--- /dev/null
+/***************************************************************************/
+/* */
+/* ftincrem.h */
+/* */
+/* FreeType incremental loading (specification). */
+/* */
+/* Copyright 2002-2017 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 FTINCREM_H_
+#define FTINCREM_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:
+ * incremental
+ *
+ * @title:
+ * Incremental Loading
+ *
+ * @abstract:
+ * Custom Glyph Loading.
+ *
+ * @description:
+ * This section contains various functions used to perform so-called
+ * `incremental' glyph loading. This is a mode where all glyphs loaded
+ * from a given @FT_Face are provided by the client application.
+ *
+ * Apart from that, all other tables are loaded normally from the font
+ * file. This mode is useful when FreeType is used within another
+ * engine, e.g., a PostScript Imaging Processor.
+ *
+ * To enable this mode, you must use @FT_Open_Face, passing an
+ * @FT_Parameter with the @FT_PARAM_TAG_INCREMENTAL tag and an
+ * @FT_Incremental_Interface value. See the comments for
+ * @FT_Incremental_InterfaceRec for an example.
+ *
+ */
+
+
+ /***************************************************************************
+ *
+ * @type:
+ * FT_Incremental
+ *
+ * @description:
+ * An opaque type describing a user-provided object used to implement
+ * `incremental' glyph loading within FreeType. This is used to support
+ * embedded fonts in certain environments (e.g., PostScript interpreters),
+ * where the glyph data isn't in the font file, or must be overridden by
+ * different values.
+ *
+ * @note:
+ * It is up to client applications to create and implement @FT_Incremental
+ * objects, as long as they provide implementations for the methods
+ * @FT_Incremental_GetGlyphDataFunc, @FT_Incremental_FreeGlyphDataFunc
+ * and @FT_Incremental_GetGlyphMetricsFunc.
+ *
+ * See the description of @FT_Incremental_InterfaceRec to understand how
+ * to use incremental objects with FreeType.
+ *
+ */
+ typedef struct FT_IncrementalRec_* FT_Incremental;
+
+
+ /***************************************************************************
+ *
+ * @struct:
+ * FT_Incremental_MetricsRec
+ *
+ * @description:
+ * A small structure used to contain the basic glyph metrics returned
+ * by the @FT_Incremental_GetGlyphMetricsFunc method.
+ *
+ * @fields:
+ * bearing_x ::
+ * Left bearing, in font units.
+ *
+ * bearing_y ::
+ * Top bearing, in font units.
+ *
+ * advance ::
+ * Horizontal component of glyph advance, in font units.
+ *
+ * advance_v ::
+ * Vertical component of glyph advance, in font units.
+ *
+ * @note:
+ * These correspond to horizontal or vertical metrics depending on the
+ * value of the `vertical' argument to the function
+ * @FT_Incremental_GetGlyphMetricsFunc.
+ *
+ */
+ typedef struct FT_Incremental_MetricsRec_
+ {
+ FT_Long bearing_x;
+ FT_Long bearing_y;
+ FT_Long advance;
+ FT_Long advance_v; /* since 2.3.12 */
+
+ } FT_Incremental_MetricsRec;
+
+
+ /***************************************************************************
+ *
+ * @struct:
+ * FT_Incremental_Metrics
+ *
+ * @description:
+ * A handle to an @FT_Incremental_MetricsRec structure.
+ *
+ */
+ typedef struct FT_Incremental_MetricsRec_* FT_Incremental_Metrics;
+
+
+ /***************************************************************************
+ *
+ * @type:
+ * FT_Incremental_GetGlyphDataFunc
+ *
+ * @description:
+ * A function called by FreeType to access a given glyph's data bytes
+ * during @FT_Load_Glyph or @FT_Load_Char if incremental loading is
+ * enabled.
+ *
+ * Note that the format of the glyph's data bytes depends on the font
+ * file format. For TrueType, it must correspond to the raw bytes within
+ * the `glyf' table. For PostScript formats, it must correspond to the
+ * *unencrypted* charstring bytes, without any `lenIV' header. It is
+ * undefined for any other format.
+ *
+ * @input:
+ * incremental ::
+ * Handle to an opaque @FT_Incremental handle provided by the client
+ * application.
+ *
+ * glyph_index ::
+ * Index of relevant glyph.
+ *
+ * @output:
+ * adata ::
+ * A structure describing the returned glyph data bytes (which will be
+ * accessed as a read-only byte block).
+ *
+ * @return:
+ * FreeType error code. 0~means success.
+ *
+ * @note:
+ * If this function returns successfully the method
+ * @FT_Incremental_FreeGlyphDataFunc will be called later to release
+ * the data bytes.
+ *
+ * Nested calls to @FT_Incremental_GetGlyphDataFunc can happen for
+ * compound glyphs.
+ *
+ */
+ typedef FT_Error
+ (*FT_Incremental_GetGlyphDataFunc)( FT_Incremental incremental,
+ FT_UInt glyph_index,
+ FT_Data* adata );
+
+
+ /***************************************************************************
+ *
+ * @type:
+ * FT_Incremental_FreeGlyphDataFunc
+ *
+ * @description:
+ * A function used to release the glyph data bytes returned by a
+ * successful call to @FT_Incremental_GetGlyphDataFunc.
+ *
+ * @input:
+ * incremental ::
+ * A handle to an opaque @FT_Incremental handle provided by the client
+ * application.
+ *
+ * data ::
+ * A structure describing the glyph data bytes (which will be accessed
+ * as a read-only byte block).
+ *
+ */
+ typedef void
+ (*FT_Incremental_FreeGlyphDataFunc)( FT_Incremental incremental,
+ FT_Data* data );
+
+
+ /***************************************************************************
+ *
+ * @type:
+ * FT_Incremental_GetGlyphMetricsFunc
+ *
+ * @description:
+ * A function used to retrieve the basic metrics of a given glyph index
+ * before accessing its data. This is necessary because, in certain
+ * formats like TrueType, the metrics are stored in a different place from
+ * the glyph images proper.
+ *
+ * @input:
+ * incremental ::
+ * A handle to an opaque @FT_Incremental handle provided by the client
+ * application.
+ *
+ * glyph_index ::
+ * Index of relevant glyph.
+ *
+ * vertical ::
+ * If true, return vertical metrics.
+ *
+ * ametrics ::
+ * This parameter is used for both input and output.
+ * The original glyph metrics, if any, in font units. If metrics are
+ * not available all the values must be set to zero.
+ *
+ * @output:
+ * ametrics ::
+ * The replacement glyph metrics in font units.
+ *
+ */
+ typedef FT_Error
+ (*FT_Incremental_GetGlyphMetricsFunc)
+ ( FT_Incremental incremental,
+ FT_UInt glyph_index,
+ FT_Bool vertical,
+ FT_Incremental_MetricsRec *ametrics );
+
+
+ /**************************************************************************
+ *
+ * @struct:
+ * FT_Incremental_FuncsRec
+ *
+ * @description:
+ * A table of functions for accessing fonts that load data
+ * incrementally. Used in @FT_Incremental_InterfaceRec.
+ *
+ * @fields:
+ * get_glyph_data ::
+ * The function to get glyph data. Must not be null.
+ *
+ * free_glyph_data ::
+ * The function to release glyph data. Must not be null.
+ *
+ * get_glyph_metrics ::
+ * The function to get glyph metrics. May be null if the font does
+ * not provide overriding glyph metrics.
+ *
+ */
+ typedef struct FT_Incremental_FuncsRec_
+ {
+ FT_Incremental_GetGlyphDataFunc get_glyph_data;
+ FT_Incremental_FreeGlyphDataFunc free_glyph_data;
+ FT_Incremental_GetGlyphMetricsFunc get_glyph_metrics;
+
+ } FT_Incremental_FuncsRec;
+
+
+ /***************************************************************************
+ *
+ * @struct:
+ * FT_Incremental_InterfaceRec
+ *
+ * @description:
+ * A structure to be used with @FT_Open_Face to indicate that the user
+ * wants to support incremental glyph loading. You should use it with
+ * @FT_PARAM_TAG_INCREMENTAL as in the following example:
+ *
+ * {
+ * FT_Incremental_InterfaceRec inc_int;
+ * FT_Parameter parameter;
+ * FT_Open_Args open_args;
+ *
+ *
+ * // set up incremental descriptor
+ * inc_int.funcs = my_funcs;
+ * inc_int.object = my_object;
+ *
+ * // set up optional parameter
+ * parameter.tag = FT_PARAM_TAG_INCREMENTAL;
+ * parameter.data = &inc_int;
+ *
+ * // set up FT_Open_Args structure
+ * open_args.flags = FT_OPEN_PATHNAME | FT_OPEN_PARAMS;
+ * open_args.pathname = my_font_pathname;
+ * open_args.num_params = 1;
+ * open_args.params = ¶meter; // we use one optional argument
+ *
+ * // open the font
+ * error = FT_Open_Face( library, &open_args, index, &face );
+ * ...
+ * }
+ *
+ */
+ typedef struct FT_Incremental_InterfaceRec_
+ {
+ const FT_Incremental_FuncsRec* funcs;
+ FT_Incremental object;
+
+ } FT_Incremental_InterfaceRec;
+
+
+ /***************************************************************************
+ *
+ * @type:
+ * FT_Incremental_Interface
+ *
+ * @description:
+ * A pointer to an @FT_Incremental_InterfaceRec structure.
+ *
+ */
+ typedef FT_Incremental_InterfaceRec* FT_Incremental_Interface;
+
+
+ /***************************************************************************
+ *
+ * @constant:
+ * FT_PARAM_TAG_INCREMENTAL
+ *
+ * @description:
+ * A constant used as the tag of @FT_Parameter structures to indicate
+ * an incremental loading object to be used by FreeType.
+ *
+ */
+#define FT_PARAM_TAG_INCREMENTAL FT_MAKE_TAG( 'i', 'n', 'c', 'r' )
+
+ /* */
+
+
+FT_END_HEADER
+
+#endif /* FTINCREM_H_ */
+
+
+/* END */
projects / reactos.git / blobdiff