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FreeType-2.8.1 API Reference

Multiple Masters

Synopsis

FT_MM_AxisFT_Set_Var_Design_Coordinates
FT_Multi_MasterFT_Get_Var_Design_Coordinates
FT_Var_AxisFT_Set_MM_Blend_Coordinates
FT_Var_Named_StyleFT_Get_MM_Blend_Coordinates
FT_MM_VarFT_Set_Var_Blend_Coordinates
FT_Get_Multi_MasterFT_Get_Var_Blend_Coordinates
FT_Get_MM_VarFT_VAR_AXIS_FLAG_XXX
FT_Set_MM_Design_CoordinatesFT_Get_Var_Axis_Flags

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.

FT_MM_Axis

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  typedef struct  FT_MM_Axis_
  {
    FT_String*  name;
    FT_Long     minimum;
    FT_Long     maximum;

  } FT_MM_Axis;

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.

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FT_Multi_Master

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  typedef struct  FT_Multi_Master_
  {
    FT_UInt     num_axis;
    FT_UInt     num_designs;
    FT_MM_Axis  axis[T1_MAX_MM_AXIS];

  } FT_Multi_Master;

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.

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FT_Var_Axis

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  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;

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.

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FT_Var_Named_Style

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  typedef struct  FT_Var_Named_Style_
  {
    FT_Fixed*  coords;
    FT_UInt    strid;
    FT_UInt    psid;   /* since 2.7.1 */

  } FT_Var_Named_Style;

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.

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FT_MM_Var

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  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;

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.

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FT_Get_Multi_Master

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_Multi_Master( FT_Face           face,
                       FT_Multi_Master  *amaster );

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.

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FT_Get_MM_Var

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_MM_Var( FT_Face      face,
                 FT_MM_Var*  *amaster );

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 ‘free’ after use.

return

FreeType error code. 0 means success.

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FT_Set_MM_Design_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Set_MM_Design_Coordinates( FT_Face   face,
                                FT_UInt   num_coords,
                                FT_Long*  coords );

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

To reset all axes to the default values, call the function with ‘num_coords’ set to zero and ‘coords’ set to NULL (new feature in FreeType version 2.8.1).

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FT_Set_Var_Design_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Set_Var_Design_Coordinates( FT_Face    face,
                                 FT_UInt    num_coords,
                                 FT_Fixed*  coords );

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

To reset all axes to the default values, call the function with ‘num_coords’ set to zero and ‘coords’ set to NULL (new feature in FreeType version 2.8.1).

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FT_Get_Var_Design_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_Var_Design_Coordinates( FT_Face    face,
                                 FT_UInt    num_coords,
                                 FT_Fixed*  coords );

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.

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FT_Set_MM_Blend_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Set_MM_Blend_Coordinates( FT_Face    face,
                               FT_UInt    num_coords,
                               FT_Fixed*  coords );

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 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

To reset all axes to the default values, call the function with ‘num_coords’ set to zero and ‘coords’ set to NULL (new feature in FreeType version 2.8.1).

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FT_Get_MM_Blend_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_MM_Blend_Coordinates( FT_Face    face,
                               FT_UInt    num_coords,
                               FT_Fixed*  coords );

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.

return

FreeType error code. 0 means success.

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FT_Set_Var_Blend_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Set_Var_Blend_Coordinates( FT_Face    face,
                                FT_UInt    num_coords,
                                FT_Fixed*  coords );

This is another name of FT_Set_MM_Blend_Coordinates.

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FT_Get_Var_Blend_Coordinates

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_Var_Blend_Coordinates( FT_Face    face,
                                FT_UInt    num_coords,
                                FT_Fixed*  coords );

This is another name of FT_Get_MM_Blend_Coordinates.

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FT_VAR_AXIS_FLAG_XXX

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

#define FT_VAR_AXIS_FLAG_HIDDEN  1

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.

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FT_Get_Var_Axis_Flags

Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).

  FT_EXPORT( FT_Error )
  FT_Get_Var_Axis_Flags( FT_MM_Var*  master,
                         FT_UInt     axis_index,
                         FT_UInt*    flags );

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.

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