diff --git a/src/hb-ot-var.cc b/src/hb-ot-var.cc
index 6b8b09b6b..1fe57383c 100644
--- a/src/hb-ot-var.cc
+++ b/src/hb-ot-var.cc
@@ -52,11 +52,11 @@
/**
* hb_ot_var_has_data:
- * @face: #hb_face_t to test
+ * @face: The #hb_face_t to work on
*
- * This function allows to verify the presence of OpenType variation data on the face.
+ * Tests whether a face includes any OpenType variation data in the `fvar` table.
*
- * Return value: true if face has a `fvar' table and false otherwise
+ * Return value: true if data found, false otherwise
*
* Since: 1.4.2
**/
@@ -68,6 +68,11 @@ hb_ot_var_has_data (hb_face_t *face)
/**
* hb_ot_var_get_axis_count:
+ * @face: The #hb_face_t to work on
+ *
+ * Fetches the number of OpenType variation axes included in the face.
+ *
+ * Return value: the number of variation axes defined
*
* Since: 1.4.2
**/
@@ -80,9 +85,17 @@ hb_ot_var_get_axis_count (hb_face_t *face)
#ifndef HB_DISABLE_DEPRECATED
/**
* hb_ot_var_get_axes:
+ * @face: #hb_face_t to work upon
+ * @start_offset: offset of the first lookup to retrieve
+ * @axes_count: (inout) (allow-none): Input = the maximum number of variation axes to return;
+ * Output = the actual number of variation axes returned (may be zero)
+ * @axes_array: (out caller-allocates) (array length=axes_count): The array of variation axes found
+ *
+ * Fetches a list of all variation axes in the specified face. The list returned will begin
+ * at the offset provided.
*
* Since: 1.4.2
- * Deprecated: 2.2.0
+ * Deprecated: 2.2.0: use hb_ot_var_get_axis_infos() instead
**/
unsigned int
hb_ot_var_get_axes (hb_face_t *face,
@@ -95,9 +108,16 @@ hb_ot_var_get_axes (hb_face_t *face,
/**
* hb_ot_var_find_axis:
+ * @face: #hb_face_t to work upon
+ * @axis_tag: The #hb_tag_t of the variation axis to query
+ * @axis_index: The index of the variation axis
+ * @axis_info: (out): The #hb_ot_var_axis_info_t of the axis tag queried
+ *
+ * Fetches the variation-axis information corresponding to the specified axis tag
+ * in the specified face.
*
* Since: 1.4.2
- * Deprecated: 2.2.0
+ * Deprecated: 2.2.0 - use hb_ot_var_find_axis_info() instead
**/
hb_bool_t
hb_ot_var_find_axis (hb_face_t *face,
@@ -111,6 +131,16 @@ hb_ot_var_find_axis (hb_face_t *face,
/**
* hb_ot_var_get_axis_infos:
+ * @face: #hb_face_t to work upon
+ * @start_offset: offset of the first lookup to retrieve
+ * @axes_count: (inout) (allow-none): Input = the maximum number of variation axes to return;
+ * Output = the actual number of variation axes returned (may be zero)
+ * @axes_array: (out caller-allocates) (array length=axes_count): The array of variation axes found
+ *
+ * Fetches a list of all variation axes in the specified face. The list returned will begin
+ * at the offset provided.
+ *
+ * Return value: the number of variation axes in the face
*
* Since: 2.2.0
**/
@@ -125,6 +155,14 @@ hb_ot_var_get_axis_infos (hb_face_t *face,
/**
* hb_ot_var_find_axis_info:
+ * @face: #hb_face_t to work upon
+ * @axis_tag: The #hb_tag_t of the variation axis to query
+ * @axis_info: (out): The #hb_ot_var_axis_info_t of the axis tag queried
+ *
+ * Fetches the variation-axis information corresponding to the specified axis tag
+ * in the specified face.
+ *
+ * Return value: true if data found, false otherwise
*
* Since: 2.2.0
**/
@@ -141,12 +179,34 @@ hb_ot_var_find_axis_info (hb_face_t *face,
* Named instances.
*/
+/**
+ * hb_ot_var_get_named_instance_count:
+ * @face: The #hb_face_t to work on
+ *
+ * Fetches the number of named instances included in the face.
+ *
+ * Return value: the number of named instances defined
+ *
+ * Since: 2.2.0
+ **/
unsigned int
hb_ot_var_get_named_instance_count (hb_face_t *face)
{
return face->table.fvar->get_instance_count ();
}
+/**
+ * hb_ot_var_named_instance_get_subfamily_name_id:
+ * @face: The #hb_face_t to work on
+ * @instance_index: The index of the named instance to query
+ *
+ * Fetches the `name` table Name ID that provides display names for
+ * the "Subfamily name" defined for the given named instance in the face.
+ *
+ * Return value: the Name ID found for the Subfamily name
+ *
+ * Since: 2.2.0
+ **/
hb_ot_name_id_t
hb_ot_var_named_instance_get_subfamily_name_id (hb_face_t *face,
unsigned int instance_index)
@@ -154,6 +214,18 @@ hb_ot_var_named_instance_get_subfamily_name_id (hb_face_t *face,
return face->table.fvar->get_instance_subfamily_name_id (instance_index);
}
+/**
+ * hb_ot_var_named_instance_get_postscript_name_id:
+ * @face: The #hb_face_t to work on
+ * @instance_index: The index of the named instance to query
+ *
+ * Fetches the `name` table Name ID that provides display names for
+ * the "PostScript name" defined for the given named instance in the face.
+ *
+ * Return value: the Name ID found for the PostScript name
+ *
+ * Since: 2.2.0
+ **/
hb_ot_name_id_t
hb_ot_var_named_instance_get_postscript_name_id (hb_face_t *face,
unsigned int instance_index)
@@ -161,6 +233,21 @@ hb_ot_var_named_instance_get_postscript_name_id (hb_face_t *face,
return face->table.fvar->get_instance_postscript_name_id (instance_index);
}
+/**
+ * hb_ot_var_named_instance_get_design_coords:
+ * @face: The #hb_face_t to work on
+ * @instance_index: The index of the named instance to query
+ * @coords_length: (inout) (allow-none): Input = the maximum number of coordinates to return;
+ * Output = the actual number of coordinates returned (may be zero)
+ * @coords: (out) (array length=coords_length): The array of coordinates found for the query
+ *
+ * Fetches the design-space coordinates corresponding to the given
+ * named instance in the face.
+ *
+ * Return value: the number of variation axes in the face
+ *
+ * Since: 2.2.0
+ **/
unsigned int
hb_ot_var_named_instance_get_design_coords (hb_face_t *face,
unsigned int instance_index,
@@ -173,6 +260,13 @@ hb_ot_var_named_instance_get_design_coords (hb_face_t *face,
/**
* hb_ot_var_normalize_variations:
+ * @face: The #hb_face_t to work on
+ * @variations: The array of variations to normalize
+ * @variations_length: The number of variations to normalize
+ * @coords: (out) (array length=coords_length): The array of normalized coordinates
+ * @coords_length: The length of the coordinate array
+ *
+ * Normalizes all of the coordinates in the given list of variation axes.
*
* Since: 1.4.2
**/
@@ -200,6 +294,17 @@ hb_ot_var_normalize_variations (hb_face_t *face,
/**
* hb_ot_var_normalize_coords:
+ * @face: The #hb_face_t to work on
+ * @coords_length: The length of the coordinate array
+ * @design_coords: The design-space coordinates to normalize
+ * @normalized_coords: (out): The normalized coordinates
+ *
+ * Normalizes the given design-space coordinates. The minimum and maximum
+ * values for the axis are mapped to the interval [-1,1], with the default
+ * axis value mapped to 0.
+ *
+ * Any additional scaling defined in the face's `avar` table is also
+ * applied, as described at https://docs.microsoft.com/en-us/typography/opentype/spec/avar
*
* Since: 1.4.2
**/
diff --git a/src/hb-ot-var.h b/src/hb-ot-var.h
index df89bc5a2..fc5a9f3ca 100644
--- a/src/hb-ot-var.h
+++ b/src/hb-ot-var.h
@@ -35,11 +35,36 @@
HB_BEGIN_DECLS
-
+/**
+ * hb_tag_t:
+ * @HB_OT_TAG_VAR_AXIS_ITALIC: Registered tag for the roman/italic axis
+ */
#define HB_OT_TAG_VAR_AXIS_ITALIC HB_TAG('i','t','a','l')
+
+/**
+ * hb_tag_t:
+ * @HB_OT_TAG_VAR_AXIS_OPTICAL_SIZE: Registered tag for the optical-size axis
+ *
+ * Note: The optical-size axis supersedes the OpenType `size` feature.
+ */
#define HB_OT_TAG_VAR_AXIS_OPTICAL_SIZE HB_TAG('o','p','s','z')
+
+/**
+ * hb_tag_t:
+ * @HB_OT_TAG_VAR_AXIS_SLANT: Registered tag for the slant axis
+ */
#define HB_OT_TAG_VAR_AXIS_SLANT HB_TAG('s','l','n','t')
+
+/**
+ * hb_tag_t:
+ * @HB_OT_TAG_VAR_AXIS_WIDTH: Registered tag for the width axis
+ */
#define HB_OT_TAG_VAR_AXIS_WIDTH HB_TAG('w','d','t','h')
+
+/**
+ * hb_tag_t:
+ * @HB_OT_TAG_VAR_AXIS_WEIGHT: Registered tag for the weight axis
+ */
#define HB_OT_TAG_VAR_AXIS_WEIGHT HB_TAG('w','g','h','t')
@@ -73,6 +98,20 @@ typedef enum { /*< flags >*/
/**
* hb_ot_var_axis_info_t:
+ * @axis_index: Index of the axis in the variation-axis array
+ * @tag: The #hb_tag_t tag identifying the design variation of the axis
+ * @name_id: The `name` table Name ID that provides display names for the axis
+ * @flags: The #hb_ot_var_axis_flags_t flags for the axis
+ * @min_value: The mininum value on the variation axis that the font covers
+ * @default_value: The position on the variation axis corresponding to the font's defaults
+ * @max_value: The maximum value on the variation axis that the font covers
+ *
+ * Data type for holding variation-axis values.
+ *
+ * The minimum, default, and maximum values are in un-normalized, user scales.
+ *
+ * Note: at present, the only flag defined for @flags is
+ * #HB_OT_VAR_AXIS_FLAG_HIDDEN.
*
* Since: 2.2.0
*/