[sdf] Added common elements for sdf' and bsdf' renderers.
* src/sdf/ftsdfrend.c (*): Added common renderer struct and declaration of both the renderers. * src/sdf/ftsdfcommon.h (*): Added common properties, typedefs, macros etc. * src/sdf/ftsdferrs.h (*): Error definitions for the module.
This commit is contained in:
Anuj Verma
parent
29de1ff668
commit
e087e937e8
@ -1,7 +1,136 @@
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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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@ -2,6 +2,15 @@
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#ifndef 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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@ -2,6 +2,95 @@
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#ifndef 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'.
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* It is basically used to store various parameters required by the
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* renderer and some additional parameters which can be used to
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* tweak the 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
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* rendere. `spread' defines the maximum unsigned value that
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* will be present in the final SDF output. For default value
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* check `ftsdfcommon.h'.
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*
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* flip_sign ::
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* By default the position values are inside the contours i.e.
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* filled by a contour. If this property is true then that output
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* will be opposite from the default i.e. negative will be filled
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* by a contour.
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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 glyph which do
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* not have self intersecting contours. Also, removing overlaps
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* require a considerable amount of extra memory and this is not
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* valid while generating SDF from bitmap.
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*
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* @note:
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* All properties except `overlaps' is valid for both `sdf' and
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* `bsdf' renderer.
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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's just a converter which
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* convert 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 a 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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