From 2ffa46054d13c639cf9f7846a74ad3ebd07b9f5c Mon Sep 17 00:00:00 2001
From: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Date: Mon, 10 Nov 2014 10:52:22 +0100
Subject: [PATCH] Use single finger pan to scroll text edits on touch screens.
Change the number of pan points to 1 for these classes as a
workaround until pan/tap gestures are fully fixed.
Task-number: QTBUG-40461
Change-Id: I0d68726a545ee6148f3ab88f2ab7308b10464ecd
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
---
src/widgets/kernel/qstandardgestures.cpp | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/src/widgets/kernel/qstandardgestures.cpp b/src/widgets/kernel/qstandardgestures.cpp
index 6656903e70d..53e5d091faf 100644
--- a/src/widgets/kernel/qstandardgestures.cpp
+++ b/src/widgets/kernel/qstandardgestures.cpp
@@ -38,6 +38,7 @@
#include "qwidget.h"
#include "qabstractscrollarea.h"
#include <qgraphicssceneevent.h>
+#include <QtGui/QTouchDevice>
#include "qdebug.h"
#ifndef QT_NO_GESTURES
@@ -67,8 +68,26 @@ static QPointF panOffset(const QList<QTouchEvent::TouchPoint> &touchPoints, int
return result / qreal(count);
}
+// ### fixme: Remove this
+// Use single finger pan to scroll QPlainTextEdit/QTextEdit
+// by changing the number of pan points to 1 for these classes.
+// This used to be Qt 4's behavior on Windows which was achieved using native
+// Windows gesture recognizers for these classes.
+// The other classes inheriting QScrollArea still use standard 2 finger pan.
+// In the long run, they should also use single finger pan to
+// scroll on touch screens, however, this requires a distinct Tap&Hold-followed-by-pan
+// type gesture to avoid clashes with item view selection and DnD.
+
+static inline int panTouchPoints(const QTouchEvent *event, const QObject *object,
+ int defaultTouchPoints)
+{
+ return event->device()->type() == QTouchDevice::TouchScreen && object && object->parent()
+ && (object->parent()->inherits("QPlainTextEdit") || object->parent()->inherits("QTextEdit"))
+ ? 1 : defaultTouchPoints;
+}
+
QGestureRecognizer::Result QPanGestureRecognizer::recognize(QGesture *state,
- QObject *,
+ QObject *object,
QEvent *event)
{
QPanGesture *q = static_cast<QPanGesture *>(state);
@@ -81,7 +100,7 @@ QGestureRecognizer::Result QPanGestureRecognizer::recognize(QGesture *state,
result = QGestureRecognizer::MayBeGesture;
QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
d->lastOffset = d->offset = QPointF();
- d->pointCount = m_pointCount;
+ d->pointCount = panTouchPoints(ev, object, m_pointCount);
break;
}
case QEvent::TouchEnd: {
--
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