Display the current zoom percentage in the 2D editor

This makes it possible for the user to know precisely the current
zoom level. The zoom percentage can be clicked to reset it to 100%
(similar to Firefox).

editor/plugins/canvas_item_editor_plugin.cpp

@@ -3678,7 +3678,6 @@ void CanvasItemEditor::_notification(int p_what) {
 		key_auto_insert_button->set_icon(get_icon("AutoKey", "EditorIcons"));
 
 		zoom_minus->set_icon(get_icon("ZoomLess", "EditorIcons"));
-		zoom_reset->set_icon(get_icon("ZoomReset", "EditorIcons"));
 		zoom_plus->set_icon(get_icon("ZoomMore", "EditorIcons"));
 
 		presets_menu->set_icon(get_icon("ControlLayout", "EditorIcons"));
@@ -4036,9 +4035,22 @@ void CanvasItemEditor::_zoom_on_position(float p_zoom, Point2 p_position) {
 	view_offset.x = Math::round(view_offset.x + ofs.x);
 	view_offset.y = Math::round(view_offset.y + ofs.y);
 
+	_update_zoom_label();
 	update_viewport();
 }
 
+void CanvasItemEditor::_update_zoom_label() {
+	String zoom_text;
+	if (zoom >= 10) {
+		// Don't show a decimal when the zoom level is higher than 1000 %
+		zoom_text = rtos(Math::round(zoom * 100)) + " %";
+	} else {
+		zoom_text = rtos(Math::stepify(zoom * 100, 0.1)) + " %";
+	}
+
+	zoom_reset->set_text(zoom_text);
+}
+
 void CanvasItemEditor::_button_zoom_minus() {
 	_zoom_on_position(zoom / Math_SQRT2, viewport_scrollable->get_size() / 2.0);
 }
@@ -4811,6 +4823,7 @@ void CanvasItemEditor::set_state(const Dictionary &p_state) {
 	Dictionary state = p_state;
 	if (state.has("zoom")) {
 		zoom = p_state["zoom"];
+		_update_zoom_label();
 	}
 
 	if (state.has("ofs")) {
@@ -5128,6 +5141,8 @@ CanvasItemEditor::CanvasItemEditor(EditorNode *p_editor) {
 	zoom_hb = memnew(HBoxContainer);
 	viewport->add_child(zoom_hb);
 	zoom_hb->set_begin(Point2(5, 5));
+	// Bring the zoom percentage closer to the zoom buttons
+	zoom_hb->add_constant_override("separation", Math::round(-8 * EDSCALE));
 
 	zoom_minus = memnew(ToolButton);
 	zoom_hb->add_child(zoom_minus);
@@ -5140,6 +5155,9 @@ CanvasItemEditor::CanvasItemEditor(EditorNode *p_editor) {
 	zoom_reset->connect("pressed", this, "_button_zoom_reset");
 	zoom_reset->set_shortcut(ED_SHORTCUT("canvas_item_editor/zoom_reset", TTR("Zoom Reset"), KEY_MASK_CMD | KEY_0));
 	zoom_reset->set_focus_mode(FOCUS_NONE);
+	zoom_reset->set_text_align(Button::TextAlign::ALIGN_CENTER);
+	// Prevent the button's size from changing when the text size changes
+	zoom_reset->set_custom_minimum_size(Size2(75 * EDSCALE, 0));
 
 	zoom_plus = memnew(ToolButton);
 	zoom_hb->add_child(zoom_plus);

editor/plugins/canvas_item_editor_plugin.h

@@ -525,6 +525,7 @@ private:
 
 	HBoxContainer *zoom_hb;
 	void _zoom_on_position(float p_zoom, Point2 p_position = Point2());
+	void _update_zoom_label();
 	void _button_zoom_minus();
 	void _button_zoom_reset();
 	void _button_zoom_plus();