ref: b1b476215e1c0e0cb5649a9b081589257be70d3e
dir: /include/freetype/ftglyph.h/
/***************************************************************************/
/* */
/* ftglyph.h */
/* */
/* FreeType convenience functions to handle glyphs (specification). */
/* */
/* Copyright 1996-2001 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. */
/* */
/***************************************************************************/
/*************************************************************************/
/* */
/* This file contains the definition of several convenience functions */
/* that can be used by client applications to easily retrieve glyph */
/* bitmaps and outlines from a given face. */
/* */
/* These functions should be optional if you are writing a font server */
/* or text layout engine on top of FreeType. However, they are pretty */
/* handy for many other simple uses of the library. */
/* */
/*************************************************************************/
#ifndef __FTGLYPH_H__
#define __FTGLYPH_H__
#include <ft2build.h>
#include FT_FREETYPE_H
FT_BEGIN_HEADER
/*************************************************************************/
/* */
/* <Section> */
/* glyph_management */
/* */
/* <Title> */
/* Glyph Management */
/* */
/* <Abstract> */
/* Generic interface to manage individual glyph data. */
/* */
/* <Description> */
/* This section contains definitions used to manage glyph data */
/* through generic FT_Glyph objects. Each of them can contain a */
/* bitmap, a vector outline, or even images in other formats. */
/* */
/*************************************************************************/
/* forward declaration to a private type */
typedef struct FT_Glyph_Class_ FT_Glyph_Class;
/*************************************************************************/
/* */
/* <Type> */
/* FT_Glyph */
/* */
/* <Description> */
/* Handle to an object used to model generic glyph images. It is a */
/* pointer to the @FT_GlyphRec structure and can contain a glyph */
/* bitmap or pointer. */
/* */
/* <Note> */
/* Glyph objects are not owned by the library. You must thus release */
/* them manually (through @FT_Done_Glyph) _before_ calling */
/* @FT_Done_FreeType. */
/* */
typedef struct FT_GlyphRec_* FT_Glyph;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_GlyphRec */
/* */
/* <Description> */
/* The root glyph structure contains a given glyph image plus its */
/* advance width in 16.16 fixed float format. */
/* */
/* <Fields> */
/* library :: A handle to the FreeType library object. */
/* */
/* clazz :: A pointer to the glyph's class. Private. */
/* */
/* format :: The format of the glyph's image. */
/* */
/* advance :: A 16.16 vector that gives the glyph's advance width. */
/* */
typedef struct FT_GlyphRec_
{
FT_Library library;
const FT_Glyph_Class* clazz;
FT_Glyph_Format format;
FT_Vector advance;
} FT_GlyphRec;
/*************************************************************************/
/* */
/* <Type> */
/* FT_BitmapGlyph */
/* */
/* <Description> */
/* A handle to an object used to model a bitmap glyph image. This is */
/* a sub-class of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec. */
/* */
typedef struct FT_BitmapGlyphRec_* FT_BitmapGlyph;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_BitmapGlyphRec */
/* */
/* <Description> */
/* A structure used for bitmap glyph images. This really is a */
/* `sub-class' of `FT_GlyphRec'. */
/* */
/* <Fields> */
/* root :: The root FT_Glyph fields. */
/* */
/* left :: The left-side bearing, i.e., the horizontal distance */
/* from the current pen position to the left border of the */
/* glyph bitmap. */
/* */
/* top :: The top-side bearing, i.e., the vertical distance from */
/* the current pen position to the top border of the glyph */
/* bitmap. This distance is positive for upwards-y! */
/* */
/* bitmap :: A descriptor for the bitmap. */
/* */
/* <Note> */
/* You can typecast FT_Glyph to FT_BitmapGlyph if you have */
/* glyph->format == ft_glyph_format_bitmap. This lets you access */
/* the bitmap's contents easily. */
/* */
/* The corresponding pixel buffer is always owned by the BitmapGlyph */
/* and is thus created and destroyed with it. */
/* */
typedef struct FT_BitmapGlyphRec_
{
FT_GlyphRec root;
FT_Int left;
FT_Int top;
FT_Bitmap bitmap;
} FT_BitmapGlyphRec;
/*************************************************************************/
/* */
/* <Type> */
/* FT_OutlineGlyph */
/* */
/* <Description> */
/* A handle to an object used to model an outline glyph image. This */
/* is a sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec. */
/* */
typedef struct FT_OutlineGlyphRec_* FT_OutlineGlyph;
/*************************************************************************/
/* */
/* <Struct> */
/* FT_OutlineGlyphRec */
/* */
/* <Description> */
/* A structure used for outline (vectorial) glyph images. This */
/* really is a `sub-class' of `FT_GlyphRec'. */
/* */
/* <Fields> */
/* root :: The root FT_Glyph fields. */
/* */
/* outline :: A descriptor for the outline. */
/* */
/* <Note> */
/* You can typecast FT_Glyph to FT_OutlineGlyph if you have */
/* glyph->format == ft_glyph_format_outline. This lets you access */
/* the outline's content easily. */
/* */
/* As the outline is extracted from a glyph slot, its coordinates are */
/* expressed normally in 26.6 pixels, unless the flag */
/* FT_LOAD_NO_SCALE was used in FT_Load_Glyph() or FT_Load_Char(). */
/* */
/* The outline's tables are always owned by the object and are */
/* destroyed with it. */
/* */
typedef struct FT_OutlineGlyphRec_
{
FT_GlyphRec root;
FT_Outline outline;
} FT_OutlineGlyphRec;
/*************************************************************************/
/* */
/* <Function> */
/* FT_Get_Glyph */
/* */
/* <Description> */
/* A function used to extract a glyph image from a slot. */
/* */
/* <Input> */
/* slot :: A handle to the source glyph slot. */
/* */
/* <Output> */
/* aglyph :: A handle to the glyph object. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_EXPORT( FT_Error )
FT_Get_Glyph( FT_GlyphSlot slot,
FT_Glyph *aglyph );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Glyph_Copy */
/* */
/* <Description> */
/* A function used to copy a glyph image. */
/* */
/* <Input> */
/* source :: A handle to the source glyph object. */
/* */
/* <Output> */
/* target :: A handle to the target glyph object. 0 in case of */
/* error. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_EXPORT( FT_Error )
FT_Glyph_Copy( FT_Glyph source,
FT_Glyph *target );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Glyph_Transform */
/* */
/* <Description> */
/* Transforms a glyph image if its format is scalable. */
/* */
/* <InOut> */
/* glyph :: A handle to the target glyph object. */
/* */
/* <Input> */
/* matrix :: A pointer to a 2x2 matrix to apply. */
/* */
/* delta :: A pointer to a 2d vector to apply. Coordinates are */
/* expressed in 1/64th of a pixel. */
/* */
/* <Return> */
/* FreeType error code (the glyph format is not scalable if it is */
/* not zero). */
/* */
/* <Note> */
/* The 2x2 transformation matrix is also applied to the glyph's */
/* advance vector. */
/* */
FT_EXPORT( FT_Error )
FT_Glyph_Transform( FT_Glyph glyph,
FT_Matrix* matrix,
FT_Vector* delta );
/* */
/*************************************************************************/
/* */
/* <Function> */
/* FT_Glyph_Get_CBox */
/* */
/* <Description> */
/* Returns a glyph'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 */
/* which 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> */
/* glyph :: A handle to the source glyph object. */
/* */
/* mode :: The mode which indicates how to interpret the returned */
/* bounding box values. */
/* */
/* <Output> */
/* acbox :: The glyph coordinate bounding box. Coordinates are */
/* expressed in 1/64th of pixels if it is grid-fitted. */
/* */
/* <Note> */
/* Coordinates are relative to the glyph origin, using the Y-upwards */
/* convention. */
/* */
/* If the glyph has been loaded with FT_LOAD_NO_SCALE, `bbox_mode' */
/* must be set to `ft_glyph_bbox_unscaled' to get unscaled font */
/* units. */
/* */
/* If `bbox_mode' is set to `ft_glyph_bbox_subpixels' the bbox */
/* coordinates are returned in 26.6 pixels (i.e. 1/64th of pixels). */
/* */
/* Note that the maximum coordinates are exclusive, which means that */
/* one can compute the width and height of the glyph image (be it in */
/* integer or 26.6 pixels) as: */
/* */
/* width = bbox.xMax - bbox.xMin; */
/* height = bbox.yMax - bbox.yMin; */
/* */
/* Note also that for 26.6 coordinates, if `bbox_mode' is set to */
/* `ft_glyph_bbox_gridfit', the coordinates will also be grid-fitted, */
/* which corresponds to: */
/* */
/* bbox.xMin = FLOOR(bbox.xMin); */
/* bbox.yMin = FLOOR(bbox.yMin); */
/* bbox.xMax = CEILING(bbox.xMax); */
/* bbox.yMax = CEILING(bbox.yMax); */
/* */
/* To get the bbox in pixel coordinates, set `bbox_mode' to */
/* `ft_glyph_bbox_truncate'. */
/* */
/* To get the bbox in grid-fitted pixel coordinates, set `bbox_mode' */
/* to `ft_glyph_bbox_pixels'. */
/* */
/* The default value for `bbox_mode' is `ft_glyph_bbox_pixels'. */
/* */
enum
{
ft_glyph_bbox_unscaled = 0, /* return unscaled font units */
ft_glyph_bbox_subpixels = 0, /* return unfitted 26.6 coordinates */
ft_glyph_bbox_gridfit = 1, /* return grid-fitted 26.6 coordinates */
ft_glyph_bbox_truncate = 2, /* return coordinates in integer pixels */
ft_glyph_bbox_pixels = 3 /* return grid-fitted pixel coordinates */
};
FT_EXPORT( void )
FT_Glyph_Get_CBox( FT_Glyph glyph,
FT_UInt bbox_mode,
FT_BBox *acbox );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Glyph_To_Bitmap */
/* */
/* <Description> */
/* Converts a given glyph object to a bitmap glyph object. */
/* */
/* <InOut> */
/* the_glyph :: A pointer to a handle to the target glyph. */
/* */
/* <Input> */
/* render_mode :: A set of bit flags that describe how the data is */
/* */
/* */
/* origin :: A pointer to a vector used to translate the glyph */
/* image before rendering. Can be 0 (if no */
/* translation). The origin is expressed in */
/* 26.6 pixels. */
/* */
/* destroy :: A boolean that indicates that the original glyph */
/* image should be destroyed by this function. It is */
/* never destroyed in case of error. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
/* <Note> */
/* The glyph image is translated with the `origin' vector before */
/* rendering. In case of error, it it translated back to its */
/* original position and the glyph is left untouched. */
/* */
/* The first parameter is a pointer to a FT_Glyph handle, that will */
/* be replaced by this function. Typically, you would use (omitting */
/* error handling): */
/* */
/* */
/* { */
/* FT_Glyph glyph; */
/* FT_BitmapGlyph glyph_bitmap; */
/* */
/* */
/* // load glyph */
/* error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAUT ); */
/* */
/* // extract glyph image */
/* error = FT_Get_Glyph( face->glyph, &glyph ); */
/* */
/* // convert to a bitmap (default render mode + destroy old) */
/* if ( glyph->format != ft_glyph_format_bitmap ) */
/* { */
/* error = FT_Glyph_To_Bitmap( &glyph, ft_render_mode_default, */
/* 0, 1 ); */
/* if ( error ) // glyph unchanged */
/* ... */
/* } */
/* */
/* // access bitmap content by typecasting */
/* glyph_bitmap = (FT_BitmapGlyph)glyph; */
/* */
/* // do funny stuff with it, like blitting/drawing */
/* ... */
/* */
/* // discard glyph image (bitmap or not) */
/* FT_Done_Glyph( glyph ); */
/* } */
/* */
/* */
/* This function will always fail if the glyph's format isn't */
/* scalable. */
/* */
FT_EXPORT( FT_Error )
FT_Glyph_To_Bitmap( FT_Glyph* the_glyph,
FT_ULong render_mode,
FT_Vector* origin,
FT_Bool destroy );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Done_Glyph */
/* */
/* <Description> */
/* Destroys a given glyph. */
/* */
/* <Input> */
/* glyph :: A handle to the target glyph object. */
/* */
FT_EXPORT( void )
FT_Done_Glyph( FT_Glyph glyph );
/* other helpful functions */
/*************************************************************************/
/* */
/* <Section> */
/* computations */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* FT_Matrix_Multiply */
/* */
/* <Description> */
/* Performs the matrix operation `b = a*b'. */
/* */
/* <Input> */
/* a :: A pointer to matrix `a'. */
/* */
/* <InOut> */
/* b :: A pointer to matrix `b'. */
/* */
/* <Note> */
/* The result is undefined if either `a' or `b' is zero. */
/* */
FT_EXPORT( void )
FT_Matrix_Multiply( FT_Matrix* a,
FT_Matrix* b );
/*************************************************************************/
/* */
/* <Function> */
/* FT_Matrix_Invert */
/* */
/* <Description> */
/* Inverts a 2x2 matrix. Returns an error if it can't be inverted. */
/* */
/* <InOut> */
/* matrix :: A pointer to the target matrix. Remains untouched in */
/* case of error. */
/* */
/* <Return> */
/* FreeType error code. 0 means success. */
/* */
FT_EXPORT( FT_Error )
FT_Matrix_Invert( FT_Matrix* matrix );
/* */
FT_END_HEADER
#endif /* __FTGLYPH_H__ */
/* END */