| /**************************************************************************** |
| * |
| * ftglyph.h |
| * |
| * FreeType convenience functions to handle glyphs (specification). |
| * |
| * Copyright (C) 1996-2022 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 <freetype/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. These objects are |
| * detached from @FT_Face, contrary to @FT_GlyphSlot. |
| * |
| */ |
| |
| |
| /* 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_New_Glyph |
| * |
| * @description: |
| * A function used to create a new empty glyph image. Note that the |
| * created @FT_Glyph object must be released with @FT_Done_Glyph. |
| * |
| * @input: |
| * library :: |
| * A handle to the FreeType library object. |
| * |
| * format :: |
| * The format of the glyph's image. |
| * |
| * @output: |
| * aglyph :: |
| * A handle to the glyph object. |
| * |
| * @return: |
| * FreeType error code. 0~means success. |
| * |
| * @since: |
| * 2.10 |
| */ |
| FT_EXPORT( FT_Error ) |
| FT_New_Glyph( FT_Library library, |
| FT_Glyph_Format format, |
| FT_Glyph *aglyph ); |
| |
| |
| /************************************************************************** |
| * |
| * @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, |
| const FT_Matrix* matrix, |
| const 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 is 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, &glyphs[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, |
| const 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: */ |
