CheckButton checked/unchecked icon can be on both sides

If `inverted` is set to true on `CheckButton` the checked/unchecked icon
will be drawn in the right for for right-to-left layouts
or in the left for left-to-right layouts.

Author: pafuent

doc/classes/CheckButton.xml

@@ -9,9 +9,27 @@
 	</description>
 	<tutorials>
 	</tutorials>
+	<methods>
+		<method name="set_invert">
+			<return type="bool" />
+			<param index="0" name="invert" type="bool" />
+			<description>
+				If [code]true[/code] [theme_item checked]/[theme_item unchecked] will be drawn in the right for for right-to-left layouts or in the left for left-to-right layouts.
+			</description>
+		</method>
+		<method name="is_invert" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] when [theme_item checked]/[theme_item unchecked] is drawn in the right for for right-to-left layouts or in the left for left-to-right layouts.
+			</description>
+		</method>
+	</methods>
 	<members>
 		<member name="alignment" type="int" setter="set_text_alignment" getter="get_text_alignment" overrides="Button" enum="HorizontalAlignment" default="0" />
 		<member name="toggle_mode" type="bool" setter="set_toggle_mode" getter="is_toggle_mode" overrides="BaseButton" default="true" />
+		<member name="invert" type="bool" setter="set_invert" getter="is_invert" default="false">
+			If [code]true[/code] [theme_item checked]/[theme_item unchecked] will be drawn in the right for for right-to-left layouts or in the left for left-to-right layouts.
+		</member>
 	</members>
 	<theme_items>
 		<theme_item name="button_checked_color" data_type="color" type="Color" default="Color(1, 1, 1, 1)">

scene/gui/check_button.cpp

@@ -83,18 +83,20 @@ Size2 CheckButton::get_minimum_size() const {
 	return minsize;
 }
 
+void CheckButton::_set_left_and_right_internal_margins() {
+	bool rtl = is_layout_rtl();
+	Side icon_side = (rtl ^ invert) ? SIDE_LEFT : SIDE_RIGHT;
+	Side text_side = (rtl ^ invert) ? SIDE_RIGHT : SIDE_LEFT;
+	_set_internal_margin(icon_side, get_icon_size().width);
+	_set_internal_margin(text_side, 0.f);
+}
+
 void CheckButton::_notification(int p_what) {
 	switch (p_what) {
 		case NOTIFICATION_THEME_CHANGED:
 		case NOTIFICATION_LAYOUT_DIRECTION_CHANGED:
 		case NOTIFICATION_TRANSLATION_CHANGED: {
-			if (is_layout_rtl()) {
-				_set_internal_margin(SIDE_LEFT, get_icon_size().width);
-				_set_internal_margin(SIDE_RIGHT, 0.f);
-			} else {
-				_set_internal_margin(SIDE_LEFT, 0.f);
-				_set_internal_margin(SIDE_RIGHT, get_icon_size().width);
-			}
+			_set_left_and_right_internal_margins();
 		} break;
 
 		case NOTIFICATION_DRAW: {
@@ -125,7 +127,7 @@ void CheckButton::_notification(int p_what) {
 			Vector2 ofs;
 			Size2 tex_size = get_icon_size();
 
-			if (rtl) {
+			if (rtl ^ invert) {
 				ofs.x = theme_cache.normal_style->get_margin(SIDE_LEFT);
 			} else {
 				ofs.x = get_size().width - (tex_size.width + theme_cache.normal_style->get_margin(SIDE_RIGHT));
@@ -142,6 +144,10 @@ void CheckButton::_notification(int p_what) {
 }
 
 void CheckButton::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_invert", "invert"), &CheckButton::set_invert);
+	ClassDB::bind_method(D_METHOD("is_invert"), &CheckButton::is_invert);
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "invert"), "set_invert", "is_invert");
+
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, CheckButton, h_separation);
 	BIND_THEME_ITEM(Theme::DATA_TYPE_CONSTANT, CheckButton, check_v_offset);
 	BIND_THEME_ITEM_CUSTOM(Theme::DATA_TYPE_STYLEBOX, CheckButton, normal_style, "normal");
@@ -159,17 +165,27 @@ void CheckButton::_bind_methods() {
 	BIND_THEME_ITEM(Theme::DATA_TYPE_COLOR, CheckButton, button_unchecked_color);
 }
 
+void CheckButton::set_invert(bool p_invert) {
+	if (p_invert == invert) {
+		return;
+	}
+	invert = p_invert;
+	_set_left_and_right_internal_margins();
+	queue_redraw();
+}
+
+bool CheckButton::is_invert() const {
+	return invert;
+}
+
 CheckButton::CheckButton(const String &p_text) :
 		Button(p_text) {
 	set_toggle_mode(true);
 
 	set_text_alignment(HORIZONTAL_ALIGNMENT_LEFT);
 
-	if (is_layout_rtl()) {
-		_set_internal_margin(SIDE_LEFT, get_icon_size().width);
-	} else {
-		_set_internal_margin(SIDE_RIGHT, get_icon_size().width);
-	}
+	Side icon_side = (is_layout_rtl() ^ invert) ? SIDE_LEFT : SIDE_RIGHT;
+	_set_internal_margin(icon_side, get_icon_size().width);
 }
 
 CheckButton::~CheckButton() {

scene/gui/check_button.h

@@ -53,6 +53,10 @@ class CheckButton : public Button {
 		Color button_unchecked_color;
 	} theme_cache;
 
+	bool invert = false;
+
+	void _set_left_and_right_internal_margins();
+
 protected:
 	Size2 get_icon_size() const;
 	virtual Size2 get_minimum_size() const override;
@@ -61,6 +65,9 @@ class CheckButton : public Button {
 	static void _bind_methods();
 
 public:
+	void set_invert(bool p_invert);
+	bool is_invert() const;
+
 	CheckButton(const String &p_text = String());
 	~CheckButton();
 };