xcb: Deliver mouse enter event to window when closing modal window

When a modal window is closed and the mouse is not under the modal
window - find a proper window and send a fake enter event.

Added auto test for checking enter event on window when modal window
is closed.

Task-number: QTBUG-35109
Change-Id: I370b52d386503820ac9de21e6d05fd019ca456ec
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

3 files changed, 243 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 46b7b70f80..7eae2d92ab 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -50,6 +50,7 @@
 #include "qxcbsystemtraytracker.h"
 
 #include <qpa/qplatformintegration.h>
+#include <qpa/qplatformcursor.h>
 
 #include <algorithm>
 
@@ -261,6 +262,26 @@ static inline XTextProperty* qstringToXTP(Display *dpy, const QString& s)
 }
 #endif // XCB_USE_XLIB
 
+// TODO move this into a utility function in QWindow or QGuiApplication
+static QWindow *childWindowAt(QWindow *win, const QPoint &p)
+{
+    foreach (QObject *obj, win->children()) {
+        if (obj->isWindowType()) {
+            QWindow *childWin = static_cast<QWindow *>(obj);
+            if (childWin->isVisible()) {
+                if (QWindow *recurse = childWindowAt(childWin, p))
+                    return recurse;
+            }
+        }
+    }
+    if (!win->isTopLevel()
+            && !(win->flags() & Qt::WindowTransparentForInput)
+            && win->geometry().contains(win->parent()->mapFromGlobal(p))) {
+        return win;
+    }
+    return Q_NULLPTR;
+}
+
 static const char *wm_window_type_property_id = "_q_xcb_wm_window_type";
 
 QXcbWindow::QXcbWindow(QWindow *window)
@@ -855,6 +876,33 @@ void QXcbWindow::hide()
         connection()->setMouseGrabber(Q_NULLPTR);
 
     m_mapped = false;
+
+    // Hiding a modal window doesn't send an enter event to its transient parent when the
+    // mouse is already over the parent window, so the enter event must be emulated.
+    if (window()->isModal()) {
+        // Get the cursor position at modal window screen
+        const QPoint nativePos = xcbScreen()->cursor()->pos();
+        const QPoint cursorPos = QHighDpi::fromNativePixels(nativePos, xcbScreen()->screenForPosition(nativePos)->screen());
+
+        // Find the top level window at cursor position.
+        // Don't use QGuiApplication::topLevelAt(): search only the virtual siblings of this window's screen
+        QWindow *enterWindow = Q_NULLPTR;
+        foreach (QPlatformScreen *screen, xcbScreen()->virtualSiblings()) {
+            if (screen->geometry().contains(cursorPos)) {
+                const QPoint devicePosition = QHighDpi::toNativePixels(cursorPos, screen->screen());
+                enterWindow = screen->topLevelAt(devicePosition);
+                break;
+            }
+        }
+
+        if (enterWindow && enterWindow != window()) {
+            // Find the child window at cursor position, otherwise use the top level window
+            if (QWindow *childWindow = childWindowAt(enterWindow, cursorPos))
+                enterWindow = childWindow;
+            const QPoint localPos = enterWindow->mapFromGlobal(cursorPos);
+            QWindowSystemInterface::handleEnterEvent(enterWindow, localPos, cursorPos);
+        }
+    }
 }
 
 static QWindow *tlWindow(QWindow *window)
diff --git a/tests/auto/gui/kernel/qwindow/BLACKLIST b/tests/auto/gui/kernel/qwindow/BLACKLIST
index 26cace1403..cfbd47745f 100644
--- a/tests/auto/gui/kernel/qwindow/BLACKLIST
+++ b/tests/auto/gui/kernel/qwindow/BLACKLIST
@@ -6,3 +6,5 @@ ubuntu-14.04
 ubuntu-14.04
 [modalWithChildWindow]
 ubuntu-14.04
+[modalWindowEnterEventOnHide_QTBUG35109]
+ubuntu-14.04
diff --git a/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp b/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
index a89f0da4d2..0cce5a072c 100644
--- a/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
+++ b/tests/auto/gui/kernel/qwindow/tst_qwindow.cpp
@@ -92,6 +92,9 @@ private slots:
     void modalWithChildWindow();
     void modalWindowModallity();
     void modalWindowPosition();
+#ifndef QT_NO_CURSOR
+    void modalWindowEnterEventOnHide_QTBUG35109();
+#endif
     void windowsTransientChildren();
     void requestUpdate();
     void initTestCase();
@@ -706,10 +709,24 @@ public:
             }
         }
     }
+    bool event(QEvent *e) {
+        switch (e->type()) {
+        case QEvent::Enter:
+            ++enterEventCount;
+            break;
+        case QEvent::Leave:
+            ++leaveEventCount;
+            break;
+        default:
+            break;
+        }
+        return QWindow::event(e);
+    }
     void resetCounters() {
         mousePressedCount = mouseReleasedCount = mouseMovedCount = mouseDoubleClickedCount = 0;
         mouseSequenceSignature = QString();
         touchPressedCount = touchReleasedCount = touchMovedCount = 0;
+        enterEventCount = leaveEventCount = 0;
     }
 
     InputTestWindow() {
@@ -727,6 +744,7 @@ public:
     QPointF mousePressScreenPos, mouseMoveScreenPos, mousePressLocalPos;
     int touchPressedCount, touchReleasedCount, touchMovedCount;
     QEvent::Type touchEventType;
+    int enterEventCount, leaveEventCount;
 
     bool ignoreMouse, ignoreTouch;
 
@@ -1732,6 +1750,181 @@ void tst_QWindow::modalWindowPosition()
     QCOMPARE(window.geometry(), origGeo);
 }
 
+#ifndef QT_NO_CURSOR
+void tst_QWindow::modalWindowEnterEventOnHide_QTBUG35109()
+{
+    if (QGuiApplication::platformName() == QLatin1String("cocoa"))
+        QSKIP("This test fails on OS X on CI");
+
+    const QPoint center = QGuiApplication::primaryScreen()->availableGeometry().center();
+
+    const int childOffset = 16;
+    const QPoint rootPos = center - QPoint(m_testWindowSize.width(),
+                                           m_testWindowSize.height())/2;
+    const QPoint modalPos = rootPos + QPoint(childOffset * 5,
+                                             childOffset * 5);
+    const QPoint cursorPos = rootPos - QPoint(80, 80);
+
+    // Test whether tlw can receive the enter event
+    {
+        QCursor::setPos(cursorPos);
+        QCoreApplication::processEvents();
+
+        InputTestWindow root;
+        root.setTitle(__FUNCTION__);
+        root.setGeometry(QRect(rootPos, m_testWindowSize));
+        root.show();
+        QVERIFY(QTest::qWaitForWindowExposed(&root));
+        root.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&root));
+
+        // Move the mouse over the root window, but not over the modal window.
+        QCursor::setPos(rootPos + QPoint(childOffset * 5 / 2,
+                                         childOffset * 5 / 2));
+
+        // Wait for the enter event. It must be delivered here, otherwise second
+        // compare can PASS because of this event even after "resetCounters()".
+        QTRY_COMPARE(root.enterEventCount, 1);
+        QTRY_COMPARE(root.leaveEventCount, 0);
+
+        QWindow modal;
+        modal.setTitle(QLatin1String("Modal - ") + __FUNCTION__);
+        modal.setTransientParent(&root);
+        modal.resize(m_testWindowSize/2);
+        modal.setFramePosition(modalPos);
+        modal.setModality(Qt::ApplicationModal);
+        modal.show();
+        QVERIFY(QTest::qWaitForWindowExposed(&modal));
+        modal.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&modal));
+
+        QCoreApplication::processEvents();
+        QTRY_COMPARE(root.leaveEventCount, 1);
+
+        root.resetCounters();
+        modal.close();
+
+        // Check for the enter event
+        QTRY_COMPARE(root.enterEventCount, 1);
+    }
+
+    // Test whether child window can receive the enter event
+    {
+        QCursor::setPos(cursorPos);
+        QCoreApplication::processEvents();
+
+        QWindow root;
+        root.setTitle(__FUNCTION__);
+        root.setGeometry(QRect(rootPos, m_testWindowSize));
+
+        QWindow childLvl1;
+        childLvl1.setParent(&root);
+        childLvl1.setGeometry(childOffset,
+                              childOffset,
+                              m_testWindowSize.width() - childOffset,
+                              m_testWindowSize.height() - childOffset);
+
+        InputTestWindow childLvl2;
+        childLvl2.setParent(&childLvl1);
+        childLvl2.setGeometry(childOffset,
+                              childOffset,
+                              childLvl1.width() - childOffset,
+                              childLvl1.height() - childOffset);
+
+        root.show();
+        childLvl1.show();
+        childLvl2.show();
+
+        QVERIFY(QTest::qWaitForWindowExposed(&root));
+        root.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&root));
+        QVERIFY(childLvl1.isVisible());
+        QVERIFY(childLvl2.isVisible());
+
+        // Move the mouse over the child window, but not over the modal window.
+        // Be sure that the value is almost left-top of second child window for
+        // checking proper position mapping.
+        QCursor::setPos(rootPos + QPoint(childOffset * 5 / 2,
+                                         childOffset * 5 / 2));
+
+        // Wait for the enter event. It must be delivered here, otherwise second
+        // compare can PASS because of this event even after "resetCounters()".
+        QTRY_COMPARE(childLvl2.enterEventCount, 1);
+        QTRY_COMPARE(childLvl2.leaveEventCount, 0);
+
+        QWindow modal;
+        modal.setTitle(QLatin1String("Modal - ") + __FUNCTION__);
+        modal.setTransientParent(&root);
+        modal.resize(m_testWindowSize/2);
+        modal.setFramePosition(modalPos);
+        modal.setModality(Qt::ApplicationModal);
+        modal.show();
+        QVERIFY(QTest::qWaitForWindowExposed(&modal));
+        modal.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&modal));
+
+        QCoreApplication::processEvents();
+        QTRY_COMPARE(childLvl2.leaveEventCount, 1);
+
+        childLvl2.resetCounters();
+        modal.close();
+
+        // Check for the enter event
+        QTRY_COMPARE(childLvl2.enterEventCount, 1);
+    }
+
+    // Test whether tlw can receive the enter event if mouse is over the invisible child windnow
+    {
+        QCursor::setPos(cursorPos);
+        QCoreApplication::processEvents();
+
+        InputTestWindow root;
+        root.setTitle(__FUNCTION__);
+        root.setGeometry(QRect(rootPos, m_testWindowSize));
+
+        QWindow child;
+        child.setParent(&root);
+        child.setGeometry(QRect(QPoint(), m_testWindowSize));
+
+        root.show();
+
+        QVERIFY(QTest::qWaitForWindowExposed(&root));
+        root.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&root));
+        QVERIFY(!child.isVisible());
+
+        // Move the mouse over the child window, but not over the modal window.
+        QCursor::setPos(rootPos + QPoint(childOffset * 5 / 2,
+                                         childOffset * 5 / 2));
+
+        // Wait for the enter event. It must be delivered here, otherwise second
+        // compare can PASS because of this event even after "resetCounters()".
+        QTRY_COMPARE(root.enterEventCount, 1);
+        QTRY_COMPARE(root.leaveEventCount, 0);
+
+        QWindow modal;
+        modal.setTitle(QLatin1String("Modal - ") + __FUNCTION__);
+        modal.setTransientParent(&root);
+        modal.resize(m_testWindowSize/2);
+        modal.setFramePosition(modalPos);
+        modal.setModality(Qt::ApplicationModal);
+        modal.show();
+        QVERIFY(QTest::qWaitForWindowExposed(&modal));
+        modal.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&modal));
+
+        QCoreApplication::processEvents();
+        QTRY_COMPARE(root.leaveEventCount, 1);
+
+        root.resetCounters();
+        modal.close();
+
+        // Check for the enter event
+        QTRY_COMPARE(root.enterEventCount, 1);
+    }
+}
+#endif
+
 class ColoredWindow : public QRasterWindow {
 public:
     explicit ColoredWindow(const QColor &color, QWindow *parent = 0) : QRasterWindow(parent), m_color(color) {}