Use QPlatformTheme::TouchDoubleTapDistance for touch events

... and update the cached values on theme change.

Modify tst_QWidget::touchEventSynthesizedMouseEvent()
to avoid unexpected double click detection.

Change-Id: I151c47e851ebba7550b1b09caca2781c28d7d3d9
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

3 files changed, 21 insertions, 10 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 424af20f26..a67214bd9a 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -181,7 +181,9 @@ ulong QGuiApplicationPrivate::mousePressTime = 0;
 Qt::MouseButton QGuiApplicationPrivate::mousePressButton = Qt::NoButton;
 int QGuiApplicationPrivate::mousePressX = 0;
 int QGuiApplicationPrivate::mousePressY = 0;
-int QGuiApplicationPrivate::mouse_double_click_distance = -1;
+
+static int mouseDoubleClickDistance = -1;
+static int touchDoubleTapDistance = -1;
 
 QWindow *QGuiApplicationPrivate::currentMousePressWindow = 0;
 
@@ -257,6 +259,12 @@ static inline void clearFontUnlocked()
     QGuiApplicationPrivate::app_font = 0;
 }
 
+static void initThemeHints()
+{
+    mouseDoubleClickDistance = QGuiApplicationPrivate::platformTheme()->themeHint(QPlatformTheme::MouseDoubleClickDistance).toInt();
+    touchDoubleTapDistance = QGuiApplicationPrivate::platformTheme()->themeHint(QPlatformTheme::TouchDoubleTapDistance).toInt();
+}
+
 static bool checkNeedPortalSupport()
 {
 #if QT_CONFIG(dbus)
@@ -1519,8 +1527,7 @@ void QGuiApplicationPrivate::init()
 
     initPalette();
     QFont::initialize();
-
-    mouse_double_click_distance = platformTheme()->themeHint(QPlatformTheme::MouseDoubleClickDistance).toInt();
+    initThemeHints();
 
 #ifndef QT_NO_CURSOR
     QCursorData::initialize();
@@ -2030,8 +2037,10 @@ void QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::Mo
 
     if (mouseMove) {
         QGuiApplicationPrivate::lastCursorPosition = globalPoint;
-        if (qAbs(globalPoint.x() - mousePressX) > mouse_double_click_distance||
-            qAbs(globalPoint.y() - mousePressY) > mouse_double_click_distance)
+        const auto doubleClickDistance = e->source == Qt::MouseEventNotSynthesized ?
+                    mouseDoubleClickDistance : touchDoubleTapDistance;
+        if (qAbs(globalPoint.x() - mousePressX) > doubleClickDistance ||
+            qAbs(globalPoint.y() - mousePressY) > doubleClickDistance)
             mousePressButton = Qt::NoButton;
     } else {
         mouse_buttons = e->buttons;
@@ -3988,6 +3997,7 @@ void QGuiApplicationPrivate::notifyThemeChanged()
         clearFontUnlocked();
         initFontUnlocked();
     }
+    initThemeHints();
 }
 
 void QGuiApplicationPrivate::sendApplicationPaletteChange(bool toAllWidgets, const char *className)
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 042a36c31f..482d45e5c3 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -211,7 +211,6 @@ public:
     static Qt::MouseButton mousePressButton;
     static int mousePressX;
     static int mousePressY;
-    static int mouse_double_click_distance;
     static QPointF lastCursorPosition;
     static QWindow *currentMouseWindow;
     static QWindow *currentMousePressWindow;
diff --git a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
index 3b9c9060fa..780cb01e40 100644
--- a/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
+++ b/tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp
@@ -10152,7 +10152,8 @@ void tst_QWidget::touchEventSynthesizedMouseEvent()
         // We should see propagation of the TouchBegin into a MouseButtonPress
         TouchMouseWidget parent;
         TouchMouseWidget child(&parent);
-        child.move(5, 5);
+        const QPoint childPos(5, 5);
+        child.move(childPos);
         child.setAcceptMouse(false);
         parent.show();
         QVERIFY(QTest::qWaitForWindowExposed(parent.windowHandle()));
@@ -10161,13 +10162,14 @@ void tst_QWidget::touchEventSynthesizedMouseEvent()
         QCOMPARE(child.m_touchEventCount, 0);
         QCOMPARE(child.m_mouseEventCount, 0);
 
-        QTest::touchEvent(parent.window(), m_touchScreen).press(0, QPoint(10, 10), &child);
+        const QPoint touchPos(20, 20);
+        QTest::touchEvent(parent.window(), m_touchScreen).press(0, touchPos, &child);
         QCOMPARE(parent.m_touchEventCount, 0);
         QCOMPARE(parent.m_mouseEventCount, 1);
-        QCOMPARE(parent.m_lastMouseEventPos, QPointF(15, 15));
+        QCOMPARE(parent.m_lastMouseEventPos, childPos + touchPos);
         QCOMPARE(child.m_touchEventCount, 0);
         QCOMPARE(child.m_mouseEventCount, 1); // Attempt at mouse event before propagation
-        QCOMPARE(child.m_lastMouseEventPos, QPointF(10, 10));
+        QCOMPARE(child.m_lastMouseEventPos, touchPos);
     }
 }