[wxWidgets.git] / src / png / pngwtran.c


/* pngwtran.c - transforms the data in a row for PNG writers
 *
 * libpng 1.0.1
 * 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
 */

#define PNG_INTERNAL
#include "png.h"

/* Transform the data according to the users wishes.  The order of
 * transformations is significant.
 */
void
png_do_write_transformations(png_structp png_ptr)
{
   png_debug(1, "in png_do_write_transformations\n");

#if defined(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_uint_32 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
#if defined(PNG_WRITE_FILLER_SUPPORTED)
   if (png_ptr->transformations & PNG_FILLER)
      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
         png_ptr->flags);
#endif
#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_PACKSWAP)
      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(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
#if defined(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
#if defined(PNG_WRITE_SWAP_SUPPORTED)
   if (png_ptr->transformations & PNG_SWAP_BYTES)
      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(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
#if defined(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
#if defined(PNG_WRITE_BGR_SUPPORTED)
   if (png_ptr->transformations & PNG_BGR)
      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_INVERT_SUPPORTED)
   if (png_ptr->transformations & PNG_INVERT_MONO)
      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
}

#if defined(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
png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
{
   png_debug(1, "in png_do_pack\n");
   if (row_info->bit_depth == 8 &&
#if defined(PNG_USELESS_TESTS_SUPPORTED)
       row != NULL && row_info != NULL &&
#endif
      row_info->channels == 1)
   {
      switch ((int)bit_depth)
      {
         case 1:
         {
            png_bytep sp, dp;
            int mask, v;
            png_uint_32 i;

            sp = row;
            dp = row;
            mask = 0x80;
            v = 0;
            for (i = 0; i < row_info->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;

            sp = row;
            dp = row;
            shift = 6;
            v = 0;
            for (i = 0; i < row_info->width; i++)
            {
               png_byte value;

               value = (png_byte)(*sp & 0x3);
               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;

            sp = row;
            dp = row;
            shift = 4;
            v = 0;
            for (i = 0; i < row_info->width; i++)
            {
               png_byte value;

               value = (png_byte)(*sp & 0xf);
               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;
         }
      }
      row_info->bit_depth = (png_byte)bit_depth;
      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
      row_info->rowbytes =
         ((row_info->width * row_info->pixel_depth + 7) >> 3);
   }
}
#endif

#if defined(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
png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
{
   png_debug(1, "in png_do_shift\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL &&
#else
   if (
#endif
      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
   {
      int shift_start[4], shift_dec[4];
      png_uint_32 channels;

      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;
         png_uint_32 i;
         png_byte mask;

         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 (bp = row, i = 0; i < row_info->rowbytes; 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;
         png_uint_32 i;

         for (bp = row, i = 0; i < row_info->width; i++)
         {
            png_uint_32 c;

            for (c = 0; c < channels; c++, bp++)
            {
               png_uint_16 v;
               int j;

               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;

         for (bp = row, i = 0; i < row_info->width * row_info->channels; i++)
         {
            png_uint_32 c;

            for (c = 0; c < channels; c++, bp += 2)
            {
               png_uint_16 value, v;
               int j;

               v = ((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 + 1) = (png_byte)(value & 0xff);
            }
         }
      }
   }
}
#endif

#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
void
png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_write_swap_alpha\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
      {
         /* This converts from ARGB to RGBA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_byte save;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               save = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save;
            }
         }
         /* This converts from AARRGGBB to RRGGBBAA */
         else
         {
            png_bytep sp, dp;
            png_byte save[2];
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               save[0] = *(sp++);
               save[1] = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save[0];
               *(dp++) = save[1];
            }
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         /* This converts from AG to GA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_byte save;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               save = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save;
            }
         }
         /* This converts from AAGG to GGAA */
         else
         {
            png_bytep sp, dp;
            png_byte save[2];
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               save[0] = *(sp++);
               save[1] = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = save[0];
               *(dp++) = save[1];
            }
         }
      }
   }
}
#endif

#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
void
png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
{
   png_debug(1, "in png_do_write_invert_alpha\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
   if (row != NULL && row_info != NULL)
#endif
   {
      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
      {
         /* This inverts the alpha channel in RGBA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = 255 - *(sp++);
            }
         }
         /* This inverts the alpha channel in RRGGBBAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = 255 - *(sp++);
               *(dp++) = 255 - *(sp++);
            }
         }
      }
      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
      {
         /* This inverts the alpha channel in GA */
         if (row_info->bit_depth == 8)
         {
            png_bytep sp, dp;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = 255 - *(sp++);
            }
         }
         /* This inverts the alpha channel in GGAA */
         else
         {
            png_bytep sp, dp;
            png_uint_32 i;

            for (i = 0, sp = dp = row; i < row_info->width; i++)
            {
               *(dp++) = *(sp++);
               *(dp++) = *(sp++);
               *(dp++) = 255 - *(sp++);
               *(dp++) = 255 - *(sp++);
            }
         }
      }
   }
}
#endif
Commit	Line	Data
c801d85f KB	1
	2	/* pngwtran.c - transforms the data in a row for PNG writers
	3	*
	4	* libpng 1.0.1
	5	* For conditions of distribution and use, see copyright notice in png.h
	6	* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
	7	* Copyright (c) 1996, 1997 Andreas Dilger
	8	* Copyright (c) 1998, Glenn Randers-Pehrson
	9	* March 15, 1998
	10	*/
	11
	12	#define PNG_INTERNAL
	13	#include "png.h"
	14
	15	/* Transform the data according to the users wishes. The order of
	16	* transformations is significant.
	17	*/
	18	void
	19	png_do_write_transformations(png_structp png_ptr)
	20	{
	21	png_debug(1, "in png_do_write_transformations\n");
	22
	23	#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
	24	if (png_ptr->transformations & PNG_USER_TRANSFORM)
	25	if(png_ptr->write_user_transform_fn != NULL)
	26	((png_ptr->write_user_transform_fn)) / user write transform function */
	27	(png_ptr, /* png_ptr */
	28	&(png_ptr->row_info), /* row_info: */
	29	/* png_uint_32 width; width of row */
	30	/* png_uint_32 rowbytes; number of bytes in row */
	31	/* png_byte color_type; color type of pixels */
	32	/* png_byte bit_depth; bit depth of samples */
	33	/* png_byte channels; number of channels (1-4) */
	34	/* png_byte pixel_depth; bits per pixel (depthchannels) /
	35	png_ptr->row_buf + 1); /* start of pixel data for row */
	36	#endif
	37	#if defined(PNG_WRITE_FILLER_SUPPORTED)
	38	if (png_ptr->transformations & PNG_FILLER)
	39	png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
	40	png_ptr->flags);
	41	#endif
	42	#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
	43	if (png_ptr->transformations & PNG_PACKSWAP)
	44	png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
	45	#endif
	46	#if defined(PNG_WRITE_PACK_SUPPORTED)
	47	if (png_ptr->transformations & PNG_PACK)
	48	png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
	49	(png_uint_32)png_ptr->bit_depth);
	50	#endif
	51	#if defined(PNG_WRITE_SHIFT_SUPPORTED)
	52	if (png_ptr->transformations & PNG_SHIFT)
	53	png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
	54	&(png_ptr->shift));
	55	#endif
	56	#if defined(PNG_WRITE_SWAP_SUPPORTED)
	57	if (png_ptr->transformations & PNG_SWAP_BYTES)
	58	png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
	59	#endif
	60	#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
	61	if (png_ptr->transformations & PNG_INVERT_ALPHA)
	62	png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
	63	#endif
	64	#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
65	if (png_ptr->transformations & PNG_SWAP_ALPHA)
66	png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
67	#endif
68	#if defined(PNG_WRITE_BGR_SUPPORTED)
69	if (png_ptr->transformations & PNG_BGR)
70	png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
71	#endif
72	#if defined(PNG_WRITE_INVERT_SUPPORTED)
73	if (png_ptr->transformations & PNG_INVERT_MONO)
74	png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
75	#endif
76	}
77
78	#if defined(PNG_WRITE_PACK_SUPPORTED)
79	/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
80	* row_info bit depth should be 8 (one pixel per byte). The channels
81	* should be 1 (this only happens on grayscale and paletted images).
82	*/
83	void
84	png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
85	{
86	png_debug(1, "in png_do_pack\n");
87	if (row_info->bit_depth == 8 &&
88	#if defined(PNG_USELESS_TESTS_SUPPORTED)
89	row != NULL && row_info != NULL &&
90	#endif
91	row_info->channels == 1)
92	{
93	switch ((int)bit_depth)
94	{
95	case 1:
96	{
97	png_bytep sp, dp;
98	int mask, v;
99	png_uint_32 i;
100
101	sp = row;
102	dp = row;
103	mask = 0x80;
104	v = 0;
105	for (i = 0; i < row_info->width; i++)
106	{
107	if (*sp != 0)
108	v \|= mask;
109	sp++;
110	if (mask > 1)
111	mask >>= 1;
112	else
113	{
114	mask = 0x80;
115	*dp = (png_byte)v;
116	dp++;
117	v = 0;
118	}
119	}
120	if (mask != 0x80)
121	*dp = (png_byte)v;
122	break;
123	}
124	case 2:
125	{
126	png_bytep sp, dp;
127	int shift, v;
128	png_uint_32 i;
129
130	sp = row;
131	dp = row;
132	shift = 6;
133	v = 0;
134	for (i = 0; i < row_info->width; i++)
135	{
136	png_byte value;
137
138	value = (png_byte)(*sp & 0x3);
139	v \|= (value << shift);
140	if (shift == 0)
141	{
142	shift = 6;
143	*dp = (png_byte)v;
144	dp++;
145	v = 0;
146	}
147	else
148	shift -= 2;
149	sp++;
150	}
151	if (shift != 6)
152	*dp = (png_byte)v;
153	break;
154	}
155	case 4:
156	{
157	png_bytep sp, dp;
158	int shift, v;
159	png_uint_32 i;
160
161	sp = row;
162	dp = row;
163	shift = 4;
164	v = 0;
165	for (i = 0; i < row_info->width; i++)
166	{
167	png_byte value;
168
169	value = (png_byte)(*sp & 0xf);
170	v \|= (value << shift);
171
172	if (shift == 0)
173	{
174	shift = 4;
175	*dp = (png_byte)v;
176	dp++;
177	v = 0;
178	}
179	else
180	shift -= 4;
181
182	sp++;
183	}
184	if (shift != 4)
185	*dp = (png_byte)v;
186	break;
187	}
188	}
189	row_info->bit_depth = (png_byte)bit_depth;
190	row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
191	row_info->rowbytes =
192	((row_info->width * row_info->pixel_depth + 7) >> 3);
193	}
194	}
195	#endif
196
197	#if defined(PNG_WRITE_SHIFT_SUPPORTED)
198	/* Shift pixel values to take advantage of whole range. Pass the
199	* true number of bits in bit_depth. The row should be packed
200	* according to row_info->bit_depth. Thus, if you had a row of
201	* bit depth 4, but the pixels only had values from 0 to 7, you
202	* would pass 3 as bit_depth, and this routine would translate the
203	* data to 0 to 15.
204	*/
205	void
206	png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
207	{
208	png_debug(1, "in png_do_shift\n");
209	#if defined(PNG_USELESS_TESTS_SUPPORTED)
210	if (row != NULL && row_info != NULL &&
211	#else
212	if (
213	#endif
214	row_info->color_type != PNG_COLOR_TYPE_PALETTE)
215	{
216	int shift_start[4], shift_dec[4];
217	png_uint_32 channels;
218
219	channels = 0;
220	if (row_info->color_type & PNG_COLOR_MASK_COLOR)
221	{
222	shift_start[channels] = row_info->bit_depth - bit_depth->red;
223	shift_dec[channels] = bit_depth->red;
224	channels++;
225	shift_start[channels] = row_info->bit_depth - bit_depth->green;
226	shift_dec[channels] = bit_depth->green;
227	channels++;
228	shift_start[channels] = row_info->bit_depth - bit_depth->blue;
229	shift_dec[channels] = bit_depth->blue;
230	channels++;
231	}
232	else
233	{
234	shift_start[channels] = row_info->bit_depth - bit_depth->gray;
235	shift_dec[channels] = bit_depth->gray;
236	channels++;
237	}
238	if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
239	{
240	shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
241	shift_dec[channels] = bit_depth->alpha;
242	channels++;
243	}
244
245	/* with low row depths, could only be grayscale, so one channel */
246	if (row_info->bit_depth < 8)
247	{
248	png_bytep bp;
249	png_uint_32 i;
250	png_byte mask;
251
252	if (bit_depth->gray == 1 && row_info->bit_depth == 2)
253	mask = 0x55;
254	else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
255	mask = 0x11;
256	else
257	mask = 0xff;
258
259	for (bp = row, i = 0; i < row_info->rowbytes; i++, bp++)
260	{
261	png_uint_16 v;
262	int j;
263
264	v = *bp;
265	*bp = 0;
266	for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
267	{
268	if (j > 0)
269	*bp \|= (png_byte)((v << j) & 0xff);
270	else
271	*bp \|= (png_byte)((v >> (-j)) & mask);
272	}
273	}
274	}
275	else if (row_info->bit_depth == 8)
276	{
277	png_bytep bp;
278	png_uint_32 i;
279
280	for (bp = row, i = 0; i < row_info->width; i++)
281	{
282	png_uint_32 c;
283
284	for (c = 0; c < channels; c++, bp++)
285	{
286	png_uint_16 v;
287	int j;
288
289	v = *bp;
290	*bp = 0;
291	for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
292	{
293	if (j > 0)
294	*bp \|= (png_byte)((v << j) & 0xff);
295	else
296	*bp \|= (png_byte)((v >> (-j)) & 0xff);
297	}
298	}
299	}
300	}
301	else
302	{
303	png_bytep bp;
304	png_uint_32 i;
305
306	for (bp = row, i = 0; i < row_info->width * row_info->channels; i++)
307	{
308	png_uint_32 c;
309
310	for (c = 0; c < channels; c++, bp += 2)
311	{
312	png_uint_16 value, v;
313	int j;
314
315	v = ((png_uint_16)(bp) << 8) + (bp + 1);
316	value = 0;
317	for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
318	{
319	if (j > 0)
320	value \|= (png_uint_16)((v << j) & (png_uint_16)0xffff);
321	else
322	value \|= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
323	}
324	*bp = (png_byte)(value >> 8);
325	*(bp + 1) = (png_byte)(value & 0xff);
326	}
327	}
328	}
329	}
330	}
331	#endif
332
333	#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
334	void
335	png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
336	{
337	png_debug(1, "in png_do_write_swap_alpha\n");
338	#if defined(PNG_USELESS_TESTS_SUPPORTED)
339	if (row != NULL && row_info != NULL)
340	#endif
341	{
342	if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
343	{
344	/* This converts from ARGB to RGBA */
345	if (row_info->bit_depth == 8)
346	{
347	png_bytep sp, dp;
348	png_byte save;
349	png_uint_32 i;
350
351	for (i = 0, sp = dp = row; i < row_info->width; i++)
352	{
353	save = *(sp++);
354	(dp++) = (sp++);
355	(dp++) = (sp++);
356	(dp++) = (sp++);
357	*(dp++) = save;
358	}
359	}
360	/* This converts from AARRGGBB to RRGGBBAA */
361	else
362	{
363	png_bytep sp, dp;
364	png_byte save[2];
365	png_uint_32 i;
366
367	for (i = 0, sp = dp = row; i < row_info->width; i++)
368	{
369	save[0] = *(sp++);
370	save[1] = *(sp++);
371	(dp++) = (sp++);
372	(dp++) = (sp++);
373	(dp++) = (sp++);
374	(dp++) = (sp++);
375	(dp++) = (sp++);
376	(dp++) = (sp++);
377	*(dp++) = save[0];
378	*(dp++) = save[1];
379	}
380	}
381	}
382	else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
383	{
384	/* This converts from AG to GA */
385	if (row_info->bit_depth == 8)
386	{
387	png_bytep sp, dp;
388	png_byte save;
389	png_uint_32 i;
390
391	for (i = 0, sp = dp = row; i < row_info->width; i++)
392	{
393	save = *(sp++);
394	(dp++) = (sp++);
395	*(dp++) = save;
396	}
397	}
398	/* This converts from AAGG to GGAA */
399	else
400	{
401	png_bytep sp, dp;
402	png_byte save[2];
403	png_uint_32 i;
404
405	for (i = 0, sp = dp = row; i < row_info->width; i++)
406	{
407	save[0] = *(sp++);
408	save[1] = *(sp++);
409	(dp++) = (sp++);
410	(dp++) = (sp++);
411	*(dp++) = save[0];
412	*(dp++) = save[1];
413	}
414	}
415	}
416	}
417	}
418	#endif
419
420	#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
421	void
422	png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
423	{
424	png_debug(1, "in png_do_write_invert_alpha\n");
425	#if defined(PNG_USELESS_TESTS_SUPPORTED)
426	if (row != NULL && row_info != NULL)
427	#endif
428	{
429	if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
430	{
431	/* This inverts the alpha channel in RGBA */
432	if (row_info->bit_depth == 8)
433	{
434	png_bytep sp, dp;
435	png_uint_32 i;
436
437	for (i = 0, sp = dp = row; i < row_info->width; i++)
438	{
439	(dp++) = (sp++);
440	(dp++) = (sp++);
441	(dp++) = (sp++);
442	(dp++) = 255 - (sp++);
443	}
444	}
445	/* This inverts the alpha channel in RRGGBBAA */
446	else
447	{
448	png_bytep sp, dp;
449	png_uint_32 i;
450
451	for (i = 0, sp = dp = row; i < row_info->width; i++)
452	{
453	(dp++) = (sp++);
454	(dp++) = (sp++);
455	(dp++) = (sp++);
456	(dp++) = (sp++);
457	(dp++) = (sp++);
458	(dp++) = (sp++);
459	(dp++) = 255 - (sp++);
460	(dp++) = 255 - (sp++);
461	}
462	}
463	}
464	else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
465	{
466	/* This inverts the alpha channel in GA */
467	if (row_info->bit_depth == 8)
468	{
469	png_bytep sp, dp;
470	png_uint_32 i;
471
472	for (i = 0, sp = dp = row; i < row_info->width; i++)
473	{
474	(dp++) = (sp++);
475	(dp++) = 255 - (sp++);
476	}
477	}
478	/* This inverts the alpha channel in GGAA */
479	else
480	{
481	png_bytep sp, dp;
482	png_uint_32 i;
483
484	for (i = 0, sp = dp = row; i < row_info->width; i++)
485	{
486	(dp++) = (sp++);
487	(dp++) = (sp++);
488	(dp++) = 255 - (sp++);
489	(dp++) = 255 - (sp++);
490	}
491	}
492	}
493	}
494	}
495	#endif