/***************************************************************************/

/*                                                                         */

/*  ftstroke.h                                                             */

/*                                                                         */

/*    FreeType path stroker (specification).                               */

/*                                                                         */

/*  Copyright 2002, 2003, 2004, 2005, 2006, 2008, 2009 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; i.e., the two joining lines

   *     are extended until they intersect.

   *

   *   FT_STROKER_LINEJOIN_MITER ::

   *     Same as beveled rendering, except that an additional line

   *     break is added if the angle between the two joining lines

   *     is too closed (this is useful to avoid unpleasant spikes

   *     in beveled rendering).

   */

  typedef enum  FT_Stroker_LineJoin_

  {

    FT_STROKER_LINEJOIN_ROUND = 0,

    FT_STROKER_LINEJOIN_BEVEL,

    FT_STROKER_LINEJOIN_MITER

  } 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 style,

   *     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