FreeType-2.2.1 API Reference

Multiple Masters

Synopsis

	FT_MM_Axis		FT_Get_MM_Var
	FT_Multi_Master		FT_Set_MM_Design_Coordinates
	FT_Var_Axis		FT_Set_Var_Design_Coordinates
	FT_Var_Named_Style		FT_Set_MM_Blend_Coordinates
	FT_MM_Var		FT_Set_Var_Blend_Coordinates
	FT_Get_Multi_Master

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.

George Williams has extended this interface to make it work with both Type 1 Multiple Masters fonts and GX distortable (var) fonts. Some of these routines only work with MM fonts, others will work with both types. They are similar enough that a consistent interface makes sense.

FT_MM_Axis


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

  } FT_MM_Axis;

A simple structure used to model a given axis in design space for Multiple Masters fonts.

This structure can't be used for GX var 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


  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 used to model the axes and space of a Multiple Masters font.

This structure can't be used for GX var 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


  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 simple structure used to model a given axis in design space for Multiple Masters and GX var fonts.

fields

name	The axis's name. Not always meaningful for GX.
minimum	The axis's minimum design coordinate.
def	The axis's default design coordinate. FreeType computes meaningful default values for MM; it is then an integer value, not in 16.16 format.
maximum	The axis's maximum design coordinate.
tag	The axis's tag (the GX equivalent to ‘name’). FreeType provides default values for MM if possible.
strid	The entry in ‘name’ table (another GX version of ‘name’). Not meaningful for MM.

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FT_Var_Named_Style


  typedef struct  FT_Var_Named_Style_
  {
    FT_Fixed*  coords;
    FT_UInt    strid;

  } FT_Var_Named_Style;

A simple structure used to model a named style in a GX var font.

This structure can't be used for MM fonts.

fields

coords	The design coordinates for this style. This is an array with one entry for each axis.
strid	The entry in ‘name’ table identifying this style.

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FT_MM_Var


  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 used to model the axes and space of a Multiple Masters or GX var distortable font.

Some fields are specific to one format and not to the other.

fields

num_axis	The number of axes. The maximum value is 4 for MM; no limit in GX.
num_designs	The number of designs; should be normally 2^num_axis for MM fonts. Not meaningful for GX (where every glyph could have a different number of designs).
num_namedstyles	The number of named styles; only meaningful for GX which allows certain design coordinates to have a string ID (in the ‘name’ table) associated with them. The font can tell the user that, for example, Weight=1.5 is ‘Bold’.
axis	A table of axis descriptors. GX fonts contain slightly more data than MM.
namedstyles	A table of named styles. Only meaningful with GX.

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FT_Get_Multi_Master


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

Retrieves the Multiple Master descriptor of a given font.

This function can't be used with GX 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


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

Retrieves the Multiple Master/GX var descriptor of a given font.

input

face

A handle to the source face.

output

amaster

The Multiple Masters descriptor. Allocates a data structure, which the user must free (a single call to FT_FREE will do it).

return

FreeType error code. 0 means success.

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FT_Set_MM_Design_Coordinates


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

For Multiple Masters fonts, choose an interpolated font design through design coordinates.

This function can't be used with GX fonts.

inout

face

A handle to the source face.

input

num_coords	The number of design coordinates (must be equal to the number of axes in the font).
coords	An array of design coordinates.

return

FreeType error code. 0 means success.

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FT_Set_Var_Design_Coordinates


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

For Multiple Master or GX Var fonts, choose an interpolated font design through design coordinates.

inout

face

A handle to the source face.

input

num_coords	The number of design coordinates (must be equal to the number of axes in the font).
coords	An array of design coordinates.

return

FreeType error code. 0 means success.

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FT_Set_MM_Blend_Coordinates


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

For Multiple Masters and GX var fonts, choose an interpolated font design through normalized blend coordinates.

inout

face

A handle to the source face.

input

num_coords	The number of design coordinates (must be equal to the number of axes in the font).
coords	The design coordinates array (each element must be between 0 and 1.0).

return

FreeType error code. 0 means success.

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FT_Set_Var_Blend_Coordinates


  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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