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ftmm.h (27783B)

---

/****************************************************************************
*
* ftmm.h
*
*   FreeType variation font interface (specification).
*
* Copyright (C) 1996-2025 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/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:
  *   multiple_masters
  *
  * @title:
  *   OpenType Font Variations, TrueType GX, and Adobe MM Fonts
  *
  * @abstract:
  *   How to manage variable fonts with multiple design axes.
  *
  * @description:
  *   The following types and functions manage OpenType Font Variations,
  *   Adobe Multiple Master (MM) fonts, and Apple TrueType GX fonts.  These
  *   formats have in common that they allow the selection of specific
  *   design instances by setting design coordinates for one or more axes
  *   like font weight or width.
  *
  *   For historical reasons there are two interfaces.  The first, older one
  *   can be used with Adobe MM fonts only, and the second, newer one is a
  *   unified interface that handles all three font formats.  However, some
  *   differences remain and are documented accordingly; in particular,
  *   Adobe MM fonts don't have named instances (see below).
  *
  *   For Adobe MM fonts, macro @FT_IS_SFNT returns false.  For TrueType GX
  *   and OpenType Font Variations, it returns true.
  *
  *   We use mostly the terminology of the OpenType standard.  Here are some
  *   important technical terms.
  *
  *   * A 'named instance' is a tuple of design coordinates that has a
  *     string ID (i.e., an index into the font's 'name' table) associated
  *     with it.  The font can tell the user that, for example,
  *     [Weight=700,Width=110] is 'Bold'.  Another name for 'named instance'
  *     is 'named style'.
  *
  *       Adobe MM fonts don't have named instances.
  *
  *   * The 'default instance' of a variation font is that instance for
  *     which the nth axis coordinate is equal to the nth default axis
  *     coordinate (i.e., `axis[n].def` as specified in the @FT_MM_Var
  *     structure), with~n covering all axes.  In TrueType GX and OpenType
  *     Font Variations, the default instance is explicitly given.  In Adobe
  *     MM fonts, the `WeightVector` entry as found in the font file is
  *     taken as the default instance.
  *
  *       For TrueType GX and OpenType Font Variations, FreeType synthesizes
  *       a named instance for the default instance if the font does not
  *       contain such an entry.
  *
  *   * 'Design coordinates' are the axis values found in a variation font
  *      file.  Their meaning is specified by the font designer and the
  *      values are rather arbitrary.
  *
  *       For example, the 'weight' axis in design coordinates might vary
  *       between 100 (thin) and 900 (heavy) in font~A, while font~B
  *       contains values between 400 (normal) and 800 (extra bold).
  *
  *   * 'Normalized coordinates' are design coordinates mapped to a standard
  *     range; they are also called 'blend coordinates'.
  *
  *       For TrueType GX and OpenType Font Variations, the range is [-1;1],
  *       with the minimum mapped to value~-1, the default mapped to
  *       value~0, and the maximum mapped to value~1, and all other
  *       coordinates mapped to intervening points.  Please look up the
  *       [OpenType
  *       specification](https://learn.microsoft.com/en-us/typography/opentype/spec/otvaroverview)
  *       on how this mapping works in detail.
  *
  *       For Adobe MM fonts, this standard range is [0;1], with the minimum
  *       mapped to value~0 and the maximum mapped to value~1, and all other
  *       coordinates mapped to intervening points.  Please look up [Adobe
  *       TechNote
  *       #5015](https://adobe-type-tools.github.io/font-tech-notes/pdfs/5015.Type1_Supp.pdf)
  *       on how this mapping works in detail.
  *
  *       Assuming that the two fonts in the previous example are OpenType
  *       Font Variations, both font~A's [100;900] and font~B's [400;800]
  *       coordinate ranges get mapped to [-1;1].
  */


 /**************************************************************************
  *
  * @enum:
  *   T1_MAX_MM_XXX
  *
  * @description:
  *   Adobe MM font limits as defined in their specifications.
  *
  * @values:
  *   T1_MAX_MM_AXIS ::
  *     The maximum number of Adobe MM font axes.
  *
  *   T1_MAX_MM_DESIGNS ::
  *     The maximum number of Adobe MM font designs.
  *
  *   T1_MAX_MM_MAP_POINTS ::
  *     The maximum number of elements in a design map.
  *
  */
#define T1_MAX_MM_AXIS         4
#define T1_MAX_MM_DESIGNS     16
#define T1_MAX_MM_MAP_POINTS  20


 /**************************************************************************
  *
  * @struct:
  *   FT_MM_Axis
  *
  * @description:
  *   A structure to model a given axis in design space for Adobe MM fonts.
  *
  *   This structure can't be used with TrueType GX or OpenType Font
  *   Variations.
  *
  * @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 an Adobe MM font.
  *
  *   This structure can't be used with TrueType GX or OpenType Font
  *   Variations.
  *
  * @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 Adobe MM fonts,
  *   TrueType GX, and OpenType Font Variations.
  *
  * @fields:
  *   name ::
  *     The axis's name.  Not always meaningful for TrueType GX or OpenType
  *     Font Variations.
  *
  *   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 Font Variations).  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 Font Variations.  Not meaningful for Adobe MM fonts.
  *
  * @note:
  *   The fields `minimum`, `def`, and `maximum` are 16.16 fractional values
  *   for TrueType GX and OpenType Font Variations.  For Adobe MM fonts, the
  *   values are whole numbers (i.e., the fractional part is zero).
  */
 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
  *   Font Variations.
  *
  *   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 ::
  *     An index into the 'name' table identifying this instance.
  *
  *   psid ::
  *     An index into the '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 Adobe MM fonts, TrueType
  *   GX, or OpenType Font Variations.
  *
  *   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 Font Variations.
  *
  *   num_designs ::
  *     The number of designs; should be normally `2^num_axis` for Adobe MM
  *     fonts.  Not meaningful for TrueType GX or OpenType Font Variations
  *     (where every glyph could have a different number of designs).
  *
  *   num_namedstyles ::
  *     The number of named instances.  For Adobe MM fonts, this value is
  *     always zero.
  *
  *   axis ::
  *     An axis descriptor table.  TrueType GX and OpenType Font Variations
  *     contain slightly more data than Adobe MM fonts.  Memory management
  *     of this pointer is done internally by FreeType.
  *
  *   namedstyle ::
  *     An array of named instances.  Only meaningful for TrueType GX and
  *     OpenType Font Variations.  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 Font
  *   Variations.
  *
  * @input:
  *   face ::
  *     A handle to the source face.
  *
  * @output:
  *   amaster ::
  *     The Adobe MM font's variation 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 Font
  *   Variations.
  *
  * @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 returns 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 Font Variations.  For Adobe MM fonts, the values are supposed
  *   to be whole numbers (i.e., the fractional part is zero).
  *
  *   [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 returns true).  If `num_coords` is zero, this
  *   bit flag gets unset.
  *
  *   [Since 2.14] This function also sets the @FT_FACE_FLAG_VARIATION bit
  *   in @FT_Face's `face_flags` field (i.e., @FT_IS_VARIATION returns
  *   true) if any of the provided coordinates is different from the face's
  *   default value for the corresponding axis, that is, the set up face is
  *   not at its default position.
  */
 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, which must be allocated by the user.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   The design coordinates are 16.16 fractional values for TrueType GX and
  *   OpenType Font Variations.  For Adobe MM fonts, the values are whole
  *   numbers (i.e., the fractional part is zero).
  *
  * @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 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 normalized 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 Font
  *     Variations.
  *
  * @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 returns true).  If `num_coords` is zero, this
  *   bit flag gets unset.
  *
  *   [Since 2.14] This function also sets the @FT_FACE_FLAG_VARIATION bit
  *   in @FT_Face's `face_flags` field (i.e., @FT_IS_VARIATION returns
  *   true) if any of the provided coordinates is different from the face's
  *   default value for the corresponding axis, that is, the set up face is
  *   not at its default position.
  */
 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 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 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 Font Variations.
  *
  * @output:
  *   coords ::
  *     The normalized coordinates array (as 16.16 fractional values), which
  *     must be allocated by the user.
  *
  * @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 Font
  *   Variations.
  *
  * @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 MM fonts limit the number of designs, and thus the length of the
  *   weight vector, to 16~elements.
  *
  *   If `len` 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 returns true).  If `len` is zero, this bit flag is
  *   unset and 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 Font
  *   Variations.
  *
  * @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; it must be allocated by the user.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   Adobe MM fonts limit the number of designs, and thus the length of the
  *   weight vector, to~16 elements.
  *
  * @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 returns
  *   false).
  *
  *   For Adobe MM fonts, this function 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 );


 /**************************************************************************
  *
  * @function:
  *   FT_Get_Default_Named_Instance
  *
  * @description:
  *   Retrieve the index of the default named instance, to be used with
  *   @FT_Set_Named_Instance.
  *
  *   FreeType synthesizes a named instance for the default instance if the
  *   font does not contain such an entry.
  *
  * @input:
  *   face ::
  *     A handle to the source face.
  *
  * @output:
  *   instance_index ::
  *     The index of the default named instance.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   For Adobe MM fonts, this function always returns zero for
  *   `instance_index`.
  *
  * @since:
  *   2.13.1
  */
 FT_EXPORT( FT_Error )
 FT_Get_Default_Named_Instance( FT_Face   face,
                                FT_UInt  *instance_index );

 /* */


FT_END_HEADER

#endif /* FTMM_H_ */


/* END */