forked from minhngoc25a/freetype2
138 lines
3.9 KiB
C
138 lines
3.9 KiB
C
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/****************************************************
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*
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* This file contain common function and properties
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* for both `sdf' and `bsdf' renderer.
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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/freetype.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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/**************************************************************************
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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 it is defined to 1 then the rasterizer will use squared distances */
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/* for computation. It can greatly improve the performance but there is */
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/* a chance of overflow and artifacts. You can safely use it upto 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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/* Convenient macro which calls the function */
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/* and returns if any 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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/* [IMPORTANT]: The macro `VECTOR_LENGTH_16D16' is not always the same */
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/* and must not be used anywhere except a few places. This macro is */
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/* controlled by the `USE_SQUARED_DISTANCES' macro. It compute squared */
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/* distance or actual distance based on `USE_SQUARED_DISTANCES' value. */
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/* By using squared distances the performance can be greatly improved */
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/* but there is a risk of overflow. Use it wisely. */
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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_Fixed FT_16D16; /* 16.16 fixed point representation */
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typedef FT_Fixed FT_26D6; /* 26.6 fixed point representation */
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typedef FT_Short FT_6D10; /* 6.10 fixed point representation */
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typedef FT_BBox FT_CBox; /* control box of a curve */
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/**************************************************************************
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*
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* common functions
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*
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*/
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/* Original Algorithm: https://github.com/chmike/fpsqrt */
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/* Use this to compute the square root of a 16.16 fixed */
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/* point number. */
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static FT_16D16
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square_root( FT_16D16 val )
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{
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FT_ULong t, q, b, r;
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r = val;
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b = 0x40000000;
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q = 0;
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while( b > 0x40 )
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{
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t = q + b;
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if( r >= t )
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{
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r -= t;
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q = t + b;
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}
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r <<= 1;
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b >>= 1;
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}
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q >>= 8;
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return q;
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}
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FT_END_HEADER
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#endif /* FTSDFCOMMON_H_ */
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/* END */
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