ = *sp++, *dp++ = *sp, sp += 3;
- }
+ if (flags & PNG_FLAG_FILLER_AFTER)
+ {
+ /* This converts from GX or GA to G */
+ for (i = 0; i < row_width; i++)
+ {
+ *dp++ = *sp++;
+ sp++;
+ }
+ }
- row_info->pixel_depth = 48;
- }
+ else
+ {
+ /* This converts from XG or AG to G */
+ for (i = 0; i < row_width; i++)
+ {
+ sp++;
+ *dp++ = *sp++;
+ }
+ }
- else
- return; /* bad bit depth */
+ row_info->pixel_depth = 8;
+ row_info->rowbytes = row_width;
+ }
- row_info->channels = 3;
+ else /* if (row_info->bit_depth == 16) */
+ {
+ if (flags & PNG_FLAG_FILLER_AFTER)
+ {
+ /* This converts from GGXX or GGAA to GG */
+ sp += 4; dp += 2;
+ for (i = 1; i < row_width; i++)
+ {
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ sp += 2;
+ }
+ }
- /* Finally fix the color type if it records an alpha channel */
- if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- row_info->color_type = PNG_COLOR_TYPE_RGB;
- }
+ else
+ {
+ /* This converts from XXGG or AAGG to GG */
+ for (i = 0; i < row_width; i++)
+ {
+ sp += 2;
+ *dp++ = *sp++;
+ *dp++ = *sp++;
+ }
+ }
- else
- return; /* The filler channel has gone already */
+ row_info->pixel_depth = 16;
+ row_info->rowbytes = row_width * 2;
+ }
+ row_info->channels = 1;
+ }
- /* Fix the rowbytes value. */
- row_info->rowbytes = dp-row;
+ if (flags & PNG_FLAG_STRIP_ALPHA)
+ row_info->color_type = (png_byte)(row_info->color_type &
+ ~PNG_COLOR_MASK_ALPHA);
+ }
}
#endif
@@ -648,16 +703,11 @@ png_get_user_transform_ptr(png_const_structp png_ptr)
}
#endif
-#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
png_uint_32 PNGAPI
png_get_current_row_number(png_const_structp png_ptr)
{
- /* See the comments in png.h - this is the sub-image row when reading and
- * interlaced image.
- */
if (png_ptr != NULL)
return png_ptr->row_number;
-
return PNG_UINT_32_MAX; /* help the app not to fail silently */
}
@@ -668,7 +718,6 @@ png_get_current_pass_number(png_const_structp png_ptr)
return png_ptr->pass;
return 8; /* invalid */
}
-#endif /* PNG_USER_TRANSFORM_INFO_SUPPORTED */
#endif /* PNG_READ_USER_TRANSFORM_SUPPORTED ||
PNG_WRITE_USER_TRANSFORM_SUPPORTED */
#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
generated by cgit v1.1 at 2024-09-18 00:08:25 +0000