[Complex Text Layouts] Add variable fonts support.

modules/text_server_adv/dynamic_font_adv.cpp

@@ -32,6 +32,7 @@
 
 #include FT_STROKER_H
 #include FT_ADVANCES_H
+#include FT_MULTIPLE_MASTERS_H
 
 DynamicFontDataAdvanced::DataAtSize *DynamicFontDataAdvanced::get_data_for_size(int p_size, int p_outline_size) {
 	ERR_FAIL_COND_V(!valid, nullptr);
@@ -134,14 +135,89 @@ DynamicFontDataAdvanced::DataAtSize *DynamicFontDataAdvanced::get_data_for_size(
 			memdelete(fds);
 			ERR_FAIL_V_MSG(nullptr, "Error loading HB font.");
 		}
+
 		if (p_outline_size != 0) {
 			size_cache_outline[id] = fds;
 		} else {
 			size_cache[id] = fds;
 		}
+
+		// Write variations.
+		if (fds->face->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS) {
+			FT_MM_Var *amaster;
+
+			FT_Get_MM_Var(fds->face, &amaster);
+
+			Vector<hb_variation_t> hb_vars;
+			Vector<FT_Fixed> coords;
+			coords.resize(amaster->num_axis);
+
+			FT_Get_Var_Design_Coordinates(fds->face, coords.size(), coords.ptrw());
+
+			for (FT_UInt i = 0; i < amaster->num_axis; i++) {
+				hb_variation_t var;
+
+				// Reset to default.
+				var.tag = amaster->axis[i].tag;
+				var.value = (double)amaster->axis[i].def / 65536.f;
+				coords.write[i] = amaster->axis[i].def;
+
+				if (variations.has(var.tag)) {
+					var.value = variations[var.tag];
+					coords.write[i] = CLAMP(variations[var.tag] * 65536.f, amaster->axis[i].minimum, amaster->axis[i].maximum);
+				}
+
+				hb_vars.push_back(var);
+			}
+
+			FT_Set_Var_Design_Coordinates(fds->face, coords.size(), coords.ptrw());
+			hb_font_set_variations(fds->hb_handle, hb_vars.empty() ? nullptr : &hb_vars[0], hb_vars.size());
+
+			FT_Done_MM_Var(library, amaster);
+		}
+	}
+	return fds;
+}
+
+Dictionary DynamicFontDataAdvanced::get_variation_list() const {
+	_THREAD_SAFE_METHOD_
+	DataAtSize *fds = const_cast<DynamicFontDataAdvanced *>(this)->get_data_for_size(base_size);
+	if (fds == nullptr) {
+		return Dictionary();
 	}
 
-	return fds;
+	Dictionary ret;
+	// Read variations.
+	if (fds->face->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS) {
+		FT_MM_Var *amaster;
+
+		FT_Get_MM_Var(fds->face, &amaster);
+
+		for (FT_UInt i = 0; i < amaster->num_axis; i++) {
+			ret[(int32_t)amaster->axis[i].tag] = Vector3i(amaster->axis[i].minimum / 65536, amaster->axis[i].maximum / 65536, amaster->axis[i].def / 65536);
+		}
+
+		FT_Done_MM_Var(library, amaster);
+	}
+	return ret;
+}
+
+void DynamicFontDataAdvanced::set_variation(const String &p_name, double p_value) {
+	_THREAD_SAFE_METHOD_
+	int32_t tag = TS->name_to_tag(p_name);
+	if (!variations.has(tag) || (variations[tag] != p_value)) {
+		variations[tag] = p_value;
+		clear_cache();
+	}
+}
+
+double DynamicFontDataAdvanced::get_variation(const String &p_name) const {
+	_THREAD_SAFE_METHOD_
+	int32_t tag = TS->name_to_tag(p_name);
+	if (!variations.has(tag)) {
+		return 0.f;
+	}
+	return variations[tag];
 }
 
 Dictionary DynamicFontDataAdvanced::get_feature_list() const {