FreeType » Docs » Format-Specific API » Multiple Masters
Multiple Masters¶
Synopsis¶
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).
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. |
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. |
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.
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. |
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. |
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.
FT_Get_MM_Var¶
Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).
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 |
return
FreeType error code. 0 means success.
FT_Done_MM_Var¶
Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).
FT_EXPORT( FT_Error )
FT_Done_MM_Var( FT_Library library,
FT_MM_Var *amaster );
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 |
return
FreeType error code. 0 means success.
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
[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_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
[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_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.
since
2.7.1
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
[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_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.
since
2.7.1
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.
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.
since
2.7.1
FT_Set_MM_WeightVector¶
Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).
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_Get_MM_WeightVector¶
Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).
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, |
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_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
|
The variation axis should not be exposed to user interfaces. |
since
2.8.1
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 |
return
FreeType error code. 0 means success.
since
2.8.1
FT_Set_Named_Instance¶
Defined in FT_MULTIPLE_MASTERS_H (freetype/ftmm.h).
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