forked from minhngoc25a/freetype2
98 lines
2.8 KiB
C
98 lines
2.8 KiB
C
/****************************************************************************
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*
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* ftsdf.h
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*
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* Signed Distance Field support (specification).
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*
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* Copyright (C) 2020-2021 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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#ifndef FTSDF_H_
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#define FTSDF_H_
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#include <ft2build.h>
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#include FT_CONFIG_CONFIG_H
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#include <freetype/ftimage.h>
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/* common properties and function */
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#include "ftsdfcommon.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_Raster_Params
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*
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* @description:
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* This struct must be passed to the raster render function
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* @FT_Raster_RenderFunc instead of @FT_Raster_Params because the
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* rasterizer requires some additional information to render properly.
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*
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* @fields:
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* root ::
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* The native raster parameters structure.
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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 maked 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 are valid for both the 'sdf' and 'bsdf' renderers; the
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* exception is `overlaps`, which gets ignored by the 'bsdf' renderer.
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*
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*/
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typedef struct SDF_Raster_Params_
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{
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FT_Raster_Params 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_Raster_Params;
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/* rasterizer to convert outline to SDF */
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FT_EXPORT_VAR( const FT_Raster_Funcs ) ft_sdf_raster;
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/* rasterizer to convert bitmap to SDF */
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FT_EXPORT_VAR( const FT_Raster_Funcs ) ft_bitmap_sdf_raster;
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FT_END_HEADER
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#endif /* FTSDF_H_ */
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/* END */
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