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Introduce a pan backend for touchscreen gestures
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6 files changed

+174
-1
lines changed

6 files changed

+174
-1
lines changed

‎lib/Gestures/GestureBackend.vala‎

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@@ -6,6 +6,8 @@
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*/
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private interface Gala.GestureBackend : Object {
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public signal float request_travel_distance ();
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public signal bool on_gesture_detected (Gesture gesture, uint32 timestamp);
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public signal void on_begin (double percentage, uint64 time);
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public signal void on_update (double percentage, uint64 time);

‎lib/Gestures/GestureController.vala‎

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@@ -89,6 +89,7 @@ public class Gala.GestureController : Object {
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private ToucheggBackend? touchegg_backend;
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private TouchpadBackend? touchpad_backend;
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private PanBackend? pan_backend;
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private ScrollBackend? scroll_backend;
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private GestureBackend? recognizing_backend;
@@ -134,6 +135,15 @@ public class Gala.GestureController : Object {
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touchegg_backend.on_end.connect (gesture_end);
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}
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public void enable_touchscreen (Clutter.Actor actor) {
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pan_backend = new PanBackend (wm, actor);
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pan_backend.request_travel_distance.connect (on_request_travel_distance);
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pan_backend.on_gesture_detected.connect (gesture_detected);
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pan_backend.on_begin.connect (gesture_begin);
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pan_backend.on_update.connect (gesture_update);
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pan_backend.on_end.connect (gesture_end);
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}
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public void enable_scroll (Clutter.Actor actor, Clutter.Orientation orientation) {
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scroll_backend = new ScrollBackend (actor, orientation, new GestureSettings ());
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scroll_backend.on_gesture_detected.connect (gesture_detected);
@@ -142,6 +152,10 @@ public class Gala.GestureController : Object {
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scroll_backend.on_end.connect (gesture_end);
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}
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private float on_request_travel_distance () {
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return target.get_travel_distance (action);
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}
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private void prepare () {
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if (timeline != null) {
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timeline = null;

‎lib/Gestures/PanBackend.vala‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,152 @@
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/*
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* Copyright 2024 elementary, Inc. (https://elementary.io)
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* SPDX-License-Identifier: GPL-3.0-or-later
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*
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* Authored by: Leonhard Kargl <[email protected]>
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*/
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internal class Gala.PanBackend : Object, GestureBackend {
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public WindowManager wm { get; construct; }
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public Clutter.Actor actor { get; construct; }
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private ModalProxy? modal_proxy;
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private Clutter.PanAxis pan_axis;
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private Clutter.PanAction pan_action;
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private GestureDirection direction;
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private float origin_x;
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private float origin_y;
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private float current_x;
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private float current_y;
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private float last_x_coord;
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private float last_y_coord;
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private uint last_n_points;
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public PanBackend (WindowManager wm, Clutter.Actor actor) {
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Object (wm: wm, actor: actor);
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}
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construct {
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pan_action = new Clutter.PanAction () {
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n_touch_points = 1
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};
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actor.add_action_full ("pan-gesture", CAPTURE, pan_action);
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pan_action.gesture_begin.connect (on_gesture_begin);
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pan_action.pan.connect (on_pan);
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pan_action.gesture_end.connect (on_gesture_end);
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pan_action.gesture_cancel.connect (on_gesture_end);
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}
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~PanBackend () {
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actor.remove_action (pan_action);
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}
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private bool on_gesture_begin () {
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if (pan_action.get_last_event (0).get_source_device ().get_device_type () != TOUCHSCREEN_DEVICE) {
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return false;
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}
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float x_coord, y_coord;
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pan_action.get_press_coords (0, out x_coord, out y_coord);
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origin_x = current_x = x_coord;
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origin_y = current_y = y_coord;
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var time = pan_action.get_last_event (0).get_time ();
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var handled = on_gesture_detected (build_gesture (), time);
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if (!handled) {
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reset ();
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return false;
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}
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modal_proxy = wm.push_modal (actor, true);
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on_begin (0, time);
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return true;
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}
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private void on_gesture_end () {
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if (modal_proxy != null) {
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// Only emit on end if we actually began the gesture
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on_end (calculate_percentage (), Meta.CURRENT_TIME);
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}
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reset ();
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}
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private void reset () {
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if (modal_proxy != null) {
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wm.pop_modal (modal_proxy);
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modal_proxy = null;
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}
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direction = GestureDirection.UNKNOWN;
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last_n_points = 0;
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last_x_coord = 0;
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last_y_coord = 0;
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}
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private bool on_pan (Clutter.PanAction pan_action, Clutter.Actor actor, bool interpolate) {
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var time = pan_action.get_last_event (0).get_time ();
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float x, y;
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pan_action.get_motion_coords (0, out x, out y);
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if (pan_action.get_n_current_points () == last_n_points) {
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current_x += x - last_x_coord;
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current_y += y - last_y_coord;
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}
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last_x_coord = x;
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last_y_coord = y;
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last_n_points = pan_action.get_n_current_points ();
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on_update (calculate_percentage (), time);
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return true;
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}
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private double calculate_percentage () {
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float current, origin;
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if (pan_axis == X_AXIS) {
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current = direction == RIGHT ? float.max (current_x, origin_x) : float.min (current_x, origin_x);
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origin = origin_x;
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} else {
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current = direction == DOWN ? float.max (current_y, origin_y) : float.min (current_y, origin_y);
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origin = origin_y;
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}
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return (current - origin).abs () / request_travel_distance ();
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}
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private Gesture build_gesture () {
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float delta_x, delta_y;
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((Clutter.GestureAction) pan_action).get_motion_delta (0, out delta_x, out delta_y);
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pan_axis = delta_x.abs () > delta_y.abs () ? Clutter.PanAxis.X_AXIS : Clutter.PanAxis.Y_AXIS;
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if (pan_axis == X_AXIS) {
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direction = delta_x > 0 ? GestureDirection.RIGHT : GestureDirection.LEFT;
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} else {
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direction = delta_y > 0 ? GestureDirection.DOWN : GestureDirection.UP;
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}
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return new Gesture () {
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type = Clutter.EventType.TOUCHPAD_SWIPE,
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direction = direction,
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fingers = (int) pan_action.get_n_current_points (),
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performed_on_device_type = Clutter.InputDeviceType.TOUCHSCREEN_DEVICE,
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origin_x = origin_x,
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origin_y = origin_y
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};
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}
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}

‎lib/Gestures/RootTarget.vala‎

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Original file line numberDiff line numberDiff line change
@@ -12,6 +12,10 @@ public interface Gala.RootTarget : Object, GestureTarget {
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*/
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public abstract Clutter.Actor? actor { get; }
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public virtual float get_travel_distance (GestureAction for_action) {
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return 0.0f;
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}
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1519
public void add_gesture_controller (GestureController controller) requires (controller.target == null) {
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controller.attached (this);
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weak_ref (controller.detached);

‎lib/Gestures/ToucheggBackend.vala‎

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Original file line numberDiff line numberDiff line change
@@ -180,7 +180,7 @@ private class Gala.ToucheggBackend : Object, GestureBackend {
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signal_params.get ("(uudiut)", out type, out direction, out percentage, out fingers,
181181
out performed_on_device_type, out elapsed_time);
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183-
if (Meta.Util.is_wayland_compositor () && performed_on_device_type != DeviceType.TOUCHSCREEN && type != PINCH) {
183+
if (Meta.Util.is_wayland_compositor () && type != PINCH) {
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return;
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}
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‎lib/meson.build‎

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@@ -31,6 +31,7 @@ gala_lib_sources = files(
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'Gestures/GestureController.vala',
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'Gestures/GestureSettings.vala',
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'Gestures/GestureTarget.vala',
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'Gestures/PanBackend.vala',
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'Gestures/PropertyTarget.vala',
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'Gestures/RootTarget.vala',
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'Gestures/ScrollBackend.vala',

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