ref: 369d8be97f537c56f2dbd1d3bd23aba74dc24cea
dir: /src/sfnt/pngshim.c/
/**************************************************************************** * * pngshim.c * * PNG Bitmap glyph support. * * Copyright (C) 2013-2021 by * Google, Inc. * Written by Stuart Gill and Behdad Esfahbod. * * This file is part of the FreeType project, and may only be used, * modified, and distributed under the terms of the FreeType project * license, LICENSE.TXT. By continuing to use, modify, or distribute * this file you indicate that you have read the license and * understand and accept it fully. * */ #include <freetype/internal/ftdebug.h> #include <freetype/internal/ftstream.h> #include <freetype/tttags.h> #include FT_CONFIG_STANDARD_LIBRARY_H #if defined( TT_CONFIG_OPTION_EMBEDDED_BITMAPS ) && \ defined( FT_CONFIG_OPTION_USE_PNG ) /* We always include <setjmp.h>, so make libpng shut up! */ #define PNG_SKIP_SETJMP_CHECK 1 #include <png.h> #include "pngshim.h" #include "sferrors.h" /* This code is freely based on cairo-png.c. There's so many ways */ /* to call libpng, and the way cairo does it is defacto standard. */ static unsigned int multiply_alpha( unsigned int alpha, unsigned int color ) { unsigned int temp = alpha * color + 0x80; return ( temp + ( temp >> 8 ) ) >> 8; } /* Premultiplies data and converts RGBA bytes => BGRA. */ static void premultiply_data( png_structp png, png_row_infop row_info, png_bytep data ) { unsigned int i = 0, limit; /* The `vector_size' attribute was introduced in gcc 3.1, which */ /* predates clang; the `__BYTE_ORDER__' preprocessor symbol was */ /* introduced in gcc 4.6 and clang 3.2, respectively. */ /* `__builtin_shuffle' for gcc was introduced in gcc 4.7.0. */ /* */ /* Intel compilers do not currently support __builtin_shuffle; */ /* The Intel check must be first. */ #if !defined( __INTEL_COMPILER ) && \ ( ( defined( __GNUC__ ) && \ ( ( __GNUC__ >= 5 ) || \ ( ( __GNUC__ == 4 ) && ( __GNUC_MINOR__ >= 7 ) ) ) ) || \ ( defined( __clang__ ) && \ ( ( __clang_major__ >= 4 ) || \ ( ( __clang_major__ == 3 ) && ( __clang_minor__ >= 2 ) ) ) ) ) && \ defined( __OPTIMIZE__ ) && \ defined( __SSE__ ) && \ __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ #ifdef __clang__ /* the clang documentation doesn't cover the two-argument case of */ /* `__builtin_shufflevector'; however, it is is implemented since */ /* version 2.8 */ #define vector_shuffle __builtin_shufflevector #else #define vector_shuffle __builtin_shuffle #endif typedef unsigned short v82 __attribute__(( vector_size( 16 ) )); if ( row_info->rowbytes > 15 ) { /* process blocks of 16 bytes in one rush, which gives a nice speed-up */ limit = row_info->rowbytes - 16 + 1; for ( ; i < limit; i += 16 ) { unsigned char* base = &data[i]; v82 s, s0, s1, a; /* clang <= 3.9 can't apply scalar values to vectors */ /* (or rather, it needs a different syntax) */ v82 n0x80 = { 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 }; v82 n0xFF = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; v82 n8 = { 8, 8, 8, 8, 8, 8, 8, 8 }; v82 ma = { 1, 1, 3, 3, 5, 5, 7, 7 }; v82 o1 = { 0, 0xFF, 0, 0xFF, 0, 0xFF, 0, 0xFF }; v82 m0 = { 1, 0, 3, 2, 5, 4, 7, 6 }; ft_memcpy( &s, base, 16 ); /* RGBA RGBA RGBA RGBA */ s0 = s & n0xFF; /* R B R B R B R B */ s1 = s >> n8; /* G A G A G A G A */ a = vector_shuffle( s1, ma ); /* A A A A A A A A */ s1 |= o1; /* G 1 G 1 G 1 G 1 */ s0 = vector_shuffle( s0, m0 ); /* B R B R B R B R */ s0 *= a; s1 *= a; s0 += n0x80; s1 += n0x80; s0 = ( s0 + ( s0 >> n8 ) ) >> n8; s1 = ( s1 + ( s1 >> n8 ) ) >> n8; s = s0 | ( s1 << n8 ); ft_memcpy( base, &s, 16 ); } } #endif /* use `vector_size' */ FT_UNUSED( png ); limit = row_info->rowbytes; for ( ; i < limit; i += 4 ) { unsigned char* base = &data[i]; unsigned int alpha = base[3]; if ( alpha == 0 ) base[0] = base[1] = base[2] = base[3] = 0; else { unsigned int red = base[0]; unsigned int green = base[1]; unsigned int blue = base[2]; if ( alpha != 0xFF ) { red = multiply_alpha( alpha, red ); green = multiply_alpha( alpha, green ); blue = multiply_alpha( alpha, blue ); } base[0] = (unsigned char)blue; base[1] = (unsigned char)green; base[2] = (unsigned char)red; base[3] = (unsigned char)alpha; } } } /* Converts RGBx bytes to BGRA. */ static void convert_bytes_to_data( png_structp png, png_row_infop row_info, png_bytep data ) { unsigned int i; FT_UNUSED( png ); for ( i = 0; i < row_info->rowbytes; i += 4 ) { unsigned char* base = &data[i]; unsigned int red = base[0]; unsigned int green = base[1]; unsigned int blue = base[2]; base[0] = (unsigned char)blue; base[1] = (unsigned char)green; base[2] = (unsigned char)red; base[3] = 0xFF; } } /* Use error callback to avoid png writing to stderr. */ static void error_callback( png_structp png, png_const_charp error_msg ) { FT_Error* error = (FT_Error*)png_get_error_ptr( png ); FT_UNUSED( error_msg ); *error = FT_THROW( Out_Of_Memory ); #ifdef PNG_SETJMP_SUPPORTED ft_longjmp( png_jmpbuf( png ), 1 ); #endif /* if we get here, then we have no choice but to abort ... */ } /* Use warning callback to avoid png writing to stderr. */ static void warning_callback( png_structp png, png_const_charp error_msg ) { FT_UNUSED( png ); FT_UNUSED( error_msg ); /* Just ignore warnings. */ } static void read_data_from_FT_Stream( png_structp png, png_bytep data, png_size_t length ) { FT_Error error; png_voidp p = png_get_io_ptr( png ); FT_Stream stream = (FT_Stream)p; if ( FT_FRAME_ENTER( length ) ) { FT_Error* e = (FT_Error*)png_get_error_ptr( png ); *e = FT_THROW( Invalid_Stream_Read ); png_error( png, NULL ); return; } ft_memcpy( data, stream->cursor, length ); FT_FRAME_EXIT(); } FT_LOCAL_DEF( FT_Error ) Load_SBit_Png( FT_GlyphSlot slot, FT_Int x_offset, FT_Int y_offset, FT_Int pix_bits, TT_SBit_Metrics metrics, FT_Memory memory, FT_Byte* data, FT_UInt png_len, FT_Bool populate_map_and_metrics, FT_Bool metrics_only ) { FT_Bitmap *map = &slot->bitmap; FT_Error error = FT_Err_Ok; FT_StreamRec stream; png_structp png; png_infop info; png_uint_32 imgWidth, imgHeight; int bitdepth, color_type, interlace; FT_Int i; /* `rows` gets modified within a 'setjmp' scope; */ /* we thus need the `volatile` keyword. */ png_byte* *volatile rows = NULL; if ( x_offset < 0 || y_offset < 0 ) { error = FT_THROW( Invalid_Argument ); goto Exit; } if ( !populate_map_and_metrics && ( (FT_UInt)x_offset + metrics->width > map->width || (FT_UInt)y_offset + metrics->height > map->rows || pix_bits != 32 || map->pixel_mode != FT_PIXEL_MODE_BGRA ) ) { error = FT_THROW( Invalid_Argument ); goto Exit; } FT_Stream_OpenMemory( &stream, data, png_len ); png = png_create_read_struct( PNG_LIBPNG_VER_STRING, &error, error_callback, warning_callback ); if ( !png ) { error = FT_THROW( Out_Of_Memory ); goto Exit; } info = png_create_info_struct( png ); if ( !info ) { error = FT_THROW( Out_Of_Memory ); png_destroy_read_struct( &png, NULL, NULL ); goto Exit; } if ( ft_setjmp( png_jmpbuf( png ) ) ) { error = FT_THROW( Invalid_File_Format ); goto DestroyExit; } png_set_read_fn( png, &stream, read_data_from_FT_Stream ); png_read_info( png, info ); png_get_IHDR( png, info, &imgWidth, &imgHeight, &bitdepth, &color_type, &interlace, NULL, NULL ); if ( error || ( !populate_map_and_metrics && ( (FT_Int)imgWidth != metrics->width || (FT_Int)imgHeight != metrics->height ) ) ) goto DestroyExit; if ( populate_map_and_metrics ) { /* reject too large bitmaps similarly to the rasterizer */ if ( imgHeight > 0x7FFF || imgWidth > 0x7FFF ) { error = FT_THROW( Array_Too_Large ); goto DestroyExit; } metrics->width = (FT_UShort)imgWidth; metrics->height = (FT_UShort)imgHeight; map->width = metrics->width; map->rows = metrics->height; map->pixel_mode = FT_PIXEL_MODE_BGRA; map->pitch = (int)( map->width * 4 ); map->num_grays = 256; } /* convert palette/gray image to rgb */ if ( color_type == PNG_COLOR_TYPE_PALETTE ) png_set_palette_to_rgb( png ); /* expand gray bit depth if needed */ if ( color_type == PNG_COLOR_TYPE_GRAY ) { #if PNG_LIBPNG_VER >= 10209 png_set_expand_gray_1_2_4_to_8( png ); #else png_set_gray_1_2_4_to_8( png ); #endif } /* transform transparency to alpha */ if ( png_get_valid(png, info, PNG_INFO_tRNS ) ) png_set_tRNS_to_alpha( png ); if ( bitdepth == 16 ) png_set_strip_16( png ); if ( bitdepth < 8 ) png_set_packing( png ); /* convert grayscale to RGB */ if ( color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA ) png_set_gray_to_rgb( png ); if ( interlace != PNG_INTERLACE_NONE ) png_set_interlace_handling( png ); png_set_filler( png, 0xFF, PNG_FILLER_AFTER ); /* recheck header after setting EXPAND options */ png_read_update_info(png, info ); png_get_IHDR( png, info, &imgWidth, &imgHeight, &bitdepth, &color_type, &interlace, NULL, NULL ); if ( bitdepth != 8 || !( color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_RGB_ALPHA ) ) { error = FT_THROW( Invalid_File_Format ); goto DestroyExit; } if ( metrics_only ) goto DestroyExit; switch ( color_type ) { default: /* Shouldn't happen, but fall through. */ case PNG_COLOR_TYPE_RGB_ALPHA: png_set_read_user_transform_fn( png, premultiply_data ); break; case PNG_COLOR_TYPE_RGB: /* Humm, this smells. Carry on though. */ png_set_read_user_transform_fn( png, convert_bytes_to_data ); break; } if ( populate_map_and_metrics ) { /* this doesn't overflow: 0x7FFF * 0x7FFF * 4 < 2^32 */ FT_ULong size = map->rows * (FT_ULong)map->pitch; error = ft_glyphslot_alloc_bitmap( slot, size ); if ( error ) goto DestroyExit; } if ( FT_NEW_ARRAY( rows, imgHeight ) ) { error = FT_THROW( Out_Of_Memory ); goto DestroyExit; } for ( i = 0; i < (FT_Int)imgHeight; i++ ) rows[i] = map->buffer + ( y_offset + i ) * map->pitch + x_offset * 4; png_read_image( png, rows ); png_read_end( png, info ); DestroyExit: /* even if reading fails with longjmp, rows must be freed */ FT_FREE( rows ); png_destroy_read_struct( &png, &info, NULL ); FT_Stream_Close( &stream ); Exit: return error; } #else /* !(TT_CONFIG_OPTION_EMBEDDED_BITMAPS && FT_CONFIG_OPTION_USE_PNG) */ /* ANSI C doesn't like empty source files */ typedef int _pngshim_dummy; #endif /* !(TT_CONFIG_OPTION_EMBEDDED_BITMAPS && FT_CONFIG_OPTION_USE_PNG) */ /* END */