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-rw-r--r--third_party/libpng/pngwtran.c631
1 files changed, 631 insertions, 0 deletions
diff --git a/third_party/libpng/pngwtran.c b/third_party/libpng/pngwtran.c
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+
+/* pngwtran.c - transforms the data in a row for PNG writers
+ *
+ * Last changed in libpng 1.5.2 [March 31, 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.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Transform the data according to the user's wishes. The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
+png_do_write_transformations(png_structp png_ptr)
+{
+ 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 */
+ &(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(&(png_ptr->row_info), png_ptr->row_buf + 1,
+ !(png_ptr->flags & PNG_FILLER_AFTER));
+#endif
+
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+ if (png_ptr->transformations & PNG_PACKSWAP)
+ png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+ if (png_ptr->transformations & PNG_PACK)
+ png_do_pack(&(png_ptr->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(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+ if (png_ptr->transformations & PNG_SHIFT)
+ png_do_shift(&(png_ptr->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(&(png_ptr->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(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_BGR_SUPPORTED
+ if (png_ptr->transformations & PNG_BGR)
+ png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+ if (png_ptr->transformations & PNG_INVERT_MONO)
+ png_do_invert(&(png_ptr->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
+ * row_info bit depth should be 8 (one pixel per byte). The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+void /* PRIVATE */
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+ png_debug(1, "in png_do_pack");
+
+ if (row_info->bit_depth == 8 &&
+ row_info->channels == 1)
+ {
+ switch ((int)bit_depth)
+ {
+ case 1:
+ {
+ png_bytep sp, dp;
+ int mask, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ mask = 0x80;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ if (*sp != 0)
+ v |= mask;
+
+ sp++;
+
+ if (mask > 1)
+ mask >>= 1;
+
+ else
+ {
+ mask = 0x80;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+ }
+
+ if (mask != 0x80)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ case 2:
+ {
+ png_bytep sp, dp;
+ int shift, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ shift = 6;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte value;
+
+ value = (png_byte)(*sp & 0x03);
+ v |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 6;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+
+ else
+ shift -= 2;
+
+ sp++;
+ }
+
+ if (shift != 6)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp, dp;
+ int shift, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ shift = 4;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte value;
+
+ value = (png_byte)(*sp & 0x0f);
+ v |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 4;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+
+ else
+ shift -= 4;
+
+ sp++;
+ }
+
+ if (shift != 4)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ default:
+ break;
+ }
+
+ row_info->bit_depth = (png_byte)bit_depth;
+ row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+ row_info->width);
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+/* Shift pixel values to take advantage of whole range. Pass the
+ * true number of bits in bit_depth. The row should be packed
+ * according to row_info->bit_depth. Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+void /* PRIVATE */
+png_do_shift(png_row_infop row_info, png_bytep row,
+ png_const_color_8p bit_depth)
+{
+ png_debug(1, "in png_do_shift");
+
+ if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ int shift_start[4], shift_dec[4];
+ int channels = 0;
+
+ if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->red;
+ shift_dec[channels] = bit_depth->red;
+ channels++;
+
+ shift_start[channels] = row_info->bit_depth - bit_depth->green;
+ shift_dec[channels] = bit_depth->green;
+ channels++;
+
+ shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+ shift_dec[channels] = bit_depth->blue;
+ channels++;
+ }
+
+ else
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+ shift_dec[channels] = bit_depth->gray;
+ channels++;
+ }
+
+ if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+ shift_dec[channels] = bit_depth->alpha;
+ channels++;
+ }
+
+ /* With low row depths, could only be grayscale, so one channel */
+ if (row_info->bit_depth < 8)
+ {
+ png_bytep bp = row;
+ png_size_t i;
+ png_byte mask;
+ png_size_t row_bytes = row_info->rowbytes;
+
+ if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+ mask = 0x55;
+
+ else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+ mask = 0x11;
+
+ else
+ mask = 0xff;
+
+ for (i = 0; i < row_bytes; i++, bp++)
+ {
+ png_uint_16 v;
+ int j;
+
+ v = *bp;
+ *bp = 0;
+
+ for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+ {
+ if (j > 0)
+ *bp |= (png_byte)((v << j) & 0xff);
+
+ else
+ *bp |= (png_byte)((v >> (-j)) & mask);
+ }
+ }
+ }
+
+ else if (row_info->bit_depth == 8)
+ {
+ png_bytep bp = row;
+ png_uint_32 i;
+ png_uint_32 istop = channels * row_info->width;
+
+ for (i = 0; i < istop; i++, bp++)
+ {
+
+ png_uint_16 v;
+ int j;
+ int c = (int)(i%channels);
+
+ v = *bp;
+ *bp = 0;
+
+ for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+ {
+ if (j > 0)
+ *bp |= (png_byte)((v << j) & 0xff);
+
+ else
+ *bp |= (png_byte)((v >> (-j)) & 0xff);
+ }
+ }
+ }
+
+ else
+ {
+ png_bytep bp;
+ png_uint_32 i;
+ png_uint_32 istop = channels * row_info->width;
+
+ for (bp = row, i = 0; i < istop; i++)
+ {
+ int c = (int)(i%channels);
+ png_uint_16 value, v;
+ int j;
+
+ v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
+ value = 0;
+
+ for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+ {
+ if (j > 0)
+ value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
+
+ else
+ value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
+ }
+ *bp++ = (png_byte)(value >> 8);
+ *bp++ = (png_byte)(value & 0xff);
+ }
+ }
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+void /* PRIVATE */
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_write_swap_alpha");
+
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This converts from ARGB to RGBA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save;
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This converts from AARRGGBB to RRGGBBAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save[2];
+ save[0] = *(sp++);
+ save[1] = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save[0];
+ *(dp++) = save[1];
+ }
+ }
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This converts from AG to GA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save;
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This converts from AAGG to GGAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save[2];
+ save[0] = *(sp++);
+ save[1] = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save[0];
+ *(dp++) = save[1];
+ }
+ }
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
+ }
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+void /* PRIVATE */
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_write_invert_alpha");
+
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in RGBA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=3; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This inverts the alpha channel in RRGGBBAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=6; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in GA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ *(dp++) = *(sp++);
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This inverts the alpha channel in GGAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=2; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+#endif /* PNG_WRITE_16BIT_SUPPORTED */
+ }
+ }
+}
+#endif
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing */
+void /* PRIVATE */
+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 */
+#endif /* PNG_WRITE_SUPPORTED */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 00:43:02 +0000