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kc3-lang/freetype/src/sdf/ftsdfcommon.h
Werner Lemberg
- src/sdf/ftsdfcommon.h
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/**************************************************************************** * * ftsdfcommon.h * * Auxiliary data for Signed Distance Field support (specification only). * * Copyright (C) 2020-2021 by * David Turner, Robert Wilhelm, and Werner Lemberg. * * Written by Anuj Verma. * * 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. * */ /**************************************************** * * This file contains common functions and properties * for both the 'sdf' and 'bsdf' renderers. * */ #ifndef FTSDFCOMMON_H_ #define FTSDFCOMMON_H_ #include <ft2build.h> #include FT_CONFIG_CONFIG_H #include <freetype/freetype.h> FT_BEGIN_HEADER /************************************************************************** * * default values (cannot be set individually for each renderer) * */ /* default spread value */ #define DEFAULT_SPREAD 8 /* minimum spread supported by the renderer */ #define MIN_SPREAD 2 /* maximum spread supported by the renderer */ #define MAX_SPREAD 32 /************************************************************************** * * common definitions (cannot be set individually for each renderer) * */ /* If this macro is set to 1 the rasterizer uses squared distances for */ /* computation. It can greatly improve the performance but there is a */ /* chance of overflow and artifacts. You can safely use it up to a */ /* pixel size of 128. */ #ifndef USE_SQUARED_DISTANCES #define USE_SQUARED_DISTANCES 0 #endif /************************************************************************** * * common macros * */ /* convert int to 26.6 fixed-point */ #define FT_INT_26D6( x ) ( x * 64 ) /* convert int to 16.16 fixed-point */ #define FT_INT_16D16( x ) ( x * 65536 ) /* convert 26.6 to 16.16 fixed-point */ #define FT_26D6_16D16( x ) ( x * 1024 ) /* Convenience macro to call a function; it */ /* jumps to label `Exit` if an error occurs. */ #define FT_CALL( x ) do \ { \ error = ( x ); \ if ( error != FT_Err_Ok ) \ goto Exit; \ } while ( 0 ) /* * The macro `VECTOR_LENGTH_16D16` computes either squared distances or * actual distances, depending on the value of `USE_SQUARED_DISTANCES`. * * By using squared distances the performance can be greatly improved but * there is a risk of overflow. */ #if USE_SQUARED_DISTANCES #define VECTOR_LENGTH_16D16( v ) ( FT_MulFix( v.x, v.x ) + \ FT_MulFix( v.y, v.y ) ) #else #define VECTOR_LENGTH_16D16( v ) FT_Vector_Length( &v ) #endif /************************************************************************** * * common typedefs * */ typedef FT_Vector FT_26D6_Vec; /* with 26.6 fixed-point components */ typedef FT_Vector FT_16D16_Vec; /* with 16.16 fixed-point components */ typedef FT_Fixed FT_16D16; /* 16.16 fixed-point representation */ typedef FT_Fixed FT_26D6; /* 26.6 fixed-point representation */ typedef FT_Short FT_6D10; /* 6.10 fixed-point representation */ typedef FT_BBox FT_CBox; /* control box of a curve */ /************************************************************************** * * common functions * */ /* * Original algorithm: * * https://github.com/chmike/fpsqrt * * Use this to compute the square root of a 16.16 fixed point number. */ static FT_16D16 square_root( FT_16D16 val ) { FT_ULong t, q, b, r; r = val; b = 0x40000000L; q = 0; while ( b > 0x40L ) { t = q + b; if ( r >= t ) { r -= t; q = t + b; } r <<= 1; b >>= 1; } q >>= 8; return q; } FT_END_HEADER #endif /* FTSDFCOMMON_H_ */ /* END */