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/****************************************************************************
*
* ftsdf.h
*
* Signed Distance Field support (specification).
*
* Copyright (C) 2020-2022 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.
*
*/
#ifndef FTSDF_H_
#define FTSDF_H_
#include <ft2build.h>
#include FT_CONFIG_CONFIG_H
#include <freetype/ftimage.h>
/* common properties and function */
#include "ftsdfcommon.h"
FT_BEGIN_HEADER
/**************************************************************************
*
* @struct:
* SDF_Raster_Params
*
* @description:
* This struct must be passed to the raster render function
* @FT_Raster_RenderFunc instead of @FT_Raster_Params because the
* rasterizer requires some additional information to render properly.
*
* @fields:
* root ::
* The native raster parameters structure.
*
* spread ::
* This is an essential parameter/property required by the renderer.
* `spread` defines the maximum unsigned value that is present in the
* final SDF output. For the default value check file
* `ftsdfcommon.h`.
*
* flip_sign ::
* By default positive values indicate positions inside of contours,
* i.e., filled by a contour. If this property is true then that
* output will be the opposite of the default, i.e., negative values
* indicate positions inside of contours.
*
* flip_y ::
* Setting this parameter to true maked the output image flipped
* along the y-axis.
*
* overlaps ::
* Set this to true to generate SDF for glyphs having overlapping
* contours. The overlapping support is limited to glyphs that do not
* have self-intersecting contours. Also, removing overlaps require a
* considerable amount of extra memory; additionally, it will not work
* if generating SDF from bitmap.
*
* @note:
* All properties are valid for both the 'sdf' and 'bsdf' renderers; the
* exception is `overlaps`, which gets ignored by the 'bsdf' renderer.
*
*/
typedef struct SDF_Raster_Params_
{
FT_Raster_Params root;
FT_UInt spread;
FT_Bool flip_sign;
FT_Bool flip_y;
FT_Bool overlaps;
} SDF_Raster_Params;
/* rasterizer to convert outline to SDF */
FT_EXPORT_VAR( const FT_Raster_Funcs ) ft_sdf_raster;
/* rasterizer to convert bitmap to SDF */
FT_EXPORT_VAR( const FT_Raster_Funcs ) ft_bitmap_sdf_raster;
FT_END_HEADER
#endif /* FTSDF_H_ */
/* END */
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