From f72544e3d05b4788edfa108b268bce6c4d95d574 Mon Sep 17 00:00:00 2001
From: vslg <slgf@protonmail.ch>
Date: Fri, 15 May 2020 20:32:44 -0300
Subject: [PATCH] Improve trackpad fix

- Add it to remaining components
- Do not use Timer, as flickDeceleration from
  Flickable is more performant
- Add a setting option for it: useTrackpadFix
---
 src/backend/user_files.py                     |  1 +
 src/gui/Base/HFlickable.qml                   | 12 ++++-
 src/gui/Base/HGridView.qml                    |  8 +---
 src/gui/Base/HListView.qml                    |  4 +-
 ...{HScrollMouseArea.qml => HTrackpadFix.qml} | 44 ++++++++-----------
 5 files changed, 33 insertions(+), 36 deletions(-)
 rename src/gui/Base/{HScrollMouseArea.qml => HTrackpadFix.qml} (55%)

diff --git a/src/backend/user_files.py b/src/backend/user_files.py
index 68f23fbf..5769a96e 100644
--- a/src/backend/user_files.py
+++ b/src/backend/user_files.py
@@ -241,6 +241,7 @@ class UISettings(JSONDataFile):
             "maxMessageCharactersPerLine": 65,
             "ownMessagesOnLeftAboveWidth": 895,
             "theme": "Midnight.qpl",
+            "useTrackpadFix": False,
             "writeAliases": {},
             "media": {
                 "autoLoad": True,
diff --git a/src/gui/Base/HFlickable.qml b/src/gui/Base/HFlickable.qml
index 92d024d7..7f1b5576 100644
--- a/src/gui/Base/HFlickable.qml
+++ b/src/gui/Base/HFlickable.qml
@@ -4,6 +4,16 @@ import QtQuick 2.12
 import QtQuick.Controls 2.12
 
 Flickable {
+    id: flickable
     interactive: contentWidth > width || contentHeight > height
-    ScrollBar.vertical: ScrollBar {}
+    ScrollBar.vertical: ScrollBar {
+        visible: flickable.interactive
+    }
+
+
+    readonly property HTrackpadFix trackpadFix: HTrackpadFix {
+        flickable: flickable
+        width: flickable.width
+        height: flickable.height
+    }
 }
diff --git a/src/gui/Base/HGridView.qml b/src/gui/Base/HGridView.qml
index 4c97e66d..f59f88d3 100644
--- a/src/gui/Base/HGridView.qml
+++ b/src/gui/Base/HGridView.qml
@@ -117,14 +117,8 @@ GridView {
     }
 
 
-    MouseArea {
+    HTrackpadFix {
         id: mouseArea
         anchors.fill: parent
-        acceptedButtons: Qt.NoButton
-        onWheel: {
-            // Allow wheel usage, will be back to false on any drag attempt
-            parent.interactive = true
-            wheel.accepted = false
-        }
     }
 }
diff --git a/src/gui/Base/HListView.qml b/src/gui/Base/HListView.qml
index 6687b15a..a5c65ee3 100644
--- a/src/gui/Base/HListView.qml
+++ b/src/gui/Base/HListView.qml
@@ -118,10 +118,8 @@ ListView {
     }
 
 
-    HScrollMouseArea {
+    HTrackpadFix {
         id: mouseArea
         anchors.fill: parent
-        acceptedButtons: Qt.NoButton
-        flickable: listView
     }
 }
diff --git a/src/gui/Base/HScrollMouseArea.qml b/src/gui/Base/HTrackpadFix.qml
similarity index 55%
rename from src/gui/Base/HScrollMouseArea.qml
rename to src/gui/Base/HTrackpadFix.qml
index 22f235ec..6db63bc3 100644
--- a/src/gui/Base/HScrollMouseArea.qml
+++ b/src/gui/Base/HTrackpadFix.qml
@@ -1,44 +1,46 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 
 import QtQuick 2.12
-import QtQuick.Controls 2.12
 
 // Mouse area model to fix scroll on trackpad
 MouseArea {
     id: mouseArea
+    enabled: window.settings.useTrackpadFix
     propagateComposedEvents: true
-    z: flickable.z + 1
+    acceptedButtons: Qt.NoButton
+
 
     onWheel: {
         wheel.accepted = false // Disable wheel to avoid too much scroll
 
-        var pos = getNewPosition(flickable, wheel)
+        const pos = getNewPosition(flickable, wheel)
         flickable.flick(0, 0)
         flickable.contentY = pos
-        cancelFlickTimer.start() // Stop the flick
     }
 
-    // Required assignment for flickable scroll to work.
-    // It must be specified when using this class.
-    property Flickable flickable
+
+    property Flickable flickable: parent
+
 
     function getNewPosition(flickable, wheel) {
         // wheel.pixelDelta will be available on high resolution trackpads.
         // Otherwise use wheel.angleDelta, which is available from mouses and
         // low resolution trackpads.
         // When higher pixelDelta, more scroll will be applied
-        var pixelDelta = wheel.pixelDelta.y || (wheel.angleDelta.y / 8)
+        const pixelDelta =
+            wheel.pixelDelta.y ||
+            wheel.angleDelta.y / 24 * Qt.styleHints.wheelScrollLines
 
         // Return current position if there was not any movement
         if (flickable.contentHeight < flickable.height || !pixelDelta)
             return flickable.contentY
 
-        var maxScroll = (
+        const maxScroll =
             flickable.contentHeight +
             flickable.originY       +
-            flickable.bottomMargin
-        ) - flickable.height
-        var minScroll = flickable.topMargin + flickable.originY
+            flickable.bottomMargin  -
+            flickable.height
+        const minScroll = flickable.topMargin + flickable.originY
 
         // Avoid overscrolling
         return Math.max(
@@ -47,19 +49,11 @@ MouseArea {
         )
     }
 
-    Timer {
-        id: cancelFlickTimer
-        interval: 100 // Flick duration in ms
-        onTriggered: {
-            flickable.cancelFlick()
-            // print("aaa")
-        }
-    }
 
-    Rectangle {
-        anchors.fill: parent
-        color: "transparent"
-        border.color: "red"
-        border.width: 5
+    Binding {
+        target: flickable
+        property: "flickDeceleration"
+        value: 8000
+        when: mouseArea.enabled
     }
 }