From fc300d1a28f46445315773ba183963c15303199e Mon Sep 17 00:00:00 2001
From: Yari Polla <skilvingr@gmail.com>
Date: Tue, 3 May 2022 01:38:42 +0200
Subject: [PATCH] taskswitcher: implement left/right swipe gesture

---
 .../navigationpanel/NavigationGestureArea.qml | 32 +++++++++----------
 .../qml/taskswitcher/TaskSwitcherState.qml    | 22 +++++++------
 2 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/components/mobileshell/qml/navigationpanel/NavigationGestureArea.qml b/components/mobileshell/qml/navigationpanel/NavigationGestureArea.qml
index 094d771f..c72093ac 100644
--- a/components/mobileshell/qml/navigationpanel/NavigationGestureArea.qml
+++ b/components/mobileshell/qml/navigationpanel/NavigationGestureArea.qml
@@ -21,11 +21,10 @@ Item {
     id: root
 
     property var taskSwitcher
-    
+
     MouseArea {
         id: mouseArea
         anchors.fill: parent
-        drag.filterChildren: true
         
         // drag gesture
         property int oldMouseY: 0
@@ -33,37 +32,36 @@ Item {
         property int oldMouseX: 0
         property int startMouseX: 0
         property bool opening: false
+
+        enabled: !taskSwitcher.visible
         
         onPressed: {
-            startMouseX = oldMouseX = mouse.y;
+            startMouseX = oldMouseX = mouse.x;
             startMouseY = oldMouseY = mouse.y;
         }
-        
-        onPositionChanged: {
-            if (!opening && Math.abs(startMouseY - oldMouseY) < root.height) {
-                oldMouseY = mouse.y;
-                return;
-            } else if (mouseArea.pressed) {
-                opening = true;
-            }
 
-            if (root.taskSwitcher.visible) {
+        onPositionChanged: {
+            if (root.taskSwitcher.visible || taskSwitcher.taskSwitcherState.currentlyBeingOpened) {
                 // update task switcher drag
                 let offsetY = (mouse.y - oldMouseY) * 0.5; // we want to make the gesture take a longer swipe than it being pixel perfect
                 let offsetX = (mouse.x - oldMouseX) * 0.7; // we want to make the gesture not too hard to swipe, but not too easy
                 taskSwitcher.taskSwitcherState.yPosition = Math.max(0, taskSwitcher.taskSwitcherState.yPosition - offsetY);
-                taskSwitcher.taskSwitcherState.xPosition -= offsetX;
+                taskSwitcher.taskSwitcherState.xPosition = taskSwitcher.taskSwitcherState.xPosition - offsetX;
             }
 
-            if (!root.taskSwitcher.visible && Math.abs(startMouseY - mouse.y) > PlasmaCore.Units.gridUnit && taskSwitcher.tasksCount) {
-                // start task switcher gesture
+            if (!root.taskSwitcher.visible && Math.abs(startMouseX - mouse.x) > PlasmaCore.Units.gridUnit && taskSwitcher.tasksCount && taskSwitcher.tasksModel.activeTask.row >= 0){
+                // start switch task gesture
+                taskSwitcher.taskSwitcherState.scrollingTasks = true;
+                root.taskSwitcher.show(false);
+            } else if (!root.taskSwitcher.visible && Math.abs(startMouseY - mouse.y) > PlasmaCore.Units.gridUnit && taskSwitcher.tasksCount) {
+                // start task switcher opening gesture
                 root.taskSwitcher.show(false);
             }
-            
+
             oldMouseY = mouse.y;
             oldMouseX = mouse.x;
         }
-        
+
         onReleased: {
             if (taskSwitcher.taskSwitcherState.currentlyBeingOpened) {
                 taskSwitcher.taskSwitcherState.updateState();
diff --git a/components/mobileshell/qml/taskswitcher/TaskSwitcherState.qml b/components/mobileshell/qml/taskswitcher/TaskSwitcherState.qml
index 242567f0..0f5229a8 100644
--- a/components/mobileshell/qml/taskswitcher/TaskSwitcherState.qml
+++ b/components/mobileshell/qml/taskswitcher/TaskSwitcherState.qml
@@ -62,6 +62,9 @@ QtObject {
     // whether we are in a swipe up gesture to open the task switcher
     property bool currentlyBeingOpened: false
     
+    // whether we are in a swipe left/right gesture to walk through tasks
+    property bool scrollingTasks: false
+    
     readonly property int currentTaskIndex: {
         let candidateIndex = Math.round(-xPosition / (taskSpacing + taskWidth));
         return Math.max(0, Math.min(taskSwitcher.tasksCount - 1, candidateIndex));
@@ -107,10 +110,10 @@ QtObject {
         let finalScale = Math.max(0, Math.min(maxScale, maxScale - subtract));
         
         // animate scale only if we are *not* opening from the homescreen
-        if (wasInActiveTask || !currentlyBeingOpened) {
+        if ((wasInActiveTask || !currentlyBeingOpened) && !scrollingTasks) {
             return finalScale;
         }
-        return 1;
+        return scrollingTasks ? maxScale : 1;
     }
     
     // ~~ signals and functions ~~
@@ -159,7 +162,7 @@ QtObject {
         cancelAnimations();
 
         // update vertical state
-        if (movingUp || root.yPosition >= openedYPosition) {
+        if ((movingUp || root.yPosition >= openedYPosition) && !scrollingTasks) {
             // open task switcher and stay
             openAnim.restart();
         } else {
@@ -197,20 +200,20 @@ QtObject {
         easing.type: Easing.OutBack
     }
     
-    property var openAnim: NumberAnimation {
+    property var openAnim: NumberAnimation { 
         target: root
         property: "yPosition"
-        to: openedYPosition 
+        to: openedYPosition
         duration: MobileShell.MobileShellSettings.animationsEnabled ? 300 : 0
-        easing.type: Easing.OutBack
+        easing.type: Easing.OutBack     
         
         onFinished: {
             root.currentlyBeingOpened = false;
         }
     }
-        
+    
     property var closeAnim: NumberAnimation { 
-        target: root 
+        target: root
         property: "yPosition"
         to: 0
         duration: MobileShell.MobileShellSettings.animationsEnabled ? PlasmaCore.Units.longDuration : 0
@@ -218,8 +221,9 @@ QtObject {
         
         onFinished: {
             root.currentlyBeingOpened = false;
+            scrollingTasks = false;
             taskSwitcher.instantHide();
-            
+
             if (root.wasInActiveTask) {
                 taskSwitcher.setSingleActiveWindow(root.currentTaskIndex);
             }