| |
| /* pngtrans.c - transforms the data in a row (used by both readers and writers) |
| * |
| * Copyright (c) 2018-2024 Cosmin Truta |
| * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson |
| * Copyright (c) 1996-1997 Andreas Dilger |
| * 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" |
| |
| #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| |
| #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) |
| /* Turn on BGR-to-RGB mapping */ |
| void PNGAPI |
| png_set_bgr(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_bgr"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->transformations |= PNG_BGR; |
| } |
| #endif |
| |
| #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) |
| /* Turn on 16-bit byte swapping */ |
| void PNGAPI |
| png_set_swap(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_swap"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| if (png_ptr->bit_depth == 16) |
| png_ptr->transformations |= PNG_SWAP_BYTES; |
| } |
| #endif |
| |
| #if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED) |
| /* Turn on pixel packing */ |
| void PNGAPI |
| png_set_packing(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_packing"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| if (png_ptr->bit_depth < 8) |
| { |
| png_ptr->transformations |= PNG_PACK; |
| # ifdef PNG_WRITE_SUPPORTED |
| png_ptr->usr_bit_depth = 8; |
| # endif |
| } |
| } |
| #endif |
| |
| #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) |
| /* Turn on packed pixel swapping */ |
| void PNGAPI |
| png_set_packswap(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_packswap"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| if (png_ptr->bit_depth < 8) |
| png_ptr->transformations |= PNG_PACKSWAP; |
| } |
| #endif |
| |
| #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED) |
| void PNGAPI |
| png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits) |
| { |
| png_debug(1, "in png_set_shift"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->transformations |= PNG_SHIFT; |
| png_ptr->shift = *true_bits; |
| } |
| #endif |
| |
| #if defined(PNG_READ_INTERLACING_SUPPORTED) || \ |
| defined(PNG_WRITE_INTERLACING_SUPPORTED) |
| int PNGAPI |
| png_set_interlace_handling(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_interlace handling"); |
| |
| if (png_ptr != 0 && png_ptr->interlaced != 0) |
| { |
| png_ptr->transformations |= PNG_INTERLACE; |
| return 7; |
| } |
| |
| return 1; |
| } |
| #endif |
| |
| #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED) |
| /* Add a filler byte on read, or remove a filler or alpha byte on write. |
| * The filler type has changed in v0.95 to allow future 2-byte fillers |
| * for 48-bit input data, as well as to avoid problems with some compilers |
| * that don't like bytes as parameters. |
| */ |
| void PNGAPI |
| png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc) |
| { |
| png_debug(1, "in png_set_filler"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| /* In libpng 1.6 it is possible to determine whether this is a read or write |
| * operation and therefore to do more checking here for a valid call. |
| */ |
| if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0) |
| { |
| # ifdef PNG_READ_FILLER_SUPPORTED |
| /* On read png_set_filler is always valid, regardless of the base PNG |
| * format, because other transformations can give a format where the |
| * filler code can execute (basically an 8 or 16-bit component RGB or G |
| * format.) |
| * |
| * NOTE: usr_channels is not used by the read code! (This has led to |
| * confusion in the past.) The filler is only used in the read code. |
| */ |
| png_ptr->filler = (png_uint_16)filler; |
| # else |
| png_app_error(png_ptr, "png_set_filler not supported on read"); |
| PNG_UNUSED(filler) /* not used in the write case */ |
| return; |
| # endif |
| } |
| |
| else /* write */ |
| { |
| # ifdef PNG_WRITE_FILLER_SUPPORTED |
| /* On write the usr_channels parameter must be set correctly at the |
| * start to record the number of channels in the app-supplied data. |
| */ |
| switch (png_ptr->color_type) |
| { |
| case PNG_COLOR_TYPE_RGB: |
| png_ptr->usr_channels = 4; |
| break; |
| |
| case PNG_COLOR_TYPE_GRAY: |
| if (png_ptr->bit_depth >= 8) |
| { |
| png_ptr->usr_channels = 2; |
| break; |
| } |
| |
| else |
| { |
| /* There simply isn't any code in libpng to strip out bits |
| * from bytes when the components are less than a byte in |
| * size! |
| */ |
| png_app_error(png_ptr, |
| "png_set_filler is invalid for" |
| " low bit depth gray output"); |
| return; |
| } |
| |
| default: |
| png_app_error(png_ptr, |
| "png_set_filler: inappropriate color type"); |
| return; |
| } |
| # else |
| png_app_error(png_ptr, "png_set_filler not supported on write"); |
| return; |
| # endif |
| } |
| |
| /* Here on success - libpng supports the operation, set the transformation |
| * and the flag to say where the filler channel is. |
| */ |
| png_ptr->transformations |= PNG_FILLER; |
| |
| if (filler_loc == PNG_FILLER_AFTER) |
| png_ptr->flags |= PNG_FLAG_FILLER_AFTER; |
| |
| else |
| png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER; |
| } |
| |
| /* Added to libpng-1.2.7 */ |
| void PNGAPI |
| png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc) |
| { |
| png_debug(1, "in png_set_add_alpha"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_set_filler(png_ptr, filler, filler_loc); |
| /* The above may fail to do anything. */ |
| if ((png_ptr->transformations & PNG_FILLER) != 0) |
| png_ptr->transformations |= PNG_ADD_ALPHA; |
| } |
| |
| #endif |
| |
| #if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \ |
| defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED) |
| void PNGAPI |
| png_set_swap_alpha(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_swap_alpha"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->transformations |= PNG_SWAP_ALPHA; |
| } |
| #endif |
| |
| #if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \ |
| defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED) |
| void PNGAPI |
| png_set_invert_alpha(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_invert_alpha"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->transformations |= PNG_INVERT_ALPHA; |
| } |
| #endif |
| |
| #if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED) |
| void PNGAPI |
| png_set_invert_mono(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_set_invert_mono"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| png_ptr->transformations |= PNG_INVERT_MONO; |
| } |
| |
| /* Invert monochrome grayscale data */ |
| void /* PRIVATE */ |
| png_do_invert(png_row_infop row_info, png_bytep row) |
| { |
| png_debug(1, "in png_do_invert"); |
| |
| /* This test removed from libpng version 1.0.13 and 1.2.0: |
| * if (row_info->bit_depth == 1 && |
| */ |
| if (row_info->color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| png_bytep rp = row; |
| size_t i; |
| size_t istop = row_info->rowbytes; |
| |
| for (i = 0; i < istop; i++) |
| { |
| *rp = (png_byte)(~(*rp)); |
| rp++; |
| } |
| } |
| |
| else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && |
| row_info->bit_depth == 8) |
| { |
| png_bytep rp = row; |
| size_t i; |
| size_t istop = row_info->rowbytes; |
| |
| for (i = 0; i < istop; i += 2) |
| { |
| *rp = (png_byte)(~(*rp)); |
| rp += 2; |
| } |
| } |
| |
| #ifdef PNG_16BIT_SUPPORTED |
| else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA && |
| row_info->bit_depth == 16) |
| { |
| png_bytep rp = row; |
| size_t i; |
| size_t istop = row_info->rowbytes; |
| |
| for (i = 0; i < istop; i += 4) |
| { |
| *rp = (png_byte)(~(*rp)); |
| *(rp + 1) = (png_byte)(~(*(rp + 1))); |
| rp += 4; |
| } |
| } |
| #endif |
| } |
| #endif |
| |
| #ifdef PNG_16BIT_SUPPORTED |
| #if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED) |
| /* Swaps byte order on 16-bit depth images */ |
| void /* PRIVATE */ |
| png_do_swap(png_row_infop row_info, png_bytep row) |
| { |
| png_debug(1, "in png_do_swap"); |
| |
| if (row_info->bit_depth == 16) |
| { |
| png_bytep rp = row; |
| png_uint_32 i; |
| png_uint_32 istop= row_info->width * row_info->channels; |
| |
| for (i = 0; i < istop; i++, rp += 2) |
| { |
| #ifdef PNG_BUILTIN_BSWAP16_SUPPORTED |
| /* Feature added to libpng-1.6.11 for testing purposes, not |
| * enabled by default. |
| */ |
| *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp); |
| #else |
| png_byte t = *rp; |
| *rp = *(rp + 1); |
| *(rp + 1) = t; |
| #endif |
| } |
| } |
| } |
| #endif |
| #endif |
| |
| #if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED) |
| static const png_byte onebppswaptable[256] = { |
| 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, |
| 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0, |
| 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, |
| 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, |
| 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, |
| 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4, |
| 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, |
| 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, |
| 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, |
| 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, |
| 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, |
| 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, |
| 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, |
| 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6, |
| 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, |
| 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, |
| 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, |
| 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1, |
| 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, |
| 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9, |
| 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, |
| 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, |
| 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, |
| 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD, |
| 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, |
| 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, |
| 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, |
| 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, |
| 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, |
| 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, |
| 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, |
| 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF |
| }; |
| |
| static const png_byte twobppswaptable[256] = { |
| 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0, |
| 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0, |
| 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4, |
| 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4, |
| 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8, |
| 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8, |
| 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC, |
| 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC, |
| 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1, |
| 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1, |
| 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5, |
| 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5, |
| 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9, |
| 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9, |
| 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD, |
| 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD, |
| 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2, |
| 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2, |
| 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6, |
| 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6, |
| 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA, |
| 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA, |
| 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE, |
| 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE, |
| 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3, |
| 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3, |
| 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7, |
| 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7, |
| 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB, |
| 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB, |
| 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF, |
| 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF |
| }; |
| |
| static const png_byte fourbppswaptable[256] = { |
| 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, |
| 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0, |
| 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71, |
| 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1, |
| 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72, |
| 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2, |
| 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73, |
| 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3, |
| 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74, |
| 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4, |
| 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75, |
| 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5, |
| 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76, |
| 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6, |
| 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77, |
| 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7, |
| 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78, |
| 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8, |
| 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79, |
| 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9, |
| 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A, |
| 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA, |
| 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B, |
| 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB, |
| 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C, |
| 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC, |
| 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D, |
| 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD, |
| 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E, |
| 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE, |
| 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F, |
| 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF |
| }; |
| |
| /* Swaps pixel packing order within bytes */ |
| void /* PRIVATE */ |
| png_do_packswap(png_row_infop row_info, png_bytep row) |
| { |
| png_debug(1, "in png_do_packswap"); |
| |
| if (row_info->bit_depth < 8) |
| { |
| png_bytep rp; |
| png_const_bytep end, table; |
| |
| end = row + row_info->rowbytes; |
| |
| if (row_info->bit_depth == 1) |
| table = onebppswaptable; |
| |
| else if (row_info->bit_depth == 2) |
| table = twobppswaptable; |
| |
| else if (row_info->bit_depth == 4) |
| table = fourbppswaptable; |
| |
| else |
| return; |
| |
| for (rp = row; rp < end; rp++) |
| *rp = table[*rp]; |
| } |
| } |
| #endif /* PACKSWAP || WRITE_PACKSWAP */ |
| |
| #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. |
| */ |
| void /* PRIVATE */ |
| png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start) |
| { |
| png_bytep sp = row; /* source pointer */ |
| png_bytep dp = row; /* destination pointer */ |
| png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */ |
| |
| png_debug(1, "in png_do_strip_channel"); |
| |
| /* 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. |
| * |
| * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc. |
| * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc. |
| */ |
| |
| /* GA, GX, XG cases */ |
| if (row_info->channels == 2) |
| { |
| if (row_info->bit_depth == 8) |
| { |
| if (at_start != 0) /* Skip initial filler */ |
| ++sp; |
| else /* Skip initial channel 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; |
| } |
| |
| row_info->pixel_depth = 8; |
| } |
| |
| else if (row_info->bit_depth == 16) |
| { |
| if (at_start != 0) /* Skip initial filler */ |
| sp += 2; |
| else /* Skip initial channel and, for sp, the filler */ |
| { |
| 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; |
| |
| /* 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; |
| } |
| |
| /* RGBA, RGBX, XRGB cases */ |
| else if (row_info->channels == 4) |
| { |
| if (row_info->bit_depth == 8) |
| { |
| if (at_start != 0) /* Skip initial filler */ |
| ++sp; |
| else /* Skip initial channels and, for sp, the filler */ |
| { |
| sp += 4; dp += 3; |
| } |
| |
| /* 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; |
| } |
| |
| row_info->pixel_depth = 24; |
| } |
| |
| else if (row_info->bit_depth == 16) |
| { |
| if (at_start != 0) /* Skip initial filler */ |
| sp += 2; |
| else /* Skip initial channels and, for sp, the filler */ |
| { |
| sp += 8; dp += 6; |
| } |
| |
| while (sp < ep) |
| { |
| /* Copy 6 bytes, skip 2 */ |
| *dp++ = *sp++; *dp++ = *sp++; |
| *dp++ = *sp++; *dp++ = *sp++; |
| *dp++ = *sp++; *dp++ = *sp; sp += 3; |
| } |
| |
| row_info->pixel_depth = 48; |
| } |
| |
| else |
| return; /* bad bit depth */ |
| |
| row_info->channels = 3; |
| |
| /* 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 |
| return; /* The filler channel has gone already */ |
| |
| /* Fix the rowbytes value. */ |
| row_info->rowbytes = (size_t)(dp-row); |
| } |
| #endif |
| |
| #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED) |
| /* Swaps red and blue bytes within a pixel */ |
| void /* PRIVATE */ |
| png_do_bgr(png_row_infop row_info, png_bytep row) |
| { |
| png_debug(1, "in png_do_bgr"); |
| |
| if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| png_uint_32 row_width = row_info->width; |
| if (row_info->bit_depth == 8) |
| { |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| { |
| png_bytep rp; |
| png_uint_32 i; |
| |
| for (i = 0, rp = row; i < row_width; i++, rp += 3) |
| { |
| png_byte save = *rp; |
| *rp = *(rp + 2); |
| *(rp + 2) = save; |
| } |
| } |
| |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| { |
| png_bytep rp; |
| png_uint_32 i; |
| |
| for (i = 0, rp = row; i < row_width; i++, rp += 4) |
| { |
| png_byte save = *rp; |
| *rp = *(rp + 2); |
| *(rp + 2) = save; |
| } |
| } |
| } |
| |
| #ifdef PNG_16BIT_SUPPORTED |
| else if (row_info->bit_depth == 16) |
| { |
| if (row_info->color_type == PNG_COLOR_TYPE_RGB) |
| { |
| png_bytep rp; |
| png_uint_32 i; |
| |
| for (i = 0, rp = row; i < row_width; i++, rp += 6) |
| { |
| png_byte save = *rp; |
| *rp = *(rp + 4); |
| *(rp + 4) = save; |
| save = *(rp + 1); |
| *(rp + 1) = *(rp + 5); |
| *(rp + 5) = save; |
| } |
| } |
| |
| else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA) |
| { |
| png_bytep rp; |
| png_uint_32 i; |
| |
| for (i = 0, rp = row; i < row_width; i++, rp += 8) |
| { |
| png_byte save = *rp; |
| *rp = *(rp + 4); |
| *(rp + 4) = save; |
| save = *(rp + 1); |
| *(rp + 1) = *(rp + 5); |
| *(rp + 5) = save; |
| } |
| } |
| } |
| #endif |
| } |
| } |
| #endif /* READ_BGR || WRITE_BGR */ |
| |
| #if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \ |
| defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED) |
| /* Added at libpng-1.5.10 */ |
| void /* PRIVATE */ |
| png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info) |
| { |
| png_debug(1, "in png_do_check_palette_indexes"); |
| |
| if (png_ptr->num_palette < (1 << row_info->bit_depth) && |
| png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */ |
| { |
| /* Calculations moved outside switch in an attempt to stop different |
| * compiler warnings. 'padding' is in *bits* within the last byte, it is |
| * an 'int' because pixel_depth becomes an 'int' in the expression below, |
| * and this calculation is used because it avoids warnings that other |
| * forms produced on either GCC or MSVC. |
| */ |
| int padding = PNG_PADBITS(row_info->pixel_depth, row_info->width); |
| png_bytep rp = png_ptr->row_buf + row_info->rowbytes; |
| |
| switch (row_info->bit_depth) |
| { |
| case 1: |
| { |
| /* in this case, all bytes must be 0 so we don't need |
| * to unpack the pixels except for the rightmost one. |
| */ |
| for (; rp > png_ptr->row_buf; rp--) |
| { |
| if ((*rp >> padding) != 0) |
| png_ptr->num_palette_max = 1; |
| padding = 0; |
| } |
| |
| break; |
| } |
| |
| case 2: |
| { |
| for (; rp > png_ptr->row_buf; rp--) |
| { |
| int i = ((*rp >> padding) & 0x03); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| i = (((*rp >> padding) >> 2) & 0x03); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| i = (((*rp >> padding) >> 4) & 0x03); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| i = (((*rp >> padding) >> 6) & 0x03); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| padding = 0; |
| } |
| |
| break; |
| } |
| |
| case 4: |
| { |
| for (; rp > png_ptr->row_buf; rp--) |
| { |
| int i = ((*rp >> padding) & 0x0f); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| i = (((*rp >> padding) >> 4) & 0x0f); |
| |
| if (i > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = i; |
| |
| padding = 0; |
| } |
| |
| break; |
| } |
| |
| case 8: |
| { |
| for (; rp > png_ptr->row_buf; rp--) |
| { |
| if (*rp > png_ptr->num_palette_max) |
| png_ptr->num_palette_max = (int) *rp; |
| } |
| |
| break; |
| } |
| |
| default: |
| break; |
| } |
| } |
| } |
| #endif /* CHECK_FOR_INVALID_INDEX */ |
| |
| #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \ |
| defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) |
| #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED |
| void PNGAPI |
| png_set_user_transform_info(png_structrp png_ptr, png_voidp |
| user_transform_ptr, int user_transform_depth, int user_transform_channels) |
| { |
| png_debug(1, "in png_set_user_transform_info"); |
| |
| if (png_ptr == NULL) |
| return; |
| |
| #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED |
| if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && |
| (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0) |
| { |
| png_app_error(png_ptr, |
| "info change after png_start_read_image or png_read_update_info"); |
| return; |
| } |
| #endif |
| |
| png_ptr->user_transform_ptr = user_transform_ptr; |
| png_ptr->user_transform_depth = (png_byte)user_transform_depth; |
| png_ptr->user_transform_channels = (png_byte)user_transform_channels; |
| } |
| #endif |
| |
| /* This function returns a pointer to the user_transform_ptr associated with |
| * the user transform functions. The application should free any memory |
| * associated with this pointer before png_write_destroy and png_read_destroy |
| * are called. |
| */ |
| #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED |
| png_voidp PNGAPI |
| png_get_user_transform_ptr(png_const_structrp png_ptr) |
| { |
| if (png_ptr == NULL) |
| return NULL; |
| |
| return png_ptr->user_transform_ptr; |
| } |
| #endif |
| |
| #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED |
| png_uint_32 PNGAPI |
| png_get_current_row_number(png_const_structrp png_ptr) |
| { |
| /* See the comments in png.h - this is the sub-image row when reading an |
| * interlaced image. |
| */ |
| if (png_ptr != NULL) |
| return png_ptr->row_number; |
| |
| return PNG_UINT_32_MAX; /* help the app not to fail silently */ |
| } |
| |
| png_byte PNGAPI |
| png_get_current_pass_number(png_const_structrp png_ptr) |
| { |
| if (png_ptr != NULL) |
| return png_ptr->pass; |
| return 8; /* invalid */ |
| } |
| #endif /* USER_TRANSFORM_INFO */ |
| #endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */ |
| #endif /* READ || WRITE */ |
