forked from minhngoc25a/freetype2
[sdf] Add common elements for 'sdf' and 'bsdf' renderers.
* src/sdf/ftsdfrend.h (SDF_Rendere_Module, ft_sdf_renderer_class, ft_bitmap_sdf_renderer_class): New structures. * src/sdf/ftsdfcommon.h (DEFAULT_SPREAD, MIN_SPREAD_MAX_SPREAD, USE_SQUARED_DISTANCES): New macros. (FT_INT_26D6, FT_INT_16D16, FT_26D6_16D16): New macros. (FT_CALL, VECTOR_LENGTH_16D16): New macros. (FT_26D6_Vec, FT_16D16_Vec, FT_16D16, FT_26D6, FT_6D10, FT_CBox): New typedefs. (square_root): New macro. * src/sdf/ftsdferrs.h: Add module error setup.
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ChangeLog
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ChangeLog
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@ -1,3 +1,20 @@
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2020-08-17 Anuj Verma <anujv@iitbhilai.ac.in>
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[sdf] Add common elements for 'sdf' and 'bsdf' renderers.
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* src/sdf/ftsdfrend.h (SDF_Rendere_Module, ft_sdf_renderer_class,
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ft_bitmap_sdf_renderer_class): New structures.
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* src/sdf/ftsdfcommon.h (DEFAULT_SPREAD, MIN_SPREAD_MAX_SPREAD,
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USE_SQUARED_DISTANCES): New macros.
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(FT_INT_26D6, FT_INT_16D16, FT_26D6_16D16): New macros.
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(FT_CALL, VECTOR_LENGTH_16D16): New macros.
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(FT_26D6_Vec, FT_16D16_Vec, FT_16D16, FT_26D6, FT_6D10, FT_CBox):
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New typedefs.
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(square_root): New macro.
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* src/sdf/ftsdferrs.h: Add module error setup.
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2020-08-16 Anuj Verma <anujv@iitbhilai.ac.in>
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2020-08-16 Anuj Verma <anujv@iitbhilai.ac.in>
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[sdf] Add files for new 'sdf' module.
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[sdf] Add files for new 'sdf' module.
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@ -1,7 +1,150 @@
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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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#ifndef FTSDFCOMMON_H_
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#define 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 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_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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/*
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* Original algorithm:
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*
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* https://github.com/chmike/fpsqrt
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*
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* Use this to compute the square root of a 16.16 fixed point number.
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*/
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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 = 0x40000000L;
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q = 0;
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while ( b > 0x40L )
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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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#endif /* FTSDFCOMMON_H_ */
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#ifndef FTSDFERRS_H_
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#ifndef FTSDFERRS_H_
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#define FTSDFERRS_H_
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#define FTSDFERRS_H_
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#include <freetype/ftmoderr.h>
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#undef FTERRORS_H_
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#undef FT_ERR_PREFIX
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#define FT_ERR_PREFIX Sdf_Err_
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#define FT_ERR_BASE FT_Mod_Err_Sdf
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#include <freetype/fterrors.h>
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#endif /* FTSDFERRS_H_ */
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#endif /* FTSDFERRS_H_ */
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#ifndef FTSDFREND_H_
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#ifndef FTSDFREND_H_
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#define FTSDFREND_H_
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#define FTSDFREND_H_
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#include <freetype/ftrender.h>
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#include <freetype/ftmodapi.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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* @struct:
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* SDF_Renderer_Module
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*
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* @description:
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* This struct extends the native renderer struct `FT_RendererRec`. It
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* is basically used to store various parameters required by the
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* renderer and some additional parameters that can be used to tweak the
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* output of the renderer.
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*
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* @fields:
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* root ::
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* The native rendere struct.
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*
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* spread ::
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* This is an essential parameter/property required by the renderer.
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* `spread` defines the maximum unsigned value that is present in the
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* final SDF output. For the default value check file
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* `ftsdfcommon.h`.
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*
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* flip_sign ::
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* By default positive values indicate positions inside of contours,
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* i.e., filled by a contour. If this property is true then that
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* output will be the opposite of the default, i.e., negative values
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* indicate positions inside of contours.
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*
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* flip_y ::
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* Setting this parameter to true makes the output image flipped
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* along the y-axis.
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*
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* overlaps ::
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* Set this to true to generate SDF for glyphs having overlapping
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* contours. The overlapping support is limited to glyphs that do not
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* have self-intersecting contours. Also, removing overlaps require a
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* considerable amount of extra memory; additionally, it will not work
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* if generating SDF from bitmap.
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*
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* @note:
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* All properties except `overlaps` are valid for both the 'sdf' and
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* 'bsdf' renderers.
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*/
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typedef struct SDF_Renderer_Module_
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{
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FT_RendererRec root;
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FT_UInt spread;
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FT_Bool flip_sign;
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FT_Bool flip_y;
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FT_Bool overlaps;
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} SDF_Renderer_Module, *SDF_Renderer;
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/**************************************************************************
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*
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* @renderer:
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* ft_sdf_renderer_class
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*
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* @description:
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* Renderer to convert @FT_Outline to signed distance fields.
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*
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*/
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FT_DECLARE_RENDERER( ft_sdf_renderer_class )
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/**************************************************************************
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*
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* @renderer:
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* ft_bitmap_sdf_renderer_class
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*
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* @description:
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* This is not exactly a renderer; it is just a converter that
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* transforms bitmaps to signed distance fields.
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*
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* @note:
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* This is not a separate module, it is part of the 'sdf' module.
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*
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*/
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FT_DECLARE_RENDERER( ft_bitmap_sdf_renderer_class )
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FT_END_HEADER
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#endif /* FTSDFREND_H_ */
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#endif /* FTSDFREND_H_ */
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