142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
/****************************************************************************
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*
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* ftsdfcommon.h
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*
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* Auxiliary data for Signed Distance Field support (specification).
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*
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* Copyright (C) 2020-2023 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* Written by Anuj Verma.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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/****************************************************
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*
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* This file contains common functions and properties
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* for both the 'sdf' and 'bsdf' renderers.
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*
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*/
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#ifndef FTSDFCOMMON_H_
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#define FTSDFCOMMON_H_
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#include <ft2build.h>
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#include FT_CONFIG_CONFIG_H
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#include <freetype/internal/ftobjs.h>
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FT_BEGIN_HEADER
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/**************************************************************************
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*
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* default values (cannot be set individually for each renderer)
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*
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*/
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/* default spread value */
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#define DEFAULT_SPREAD 8
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/* minimum spread supported by the renderer */
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#define MIN_SPREAD 2
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/* maximum spread supported by the renderer */
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#define MAX_SPREAD 32
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/* pixel size in 26.6 */
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#define ONE_PIXEL ( 1 << 6 )
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/**************************************************************************
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*
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* common definitions (cannot be set individually for each renderer)
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*
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*/
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/* If this macro is set to 1 the rasterizer uses squared distances for */
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/* computation. It can greatly improve the performance but there is a */
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/* chance of overflow and artifacts. You can safely use it up to a */
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/* pixel size of 128. */
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#ifndef USE_SQUARED_DISTANCES
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#define USE_SQUARED_DISTANCES 0
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#endif
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/**************************************************************************
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*
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* common macros
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*
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*/
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/* convert int to 26.6 fixed-point */
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#define FT_INT_26D6( x ) ( x * 64 )
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/* convert int to 16.16 fixed-point */
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#define FT_INT_16D16( x ) ( x * 65536 )
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/* convert 26.6 to 16.16 fixed-point */
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#define FT_26D6_16D16( x ) ( x * 1024 )
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/* Convenience macro to call a function; it */
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/* jumps to label `Exit` if an error occurs. */
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#define FT_CALL( x ) do \
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{ \
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error = ( x ); \
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if ( error != FT_Err_Ok ) \
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goto Exit; \
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} while ( 0 )
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/*
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* The macro `VECTOR_LENGTH_16D16` computes either squared distances or
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* actual distances, depending on the value of `USE_SQUARED_DISTANCES`.
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*
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* By using squared distances the performance can be greatly improved but
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* there is a risk of overflow.
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*/
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#if USE_SQUARED_DISTANCES
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#define VECTOR_LENGTH_16D16( v ) ( FT_MulFix( v.x, v.x ) + \
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FT_MulFix( v.y, v.y ) )
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#else
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#define VECTOR_LENGTH_16D16( v ) FT_Vector_Length( &v )
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#endif
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/**************************************************************************
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*
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* common typedefs
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*
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*/
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typedef FT_Vector FT_26D6_Vec; /* with 26.6 fixed-point components */
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typedef FT_Vector FT_16D16_Vec; /* with 16.16 fixed-point components */
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typedef FT_Int32 FT_16D16; /* 16.16 fixed-point representation */
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typedef FT_Int32 FT_26D6; /* 26.6 fixed-point representation */
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typedef FT_Byte FT_SDFFormat; /* format to represent SDF data */
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typedef FT_BBox FT_CBox; /* control box of a curve */
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FT_LOCAL( FT_16D16 )
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square_root( FT_16D16 val );
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FT_LOCAL( FT_SDFFormat )
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map_fixed_to_sdf( FT_16D16 dist,
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FT_16D16 max_value );
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FT_LOCAL( FT_SDFFormat )
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invert_sign( FT_SDFFormat dist );
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FT_END_HEADER
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#endif /* FTSDFCOMMON_H_ */
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/* END */
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