michael@0: 
michael@0: /* pngwtran.c - transforms the data in a row for PNG writers
michael@0:  *
michael@0:  * Last changed in libpng 1.6.9 [February 6, 2014]
michael@0:  * Copyright (c) 1998-2014 Glenn Randers-Pehrson
michael@0:  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
michael@0:  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
michael@0:  *
michael@0:  * This code is released under the libpng license.
michael@0:  * For conditions of distribution and use, see the disclaimer
michael@0:  * and license in png.h
michael@0:  */
michael@0: 
michael@0: #include "pngpriv.h"
michael@0: 
michael@0: #ifdef PNG_WRITE_SUPPORTED
michael@0: #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
michael@0: 
michael@0: #ifdef PNG_WRITE_PACK_SUPPORTED
michael@0: /* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
michael@0:  * row_info bit depth should be 8 (one pixel per byte).  The channels
michael@0:  * should be 1 (this only happens on grayscale and paletted images).
michael@0:  */
michael@0: static void
michael@0: png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
michael@0: {
michael@0:    png_debug(1, "in png_do_pack");
michael@0: 
michael@0:    if (row_info->bit_depth == 8 &&
michael@0:       row_info->channels == 1)
michael@0:    {
michael@0:       switch ((int)bit_depth)
michael@0:       {
michael@0:          case 1:
michael@0:          {
michael@0:             png_bytep sp, dp;
michael@0:             int mask, v;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             sp = row;
michael@0:             dp = row;
michael@0:             mask = 0x80;
michael@0:             v = 0;
michael@0: 
michael@0:             for (i = 0; i < row_width; i++)
michael@0:             {
michael@0:                if (*sp != 0)
michael@0:                   v |= mask;
michael@0: 
michael@0:                sp++;
michael@0: 
michael@0:                if (mask > 1)
michael@0:                   mask >>= 1;
michael@0: 
michael@0:                else
michael@0:                {
michael@0:                   mask = 0x80;
michael@0:                   *dp = (png_byte)v;
michael@0:                   dp++;
michael@0:                   v = 0;
michael@0:                }
michael@0:             }
michael@0: 
michael@0:             if (mask != 0x80)
michael@0:                *dp = (png_byte)v;
michael@0: 
michael@0:             break;
michael@0:          }
michael@0: 
michael@0:          case 2:
michael@0:          {
michael@0:             png_bytep sp, dp;
michael@0:             int shift, v;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             sp = row;
michael@0:             dp = row;
michael@0:             shift = 6;
michael@0:             v = 0;
michael@0: 
michael@0:             for (i = 0; i < row_width; i++)
michael@0:             {
michael@0:                png_byte value;
michael@0: 
michael@0:                value = (png_byte)(*sp & 0x03);
michael@0:                v |= (value << shift);
michael@0: 
michael@0:                if (shift == 0)
michael@0:                {
michael@0:                   shift = 6;
michael@0:                   *dp = (png_byte)v;
michael@0:                   dp++;
michael@0:                   v = 0;
michael@0:                }
michael@0: 
michael@0:                else
michael@0:                   shift -= 2;
michael@0: 
michael@0:                sp++;
michael@0:             }
michael@0: 
michael@0:             if (shift != 6)
michael@0:                *dp = (png_byte)v;
michael@0: 
michael@0:             break;
michael@0:          }
michael@0: 
michael@0:          case 4:
michael@0:          {
michael@0:             png_bytep sp, dp;
michael@0:             int shift, v;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             sp = row;
michael@0:             dp = row;
michael@0:             shift = 4;
michael@0:             v = 0;
michael@0: 
michael@0:             for (i = 0; i < row_width; i++)
michael@0:             {
michael@0:                png_byte value;
michael@0: 
michael@0:                value = (png_byte)(*sp & 0x0f);
michael@0:                v |= (value << shift);
michael@0: 
michael@0:                if (shift == 0)
michael@0:                {
michael@0:                   shift = 4;
michael@0:                   *dp = (png_byte)v;
michael@0:                   dp++;
michael@0:                   v = 0;
michael@0:                }
michael@0: 
michael@0:                else
michael@0:                   shift -= 4;
michael@0: 
michael@0:                sp++;
michael@0:             }
michael@0: 
michael@0:             if (shift != 4)
michael@0:                *dp = (png_byte)v;
michael@0: 
michael@0:             break;
michael@0:          }
michael@0: 
michael@0:          default:
michael@0:             break;
michael@0:       }
michael@0: 
michael@0:       row_info->bit_depth = (png_byte)bit_depth;
michael@0:       row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
michael@0:       row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
michael@0:           row_info->width);
michael@0:    }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_SHIFT_SUPPORTED
michael@0: /* Shift pixel values to take advantage of whole range.  Pass the
michael@0:  * true number of bits in bit_depth.  The row should be packed
michael@0:  * according to row_info->bit_depth.  Thus, if you had a row of
michael@0:  * bit depth 4, but the pixels only had values from 0 to 7, you
michael@0:  * would pass 3 as bit_depth, and this routine would translate the
michael@0:  * data to 0 to 15.
michael@0:  */
michael@0: static void
michael@0: png_do_shift(png_row_infop row_info, png_bytep row,
michael@0:     png_const_color_8p bit_depth)
michael@0: {
michael@0:    png_debug(1, "in png_do_shift");
michael@0: 
michael@0:    if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
michael@0:    {
michael@0:       int shift_start[4], shift_dec[4];
michael@0:       int channels = 0;
michael@0: 
michael@0:       if (row_info->color_type & PNG_COLOR_MASK_COLOR)
michael@0:       {
michael@0:          shift_start[channels] = row_info->bit_depth - bit_depth->red;
michael@0:          shift_dec[channels] = bit_depth->red;
michael@0:          channels++;
michael@0: 
michael@0:          shift_start[channels] = row_info->bit_depth - bit_depth->green;
michael@0:          shift_dec[channels] = bit_depth->green;
michael@0:          channels++;
michael@0: 
michael@0:          shift_start[channels] = row_info->bit_depth - bit_depth->blue;
michael@0:          shift_dec[channels] = bit_depth->blue;
michael@0:          channels++;
michael@0:       }
michael@0: 
michael@0:       else
michael@0:       {
michael@0:          shift_start[channels] = row_info->bit_depth - bit_depth->gray;
michael@0:          shift_dec[channels] = bit_depth->gray;
michael@0:          channels++;
michael@0:       }
michael@0: 
michael@0:       if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
michael@0:       {
michael@0:          shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
michael@0:          shift_dec[channels] = bit_depth->alpha;
michael@0:          channels++;
michael@0:       }
michael@0: 
michael@0:       /* With low row depths, could only be grayscale, so one channel */
michael@0:       if (row_info->bit_depth < 8)
michael@0:       {
michael@0:          png_bytep bp = row;
michael@0:          png_size_t i;
michael@0:          unsigned int mask;
michael@0:          png_size_t row_bytes = row_info->rowbytes;
michael@0: 
michael@0:          if (bit_depth->gray == 1 && row_info->bit_depth == 2)
michael@0:             mask = 0x55;
michael@0: 
michael@0:          else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
michael@0:             mask = 0x11;
michael@0: 
michael@0:          else
michael@0:             mask = 0xff;
michael@0: 
michael@0:          for (i = 0; i < row_bytes; i++, bp++)
michael@0:          {
michael@0:             int j;
michael@0:             unsigned int v, out;
michael@0: 
michael@0:             v = *bp;
michael@0:             out = 0;
michael@0: 
michael@0:             for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
michael@0:             {
michael@0:                if (j > 0)
michael@0:                   out |= v << j;
michael@0: 
michael@0:                else
michael@0:                   out |= (v >> (-j)) & mask;
michael@0:             }
michael@0: 
michael@0:             *bp = (png_byte)(out & 0xff);
michael@0:          }
michael@0:       }
michael@0: 
michael@0:       else if (row_info->bit_depth == 8)
michael@0:       {
michael@0:          png_bytep bp = row;
michael@0:          png_uint_32 i;
michael@0:          png_uint_32 istop = channels * row_info->width;
michael@0: 
michael@0:          for (i = 0; i < istop; i++, bp++)
michael@0:          {
michael@0: 
michael@0:             const unsigned int c = i%channels;
michael@0:             int j;
michael@0:             unsigned int v, out;
michael@0: 
michael@0:             v = *bp;
michael@0:             out = 0;
michael@0: 
michael@0:             for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
michael@0:             {
michael@0:                if (j > 0)
michael@0:                   out |= v << j;
michael@0: 
michael@0:                else
michael@0:                   out |= v >> (-j);
michael@0:             }
michael@0: 
michael@0:             *bp = (png_byte)(out & 0xff);
michael@0:          }
michael@0:       }
michael@0: 
michael@0:       else
michael@0:       {
michael@0:          png_bytep bp;
michael@0:          png_uint_32 i;
michael@0:          png_uint_32 istop = channels * row_info->width;
michael@0: 
michael@0:          for (bp = row, i = 0; i < istop; i++)
michael@0:          {
michael@0:             const unsigned int c = i%channels;
michael@0:             int j;
michael@0:             unsigned int value, v;
michael@0: 
michael@0:             v = png_get_uint_16(bp);
michael@0:             value = 0;
michael@0: 
michael@0:             for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
michael@0:             {
michael@0:                if (j > 0)
michael@0:                   value |= v << j;
michael@0: 
michael@0:                else
michael@0:                   value |= v >> (-j);
michael@0:             }
michael@0:             *bp++ = (png_byte)((value >> 8) & 0xff);
michael@0:             *bp++ = (png_byte)(value & 0xff);
michael@0:          }
michael@0:       }
michael@0:    }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
michael@0: static void
michael@0: png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
michael@0: {
michael@0:    png_debug(1, "in png_do_write_swap_alpha");
michael@0: 
michael@0:    {
michael@0:       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
michael@0:       {
michael@0:          if (row_info->bit_depth == 8)
michael@0:          {
michael@0:             /* This converts from ARGB to RGBA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                png_byte save = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = save;
michael@0:             }
michael@0:          }
michael@0: 
michael@0: #ifdef PNG_WRITE_16BIT_SUPPORTED
michael@0:          else
michael@0:          {
michael@0:             /* This converts from AARRGGBB to RRGGBBAA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                png_byte save[2];
michael@0:                save[0] = *(sp++);
michael@0:                save[1] = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = save[0];
michael@0:                *(dp++) = save[1];
michael@0:             }
michael@0:          }
michael@0: #endif /* PNG_WRITE_16BIT_SUPPORTED */
michael@0:       }
michael@0: 
michael@0:       else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
michael@0:       {
michael@0:          if (row_info->bit_depth == 8)
michael@0:          {
michael@0:             /* This converts from AG to GA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                png_byte save = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = save;
michael@0:             }
michael@0:          }
michael@0: 
michael@0: #ifdef PNG_WRITE_16BIT_SUPPORTED
michael@0:          else
michael@0:          {
michael@0:             /* This converts from AAGG to GGAA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                png_byte save[2];
michael@0:                save[0] = *(sp++);
michael@0:                save[1] = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = save[0];
michael@0:                *(dp++) = save[1];
michael@0:             }
michael@0:          }
michael@0: #endif /* PNG_WRITE_16BIT_SUPPORTED */
michael@0:       }
michael@0:    }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
michael@0: static void
michael@0: png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
michael@0: {
michael@0:    png_debug(1, "in png_do_write_invert_alpha");
michael@0: 
michael@0:    {
michael@0:       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
michael@0:       {
michael@0:          if (row_info->bit_depth == 8)
michael@0:          {
michael@0:             /* This inverts the alpha channel in RGBA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                /* Does nothing
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                */
michael@0:                sp+=3; dp = sp;
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:             }
michael@0:          }
michael@0: 
michael@0: #ifdef PNG_WRITE_16BIT_SUPPORTED
michael@0:          else
michael@0:          {
michael@0:             /* This inverts the alpha channel in RRGGBBAA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                /* Does nothing
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                */
michael@0:                sp+=6; dp = sp;
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:             }
michael@0:          }
michael@0: #endif /* PNG_WRITE_16BIT_SUPPORTED */
michael@0:       }
michael@0: 
michael@0:       else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
michael@0:       {
michael@0:          if (row_info->bit_depth == 8)
michael@0:          {
michael@0:             /* This inverts the alpha channel in GA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:             }
michael@0:          }
michael@0: 
michael@0: #ifdef PNG_WRITE_16BIT_SUPPORTED
michael@0:          else
michael@0:          {
michael@0:             /* This inverts the alpha channel in GGAA */
michael@0:             png_bytep sp, dp;
michael@0:             png_uint_32 i;
michael@0:             png_uint_32 row_width = row_info->width;
michael@0: 
michael@0:             for (i = 0, sp = dp = row; i < row_width; i++)
michael@0:             {
michael@0:                /* Does nothing
michael@0:                *(dp++) = *(sp++);
michael@0:                *(dp++) = *(sp++);
michael@0:                */
michael@0:                sp+=2; dp = sp;
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:                *(dp++) = (png_byte)(255 - *(sp++));
michael@0:             }
michael@0:          }
michael@0: #endif /* PNG_WRITE_16BIT_SUPPORTED */
michael@0:       }
michael@0:    }
michael@0: }
michael@0: #endif
michael@0: 
michael@0: /* Transform the data according to the user's wishes.  The order of
michael@0:  * transformations is significant.
michael@0:  */
michael@0: void /* PRIVATE */
michael@0: png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
michael@0: {
michael@0:    png_debug(1, "in png_do_write_transformations");
michael@0: 
michael@0:    if (png_ptr == NULL)
michael@0:       return;
michael@0: 
michael@0: #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_USER_TRANSFORM)
michael@0:       if (png_ptr->write_user_transform_fn != NULL)
michael@0:          (*(png_ptr->write_user_transform_fn)) /* User write transform
michael@0:                                                  function */
michael@0:              (png_ptr,  /* png_ptr */
michael@0:              row_info,  /* row_info: */
michael@0:                 /*  png_uint_32 width;       width of row */
michael@0:                 /*  png_size_t rowbytes;     number of bytes in row */
michael@0:                 /*  png_byte color_type;     color type of pixels */
michael@0:                 /*  png_byte bit_depth;      bit depth of samples */
michael@0:                 /*  png_byte channels;       number of channels (1-4) */
michael@0:                 /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
michael@0:              png_ptr->row_buf + 1);      /* start of pixel data for row */
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_FILLER_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_FILLER)
michael@0:       png_do_strip_channel(row_info, png_ptr->row_buf + 1,
michael@0:          !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_PACKSWAP_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_PACKSWAP)
michael@0:       png_do_packswap(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_PACK_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_PACK)
michael@0:       png_do_pack(row_info, png_ptr->row_buf + 1,
michael@0:           (png_uint_32)png_ptr->bit_depth);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_SWAP_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_SWAP_BYTES)
michael@0:       png_do_swap(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_SHIFT_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_SHIFT)
michael@0:       png_do_shift(row_info, png_ptr->row_buf + 1,
michael@0:           &(png_ptr->shift));
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_SWAP_ALPHA)
michael@0:       png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_INVERT_ALPHA)
michael@0:       png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_BGR_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_BGR)
michael@0:       png_do_bgr(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: 
michael@0: #ifdef PNG_WRITE_INVERT_SUPPORTED
michael@0:    if (png_ptr->transformations & PNG_INVERT_MONO)
michael@0:       png_do_invert(row_info, png_ptr->row_buf + 1);
michael@0: #endif
michael@0: }
michael@0: #endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
michael@0: #endif /* PNG_WRITE_SUPPORTED */