tor-browser

ftoutln.h (17403B)

---

/****************************************************************************
*
* ftoutln.h
*
*   Support for the FT_Outline type used to store glyph shapes of
*   most scalable font formats (specification).
*
* Copyright (C) 1996-2025 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 FTOUTLN_H_
#define FTOUTLN_H_


#include <freetype/freetype.h>

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif


FT_BEGIN_HEADER


 /**************************************************************************
  *
  * @section:
  *   outline_processing
  *
  * @title:
  *   Outline Processing
  *
  * @abstract:
  *   Functions to create, transform, and render vectorial glyph images.
  *
  * @description:
  *   This section contains routines used to create and destroy scalable
  *   glyph images known as 'outlines'.  These can also be measured,
  *   transformed, and converted into bitmaps and pixmaps.
  *
  * @order:
  *   FT_Outline
  *   FT_Outline_New
  *   FT_Outline_Done
  *   FT_Outline_Copy
  *   FT_Outline_Translate
  *   FT_Outline_Transform
  *   FT_Outline_Embolden
  *   FT_Outline_EmboldenXY
  *   FT_Outline_Reverse
  *   FT_Outline_Check
  *
  *   FT_Outline_Get_CBox
  *   FT_Outline_Get_BBox
  *
  *   FT_Outline_Get_Bitmap
  *   FT_Outline_Render
  *   FT_Outline_Decompose
  *   FT_Outline_Funcs
  *   FT_Outline_MoveToFunc
  *   FT_Outline_LineToFunc
  *   FT_Outline_ConicToFunc
  *   FT_Outline_CubicToFunc
  *
  *   FT_Orientation
  *   FT_Outline_Get_Orientation
  *
  *   FT_OUTLINE_XXX
  *
  */


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Decompose
  *
  * @description:
  *   Walk over an outline's structure to decompose it into individual
  *   segments and Bezier arcs.  This function also emits 'move to'
  *   operations to indicate the start of new contours in the outline.
  *
  * @input:
  *   outline ::
  *     A pointer to the source target.
  *
  *   func_interface ::
  *     A table of 'emitters', i.e., function pointers called during
  *     decomposition to indicate path operations.
  *
  * @inout:
  *   user ::
  *     A typeless pointer that is passed to each emitter during the
  *     decomposition.  It can be used to store the state during the
  *     decomposition.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   Degenerate contours, segments, and Bezier arcs may be reported.  In
  *   most cases, it is best to filter these out before using the outline
  *   for stroking or other path modification purposes (which may cause
  *   degenerate segments to become non-degenerate and visible, like when
  *   stroke caps are used or the path is otherwise outset).  Some glyph
  *   outlines may contain deliberate degenerate single points for mark
  *   attachement.
  *
  *   Similarly, the function returns success for an empty outline also
  *   (doing nothing, that is, not calling any emitter); if necessary, you
  *   should filter this out, too.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Decompose( FT_Outline*              outline,
                       const FT_Outline_Funcs*  func_interface,
                       void*                    user );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_New
  *
  * @description:
  *   Create a new outline of a given size.
  *
  * @input:
  *   library ::
  *     A handle to the library object from where the outline is allocated.
  *     Note however that the new outline will **not** necessarily be
  *     **freed**, when destroying the library, by @FT_Done_FreeType.
  *
  *   numPoints ::
  *     The maximum number of points within the outline.  Must be smaller
  *     than or equal to 0xFFFF (65535).
  *
  *   numContours ::
  *     The maximum number of contours within the outline.  This value must
  *     be in the range 0 to `numPoints`.
  *
  * @output:
  *   anoutline ::
  *     A handle to the new outline.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   The reason why this function takes a `library` parameter is simply to
  *   use the library's memory allocator.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_New( FT_Library   library,
                 FT_UInt      numPoints,
                 FT_Int       numContours,
                 FT_Outline  *anoutline );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Done
  *
  * @description:
  *   Destroy an outline created with @FT_Outline_New.
  *
  * @input:
  *   library ::
  *     A handle of the library object used to allocate the outline.
  *
  *   outline ::
  *     A pointer to the outline object to be discarded.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   If the outline's 'owner' field is not set, only the outline descriptor
  *   will be released.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Done( FT_Library   library,
                  FT_Outline*  outline );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Check
  *
  * @description:
  *   Check the contents of an outline descriptor.
  *
  * @input:
  *   outline ::
  *     A handle to a source outline.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   An empty outline, or an outline with a single point only is also
  *   valid.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Check( FT_Outline*  outline );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Get_CBox
  *
  * @description:
  *   Return an outline's 'control box'.  The control box encloses all the
  *   outline's points, including Bezier control points.  Though it
  *   coincides with the exact bounding box for most glyphs, it can be
  *   slightly larger in some situations (like when rotating an outline that
  *   contains Bezier outside arcs).
  *
  *   Computing the control box is very fast, while getting the bounding box
  *   can take much more time as it needs to walk over all segments and arcs
  *   in the outline.  To get the latter, you can use the 'ftbbox'
  *   component, which is dedicated to this single task.
  *
  * @input:
  *   outline ::
  *     A pointer to the source outline descriptor.
  *
  * @output:
  *   acbox ::
  *     The outline's control box.
  *
  * @note:
  *   See @FT_Glyph_Get_CBox for a discussion of tricky fonts.
  */
 FT_EXPORT( void )
 FT_Outline_Get_CBox( const FT_Outline*  outline,
                      FT_BBox           *acbox );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Translate
  *
  * @description:
  *   Apply a simple translation to the points of an outline.
  *
  * @inout:
  *   outline ::
  *     A pointer to the target outline descriptor.
  *
  * @input:
  *   xOffset ::
  *     The horizontal offset.
  *
  *   yOffset ::
  *     The vertical offset.
  */
 FT_EXPORT( void )
 FT_Outline_Translate( const FT_Outline*  outline,
                       FT_Pos             xOffset,
                       FT_Pos             yOffset );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Copy
  *
  * @description:
  *   Copy an outline into another one.  Both objects must have the same
  *   sizes (number of points & number of contours) when this function is
  *   called.
  *
  * @input:
  *   source ::
  *     A handle to the source outline.
  *
  * @output:
  *   target ::
  *     A handle to the target outline.
  *
  * @return:
  *   FreeType error code.  0~means success.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Copy( const FT_Outline*  source,
                  FT_Outline        *target );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Transform
  *
  * @description:
  *   Apply a simple 2x2 matrix to all of an outline's points.  Useful for
  *   applying rotations, slanting, flipping, etc.
  *
  * @inout:
  *   outline ::
  *     A pointer to the target outline descriptor.
  *
  * @input:
  *   matrix ::
  *     A pointer to the transformation matrix.
  *
  * @note:
  *   You can use @FT_Outline_Translate if you need to translate the
  *   outline's points.
  */
 FT_EXPORT( void )
 FT_Outline_Transform( const FT_Outline*  outline,
                       const FT_Matrix*   matrix );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Embolden
  *
  * @description:
  *   Embolden an outline.  The new outline will be at most 4~times
  *   `strength` pixels wider and higher.  You may think of the left and
  *   bottom borders as unchanged.
  *
  *   Negative `strength` values to reduce the outline thickness are
  *   possible also.
  *
  * @inout:
  *   outline ::
  *     A handle to the target outline.
  *
  * @input:
  *   strength ::
  *     How strong the glyph is emboldened.  Expressed in 26.6 pixel format.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   The used algorithm to increase or decrease the thickness of the glyph
  *   doesn't change the number of points; this means that certain
  *   situations like acute angles or intersections are sometimes handled
  *   incorrectly.
  *
  *   If you need 'better' metrics values you should call
  *   @FT_Outline_Get_CBox or @FT_Outline_Get_BBox.
  *
  *   To get meaningful results, font scaling values must be set with
  *   functions like @FT_Set_Char_Size before calling FT_Render_Glyph.
  *
  * @example:
  *   ```
  *     FT_Load_Glyph( face, index, FT_LOAD_DEFAULT );
  *
  *     if ( face->glyph->format == FT_GLYPH_FORMAT_OUTLINE )
  *       FT_Outline_Embolden( &face->glyph->outline, strength );
  *   ```
  *
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Embolden( FT_Outline*  outline,
                      FT_Pos       strength );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_EmboldenXY
  *
  * @description:
  *   Embolden an outline.  The new outline will be `xstrength` pixels wider
  *   and `ystrength` pixels higher.  Otherwise, it is similar to
  *   @FT_Outline_Embolden, which uses the same strength in both directions.
  *
  * @since:
  *   2.4.10
  */
 FT_EXPORT( FT_Error )
 FT_Outline_EmboldenXY( FT_Outline*  outline,
                        FT_Pos       xstrength,
                        FT_Pos       ystrength );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Reverse
  *
  * @description:
  *   Reverse the drawing direction of an outline.  This is used to ensure
  *   consistent fill conventions for mirrored glyphs.
  *
  * @inout:
  *   outline ::
  *     A pointer to the target outline descriptor.
  *
  * @note:
  *   This function toggles the bit flag @FT_OUTLINE_REVERSE_FILL in the
  *   outline's `flags` field.
  *
  *   It shouldn't be used by a normal client application, unless it knows
  *   what it is doing.
  */
 FT_EXPORT( void )
 FT_Outline_Reverse( FT_Outline*  outline );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Get_Bitmap
  *
  * @description:
  *   Render an outline within a bitmap.  The outline's image is simply
  *   OR-ed to the target bitmap.
  *
  * @input:
  *   library ::
  *     A handle to a FreeType library object.
  *
  *   outline ::
  *     A pointer to the source outline descriptor.
  *
  * @inout:
  *   abitmap ::
  *     A pointer to the target bitmap descriptor.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   This function does **not create** the bitmap, it only renders an
  *   outline image within the one you pass to it!  Consequently, the
  *   various fields in `abitmap` should be set accordingly.
  *
  *   It will use the raster corresponding to the default glyph format.
  *
  *   The value of the `num_grays` field in `abitmap` is ignored.  If you
  *   select the gray-level rasterizer, and you want less than 256 gray
  *   levels, you have to use @FT_Outline_Render directly.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Get_Bitmap( FT_Library        library,
                        FT_Outline*       outline,
                        const FT_Bitmap  *abitmap );


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Render
  *
  * @description:
  *   Render an outline within a bitmap using the current scan-convert.
  *
  * @input:
  *   library ::
  *     A handle to a FreeType library object.
  *
  *   outline ::
  *     A pointer to the source outline descriptor.
  *
  * @inout:
  *   params ::
  *     A pointer to an @FT_Raster_Params structure used to describe the
  *     rendering operation.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   This advanced function uses @FT_Raster_Params as an argument.
  *   The field `params.source` will be set to `outline` before the scan
  *   converter is called, which means that the value you give to it is
  *   actually ignored.  Either `params.target` must point to preallocated
  *   bitmap, or @FT_RASTER_FLAG_DIRECT must be set in `params.flags`
  *   allowing FreeType rasterizer to be used for direct composition,
  *   translucency, etc.  See @FT_Raster_Params for more details.
  */
 FT_EXPORT( FT_Error )
 FT_Outline_Render( FT_Library         library,
                    FT_Outline*        outline,
                    FT_Raster_Params*  params );


 /**************************************************************************
  *
  * @enum:
  *   FT_Orientation
  *
  * @description:
  *   A list of values used to describe an outline's contour orientation.
  *
  *   The TrueType and PostScript specifications use different conventions
  *   to determine whether outline contours should be filled or unfilled.
  *
  * @values:
  *   FT_ORIENTATION_TRUETYPE ::
  *     According to the TrueType specification, clockwise contours must be
  *     filled, and counter-clockwise ones must be unfilled.
  *
  *   FT_ORIENTATION_POSTSCRIPT ::
  *     According to the PostScript specification, counter-clockwise
  *     contours must be filled, and clockwise ones must be unfilled.
  *
  *   FT_ORIENTATION_FILL_RIGHT ::
  *     This is identical to @FT_ORIENTATION_TRUETYPE, but is used to
  *     remember that in TrueType, everything that is to the right of the
  *     drawing direction of a contour must be filled.
  *
  *   FT_ORIENTATION_FILL_LEFT ::
  *     This is identical to @FT_ORIENTATION_POSTSCRIPT, but is used to
  *     remember that in PostScript, everything that is to the left of the
  *     drawing direction of a contour must be filled.
  *
  *   FT_ORIENTATION_NONE ::
  *     The orientation cannot be determined.  That is, different parts of
  *     the glyph have different orientation.
  *
  */
 typedef enum  FT_Orientation_
 {
   FT_ORIENTATION_TRUETYPE   = 0,
   FT_ORIENTATION_POSTSCRIPT = 1,
   FT_ORIENTATION_FILL_RIGHT = FT_ORIENTATION_TRUETYPE,
   FT_ORIENTATION_FILL_LEFT  = FT_ORIENTATION_POSTSCRIPT,
   FT_ORIENTATION_NONE

 } FT_Orientation;


 /**************************************************************************
  *
  * @function:
  *   FT_Outline_Get_Orientation
  *
  * @description:
  *   This function analyzes a glyph outline and tries to compute its fill
  *   orientation (see @FT_Orientation).  This is done by integrating the
  *   total area covered by the outline. The positive integral corresponds
  *   to the clockwise orientation and @FT_ORIENTATION_POSTSCRIPT is
  *   returned. The negative integral corresponds to the counter-clockwise
  *   orientation and @FT_ORIENTATION_TRUETYPE is returned.
  *
  *   Note that this will return @FT_ORIENTATION_TRUETYPE for empty
  *   outlines.
  *
  * @input:
  *   outline ::
  *     A handle to the source outline.
  *
  * @return:
  *   The orientation.
  *
  */
 FT_EXPORT( FT_Orientation )
 FT_Outline_Get_Orientation( FT_Outline*  outline );


 /* */


FT_END_HEADER

#endif /* FTOUTLN_H_ */


/* END */


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