/**************************************************************************** * * sfnt.h * * High-level 'sfnt' driver interface (specification). * * Copyright (C) 1996-2023 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. * */ #ifndef SFNT_H_ #define SFNT_H_ #include <freetype/internal/ftdrv.h> #include <freetype/internal/tttypes.h> #include <freetype/internal/wofftypes.h> FT_BEGIN_HEADER /************************************************************************** * * @functype: * TT_Init_Face_Func * * @description: * First part of the SFNT face object initialization. This finds the * face in a SFNT file or collection, and load its format tag in * face->format_tag. * * @input: * stream :: * The input stream. * * face :: * A handle to the target face object. * * face_index :: * The index of the TrueType font, if we are opening a collection, in * bits 0-15. The numbered instance index~+~1 of a GX (sub)font, if * applicable, in bits 16-30. * * num_params :: * The number of additional parameters. * * params :: * Optional additional parameters. * * @return: * FreeType error code. 0 means success. * * @note: * The stream cursor must be at the font file's origin. * * This function recognizes fonts embedded in a 'TrueType collection'. * * Once the format tag has been validated by the font driver, it should * then call the TT_Load_Face_Func() callback to read the rest of the * SFNT tables in the object. */ TT_Init_Face_Func; /************************************************************************** * * @functype: * TT_Load_Face_Func * * @description: * Second part of the SFNT face object initialization. This loads the * common SFNT tables (head, OS/2, maxp, metrics, etc.) in the face * object. * * @input: * stream :: * The input stream. * * face :: * A handle to the target face object. * * face_index :: * The index of the TrueType font, if we are opening a collection, in * bits 0-15. The numbered instance index~+~1 of a GX (sub)font, if * applicable, in bits 16-30. * * num_params :: * The number of additional parameters. * * params :: * Optional additional parameters. * * @return: * FreeType error code. 0 means success. * * @note: * This function must be called after TT_Init_Face_Func(). */ TT_Load_Face_Func; /************************************************************************** * * @functype: * TT_Done_Face_Func * * @description: * A callback used to delete the common SFNT data from a face. * * @input: * face :: * A handle to the target face object. * * @note: * This function does NOT destroy the face object. */ TT_Done_Face_Func; /************************************************************************** * * @functype: * TT_Load_Any_Func * * @description: * Load any font table into client memory. * * @input: * face :: * The face object to look for. * * tag :: * The tag of table to load. Use the value 0 if you want to access the * whole font file, else set this parameter to a valid TrueType table * tag that you can forge with the MAKE_TT_TAG macro. * * offset :: * The starting offset in the table (or the file if tag == 0). * * length :: * The address of the decision variable: * * If `length == NULL`: Loads the whole table. Returns an error if * 'offset' == 0! * * If `*length == 0`: Exits immediately; returning the length of the * given table or of the font file, depending on the value of 'tag'. * * If `*length != 0`: Loads the next 'length' bytes of table or font, * starting at offset 'offset' (in table or font too). * * @output: * buffer :: * The address of target buffer. * * @return: * TrueType error code. 0 means success. */ TT_Load_Any_Func; /************************************************************************** * * @functype: * TT_Find_SBit_Image_Func * * @description: * Check whether an embedded bitmap (an 'sbit') exists for a given glyph, * at a given strike. * * @input: * face :: * The target face object. * * glyph_index :: * The glyph index. * * strike_index :: * The current strike index. * * @output: * arange :: * The SBit range containing the glyph index. * * astrike :: * The SBit strike containing the glyph index. * * aglyph_offset :: * The offset of the glyph data in 'EBDT' table. * * @return: * FreeType error code. 0 means success. Returns * SFNT_Err_Invalid_Argument if no sbit exists for the requested glyph. */ TT_Find_SBit_Image_Func; /************************************************************************** * * @functype: * TT_Load_SBit_Metrics_Func * * @description: * Get the big metrics for a given embedded bitmap. * * @input: * stream :: * The input stream. * * range :: * The SBit range containing the glyph. * * @output: * big_metrics :: * A big SBit metrics structure for the glyph. * * @return: * FreeType error code. 0 means success. * * @note: * The stream cursor must be positioned at the glyph's offset within the * 'EBDT' table before the call. * * If the image format uses variable metrics, the stream cursor is * positioned just after the metrics header in the 'EBDT' table on * function exit. */ TT_Load_SBit_Metrics_Func; /************************************************************************** * * @functype: * TT_Load_SBit_Image_Func * * @description: * Load a given glyph sbit image from the font resource. This also * returns its metrics. * * @input: * face :: * The target face object. * * strike_index :: * The strike index. * * glyph_index :: * The current glyph index. * * load_flags :: * The current load flags. * * stream :: * The input stream. * * @output: * amap :: * The target pixmap. * * ametrics :: * A big sbit metrics structure for the glyph image. * * @return: * FreeType error code. 0 means success. Returns an error if no glyph * sbit exists for the index. * * @note: * The `map.buffer` field is always freed before the glyph is loaded. */ TT_Load_SBit_Image_Func; /************************************************************************** * * @functype: * TT_Load_Svg_Doc_Func * * @description: * Scan the SVG document list to find the document containing the glyph * that has the ID 'glyph*XXX*', where *XXX* is the value of * `glyph_index` as a decimal integer. * * @inout: * glyph :: * The glyph slot from which pointers to the SVG document list is to be * grabbed. The results are stored back in the slot. * * @input: * glyph_index :: * The index of the glyph that is to be looked up. * * @return: * FreeType error code. 0 means success. */ TT_Load_Svg_Doc_Func; /************************************************************************** * * @functype: * TT_Set_SBit_Strike_Func * * @description: * Select an sbit strike for a given size request. * * @input: * face :: * The target face object. * * req :: * The size request. * * @output: * astrike_index :: * The index of the sbit strike. * * @return: * FreeType error code. 0 means success. Returns an error if no sbit * strike exists for the selected ppem values. */ TT_Set_SBit_Strike_Func; /************************************************************************** * * @functype: * TT_Load_Strike_Metrics_Func * * @description: * Load the metrics of a given strike. * * @input: * face :: * The target face object. * * strike_index :: * The strike index. * * @output: * metrics :: * the metrics of the strike. * * @return: * FreeType error code. 0 means success. Returns an error if no such * sbit strike exists. */ TT_Load_Strike_Metrics_Func; /************************************************************************** * * @functype: * TT_Get_PS_Name_Func * * @description: * Get the PostScript glyph name of a glyph. * * @input: * idx :: * The glyph index. * * PSname :: * The address of a string pointer. Will be `NULL` in case of error, * otherwise it is a pointer to the glyph name. * * You must not modify the returned string! * * @output: * FreeType error code. 0 means success. */ TT_Get_PS_Name_Func; /************************************************************************** * * @functype: * TT_Load_Metrics_Func * * @description: * Load a metrics table, which is a table with a horizontal and a * vertical version. * * @input: * face :: * A handle to the target face object. * * stream :: * The input stream. * * vertical :: * A boolean flag. If set, load the vertical one. * * @return: * FreeType error code. 0 means success. */ TT_Load_Metrics_Func; /************************************************************************** * * @functype: * TT_Get_Metrics_Func * * @description: * Load the horizontal or vertical header in a face object. * * @input: * face :: * A handle to the target face object. * * vertical :: * A boolean flag. If set, load vertical metrics. * * gindex :: * The glyph index. * * @output: * abearing :: * The horizontal (or vertical) bearing. Set to zero in case of error. * * aadvance :: * The horizontal (or vertical) advance. Set to zero in case of error. */ TT_Get_Metrics_Func; /************************************************************************** * * @functype: * TT_Set_Palette_Func * * @description: * Load the colors into `face->palette` for a given palette index. * * @input: * face :: * The target face object. * * idx :: * The palette index. * * @return: * FreeType error code. 0 means success. */ TT_Set_Palette_Func; /************************************************************************** * * @functype: * TT_Get_Colr_Layer_Func * * @description: * Iteratively get the color layer data of a given glyph index. * * @input: * face :: * The target face object. * * base_glyph :: * The glyph index the colored glyph layers are associated with. * * @inout: * iterator :: * An @FT_LayerIterator object. For the first call you should set * `iterator->p` to `NULL`. For all following calls, simply use the * same object again. * * @output: * aglyph_index :: * The glyph index of the current layer. * * acolor_index :: * The color index into the font face's color palette of the current * layer. The value 0xFFFF is special; it doesn't reference a palette * entry but indicates that the text foreground color should be used * instead (to be set up by the application outside of FreeType). * * @return: * Value~1 if everything is OK. If there are no more layers (or if there * are no layers at all), value~0 gets returned. In case of an error, * value~0 is returned also. */ TT_Get_Colr_Layer_Func; /************************************************************************** * * @functype: * TT_Get_Color_Glyph_Paint_Func * * @description: * Find the root @FT_OpaquePaint object for a given glyph ID. * * @input: * face :: * The target face object. * * base_glyph :: * The glyph index the colored glyph layers are associated with. * * @output: * paint :: * The root @FT_OpaquePaint object. * * @return: * Value~1 if everything is OK. If no color glyph is found, or the root * paint could not be retrieved, value~0 gets returned. In case of an * error, value~0 is returned also. */ TT_Get_Color_Glyph_Paint_Func; /************************************************************************** * * @functype: * TT_Get_Color_Glyph_ClipBox_Func * * @description: * Search for a 'COLR' v1 clip box for the specified `base_glyph` and * fill the `clip_box` parameter with the 'COLR' v1 'ClipBox' information * if one is found. * * @input: * face :: * A handle to the parent face object. * * base_glyph :: * The glyph index for which to retrieve the clip box. * * @output: * clip_box :: * The clip box for the requested `base_glyph` if one is found. The * clip box is computed taking scale and transformations configured on * the @FT_Face into account. @FT_ClipBox contains @FT_Vector values * in 26.6 format. * * @note: * To retrieve the clip box in font units, reset scale to units-per-em * and remove transforms configured using @FT_Set_Transform. * * @return: * Value~1 if a ClipBox is found. If no clip box is found or an * error occured, value~0 is returned. */ TT_Get_Color_Glyph_ClipBox_Func; /************************************************************************** * * @functype: * TT_Get_Paint_Layers_Func * * @description: * Access the layers of a `PaintColrLayers` table. * * @input: * face :: * The target face object. * * @inout: * iterator :: * The @FT_LayerIterator from an @FT_PaintColrLayers object, for which * the layers are to be retrieved. The internal state of the iterator * is incremented after one call to this function for retrieving one * layer. * * @output: * paint :: * The root @FT_OpaquePaint object referencing the actual paint table. * * @return: * Value~1 if everything is OK. Value~0 gets returned when the paint * object can not be retrieved or any other error occurs. */ TT_Get_Paint_Layers_Func; /************************************************************************** * * @functype: * TT_Get_Colorline_Stops_Func * * @description: * Get the gradient and solid fill information for a given glyph. * * @input: * face :: * The target face object. * * @inout: * iterator :: * An @FT_ColorStopIterator object. For the first call you should set * `iterator->p` to `NULL`. For all following calls, simply use the * same object again. * * @output: * color_stop :: * Color index and alpha value for the retrieved color stop. * * @return: * Value~1 if everything is OK. If there are no more color stops, * value~0 gets returned. In case of an error, value~0 is returned * also. */ TT_Get_Colorline_Stops_Func; /************************************************************************** * * @functype: * TT_Get_Paint_Func * * @description: * Get the paint details for a given @FT_OpaquePaint object. * * @input: * face :: * The target face object. * * opaque_paint :: * The @FT_OpaquePaint object. * * @output: * paint :: * An @FT_COLR_Paint object holding the details on `opaque_paint`. * * @return: * Value~1 if everything is OK. Value~0 if no details can be found for * this paint or any other error occured. */ TT_Get_Paint_Func; /************************************************************************** * * @functype: * TT_Blend_Colr_Func * * @description: * Blend the bitmap in `new_glyph` into `base_glyph` using the color * specified by `color_index`. If `color_index` is 0xFFFF, use * `face->foreground_color` if `face->have_foreground_color` is set. * Otherwise check `face->palette_data.palette_flags`: If present and * @FT_PALETTE_FOR_DARK_BACKGROUND is set, use BGRA value 0xFFFFFFFF * (white opaque). Otherwise use BGRA value 0x000000FF (black opaque). * * @input: * face :: * The target face object. * * color_index :: * Color index from the COLR table. * * base_glyph :: * Slot for bitmap to be merged into. The underlying bitmap may get * reallocated. * * new_glyph :: * Slot to be incooperated into `base_glyph`. * * @return: * FreeType error code. 0 means success. Returns an error if * color_index is invalid or reallocation fails. */ TT_Blend_Colr_Func; /************************************************************************** * * @functype: * TT_Get_Name_Func * * @description: * From the 'name' table, return a given ENGLISH name record in ASCII. * * @input: * face :: * A handle to the source face object. * * nameid :: * The name id of the name record to return. * * @inout: * name :: * The address of an allocated string pointer. `NULL` if no name is * present. * * @return: * FreeType error code. 0 means success. */ TT_Get_Name_Func; /************************************************************************** * * @functype: * TT_Get_Name_ID_Func * * @description: * Search whether an ENGLISH version for a given name ID is in the 'name' * table. * * @input: * face :: * A handle to the source face object. * * nameid :: * The name id of the name record to return. * * @output: * win :: * If non-negative, an index into the 'name' table with the * corresponding (3,1) or (3,0) Windows entry. * * apple :: * If non-negative, an index into the 'name' table with the * corresponding (1,0) Apple entry. * * @return: * 1 if there is either a win or apple entry (or both), 0 otheriwse. */ TT_Get_Name_ID_Func; /************************************************************************** * * @functype: * TT_Load_Table_Func * * @description: * Load a given TrueType table. * * @input: * face :: * A handle to the target face object. * * stream :: * The input stream. * * @return: * FreeType error code. 0 means success. * * @note: * The function uses `face->goto_table` to seek the stream to the start * of the table, except while loading the font directory. */ TT_Load_Table_Func; /************************************************************************** * * @functype: * TT_Free_Table_Func * * @description: * Free a given TrueType table. * * @input: * face :: * A handle to the target face object. */ TT_Free_Table_Func; /* * @functype: * TT_Face_GetKerningFunc * * @description: * Return the horizontal kerning value between two glyphs. * * @input: * face :: * A handle to the source face object. * * left_glyph :: * The left glyph index. * * right_glyph :: * The right glyph index. * * @return: * The kerning value in font units. */ TT_Face_GetKerningFunc; /************************************************************************** * * @struct: * SFNT_Interface * * @description: * This structure holds pointers to the functions used to load and free * the basic tables that are required in a 'sfnt' font file. * * @fields: * Check the various xxx_Func() descriptions for details. */ SFNT_Interface; /* transitional */ SFNT_Service; #define FT_DEFINE_SFNT_INTERFACE( \ class_, \ goto_table_, \ init_face_, \ load_face_, \ done_face_, \ get_interface_, \ load_any_, \ load_head_, \ load_hhea_, \ load_cmap_, \ load_maxp_, \ load_os2_, \ load_post_, \ load_name_, \ free_name_, \ load_kern_, \ load_gasp_, \ load_pclt_, \ load_bhed_, \ load_sbit_image_, \ get_psname_, \ free_psnames_, \ get_kerning_, \ load_font_dir_, \ load_hmtx_, \ load_eblc_, \ free_eblc_, \ set_sbit_strike_, \ load_strike_metrics_, \ load_cpal_, \ load_colr_, \ free_cpal_, \ free_colr_, \ set_palette_, \ get_colr_layer_, \ get_colr_glyph_paint_, \ get_color_glyph_clipbox, \ get_paint_layers_, \ get_colorline_stops_, \ get_paint_, \ colr_blend_, \ get_metrics_, \ get_name_, \ get_name_id_, \ load_svg_, \ free_svg_, \ load_svg_doc_ ) … FT_END_HEADER #endif /* SFNT_H_ */ /* END */
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