← Back
Editing: ftglyph.h
/***************************************************************************/ /* */ /* ftglyph.h */ /* */ /* FreeType convenience functions to handle glyphs (specification). */ /* */ /* Copyright 1996-2018 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 #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> */ /* 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-point 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 an @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 @FT_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 an @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. Note that */ /* the created @FT_Glyph object must be released with @FT_Done_Glyph. */ /* */ /* <Input> */ /* slot :: A handle to the source glyph slot. */ /* */ /* <Output> */ /* aglyph :: A handle to the glyph object. */ /* */ /* <Return> */ /* FreeType error code. 0~means success. */ /* */ /* <Note> */ /* Because `*aglyph->advance.x' and '*aglyph->advance.y' are 16.16 */ /* fixed-point numbers, `slot->advance.x' and `slot->advance.y' */ /* (which are in 26.6 fixed-point format) must be in the range */ /* ]-32768;32768[. */ /* */ 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. Note that the created */ /* @FT_Glyph object must be released with @FT_Done_Glyph. */ /* */ /* <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> */ /* Transform 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 (if not 0, the glyph format is not scalable). */ /* */ /* <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 ); /*************************************************************************/ /* */ /* <Enum> */ /* FT_Glyph_BBox_Mode */ /* */ /* <Description> */ /* The mode how the values of @FT_Glyph_Get_CBox are returned. */ /* */ /* <Values> */ /* FT_GLYPH_BBOX_UNSCALED :: */ /* Return unscaled font units. */ /* */ /* FT_GLYPH_BBOX_SUBPIXELS :: */ /* Return unfitted 26.6 coordinates. */ /* */ /* FT_GLYPH_BBOX_GRIDFIT :: */ /* Return grid-fitted 26.6 coordinates. */ /* */ /* FT_GLYPH_BBOX_TRUNCATE :: */ /* Return coordinates in integer pixels. */ /* */ /* FT_GLYPH_BBOX_PIXELS :: */ /* Return grid-fitted pixel coordinates. */ /* */ typedef enum FT_Glyph_BBox_Mode_ { FT_GLYPH_BBOX_UNSCALED = 0, FT_GLYPH_BBOX_SUBPIXELS = 0, FT_GLYPH_BBOX_GRIDFIT = 1, FT_GLYPH_BBOX_TRUNCATE = 2, FT_GLYPH_BBOX_PIXELS = 3 } FT_Glyph_BBox_Mode; /* these constants are deprecated; use the corresponding */ /* `FT_Glyph_BBox_Mode' values instead */ #define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED #define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS #define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT #define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE #define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS /*************************************************************************/ /* */ /* <Function> */ /* FT_Glyph_Get_CBox */ /* */ /* <Description> */ /* Return 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 */ /* that 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 that 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 in 26.6 pixel format. The value @FT_GLYPH_BBOX_SUBPIXELS */ /* is another name for this constant. */ /* */ /* If the font is tricky and the glyph has been loaded with */ /* @FT_LOAD_NO_SCALE, the resulting CBox is meaningless. To get */ /* reasonable values for the CBox it is necessary to load the glyph */ /* at a large ppem value (so that the hinting instructions can */ /* properly shift and scale the subglyphs), then extracting the CBox, */ /* which can be eventually converted back to font units. */ /* */ /* 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. */ /* */ FT_EXPORT( void ) FT_Glyph_Get_CBox( FT_Glyph glyph, FT_UInt bbox_mode, FT_BBox *acbox ); /*************************************************************************/ /* */ /* <Function> */ /* FT_Glyph_To_Bitmap */ /* */ /* <Description> */ /* Convert 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 describes 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> */ /* This function does nothing if the glyph format isn't scalable. */ /* */ /* The glyph image is translated with the `origin' vector before */ /* rendering. */ /* */ /* The first parameter is a pointer to an @FT_Glyph handle, that will */ /* be _replaced_ by this function (with newly allocated data). */ /* 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_DEFAULT ); */ /* */ /* // extract glyph image */ /* error = FT_Get_Glyph( face->glyph, &glyph ); */ /* */ /* // convert to a bitmap (default render mode + destroying old) */ /* if ( glyph->format != FT_GLYPH_FORMAT_BITMAP ) */ /* { */ /* error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL, */ /* 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 ); */ /* } */ /* */ /* */ /* Here another example, again without error handling: */ /* */ /* */ /* { */ /* FT_Glyph glyphs[MAX_GLYPHS] */ /* */ /* */ /* ... */ /* */ /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */ /* error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) || */ /* FT_Get_Glyph ( face->glyph, &glyph[idx] ); */ /* */ /* ... */ /* */ /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */ /* { */ /* FT_Glyph bitmap = glyphs[idx]; */ /* */ /* */ /* ... */ /* */ /* // after this call, `bitmap' no longer points into */ /* // the `glyphs' array (and the old value isn't destroyed) */ /* FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 ); */ /* */ /* ... */ /* */ /* FT_Done_Glyph( bitmap ); */ /* } */ /* */ /* ... */ /* */ /* for ( idx = 0; i < MAX_GLYPHS; i++ ) */ /* FT_Done_Glyph( glyphs[idx] ); */ /* } */ /* */ 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> */ /* Destroy 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> */ /* Perform 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. */ /* */ /* Since the function uses wrap-around arithmetic, results become */ /* meaningless if the arguments are very large. */ /* */ FT_EXPORT( void ) FT_Matrix_Multiply( const FT_Matrix* a, FT_Matrix* b ); /*************************************************************************/ /* */ /* <Function> */ /* FT_Matrix_Invert */ /* */ /* <Description> */ /* Invert a 2x2 matrix. Return 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 */ /* Local Variables: */ /* coding: utf-8 */ /* End: */
Save File
Cancel