Handle panning touch gestures (#5524)

CHANGELOG.md

@@ -23,6 +23,7 @@
 - Minor: Support more Firefox variants for incognito link opening. (#5503)
 - Minor: Replying to a message will now display the message being replied to. (#4350, #5519)
 - Minor: Links can now have prefixes and suffixes such as parentheses. (#5486, #5515)
+- Minor: Added support for scrolling in splits with touchscreen panning gestures. (#5524)
 - Bugfix: Fixed tab move animation occasionally failing to start after closing a tab. (#5426)
 - Bugfix: If a network request errors with 200 OK, Qt's error code is now reported instead of the HTTP status. (#5378)
 - Bugfix: Fixed restricted users usernames not being clickable. (#5405)

src/widgets/helper/ChannelView.cpp

@@ -54,6 +54,7 @@
 #include <QDebug>
 #include <QDesktopServices>
 #include <QEasingCurve>
+#include <QGestureEvent>
 #include <QGraphicsBlurEffect>
 #include <QJsonDocument>
 #include <QMessageBox>
@@ -369,6 +370,8 @@ ChannelView::ChannelView(InternalCtor /*tag*/, QWidget *parent, Split *split,
         this->scrollUpdateRequested();
     });
 
+    this->grabGesture(Qt::PanGesture);
+
     // TODO: Figure out if we need this, and if so, why
     // StrongFocus means we can focus this event through clicking it
     // and tabbing to it from another widget. I don't currently know
@@ -1786,8 +1789,71 @@ void ChannelView::leaveEvent(QEvent * /*event*/)
     this->unpause(PauseReason::Mouse);
 }
 
+bool ChannelView::event(QEvent *event)
+{
+    if (event->type() == QEvent::Gesture)
+    {
+        if (const auto *gestureEvent = dynamic_cast<QGestureEvent *>(event))
+        {
+            return this->gestureEvent(gestureEvent);
+        }
+    }
+
+    return BaseWidget::event(event);
+}
+
+bool ChannelView::gestureEvent(const QGestureEvent *event)
+{
+    if (QGesture *pan = event->gesture(Qt::PanGesture))
+    {
+        if (const auto *gesture = dynamic_cast<QPanGesture *>(pan))
+        {
+            switch (gesture->state())
+            {
+                case Qt::GestureStarted: {
+                    this->isPanning_ = true;
+                    // Remove any selections and hide tooltip while panning
+                    this->clearSelection();
+                    this->tooltipWidget_->hide();
+                    if (this->isScrolling_)
+                    {
+                        this->disableScrolling();
+                    }
+                }
+                break;
+
+                case Qt::GestureUpdated: {
+                    if (this->scrollBar_->isVisible())
+                    {
+                        this->scrollBar_->offset(-gesture->delta().y() * 0.1);
+                    }
+                }
+                break;
+
+                case Qt::GestureFinished:
+                case Qt::GestureCanceled:
+                default: {
+                    this->clearSelection();
+                    this->isPanning_ = false;
+                }
+                break;
+            }
+
+            return true;
+        }
+    }
+
+    return false;
+}
+
 void ChannelView::mouseMoveEvent(QMouseEvent *event)
 {
+    if (this->isPanning_)
+    {
+        // Don't do any text selection, hovering, etc while panning
+        return;
+    }
+
     /// Pause on hover
     if (float pauseTime = getSettings()->pauseOnHoverDuration;
         pauseTime > 0.001F)

src/widgets/helper/ChannelView.hpp

@@ -10,6 +10,7 @@
 #include "widgets/TooltipWidget.hpp"
 
 #include <pajlada/signals/signal.hpp>
+#include <QGestureEvent>
 #include <QMenu>
 #include <QPaintEvent>
 #include <QPointer>
@@ -216,6 +217,9 @@ protected:
 #endif
     void leaveEvent(QEvent * /*event*/) override;
 
+    bool event(QEvent *event) override;
+    bool gestureEvent(const QGestureEvent *event);
+
     void mouseMoveEvent(QMouseEvent *event) override;
     void mousePressEvent(QMouseEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
@@ -374,6 +378,7 @@ private:
     QTimer clickTimer_;
 
     bool isScrolling_ = false;
+    bool isPanning_ = false;
     QPointF lastMiddlePressPosition_;
     QPointF currentMousePosition_;
     QTimer scrollTimer_;