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freetype/include/ftglyph.h
David Turner 37379e2170 major changes to the library: 
- there is now a "convenience" API to manage glyphs in
   "include/ftglyph.h". See the demo program "ftstring" for
   an example..

  - the raster interface has been changed in order to allow
    direct composition through user-provided callbacks. This
    has been tested but isn't demonstrated for now in "demos"

 - the FT_LOAD_NO_RECURSE flag is supported, as this is
   required by some new code in the auto-hinting engine

 - some bug fixed in FT_MulFix which made FT_xxx_Transform
   return incorrect results..
2000-03-28 11:22:31 +00:00

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/***************************************************************************/
/* */
/* ftglyph.h */
/* */
/* FreeType convenience functions to handle glyphs.. */
/* */
/* Copyright 1996-1999 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're 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 <freetype.h>
typedef enum {
ft_glyph_type_none = 0,
ft_glyph_type_bitmap = 1,
ft_glyph_type_outline = 2
} FT_GlyphType;
/***********************************************************************
*
* <Struct>
* FT_GlyphRec
*
* <Description>
* The root glyph structure contains a given glyph image's metrics.
* Note that the FT_Glyph type is a pointer to FT_GlyphRec
*
* <Field>
* memory :: a handle to the memory allocator that is used to
* create/clone/destroy this glyph..
*
* glyph_type :: the glyph type..
*
* height :: height of glyph image
* width :: width of glyph image
*
* bearingX :: horizontal bearing, this is the distance from the
* the current pen position to the left of the glyph
*
* bearingY :: vertical bearing, this is the distance from the
* current pen position to the top of the glyph
*
* advance :: this is the horizontal or vertical advance for the
* glyph
*
* <Note>
* the distances expressed in the metrics are expressed in 26.6 fixed
* float sub-pixels (i.e. 1/64th of pixels).
*
* the vertical bearing has a positive value when the glyph top is
* above the baseline, and negative when it is under..
*
***********************************************************************/
typedef struct FT_GlyphRec_
{
FT_Memory memory;
FT_GlyphType glyph_type;
FT_Int height;
FT_Int width;
FT_Int bearingX;
FT_Int bearingY;
FT_Int advance;
} FT_GlyphRec, *FT_Glyph;
/***********************************************************************
*
* <Struct>
* FT_BitmapGlyphRec
*
* <Description>
* A structure used to describe a bitmap glyph image..
* Note that the FT_BitmapGlyph type is a pointer to FT_BitmapGlyphRec
*
* <Field>
* metrics :: the corresponding glyph metrics
* bitmap :: a descriptor for the bitmap.
*
* <Note>
* the "width" and "height" fields of the metrics are expressed in
* 26.6 sub-pixels. However, the width and height in pixels can be
* read directly from "bitmap.width" and "bitmap.height"
*
* this structure is used for both monochrome and anti-aliased
* bitmaps (the bitmap descriptor contains field describing the
* format of the pixel buffer)
*
* the corresponding pixel buffer is always owned by the BitmapGlyph
* and is thus creatde and destroyed with it..
*
***********************************************************************/
typedef struct FT_BitmapGlyphRec_
{
FT_GlyphRec metrics;
FT_Int left;
FT_Int top;
FT_Bitmap bitmap;
} FT_BitmapGlyphRec_, *FT_BitmapGlyph;
/***********************************************************************
*
* <Struct>
* FT_OutlineGlyphRec
*
* <Description>
* A structure used to describe a vectorial outline glyph image..
* Note that the FT_OutlineGlyph type is a pointer to FT_OutlineGlyphRec
*
* <Field>
* metrics :: the corresponding glyph metrics
* outline :: a descriptor for the outline
*
* <Note>
* the "width" and "height" fields of the metrics are expressed in
* 26.6 sub-pixels. However, the width and height in pixels can be
* read directly from "bitmap.width" and "bitmap.rows"
*
* the corresponding outline points tables is always owned by the
* object and are destroyed with it..
*
* an OutlineGlyph can be used to generate a BitmapGlyph with the
* function FT_OutlineGlyph_Render()
*
***********************************************************************/
typedef struct FT_OutlineGlyphRec_
{
FT_GlyphRec metrics;
FT_Outline outline;
} FT_OutlineGlyphRec_, *FT_OutlineGlyph;
/***********************************************************************
*
* <Function>
* FT_Get_Glyph_Bitmap
*
* <Description>
* A function used to directly return a monochrome bitmap glyph image
* from a face.
*
* <Input>
* face :: handle to source face object
* glyph_index :: glyph index in face
* load_flags :: load flags, see FT_LOAD_FLAG_XXXX constants..
* grays :: number of gray levels for anti-aliased bitmaps,
* set to 0 if you want to render a monochrome bitmap
* origin :: a pointer to the origin's position. Set to 0
* if the current transform is the identity..
*
* <Output>
* bitglyph :: pointer to the new bitmap glyph
*
* <Return>
* Error code. 0 means success.
*
* <Note>
* If the font contains glyph outlines, these will be automatically
* converted to a bitmap according to the value of "grays"
*
* If "grays" is set to 0, the result is a 1-bit monochrome bitmap
* otherwise, it is an 8-bit gray-level bitmap
*
* The number of gray levels in the result anti-aliased bitmap might
* not be "grays", depending on the current scan-converter implementation
*
* Note that it is not possible to generate 8-bit monochrome bitmaps
* with this function. Rather, use FT_Get_Glyph_Outline, then
* FT_Glyph_Render_Outline and provide your own span callbacks..
*
* When the face doesn't contain scalable outlines, this function will
* fail if the current transform is not the identity, or if the glyph
* origin's phase to the pixel grid is not 0 in both directions !!
*
***********************************************************************/
EXPORT_DEF
FT_Error FT_Get_Glyph_Bitmap( FT_Face face,
FT_UInt glyph_index,
FT_UInt load_flags,
FT_Int grays,
FT_Vector* origin,
FT_BitmapGlyph *abitglyph );
/***********************************************************************
*
* <Function>
* FT_Get_Glyph_Outline
*
* <Description>
* A function used to directly return a bitmap glyph image from a
* face. This is faster than calling FT_Load_Glyph+FT_Get_Outline_Bitmap..
*
* <Input>
* face :: handle to source face object
* glyph_index :: glyph index in face
* load_flags :: load flags, see FT_LOAD_FLAG_XXXX constants..
*
* <Output>
* vecglyph :: pointer to the new outline glyph
*
* <Return>
* Error code. 0 means success.
*
* <Note>
* If the glyph is not an outline in the face, this function will
* fail..
*
* This function will fail if the load flags FT_LOAD_NO_OUTLINE and
* FT_LOAD_NO_RECURSE are set..
*
***********************************************************************/
EXPORT_DEF
FT_Error FT_Get_Glyph_Outline( FT_Face face,
FT_UInt glyph_index,
FT_UInt load_flags,
FT_OutlineGlyph *vecglyph );
/***********************************************************************
*
* <Function>
* FT_Set_Transform
*
* <Description>
* A function used to set the transform that is applied to glyph images
* just after they're loaded in the face's glyph slot, and before they're
* returned by either FT_Get_Glyph_Bitmap or FT_Get_Glyph_Outline
*
* <Input>
* face :: handle to source face object
* matrix :: pointer to the transform's 2x2 matrix. 0 for identity
* delta :: pointer to the transform's translation. 0 for null vector
*
* <Note>
* The transform is only applied to glyph outlines when they are found
* in a font face. It is unable to transform embedded glyph bitmaps
*
***********************************************************************/
EXPORT_DEF
void FT_Set_Transform( FT_Face face,
FT_Matrix* matrix,
FT_Vector* delta );
/***********************************************************************
*
* <Function>
* FT_Done_Glyph
*
* <Description>
* Destroys a given glyph..
*
* <Input>
* glyph :: handle to target glyph object
*
***********************************************************************/
EXPORT_DEF
void FT_Done_Glyph( FT_Glyph glyph );
/***********************************************************************
*
* <Function>
* FT_Glyph_Get_Box
*
* <Description>
* Returns the glyph image's bounding box in pixels.
*
* <Input>
* glyph :: handle to target glyph object
*
* <Output>
* box :: the glyph bounding box. Coordinates are expressed in
* _integer_ pixels, with exclusive max bounds
*
* <Note>
* Coordinates are relative to the glyph origin, using the Y-upwards
* convention..
*
* The width of the box in pixels is box.xMax-box.xMin
* The height is box.yMax - box.yMin
*
***********************************************************************/
EXPORT_DEF
void FT_Glyph_Get_Box( FT_Glyph glyph,
FT_BBox *box );
#endif /* FTGLYPH_H */
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