From 0799afe2b6b9c1e06505a7e6a604cfb597b5c9ef Mon Sep 17 00:00:00 2001
From: Qunxin Liu <qxliu@google.com>
Date: Thu, 20 Apr 2023 14:02:20 -0700
Subject: [PATCH] [instancer] Add hb_subset_input_set_axis_range() API

---
 src/hb-subset-input.cc | 40 ++++++++++++++++++++++++++++++++++++++++
 src/hb-subset.h        |  7 +++++++
 2 files changed, 47 insertions(+)

diff --git a/src/hb-subset-input.cc b/src/hb-subset-input.cc
index 465af5081..16ce657a0 100644
--- a/src/hb-subset-input.cc
+++ b/src/hb-subset-input.cc
@@ -470,6 +470,46 @@ hb_subset_input_pin_axis_location (hb_subset_input_t  *input,
   float val = hb_clamp(axis_value, axis_info.min_value, axis_info.max_value);
   return input->axes_location.set (axis_tag, val);
 }
+
+/**
+ * hb_subset_input_set_axis_range: (skip)
+ * @input: a #hb_subset_input_t object.
+ * @face: a #hb_face_t object.
+ * @axis_tag: Tag of the axis
+ * @axis_min_value: Minimum value of the axis variation range to set
+ * @axis_max_value: Maximum value of the axis variation range to set
+ *
+ * Restricting the range of variation on an axis in the given subset input object.
+ * New min/max values will be clamped if they're not within the fvar axis range.
+ * If the fvar axis default value is not within the new range, the new default
+ * value will be changed to the new min or max value, whichever is closer to the fvar
+ * axis default.
+ *
+ * Note: input min value can not be bigger than input max value
+ *
+ * Return value: `true` if success, `false` otherwise
+ *
+ * Since: REPLACEME
+ **/
+HB_EXTERN hb_bool_t
+hb_subset_input_set_axis_range (hb_subset_input_t  *input,
+                                hb_face_t          *face,
+                                hb_tag_t            axis_tag,
+                                float               axis_min_value,
+                                float               axis_max_value)
+{
+  if (axis_min_value > axis_max_value)
+    return false;
+
+  hb_ot_var_axis_info_t axis_info;
+  if (!hb_ot_var_find_axis_info (face, axis_tag, &axis_info))
+    return false;
+
+  float new_min_val = hb_clamp(axis_min_value, axis_info.min_value, axis_info.max_value);
+  float new_max_val = hb_clamp(axis_max_value, axis_info.min_value, axis_info.max_value);
+  float new_default_val = hb_clamp(axis_info.default_value, new_min_val, new_max_val);
+  return input->axes_location.set (axis_tag, new_default_val);
+}
 #endif
 
 /**
diff --git a/src/hb-subset.h b/src/hb-subset.h
index 6368ff93f..e2275631f 100644
--- a/src/hb-subset.h
+++ b/src/hb-subset.h
@@ -175,6 +175,13 @@ hb_subset_input_pin_axis_location (hb_subset_input_t  *input,
 				   hb_tag_t            axis_tag,
 				   float               axis_value);
 
+HB_EXTERN hb_bool_t
+hb_subset_input_set_axis_range (hb_subset_input_t  *input,
+				hb_face_t          *face,
+				hb_tag_t            axis_tag,
+				float               axis_min_value,
+				float               axis_max_value);
+
 #ifdef HB_EXPERIMENTAL_API
 HB_EXTERN hb_bool_t
 hb_subset_input_override_name_table (hb_subset_input_t  *input,