+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+ trans_color != NULL)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ png_byte red = (png_byte)(trans_color->red & 0xff);
+ png_byte green = (png_byte)(trans_color->green & 0xff);
+ png_byte blue = (png_byte)(trans_color->blue & 0xff);
+ sp = row + (size_t)row_info->rowbytes - 1;
+ dp = row + ((size_t)row_width << 2) - 1;
+ for (i = 0; i < row_width; i++)
+ {
+ if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+ *dp-- = 0;
+
+ else
+ *dp-- = 0xff;
+
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ }
+ }
+ else if (row_info->bit_depth == 16)
+ {
+ png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+ png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+ png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+ png_byte red_low = (png_byte)(trans_color->red & 0xff);
+ png_byte green_low = (png_byte)(trans_color->green & 0xff);
+ png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+ sp = row + row_info->rowbytes - 1;
+ dp = row + ((size_t)row_width << 3) - 1;
+ for (i = 0; i < row_width; i++)
+ {
+ if (*(sp - 5) == red_high &&
+ *(sp - 4) == red_low &&
+ *(sp - 3) == green_high &&
+ *(sp - 2) == green_low &&
+ *(sp - 1) == blue_high &&
+ *(sp ) == blue_low)
+ {
+ *dp-- = 0;
+ *dp-- = 0;
+ }
+
+ else
+ {
+ *dp-- = 0xff;
+ *dp-- = 0xff;
+ }
+
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ }
+ }
+ row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+ row_info->channels = 4;
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }