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Diffstat (limited to 'modules/freetype2/include/freetype/ftmm.h')
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diff --git a/modules/freetype2/include/freetype/ftmm.h b/modules/freetype2/include/freetype/ftmm.h new file mode 100644 index 0000000000..e381ef3d30 --- /dev/null +++ b/modules/freetype2/include/freetype/ftmm.h @@ -0,0 +1,764 @@ +/**************************************************************************** + * + * ftmm.h + * + * FreeType Multiple Master font 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 FTMM_H_ +#define FTMM_H_ + + +#include <freetype/t1tables.h> + + +FT_BEGIN_HEADER + + + /************************************************************************** + * + * @section: + * multiple_masters + * + * @title: + * Multiple Masters + * + * @abstract: + * How to manage Multiple Masters fonts. + * + * @description: + * The following types and functions are used to manage Multiple Master + * fonts, i.e., the selection of specific design instances by setting + * design axis coordinates. + * + * Besides Adobe MM fonts, the interface supports Apple's TrueType GX and + * OpenType variation fonts. Some of the routines only work with Adobe + * MM fonts, others will work with all three types. They are similar + * enough that a consistent interface makes sense. + * + * For Adobe MM fonts, macro @FT_IS_SFNT returns false. For GX and + * OpenType variation fonts, it returns true. + * + */ + + + /************************************************************************** + * + * @struct: + * FT_MM_Axis + * + * @description: + * A structure to model a given axis in design space for Multiple Masters + * fonts. + * + * This structure can't be used for TrueType GX or OpenType variation + * fonts. + * + * @fields: + * name :: + * The axis's name. + * + * minimum :: + * The axis's minimum design coordinate. + * + * maximum :: + * The axis's maximum design coordinate. + */ + typedef struct FT_MM_Axis_ + { + FT_String* name; + FT_Long minimum; + FT_Long maximum; + + } FT_MM_Axis; + + + /************************************************************************** + * + * @struct: + * FT_Multi_Master + * + * @description: + * A structure to model the axes and space of a Multiple Masters font. + * + * This structure can't be used for TrueType GX or OpenType variation + * fonts. + * + * @fields: + * num_axis :: + * Number of axes. Cannot exceed~4. + * + * num_designs :: + * Number of designs; should be normally 2^num_axis even though the + * Type~1 specification strangely allows for intermediate designs to be + * present. This number cannot exceed~16. + * + * axis :: + * A table of axis descriptors. + */ + typedef struct FT_Multi_Master_ + { + FT_UInt num_axis; + FT_UInt num_designs; + FT_MM_Axis axis[T1_MAX_MM_AXIS]; + + } FT_Multi_Master; + + + /************************************************************************** + * + * @struct: + * FT_Var_Axis + * + * @description: + * A structure to model a given axis in design space for Multiple + * Masters, TrueType GX, and OpenType variation fonts. + * + * @fields: + * name :: + * The axis's name. Not always meaningful for TrueType GX or OpenType + * variation fonts. + * + * minimum :: + * The axis's minimum design coordinate. + * + * def :: + * The axis's default design coordinate. FreeType computes meaningful + * default values for Adobe MM fonts. + * + * maximum :: + * The axis's maximum design coordinate. + * + * tag :: + * The axis's tag (the equivalent to 'name' for TrueType GX and + * OpenType variation fonts). FreeType provides default values for + * Adobe MM fonts if possible. + * + * strid :: + * The axis name entry in the font's 'name' table. This is another + * (and often better) version of the 'name' field for TrueType GX or + * OpenType variation fonts. Not meaningful for Adobe MM fonts. + * + * @note: + * The fields `minimum`, `def`, and `maximum` are 16.16 fractional values + * for TrueType GX and OpenType variation fonts. For Adobe MM fonts, the + * values are integers. + */ + typedef struct FT_Var_Axis_ + { + FT_String* name; + + FT_Fixed minimum; + FT_Fixed def; + FT_Fixed maximum; + + FT_ULong tag; + FT_UInt strid; + + } FT_Var_Axis; + + + /************************************************************************** + * + * @struct: + * FT_Var_Named_Style + * + * @description: + * A structure to model a named instance in a TrueType GX or OpenType + * variation font. + * + * This structure can't be used for Adobe MM fonts. + * + * @fields: + * coords :: + * The design coordinates for this instance. This is an array with one + * entry for each axis. + * + * strid :: + * The entry in 'name' table identifying this instance. + * + * psid :: + * The entry in 'name' table identifying a PostScript name for this + * instance. Value 0xFFFF indicates a missing entry. + */ + typedef struct FT_Var_Named_Style_ + { + FT_Fixed* coords; + FT_UInt strid; + FT_UInt psid; /* since 2.7.1 */ + + } FT_Var_Named_Style; + + + /************************************************************************** + * + * @struct: + * FT_MM_Var + * + * @description: + * A structure to model the axes and space of an Adobe MM, TrueType GX, + * or OpenType variation font. + * + * Some fields are specific to one format and not to the others. + * + * @fields: + * num_axis :: + * The number of axes. The maximum value is~4 for Adobe MM fonts; no + * limit in TrueType GX or OpenType variation fonts. + * + * num_designs :: + * The number of designs; should be normally 2^num_axis for Adobe MM + * fonts. Not meaningful for TrueType GX or OpenType variation fonts + * (where every glyph could have a different number of designs). + * + * num_namedstyles :: + * The number of named styles; a 'named style' is a tuple of design + * coordinates that has a string ID (in the 'name' table) associated + * with it. The font can tell the user that, for example, + * [Weight=1.5,Width=1.1] is 'Bold'. Another name for 'named style' is + * 'named instance'. + * + * For Adobe Multiple Masters fonts, this value is always zero because + * the format does not support named styles. + * + * axis :: + * An axis descriptor table. TrueType GX and OpenType variation fonts + * contain slightly more data than Adobe MM fonts. Memory management + * of this pointer is done internally by FreeType. + * + * namedstyle :: + * A named style (instance) table. Only meaningful for TrueType GX and + * OpenType variation fonts. Memory management of this pointer is done + * internally by FreeType. + */ + typedef struct FT_MM_Var_ + { + FT_UInt num_axis; + FT_UInt num_designs; + FT_UInt num_namedstyles; + FT_Var_Axis* axis; + FT_Var_Named_Style* namedstyle; + + } FT_MM_Var; + + + /************************************************************************** + * + * @function: + * FT_Get_Multi_Master + * + * @description: + * Retrieve a variation descriptor of a given Adobe MM font. + * + * This function can't be used with TrueType GX or OpenType variation + * fonts. + * + * @input: + * face :: + * A handle to the source face. + * + * @output: + * amaster :: + * The Multiple Masters descriptor. + * + * @return: + * FreeType error code. 0~means success. + */ + FT_EXPORT( FT_Error ) + FT_Get_Multi_Master( FT_Face face, + FT_Multi_Master *amaster ); + + + /************************************************************************** + * + * @function: + * FT_Get_MM_Var + * + * @description: + * Retrieve a variation descriptor for a given font. + * + * This function works with all supported variation formats. + * + * @input: + * face :: + * A handle to the source face. + * + * @output: + * amaster :: + * The variation descriptor. Allocates a data structure, which the + * user must deallocate with a call to @FT_Done_MM_Var after use. + * + * @return: + * FreeType error code. 0~means success. + */ + FT_EXPORT( FT_Error ) + FT_Get_MM_Var( FT_Face face, + FT_MM_Var* *amaster ); + + + /************************************************************************** + * + * @function: + * FT_Done_MM_Var + * + * @description: + * Free the memory allocated by @FT_Get_MM_Var. + * + * @input: + * library :: + * A handle of the face's parent library object that was used in the + * call to @FT_Get_MM_Var to create `amaster`. + * + * @return: + * FreeType error code. 0~means success. + */ + FT_EXPORT( FT_Error ) + FT_Done_MM_Var( FT_Library library, + FT_MM_Var *amaster ); + + + /************************************************************************** + * + * @function: + * FT_Set_MM_Design_Coordinates + * + * @description: + * For Adobe MM fonts, choose an interpolated font design through design + * coordinates. + * + * This function can't be used with TrueType GX or OpenType variation + * fonts. + * + * @inout: + * face :: + * A handle to the source face. + * + * @input: + * num_coords :: + * The number of available design coordinates. If it is larger than + * the number of axes, ignore the excess values. If it is smaller than + * the number of axes, use default values for the remaining axes. + * + * coords :: + * An array of design coordinates. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * [Since 2.8.1] To reset all axes to the default values, call the + * function with `num_coords` set to zero and `coords` set to `NULL`. + * + * [Since 2.9] If `num_coords` is larger than zero, this function sets + * the @FT_FACE_FLAG_VARIATION bit in @FT_Face's `face_flags` field + * (i.e., @FT_IS_VARIATION will return true). If `num_coords` is zero, + * this bit flag gets unset. + */ + FT_EXPORT( FT_Error ) + FT_Set_MM_Design_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Long* coords ); + + + /************************************************************************** + * + * @function: + * FT_Set_Var_Design_Coordinates + * + * @description: + * Choose an interpolated font design through design coordinates. + * + * This function works with all supported variation formats. + * + * @inout: + * face :: + * A handle to the source face. + * + * @input: + * num_coords :: + * The number of available design coordinates. If it is larger than + * the number of axes, ignore the excess values. If it is smaller than + * the number of axes, use default values for the remaining axes. + * + * coords :: + * An array of design coordinates. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * The design coordinates are 16.16 fractional values for TrueType GX and + * OpenType variation fonts. For Adobe MM fonts, the values are + * integers. + * + * [Since 2.8.1] To reset all axes to the default values, call the + * function with `num_coords` set to zero and `coords` set to `NULL`. + * [Since 2.9] 'Default values' means the currently selected named + * instance (or the base font if no named instance is selected). + * + * [Since 2.9] If `num_coords` is larger than zero, this function sets + * the @FT_FACE_FLAG_VARIATION bit in @FT_Face's `face_flags` field + * (i.e., @FT_IS_VARIATION will return true). If `num_coords` is zero, + * this bit flag gets unset. + */ + FT_EXPORT( FT_Error ) + FT_Set_Var_Design_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Get_Var_Design_Coordinates + * + * @description: + * Get the design coordinates of the currently selected interpolated + * font. + * + * This function works with all supported variation formats. + * + * @input: + * face :: + * A handle to the source face. + * + * num_coords :: + * The number of design coordinates to retrieve. If it is larger than + * the number of axes, set the excess values to~0. + * + * @output: + * coords :: + * The design coordinates array. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * The design coordinates are 16.16 fractional values for TrueType GX and + * OpenType variation fonts. For Adobe MM fonts, the values are + * integers. + * + * @since: + * 2.7.1 + */ + FT_EXPORT( FT_Error ) + FT_Get_Var_Design_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Set_MM_Blend_Coordinates + * + * @description: + * Choose an interpolated font design through normalized blend + * coordinates. + * + * This function works with all supported variation formats. + * + * @inout: + * face :: + * A handle to the source face. + * + * @input: + * num_coords :: + * The number of available design coordinates. If it is larger than + * the number of axes, ignore the excess values. If it is smaller than + * the number of axes, use default values for the remaining axes. + * + * coords :: + * The design coordinates array. Each element is a 16.16 fractional + * value and must be between 0 and 1.0 for Adobe MM fonts, and between + * -1.0 and 1.0 for TrueType GX and OpenType variation fonts. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * [Since 2.8.1] To reset all axes to the default values, call the + * function with `num_coords` set to zero and `coords` set to `NULL`. + * [Since 2.9] 'Default values' means the currently selected named + * instance (or the base font if no named instance is selected). + * + * [Since 2.9] If `num_coords` is larger than zero, this function sets + * the @FT_FACE_FLAG_VARIATION bit in @FT_Face's `face_flags` field + * (i.e., @FT_IS_VARIATION will return true). If `num_coords` is zero, + * this bit flag gets unset. + */ + FT_EXPORT( FT_Error ) + FT_Set_MM_Blend_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Get_MM_Blend_Coordinates + * + * @description: + * Get the normalized blend coordinates of the currently selected + * interpolated font. + * + * This function works with all supported variation formats. + * + * @input: + * face :: + * A handle to the source face. + * + * num_coords :: + * The number of normalized blend coordinates to retrieve. If it is + * larger than the number of axes, set the excess values to~0.5 for + * Adobe MM fonts, and to~0 for TrueType GX and OpenType variation + * fonts. + * + * @output: + * coords :: + * The normalized blend coordinates array (as 16.16 fractional values). + * + * @return: + * FreeType error code. 0~means success. + * + * @since: + * 2.7.1 + */ + FT_EXPORT( FT_Error ) + FT_Get_MM_Blend_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Set_Var_Blend_Coordinates + * + * @description: + * This is another name of @FT_Set_MM_Blend_Coordinates. + */ + FT_EXPORT( FT_Error ) + FT_Set_Var_Blend_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Get_Var_Blend_Coordinates + * + * @description: + * This is another name of @FT_Get_MM_Blend_Coordinates. + * + * @since: + * 2.7.1 + */ + FT_EXPORT( FT_Error ) + FT_Get_Var_Blend_Coordinates( FT_Face face, + FT_UInt num_coords, + FT_Fixed* coords ); + + + /************************************************************************** + * + * @function: + * FT_Set_MM_WeightVector + * + * @description: + * For Adobe MM fonts, choose an interpolated font design by directly + * setting the weight vector. + * + * This function can't be used with TrueType GX or OpenType variation + * fonts. + * + * @inout: + * face :: + * A handle to the source face. + * + * @input: + * len :: + * The length of the weight vector array. If it is larger than the + * number of designs, the extra values are ignored. If it is less than + * the number of designs, the remaining values are set to zero. + * + * weightvector :: + * An array representing the weight vector. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * Adobe Multiple Master fonts limit the number of designs, and thus the + * length of the weight vector to~16. + * + * If `len` is zero and `weightvector` is `NULL`, the weight vector array + * is reset to the default values. + * + * The Adobe documentation also states that the values in the + * WeightVector array must total 1.0 +/-~0.001. In practice this does + * not seem to be enforced, so is not enforced here, either. + * + * @since: + * 2.10 + */ + FT_EXPORT( FT_Error ) + FT_Set_MM_WeightVector( FT_Face face, + FT_UInt len, + FT_Fixed* weightvector ); + + + /************************************************************************** + * + * @function: + * FT_Get_MM_WeightVector + * + * @description: + * For Adobe MM fonts, retrieve the current weight vector of the font. + * + * This function can't be used with TrueType GX or OpenType variation + * fonts. + * + * @inout: + * face :: + * A handle to the source face. + * + * len :: + * A pointer to the size of the array to be filled. If the size of the + * array is less than the number of designs, `FT_Err_Invalid_Argument` + * is returned, and `len` is set to the required size (the number of + * designs). If the size of the array is greater than the number of + * designs, the remaining entries are set to~0. On successful + * completion, `len` is set to the number of designs (i.e., the number + * of values written to the array). + * + * @output: + * weightvector :: + * An array to be filled. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * Adobe Multiple Master fonts limit the number of designs, and thus the + * length of the WeightVector to~16. + * + * @since: + * 2.10 + */ + FT_EXPORT( FT_Error ) + FT_Get_MM_WeightVector( FT_Face face, + FT_UInt* len, + FT_Fixed* weightvector ); + + + /************************************************************************** + * + * @enum: + * FT_VAR_AXIS_FLAG_XXX + * + * @description: + * A list of bit flags used in the return value of + * @FT_Get_Var_Axis_Flags. + * + * @values: + * FT_VAR_AXIS_FLAG_HIDDEN :: + * The variation axis should not be exposed to user interfaces. + * + * @since: + * 2.8.1 + */ +#define FT_VAR_AXIS_FLAG_HIDDEN 1 + + + /************************************************************************** + * + * @function: + * FT_Get_Var_Axis_Flags + * + * @description: + * Get the 'flags' field of an OpenType Variation Axis Record. + * + * Not meaningful for Adobe MM fonts (`*flags` is always zero). + * + * @input: + * master :: + * The variation descriptor. + * + * axis_index :: + * The index of the requested variation axis. + * + * @output: + * flags :: + * The 'flags' field. See @FT_VAR_AXIS_FLAG_XXX for possible values. + * + * @return: + * FreeType error code. 0~means success. + * + * @since: + * 2.8.1 + */ + FT_EXPORT( FT_Error ) + FT_Get_Var_Axis_Flags( FT_MM_Var* master, + FT_UInt axis_index, + FT_UInt* flags ); + + + /************************************************************************** + * + * @function: + * FT_Set_Named_Instance + * + * @description: + * Set or change the current named instance. + * + * @input: + * face :: + * A handle to the source face. + * + * instance_index :: + * The index of the requested instance, starting with value 1. If set + * to value 0, FreeType switches to font access without a named + * instance. + * + * @return: + * FreeType error code. 0~means success. + * + * @note: + * The function uses the value of `instance_index` to set bits 16-30 of + * the face's `face_index` field. It also resets any variation applied + * to the font, and the @FT_FACE_FLAG_VARIATION bit of the face's + * `face_flags` field gets reset to zero (i.e., @FT_IS_VARIATION will + * return false). + * + * For Adobe MM fonts (which don't have named instances) this function + * simply resets the current face to the default instance. + * + * @since: + * 2.9 + */ + FT_EXPORT( FT_Error ) + FT_Set_Named_Instance( FT_Face face, + FT_UInt instance_index ); + + /* */ + + +FT_END_HEADER + +#endif /* FTMM_H_ */ + + +/* END */ |