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Diffstat (limited to 'freetype/include/ftstroke.h')
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diff --git a/freetype/include/ftstroke.h b/freetype/include/ftstroke.h new file mode 100644 index 000000000..a498e4a88 --- /dev/null +++ b/freetype/include/ftstroke.h @@ -0,0 +1,751 @@ +/***************************************************************************/ +/* */ +/* ftstroke.h */ +/* */ +/* FreeType path stroker (specification). */ +/* */ +/* Copyright 2002-2006, 2008, 2009, 2011-2012 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 __FT_STROKE_H__ +#define __FT_STROKE_H__ + +#include <ft2build.h> +#include FT_OUTLINE_H +#include FT_GLYPH_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 coloured (and anti-aliased) border around their + * shape. + */ + + + /************************************************************** + * + * @type: + * FT_Stroker + * + * @description: + * Opaque handler 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. If the segments meet at too sharp an angle (such + * that the miter would extend from the intersection of the + * segments a distance greater than the product of the miter + * limit value and the border radius), then a bevel join (see + * above) is used instead. 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 at a line perpendicular to the bisector + * of the angle between the strokes, at the distance from the + * intersection of the segments equal to the product of the + * miter limit value and the border radius. 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 + * backwards 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 miter limit for the FT_STROKER_LINEJOIN_MITER_FIXED and + * FT_STROKER_LINEJOIN_MITER_VARIABLE line join styles, + * expressed as 16.16 fixed-point value. + * + * @note: + * The radius is expressed in the same units as the outline + * coordinates. + */ + 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 Bézier in the stroker's current sub-path, + * from the last position. + * + * @input: + * stroker :: + * The target stroker handle. + * + * control :: + * A pointer to a Bézier 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 Bézier in the stroker's current sub-path, + * from the last position. + * + * @input: + * stroker :: + * The target stroker handle. + * + * control1 :: + * A pointer to the first Bézier control point. + * + * control2 :: + * A pointer to second Bézier 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 /* __FT_STROKE_H__ */ + + +/* END */ + + +/* Local Variables: */ +/* coding: utf-8 */ +/* End: */ |