ref: d31bafcb9ce7dee7036089a394556ebf201221ec
dir: /src/sdf/ftsdfcommon.h/
/****************************************************************************
*
* ftsdfcommon.h
*
* Auxiliary data for Signed Distance Field support (specification).
*
* 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/internal/ftobjs.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_Byte FT_SDFFormat; /* format to represent SDF data */
typedef FT_BBox FT_CBox; /* control box of a curve */
FT_LOCAL( FT_16D16 )
square_root( FT_16D16 val );
FT_LOCAL( FT_SDFFormat )
map_fixed_to_sdf( FT_16D16 dist,
FT_16D16 max_value );
FT_LOCAL( FT_SDFFormat )
invert_sign( FT_SDFFormat dist );
FT_END_HEADER
#endif /* FTSDFCOMMON_H_ */
/* END */