| /**************************************************************************** |
| * |
| * ftstroke.h |
| * |
| * FreeType path stroker (specification). |
| * |
| * Copyright (C) 2002-2022 by |
| * David Turner, Robert Wilhelm, and Werner Lemberg. |
| * |
| * 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 FTSTROKE_H_ |
| #define FTSTROKE_H_ |
| |
| #include <freetype/ftoutln.h> |
| #include <freetype/ftglyph.h> |
| |
| |
| FT_BEGIN_HEADER |
| |
| |
| /************************************************************************** |
| * |
| * @section: |
| * glyph_stroker |
| * |
| * @title: |
| * Glyph Stroker |
| * |
| * @abstract: |
| * Generating bordered and stroked glyphs. |
| * |
| * @description: |
| * This component generates stroked outlines of a given vectorial glyph. |
| * It also allows you to retrieve the 'outside' and/or the 'inside' |
| * borders of the stroke. |
| * |
| * This can be useful to generate 'bordered' glyph, i.e., glyphs |
| * displayed with a colored (and anti-aliased) border around their |
| * shape. |
| * |
| * @order: |
| * FT_Stroker |
| * |
| * FT_Stroker_LineJoin |
| * FT_Stroker_LineCap |
| * FT_StrokerBorder |
| * |
| * FT_Outline_GetInsideBorder |
| * FT_Outline_GetOutsideBorder |
| * |
| * FT_Glyph_Stroke |
| * FT_Glyph_StrokeBorder |
| * |
| * FT_Stroker_New |
| * FT_Stroker_Set |
| * FT_Stroker_Rewind |
| * FT_Stroker_ParseOutline |
| * FT_Stroker_Done |
| * |
| * FT_Stroker_BeginSubPath |
| * FT_Stroker_EndSubPath |
| * |
| * FT_Stroker_LineTo |
| * FT_Stroker_ConicTo |
| * FT_Stroker_CubicTo |
| * |
| * FT_Stroker_GetBorderCounts |
| * FT_Stroker_ExportBorder |
| * FT_Stroker_GetCounts |
| * FT_Stroker_Export |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @type: |
| * FT_Stroker |
| * |
| * @description: |
| * Opaque handle to a path stroker object. |
| */ |
| typedef struct FT_StrokerRec_* FT_Stroker; |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_Stroker_LineJoin |
| * |
| * @description: |
| * These values determine how two joining lines are rendered in a |
| * stroker. |
| * |
| * @values: |
| * FT_STROKER_LINEJOIN_ROUND :: |
| * Used to render rounded line joins. Circular arcs are used to join |
| * two lines smoothly. |
| * |
| * FT_STROKER_LINEJOIN_BEVEL :: |
| * Used to render beveled line joins. The outer corner of the joined |
| * lines is filled by enclosing the triangular region of the corner |
| * with a straight line between the outer corners of each stroke. |
| * |
| * FT_STROKER_LINEJOIN_MITER_FIXED :: |
| * Used to render mitered line joins, with fixed bevels if the miter |
| * limit is exceeded. The outer edges of the strokes for the two |
| * segments are extended until they meet at an angle. A bevel join |
| * (see above) is used if the segments meet at too sharp an angle and |
| * the outer edges meet beyond a distance corresponding to the meter |
| * limit. This prevents long spikes being created. |
| * `FT_STROKER_LINEJOIN_MITER_FIXED` generates a miter line join as |
| * used in PostScript and PDF. |
| * |
| * FT_STROKER_LINEJOIN_MITER_VARIABLE :: |
| * FT_STROKER_LINEJOIN_MITER :: |
| * Used to render mitered line joins, with variable bevels if the miter |
| * limit is exceeded. The intersection of the strokes is clipped |
| * perpendicularly to the bisector, at a distance corresponding to |
| * the miter limit. This prevents long spikes being created. |
| * `FT_STROKER_LINEJOIN_MITER_VARIABLE` generates a mitered line join |
| * as used in XPS. `FT_STROKER_LINEJOIN_MITER` is an alias for |
| * `FT_STROKER_LINEJOIN_MITER_VARIABLE`, retained for backward |
| * compatibility. |
| */ |
| typedef enum FT_Stroker_LineJoin_ |
| { |
| FT_STROKER_LINEJOIN_ROUND = 0, |
| FT_STROKER_LINEJOIN_BEVEL = 1, |
| FT_STROKER_LINEJOIN_MITER_VARIABLE = 2, |
| FT_STROKER_LINEJOIN_MITER = FT_STROKER_LINEJOIN_MITER_VARIABLE, |
| FT_STROKER_LINEJOIN_MITER_FIXED = 3 |
| |
| } FT_Stroker_LineJoin; |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_Stroker_LineCap |
| * |
| * @description: |
| * These values determine how the end of opened sub-paths are rendered in |
| * a stroke. |
| * |
| * @values: |
| * FT_STROKER_LINECAP_BUTT :: |
| * The end of lines is rendered as a full stop on the last point |
| * itself. |
| * |
| * FT_STROKER_LINECAP_ROUND :: |
| * The end of lines is rendered as a half-circle around the last point. |
| * |
| * FT_STROKER_LINECAP_SQUARE :: |
| * The end of lines is rendered as a square around the last point. |
| */ |
| typedef enum FT_Stroker_LineCap_ |
| { |
| FT_STROKER_LINECAP_BUTT = 0, |
| FT_STROKER_LINECAP_ROUND, |
| FT_STROKER_LINECAP_SQUARE |
| |
| } FT_Stroker_LineCap; |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_StrokerBorder |
| * |
| * @description: |
| * These values are used to select a given stroke border in |
| * @FT_Stroker_GetBorderCounts and @FT_Stroker_ExportBorder. |
| * |
| * @values: |
| * FT_STROKER_BORDER_LEFT :: |
| * Select the left border, relative to the drawing direction. |
| * |
| * FT_STROKER_BORDER_RIGHT :: |
| * Select the right border, relative to the drawing direction. |
| * |
| * @note: |
| * Applications are generally interested in the 'inside' and 'outside' |
| * borders. However, there is no direct mapping between these and the |
| * 'left' and 'right' ones, since this really depends on the glyph's |
| * drawing orientation, which varies between font formats. |
| * |
| * You can however use @FT_Outline_GetInsideBorder and |
| * @FT_Outline_GetOutsideBorder to get these. |
| */ |
| typedef enum FT_StrokerBorder_ |
| { |
| FT_STROKER_BORDER_LEFT = 0, |
| FT_STROKER_BORDER_RIGHT |
| |
| } FT_StrokerBorder; |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Outline_GetInsideBorder |
| * |
| * @description: |
| * Retrieve the @FT_StrokerBorder value corresponding to the 'inside' |
| * borders of a given outline. |
| * |
| * @input: |
| * outline :: |
| * The source outline handle. |
| * |
| * @return: |
| * The border index. @FT_STROKER_BORDER_RIGHT for empty or invalid |
| * outlines. |
| */ |
| FT_EXPORT( FT_StrokerBorder ) |
| FT_Outline_GetInsideBorder( FT_Outline* outline ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Outline_GetOutsideBorder |
| * |
| * @description: |
| * Retrieve the @FT_StrokerBorder value corresponding to the 'outside' |
| * borders of a given outline. |
| * |
| * @input: |
| * outline :: |
| * The source outline handle. |
| * |
| * @return: |
| * The border index. @FT_STROKER_BORDER_LEFT for empty or invalid |
| * outlines. |
| */ |
| FT_EXPORT( FT_StrokerBorder ) |
| FT_Outline_GetOutsideBorder( FT_Outline* outline ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_New |
| * |
| * @description: |
| * Create a new stroker object. |
| * |
| * @input: |
| * library :: |
| * FreeType library handle. |
| * |
| * @output: |
| * astroker :: |
| * A new stroker object handle. `NULL` in case of error. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_New( FT_Library library, |
| FT_Stroker *astroker ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_Set |
| * |
| * @description: |
| * Reset a stroker object's attributes. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * radius :: |
| * The border radius. |
| * |
| * line_cap :: |
| * The line cap style. |
| * |
| * line_join :: |
| * The line join style. |
| * |
| * miter_limit :: |
| * The maximum reciprocal sine of half-angle at the miter join, |
| * expressed as 16.16 fixed point value. |
| * |
| * @note: |
| * The `radius` is expressed in the same units as the outline |
| * coordinates. |
| * |
| * The `miter_limit` multiplied by the `radius` gives the maximum size |
| * of a miter spike, at which it is clipped for |
| * @FT_STROKER_LINEJOIN_MITER_VARIABLE or replaced with a bevel join for |
| * @FT_STROKER_LINEJOIN_MITER_FIXED. |
| * |
| * This function calls @FT_Stroker_Rewind automatically. |
| */ |
| FT_EXPORT( void ) |
| FT_Stroker_Set( FT_Stroker stroker, |
| FT_Fixed radius, |
| FT_Stroker_LineCap line_cap, |
| FT_Stroker_LineJoin line_join, |
| FT_Fixed miter_limit ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_Rewind |
| * |
| * @description: |
| * Reset a stroker object without changing its attributes. You should |
| * call this function before beginning a new series of calls to |
| * @FT_Stroker_BeginSubPath or @FT_Stroker_EndSubPath. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| */ |
| FT_EXPORT( void ) |
| FT_Stroker_Rewind( FT_Stroker stroker ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_ParseOutline |
| * |
| * @description: |
| * A convenience function used to parse a whole outline with the stroker. |
| * The resulting outline(s) can be retrieved later by functions like |
| * @FT_Stroker_GetCounts and @FT_Stroker_Export. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * outline :: |
| * The source outline. |
| * |
| * opened :: |
| * A boolean. If~1, the outline is treated as an open path instead of |
| * a closed one. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * If `opened` is~0 (the default), the outline is treated as a closed |
| * path, and the stroker generates two distinct 'border' outlines. |
| * |
| * If `opened` is~1, the outline is processed as an open path, and the |
| * stroker generates a single 'stroke' outline. |
| * |
| * This function calls @FT_Stroker_Rewind automatically. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_ParseOutline( FT_Stroker stroker, |
| FT_Outline* outline, |
| FT_Bool opened ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_BeginSubPath |
| * |
| * @description: |
| * Start a new sub-path in the stroker. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * to :: |
| * A pointer to the start vector. |
| * |
| * open :: |
| * A boolean. If~1, the sub-path is treated as an open one. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * This function is useful when you need to stroke a path that is not |
| * stored as an @FT_Outline object. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_BeginSubPath( FT_Stroker stroker, |
| FT_Vector* to, |
| FT_Bool open ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_EndSubPath |
| * |
| * @description: |
| * Close the current sub-path in the stroker. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * You should call this function after @FT_Stroker_BeginSubPath. If the |
| * subpath was not 'opened', this function 'draws' a single line segment |
| * to the start position when needed. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_EndSubPath( FT_Stroker stroker ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_LineTo |
| * |
| * @description: |
| * 'Draw' a single line segment in the stroker's current sub-path, from |
| * the last position. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * to :: |
| * A pointer to the destination point. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * You should call this function between @FT_Stroker_BeginSubPath and |
| * @FT_Stroker_EndSubPath. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_LineTo( FT_Stroker stroker, |
| FT_Vector* to ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_ConicTo |
| * |
| * @description: |
| * 'Draw' a single quadratic Bezier in the stroker's current sub-path, |
| * from the last position. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * control :: |
| * A pointer to a Bezier control point. |
| * |
| * to :: |
| * A pointer to the destination point. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * You should call this function between @FT_Stroker_BeginSubPath and |
| * @FT_Stroker_EndSubPath. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_ConicTo( FT_Stroker stroker, |
| FT_Vector* control, |
| FT_Vector* to ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_CubicTo |
| * |
| * @description: |
| * 'Draw' a single cubic Bezier in the stroker's current sub-path, from |
| * the last position. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * control1 :: |
| * A pointer to the first Bezier control point. |
| * |
| * control2 :: |
| * A pointer to second Bezier control point. |
| * |
| * to :: |
| * A pointer to the destination point. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * You should call this function between @FT_Stroker_BeginSubPath and |
| * @FT_Stroker_EndSubPath. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_CubicTo( FT_Stroker stroker, |
| FT_Vector* control1, |
| FT_Vector* control2, |
| FT_Vector* to ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_GetBorderCounts |
| * |
| * @description: |
| * Call this function once you have finished parsing your paths with the |
| * stroker. It returns the number of points and contours necessary to |
| * export one of the 'border' or 'stroke' outlines generated by the |
| * stroker. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * border :: |
| * The border index. |
| * |
| * @output: |
| * anum_points :: |
| * The number of points. |
| * |
| * anum_contours :: |
| * The number of contours. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @note: |
| * When an outline, or a sub-path, is 'closed', the stroker generates two |
| * independent 'border' outlines, named 'left' and 'right'. |
| * |
| * When the outline, or a sub-path, is 'opened', the stroker merges the |
| * 'border' outlines with caps. The 'left' border receives all points, |
| * while the 'right' border becomes empty. |
| * |
| * Use the function @FT_Stroker_GetCounts instead if you want to retrieve |
| * the counts associated to both borders. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Stroker_GetBorderCounts( FT_Stroker stroker, |
| FT_StrokerBorder border, |
| FT_UInt *anum_points, |
| FT_UInt *anum_contours ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_ExportBorder |
| * |
| * @description: |
| * Call this function after @FT_Stroker_GetBorderCounts to export the |
| * corresponding border to your own @FT_Outline structure. |
| * |
| * Note that this function appends the border points and contours to your |
| * outline, but does not try to resize its arrays. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * border :: |
| * The border index. |
| * |
| * outline :: |
| * The target outline handle. |
| * |
| * @note: |
| * Always call this function after @FT_Stroker_GetBorderCounts to get |
| * sure that there is enough room in your @FT_Outline object to receive |
| * all new data. |
| * |
| * When an outline, or a sub-path, is 'closed', the stroker generates two |
| * independent 'border' outlines, named 'left' and 'right'. |
| * |
| * When the outline, or a sub-path, is 'opened', the stroker merges the |
| * 'border' outlines with caps. The 'left' border receives all points, |
| * while the 'right' border becomes empty. |
| * |
| * Use the function @FT_Stroker_Export instead if you want to retrieve |
| * all borders at once. |
| */ |
| FT_EXPORT( void ) |
| FT_Stroker_ExportBorder( FT_Stroker stroker, |
| FT_StrokerBorder border, |
| FT_Outline* outline ); |
| |
| |
| /************************************************************************** |
| * |
| * @function: |
| * FT_Stroker_GetCounts |
| * |
| * @description: |
| * Call this function once you have finished parsing your paths with the |
| * stroker. It returns the number of points and contours necessary to |
| * export all points/borders from the stroked outline/path. |
| * |
| * @input: |
| * stroker :: |
| * The target stroker handle. |
| * |
| * @output: |
| * anum_points :: |
| * The number of points. |
| * |
| * anum_contours :: |
| * The number of contours. |
| * |
| * @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 all |
| * borders to your own @FT_Outline structure. |
| * |
| * Note that this function appends the border points and contours to your |
| * outline, but does 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. |
| * |
| * Adding stroke may yield a significantly wider and taller glyph |
| * depending on how large of a radius was used to stroke the glyph. You |
| * may need to manually adjust horizontal and vertical advance amounts to |
| * account for this added size. |
| */ |
| 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. |
| * |
| * Adding stroke may yield a significantly wider and taller glyph |
| * depending on how large of a radius was used to stroke the glyph. You |
| * may need to manually adjust horizontal and vertical advance amounts to |
| * account for this added size. |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_Glyph_StrokeBorder( FT_Glyph *pglyph, |
| FT_Stroker stroker, |
| FT_Bool inside, |
| FT_Bool destroy ); |
| |
| /* */ |
| |
| FT_END_HEADER |
| |
| #endif /* FTSTROKE_H_ */ |
| |
| |
| /* END */ |
| |
| |
| /* Local Variables: */ |
| /* coding: utf-8 */ |
| /* End: */ |
