717 lines
19 KiB
C
717 lines
19 KiB
C
/***************************************************************************/
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/* */
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/* ftstroke.h */
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/* */
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/* FreeType path stroker (specification). */
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/* */
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/* Copyright 2002, 2003, 2004, 2005, 2006, 2008 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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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 __FT_STROKE_H__
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#define __FT_STROKE_H__
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#include <ft2build.h>
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#include FT_OUTLINE_H
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#include FT_GLYPH_H
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FT_BEGIN_HEADER
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/************************************************************************
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*
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* @section:
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* glyph_stroker
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*
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* @title:
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* Glyph Stroker
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*
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* @abstract:
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* Generating bordered and stroked glyphs.
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*
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* @description:
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* This component generates stroked outlines of a given vectorial
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* glyph. It also allows you to retrieve the `outside' and/or the
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* `inside' borders of the stroke.
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*
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* This can be useful to generate `bordered' glyph, i.e., glyphs
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* displayed with a coloured (and anti-aliased) border around their
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* shape.
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*/
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/**************************************************************
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*
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* @type:
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* FT_Stroker
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*
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* @description:
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* Opaque handler to a path stroker object.
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*/
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typedef struct FT_StrokerRec_* FT_Stroker;
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/**************************************************************
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*
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* @enum:
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* FT_Stroker_LineJoin
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*
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* @description:
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* These values determine how two joining lines are rendered
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* in a stroker.
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*
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* @values:
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* FT_STROKER_LINEJOIN_ROUND ::
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* Used to render rounded line joins. Circular arcs are used
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* to join two lines smoothly.
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*
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* FT_STROKER_LINEJOIN_BEVEL ::
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* Used to render beveled line joins; i.e., the two joining lines
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* are extended until they intersect.
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*
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* FT_STROKER_LINEJOIN_MITER ::
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* Same as beveled rendering, except that an additional line
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* break is added if the angle between the two joining lines
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* is too closed (this is useful to avoid unpleasant spikes
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* in beveled rendering).
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*/
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typedef enum FT_Stroker_LineJoin_
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{
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FT_STROKER_LINEJOIN_ROUND = 0,
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FT_STROKER_LINEJOIN_BEVEL,
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FT_STROKER_LINEJOIN_MITER
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} FT_Stroker_LineJoin;
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/**************************************************************
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*
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* @enum:
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* FT_Stroker_LineCap
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*
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* @description:
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* These values determine how the end of opened sub-paths are
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* rendered in a stroke.
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*
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* @values:
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* FT_STROKER_LINECAP_BUTT ::
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* The end of lines is rendered as a full stop on the last
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* point itself.
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*
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* FT_STROKER_LINECAP_ROUND ::
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* The end of lines is rendered as a half-circle around the
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* last point.
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*
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* FT_STROKER_LINECAP_SQUARE ::
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* The end of lines is rendered as a square around the
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* last point.
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*/
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typedef enum FT_Stroker_LineCap_
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{
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FT_STROKER_LINECAP_BUTT = 0,
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FT_STROKER_LINECAP_ROUND,
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FT_STROKER_LINECAP_SQUARE
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} FT_Stroker_LineCap;
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/**************************************************************
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*
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* @enum:
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* FT_StrokerBorder
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*
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* @description:
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* These values are used to select a given stroke border
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* in @FT_Stroker_GetBorderCounts and @FT_Stroker_ExportBorder.
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*
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* @values:
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* FT_STROKER_BORDER_LEFT ::
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* Select the left border, relative to the drawing direction.
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*
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* FT_STROKER_BORDER_RIGHT ::
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* Select the right border, relative to the drawing direction.
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*
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* @note:
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* Applications are generally interested in the `inside' and `outside'
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* borders. However, there is no direct mapping between these and the
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* `left' and `right' ones, since this really depends on the glyph's
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* drawing orientation, which varies between font formats.
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*
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* You can however use @FT_Outline_GetInsideBorder and
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* @FT_Outline_GetOutsideBorder to get these.
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*/
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typedef enum FT_StrokerBorder_
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{
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FT_STROKER_BORDER_LEFT = 0,
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FT_STROKER_BORDER_RIGHT
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} FT_StrokerBorder;
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/**************************************************************
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*
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* @function:
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* FT_Outline_GetInsideBorder
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*
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* @description:
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* Retrieve the @FT_StrokerBorder value corresponding to the
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* `inside' borders of a given outline.
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*
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* @input:
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* outline ::
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* The source outline handle.
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*
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* @return:
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* The border index. @FT_STROKER_BORDER_LEFT for empty or invalid
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* outlines.
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*/
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FT_EXPORT( FT_StrokerBorder )
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FT_Outline_GetInsideBorder( FT_Outline* outline );
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/**************************************************************
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*
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* @function:
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* FT_Outline_GetOutsideBorder
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*
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* @description:
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* Retrieve the @FT_StrokerBorder value corresponding to the
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* `outside' borders of a given outline.
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*
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* @input:
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* outline ::
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* The source outline handle.
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*
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* @return:
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* The border index. @FT_STROKER_BORDER_LEFT for empty or invalid
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* outlines.
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*/
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FT_EXPORT( FT_StrokerBorder )
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FT_Outline_GetOutsideBorder( FT_Outline* outline );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_New
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*
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* @description:
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* Create a new stroker object.
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*
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* @input:
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* library ::
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* FreeType library handle.
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*
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* @output:
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* astroker ::
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* A new stroker object handle. NULL in case of error.
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*
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* @return:
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* FreeType error code. 0~means success.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_New( FT_Library library,
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FT_Stroker *astroker );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_Set
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*
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* @description:
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* Reset a stroker object's attributes.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* radius ::
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* The border radius.
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*
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* line_cap ::
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* The line cap style.
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*
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* line_join ::
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* The line join style.
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*
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* miter_limit ::
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* The miter limit for the FT_STROKER_LINEJOIN_MITER style,
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* expressed as 16.16 fixed point value.
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*
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* @note:
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* The radius is expressed in the same units that the outline
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* coordinates.
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*/
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FT_EXPORT( void )
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FT_Stroker_Set( FT_Stroker stroker,
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FT_Fixed radius,
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FT_Stroker_LineCap line_cap,
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FT_Stroker_LineJoin line_join,
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FT_Fixed miter_limit );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_Rewind
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*
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* @description:
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* Reset a stroker object without changing its attributes.
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* You should call this function before beginning a new
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* series of calls to @FT_Stroker_BeginSubPath or
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* @FT_Stroker_EndSubPath.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*/
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FT_EXPORT( void )
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FT_Stroker_Rewind( FT_Stroker stroker );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_ParseOutline
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*
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* @description:
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* A convenience function used to parse a whole outline with
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* the stroker. The resulting outline(s) can be retrieved
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* later by functions like @FT_Stroker_GetCounts and @FT_Stroker_Export.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* outline ::
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* The source outline.
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*
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* opened ::
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* A boolean. If~1, the outline is treated as an open path instead
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* of a closed one.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* If `opened' is~0 (the default), the outline is treated as a closed
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* path, and the stroker will generate two distinct `border' outlines.
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*
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* If `opened' is~1, the outline is processed as an open path, and the
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* stroker will generate a single `stroke' outline.
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*
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* This function calls @FT_Stroker_Rewind automatically.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_ParseOutline( FT_Stroker stroker,
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FT_Outline* outline,
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FT_Bool opened );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_BeginSubPath
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*
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* @description:
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* Start a new sub-path in the stroker.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* to ::
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* A pointer to the start vector.
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*
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* open ::
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* A boolean. If~1, the sub-path is treated as an open one.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* This function is useful when you need to stroke a path that is
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* not stored as an @FT_Outline object.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_BeginSubPath( FT_Stroker stroker,
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FT_Vector* to,
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FT_Bool open );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_EndSubPath
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*
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* @description:
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* Close the current sub-path in the stroker.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* You should call this function after @FT_Stroker_BeginSubPath.
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* If the subpath was not `opened', this function will `draw' a
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* single line segment to the start position when needed.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_EndSubPath( FT_Stroker stroker );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_LineTo
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*
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* @description:
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* `Draw' a single line segment in the stroker's current sub-path,
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* from the last position.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* to ::
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* A pointer to the destination point.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* You should call this function between @FT_Stroker_BeginSubPath and
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* @FT_Stroker_EndSubPath.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_LineTo( FT_Stroker stroker,
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FT_Vector* to );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_ConicTo
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*
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* @description:
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* `Draw' a single quadratic Bézier in the stroker's current sub-path,
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* from the last position.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* control ::
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* A pointer to a Bézier control point.
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*
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* to ::
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* A pointer to the destination point.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* You should call this function between @FT_Stroker_BeginSubPath and
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* @FT_Stroker_EndSubPath.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_ConicTo( FT_Stroker stroker,
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FT_Vector* control,
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FT_Vector* to );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_CubicTo
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*
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* @description:
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* `Draw' a single cubic Bézier in the stroker's current sub-path,
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* from the last position.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* control1 ::
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* A pointer to the first Bézier control point.
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*
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* control2 ::
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* A pointer to second Bézier control point.
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*
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* to ::
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* A pointer to the destination point.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* You should call this function between @FT_Stroker_BeginSubPath and
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* @FT_Stroker_EndSubPath.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_CubicTo( FT_Stroker stroker,
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FT_Vector* control1,
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FT_Vector* control2,
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FT_Vector* to );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_GetBorderCounts
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*
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* @description:
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* Call this function once you have finished parsing your paths
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* with the stroker. It will return the number of points and
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* contours necessary to export one of the `border' or `stroke'
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* outlines generated by the stroker.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* border ::
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* The border index.
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*
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* @output:
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* anum_points ::
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* The number of points.
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*
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* anum_contours ::
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* The number of contours.
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*
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* @return:
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* FreeType error code. 0~means success.
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*
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* @note:
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* When an outline, or a sub-path, is `closed', the stroker generates
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* two independent `border' outlines, named `left' and `right'.
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*
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* When the outline, or a sub-path, is `opened', the stroker merges
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* the `border' outlines with caps. The `left' border receives all
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* points, while the `right' border becomes empty.
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*
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* Use the function @FT_Stroker_GetCounts instead if you want to
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* retrieve the counts associated to both borders.
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*/
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FT_EXPORT( FT_Error )
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FT_Stroker_GetBorderCounts( FT_Stroker stroker,
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FT_StrokerBorder border,
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FT_UInt *anum_points,
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FT_UInt *anum_contours );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_ExportBorder
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*
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* @description:
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* Call this function after @FT_Stroker_GetBorderCounts to
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* export the corresponding border to your own @FT_Outline
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* structure.
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*
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* Note that this function will append the border points and
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* contours to your outline, but will not try to resize its
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* arrays.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* border ::
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* The border index.
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*
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* outline ::
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* The target outline handle.
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*
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* @note:
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* Always call this function after @FT_Stroker_GetBorderCounts to
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* get sure that there is enough room in your @FT_Outline object to
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* receive all new data.
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*
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* When an outline, or a sub-path, is `closed', the stroker generates
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* two independent `border' outlines, named `left' and `right'
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*
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* When the outline, or a sub-path, is `opened', the stroker merges
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* the `border' outlines with caps. The `left' border receives all
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* points, while the `right' border becomes empty.
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*
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* Use the function @FT_Stroker_Export instead if you want to
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* retrieve all borders at once.
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*/
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FT_EXPORT( void )
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FT_Stroker_ExportBorder( FT_Stroker stroker,
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FT_StrokerBorder border,
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FT_Outline* outline );
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/**************************************************************
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*
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* @function:
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* FT_Stroker_GetCounts
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*
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* @description:
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* Call this function once you have finished parsing your paths
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* with the stroker. It returns the number of points and
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* contours necessary to export all points/borders from the stroked
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* outline/path.
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*
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* @input:
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* stroker ::
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* The target stroker handle.
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*
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* @output:
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* anum_points ::
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* The number of points.
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*
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* anum_contours ::
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* The number of contours.
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|
*
|
|
* @return:
|
|
* FreeType error code. 0~means success.
|
|
*/
|
|
FT_EXPORT( FT_Error )
|
|
FT_Stroker_GetCounts( FT_Stroker stroker,
|
|
FT_UInt *anum_points,
|
|
FT_UInt *anum_contours );
|
|
|
|
|
|
/**************************************************************
|
|
*
|
|
* @function:
|
|
* FT_Stroker_Export
|
|
*
|
|
* @description:
|
|
* Call this function after @FT_Stroker_GetBorderCounts to
|
|
* export the all borders to your own @FT_Outline structure.
|
|
*
|
|
* Note that this function will append the border points and
|
|
* contours to your outline, but will not try to resize its
|
|
* arrays.
|
|
*
|
|
* @input:
|
|
* stroker ::
|
|
* The target stroker handle.
|
|
*
|
|
* outline ::
|
|
* The target outline handle.
|
|
*/
|
|
FT_EXPORT( void )
|
|
FT_Stroker_Export( FT_Stroker stroker,
|
|
FT_Outline* outline );
|
|
|
|
|
|
/**************************************************************
|
|
*
|
|
* @function:
|
|
* FT_Stroker_Done
|
|
*
|
|
* @description:
|
|
* Destroy a stroker object.
|
|
*
|
|
* @input:
|
|
* stroker ::
|
|
* A stroker handle. Can be NULL.
|
|
*/
|
|
FT_EXPORT( void )
|
|
FT_Stroker_Done( FT_Stroker stroker );
|
|
|
|
|
|
/**************************************************************
|
|
*
|
|
* @function:
|
|
* FT_Glyph_Stroke
|
|
*
|
|
* @description:
|
|
* Stroke a given outline glyph object with a given stroker.
|
|
*
|
|
* @inout:
|
|
* pglyph ::
|
|
* Source glyph handle on input, new glyph handle on output.
|
|
*
|
|
* @input:
|
|
* stroker ::
|
|
* A stroker handle.
|
|
*
|
|
* destroy ::
|
|
* A Boolean. If~1, the source glyph object is destroyed
|
|
* on success.
|
|
*
|
|
* @return:
|
|
* FreeType error code. 0~means success.
|
|
*
|
|
* @note:
|
|
* The source glyph is untouched in case of error.
|
|
*/
|
|
FT_EXPORT( FT_Error )
|
|
FT_Glyph_Stroke( FT_Glyph *pglyph,
|
|
FT_Stroker stroker,
|
|
FT_Bool destroy );
|
|
|
|
|
|
/**************************************************************
|
|
*
|
|
* @function:
|
|
* FT_Glyph_StrokeBorder
|
|
*
|
|
* @description:
|
|
* Stroke a given outline glyph object with a given stroker, but
|
|
* only return either its inside or outside border.
|
|
*
|
|
* @inout:
|
|
* pglyph ::
|
|
* Source glyph handle on input, new glyph handle on output.
|
|
*
|
|
* @input:
|
|
* stroker ::
|
|
* A stroker handle.
|
|
*
|
|
* inside ::
|
|
* A Boolean. If~1, return the inside border, otherwise
|
|
* the outside border.
|
|
*
|
|
* destroy ::
|
|
* A Boolean. If~1, the source glyph object is destroyed
|
|
* on success.
|
|
*
|
|
* @return:
|
|
* FreeType error code. 0~means success.
|
|
*
|
|
* @note:
|
|
* The source glyph is untouched in case of error.
|
|
*/
|
|
FT_EXPORT( FT_Error )
|
|
FT_Glyph_StrokeBorder( FT_Glyph *pglyph,
|
|
FT_Stroker stroker,
|
|
FT_Bool inside,
|
|
FT_Bool destroy );
|
|
|
|
/* */
|
|
|
|
FT_END_HEADER
|
|
|
|
#endif /* __FT_STROKE_H__ */
|
|
|
|
|
|
/* END */
|
|
|
|
|
|
/* Local Variables: */
|
|
/* coding: utf-8 */
|
|
/* End: */
|