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Introduce a pan backend for touchscreen gestures
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5 files changed

+172
-1
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5 files changed

+172
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lines changed

‎lib/Gestures/GestureController.vala‎

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -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 +135,14 @@ 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, TouchscreenTarget target) {
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pan_backend = new PanBackend (wm, actor, target);
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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);

‎lib/Gestures/PanBackend.vala‎

Lines changed: 150 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,150 @@
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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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public TouchscreenTarget target { 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, TouchscreenTarget target) {
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Object (wm: wm, actor: actor, target: target);
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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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on_end (calculate_percentage (), Meta.CURRENT_TIME);
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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) {
103+
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;
118+
if (pan_axis == X_AXIS) {
119+
current = direction == RIGHT ? float.max (current_x, origin_x) : float.min (current_x, origin_x);
120+
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 () / target.travel_distance;
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}
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private Gesture build_gesture () {
130+
float delta_x, delta_y;
131+
((Clutter.GestureAction) pan_action).get_motion_delta (0, out delta_x, out delta_y);
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133+
pan_axis = delta_x.abs () > delta_y.abs () ? Clutter.PanAxis.X_AXIS : Clutter.PanAxis.Y_AXIS;
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135+
if (pan_axis == X_AXIS) {
136+
direction = delta_x > 0 ? GestureDirection.RIGHT : GestureDirection.LEFT;
137+
} else {
138+
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/ToucheggBackend.vala‎

Lines changed: 1 addition & 1 deletion
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/Gestures/TouchscreenTarget.vala‎

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,10 @@
1+
/*
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* Copyright 2025 elementary, Inc. (https://elementary.io)
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* SPDX-License-Identifier: GPL-3.0-or-later
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*
5+
* Authored by: Leonhard Kargl <[email protected]>
6+
*/
7+
8+
public interface Gala.TouchscreenTarget : Object {
9+
public abstract float travel_distance { get; }
10+
}

‎lib/meson.build‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -31,12 +31,14 @@ 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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'Gestures/SpringTimeline.vala',
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'Gestures/ToucheggBackend.vala',
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'Gestures/TouchpadBackend.vala',
41+
'Gestures/TouchscreenTarget.vala',
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'Gestures/WorkspaceHideTracker.vala'
4143
) + gala_common_enums
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