Restored auto snapping of controls to pixels, fixes #10847 and probably several more issues. Made it optional in the project settings but defaults to true.

editor/plugins/canvas_item_editor_plugin.cpp

@@ -2269,6 +2269,9 @@ void CanvasItemEditor::_notification(int p_what) {
 
 	if (p_what == NOTIFICATION_FIXED_PROCESS) {
 
+
+		EditorNode::get_singleton()->get_scene_root()->set_snap_controls_to_pixels(GLOBAL_GET("gui/common/snap_controls_to_pixels"));
+
 		List<Node *> &selection = editor_selection->get_selected_node_list();
 
 		bool all_control = true;

main/main.cpp

@@ -1325,6 +1325,7 @@ bool Main::start() {
 			int shadow_atlas_q2_subdiv = GLOBAL_GET("rendering/quality/shadow_atlas/quadrant_2_subdiv");
 			int shadow_atlas_q3_subdiv = GLOBAL_GET("rendering/quality/shadow_atlas/quadrant_3_subdiv");
 
+
 			sml->get_root()->set_shadow_atlas_size(shadow_atlas_size);
 			sml->get_root()->set_shadow_atlas_quadrant_subdiv(0, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q0_subdiv));
 			sml->get_root()->set_shadow_atlas_quadrant_subdiv(1, Viewport::ShadowAtlasQuadrantSubdiv(shadow_atlas_q1_subdiv));
@@ -1333,6 +1334,9 @@ bool Main::start() {
 			Viewport::Usage usage = Viewport::Usage(int(GLOBAL_GET("rendering/quality/intended_usage/framebuffer_allocation")));
 			sml->get_root()->set_usage(usage);
 
+			bool snap_controls = GLOBAL_DEF("gui/common/snap_controls_to_pixels", true);
+			sml->get_root()->set_snap_controls_to_pixels(snap_controls);
+
 		} else {
 			GLOBAL_DEF("display/window/stretch/mode", "disabled");
 			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/mode", PropertyInfo(Variant::STRING, "display/window/stretch/mode", PROPERTY_HINT_ENUM, "disabled,2d,viewport"));
@@ -1342,6 +1346,8 @@ bool Main::start() {
 			ProjectSettings::get_singleton()->set_custom_property_info("display/window/stretch/shrink", PropertyInfo(Variant::STRING, "display/window/stretch/shrink", PROPERTY_HINT_RANGE, "1,8,1"));
 			sml->set_auto_accept_quit(GLOBAL_DEF("application/config/auto_accept_quit", true));
 			sml->set_quit_on_go_back(GLOBAL_DEF("application/config/quit_on_go_back", true));
+			GLOBAL_DEF("gui/common/snap_controls_to_pixels", true);
+
 		}
 
 		String local_game_path;

scene/gui/control.cpp

@@ -1249,6 +1249,10 @@ void Control::_size_changed() {
 		new_size_cache.height = MAX(minimum_size.height, new_size_cache.height);
 	}
 
+	if (get_viewport()->is_snap_controls_to_pixels_enabled()) {
+		new_size_cache =new_size_cache.floor();
+		new_pos_cache = new_pos_cache.floor();
+	}
 	bool pos_changed = new_pos_cache != data.pos_cache;
 	bool size_changed = new_size_cache != data.size_cache;
 

scene/main/viewport.cpp

@@ -2578,6 +2578,17 @@ int Viewport::get_render_info(RenderInfo p_info) {
 	return VS::get_singleton()->viewport_get_render_info(viewport, VS::ViewportRenderInfo(p_info));
 }
 
+void Viewport::set_snap_controls_to_pixels(bool p_enable) {
+
+	snap_controls_to_pixels=p_enable;
+}
+
+bool Viewport::is_snap_controls_to_pixels_enabled() const {
+
+	return snap_controls_to_pixels;
+}
+
+
 void Viewport::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_use_arvr", "use"), &Viewport::set_use_arvr);
@@ -2680,6 +2691,9 @@ void Viewport::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_shadow_atlas_size", "size"), &Viewport::set_shadow_atlas_size);
 	ClassDB::bind_method(D_METHOD("get_shadow_atlas_size"), &Viewport::get_shadow_atlas_size);
 
+	ClassDB::bind_method(D_METHOD("set_snap_controls_to_pixels", "enabled"), &Viewport::set_snap_controls_to_pixels);
+	ClassDB::bind_method(D_METHOD("is_snap_controls_to_pixels_enabled"), &Viewport::is_snap_controls_to_pixels_enabled);
+
 	ClassDB::bind_method(D_METHOD("set_shadow_atlas_quadrant_subdiv", "quadrant", "subdiv"), &Viewport::set_shadow_atlas_quadrant_subdiv);
 	ClassDB::bind_method(D_METHOD("get_shadow_atlas_quadrant_subdiv", "quadrant"), &Viewport::get_shadow_atlas_quadrant_subdiv);
 
@@ -2707,6 +2721,7 @@ void Viewport::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "physics_object_picking"), "set_physics_object_picking", "get_physics_object_picking");
 	ADD_GROUP("GUI", "gui_");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "gui_disable_input"), "set_disable_input", "is_input_disabled");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "gui_snap_controls_to_pixels"), "set_snap_controls_to_pixels", "is_snap_controls_to_pixels_enabled");
 	ADD_GROUP("Shadow Atlas", "shadow_atlas_");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "shadow_atlas_size"), "set_shadow_atlas_size", "get_shadow_atlas_size");
 	ADD_PROPERTYI(PropertyInfo(Variant::INT, "shadow_atlas_quad_0", PROPERTY_HINT_ENUM, "Disabled,1 Shadow,4 Shadows,16 Shadows,64 Shadows,256 Shadows,1024 Shadows"), "set_shadow_atlas_quadrant_subdiv", "get_shadow_atlas_quadrant_subdiv", 0);
@@ -2822,6 +2837,8 @@ Viewport::Viewport() {
 	usage = USAGE_3D;
 	debug_draw = DEBUG_DRAW_DISABLED;
 	clear_mode = CLEAR_MODE_ALWAYS;
+
+	snap_controls_to_pixels = true;
 }
 
 Viewport::~Viewport() {

scene/main/viewport.h

@@ -1,3 +1,4 @@
+
 /*************************************************************************/
 /*  viewport.h                                                           */
 /*************************************************************************/
@@ -193,6 +194,8 @@ private:
 	bool filter;
 	bool gen_mipmaps;
 
+	bool snap_controls_to_pixels;
+
 	bool physics_object_picking;
 	List<Ref<InputEvent> > physics_picking_events;
 	ObjectID physics_object_capture;
@@ -463,6 +466,9 @@ public:
 
 	int get_render_info(RenderInfo p_info);
 
+	void set_snap_controls_to_pixels(bool p_enable);
+	bool is_snap_controls_to_pixels_enabled() const;
+
 	Viewport();
 	~Viewport();
 };