ref: b757ddb1629d524cd92eb9b39ce298e0dffd57fd
dir: /include/freetype/ftoutln.h/
/***************************************************************************/
/* */
/* ftoutln.h */
/* */
/* Support for the FT_Outline type used to store glyph shapes of */
/* most scalable font formats (specification). */
/* */
/* Copyright 1996-2017 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 <ft2build.h>
#include FT_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 Bézier 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> */
/* A contour that contains a single point only is represented by a */
/* `move to' operation followed by `line to' to the same point. In */
/* most cases, it is best to filter this out before using the */
/* outline for stroking purposes (otherwise it would result in a */
/* visible dot when round caps are used). */
/* */
/* Similarly, the function returns success for an empty outline also */
/* (doing nothing, this 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 );
FT_EXPORT( FT_Error )
FT_Outline_New_Internal( FT_Memory memory,
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. */
/* */
/* The reason why this function takes an `library' parameter is */
/* simply to use ft_mem_free(). */
/* */
FT_EXPORT( FT_Error )
FT_Outline_Done( FT_Library library,
FT_Outline* outline );
FT_EXPORT( FT_Error )
FT_Outline_Done_Internal( FT_Memory memory,
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 Bézier 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 Bézier 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. */
/* */
/* Example call: */
/* */
/* { */
/* FT_Load_Glyph( face, index, FT_LOAD_DEFAULT ); */
/* if ( face->glyph->format == FT_GLYPH_FORMAT_OUTLINE ) */
/* FT_Outline_Embolden( &face->glyph->outline, strength ); */
/* } */
/* */
/* To get meaningful results, font scaling values must be set with */
/* functions like @FT_Set_Char_Size before calling FT_Render_Glyph. */
/* */
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. */
/* */
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. */
/* This function uses an @FT_Raster_Params structure as an argument, */
/* allowing advanced features like direct composition, translucency, */
/* etc. */
/* */
/* <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> */
/* You should know what you are doing and how @FT_Raster_Params works */
/* to use this function. */
/* */
/* 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. */
/* */
/* The gray-level rasterizer always uses 256 gray levels. If you */
/* want less gray levels, you have to provide your own span callback. */
/* See the @FT_RASTER_FLAG_DIRECT value of the `flags' field in the */
/* @FT_Raster_Params structure 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 */
/* Local Variables: */
/* coding: utf-8 */
/* End: */