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- /***************************************************************************/
- /* */
- /* 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 :: An enumeration that describe how the data is */
- /* rendered. */
- /* */
- /* 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_Render_Mode 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( const 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 */
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