/***************************************************************************/ /* */ /* 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 #include FT_FREETYPE_H FT_BEGIN_HEADER /*************************************************************************/ /* */ /*
*/ /* glyph_management */ /* */ /* */ /* 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( 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 */