eglfs: Generate enter and leave events

In addition the logic in QGuiApplication that picks the target window for input
events with a null window has to be enhanced to be compatible with how real windowing
systems work: mouse events following a press are delivered to the same window until the
release, even if the cursor has left the original target window.

Task-number: QTBUG-44814
Change-Id: I3fea84ac77a5ccebeae5def64f92d8d2e03d13ff
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

src/gui/kernel/qguiapplication.cpp

@@ -147,12 +147,15 @@ QString *QGuiApplicationPrivate::displayName = 0;
 QPalette *QGuiApplicationPrivate::app_pal = 0;        // default application palette
 
 Qt::MouseButtons QGuiApplicationPrivate::buttons = Qt::NoButton;
+
 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;
 
+QWindow *QGuiApplicationPrivate::currentMousePressWindow = 0;
+
 static Qt::LayoutDirection layout_direction = Qt::LeftToRight;
 static bool force_reverse = false;
 
@@ -1703,6 +1706,17 @@ void QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::Mo
     if (e->nullWindow()) {
         window = QGuiApplication::topLevelAt(globalPoint.toPoint());
         if (window) {
+            // Moves and the release following a press must go to the same
+            // window, even if the cursor has moved on over another window.
+            if (e->buttons != Qt::NoButton) {
+                if (!currentMousePressWindow)
+                    currentMousePressWindow = window;
+                else
+                    window = currentMousePressWindow;
+            } else if (currentMousePressWindow) {
+                window = currentMousePressWindow;
+                currentMousePressWindow = 0;
+            }
             QPointF delta = globalPoint - globalPoint.toPoint();
             localPoint = window->mapFromGlobal(globalPoint.toPoint()) + delta;
         }

src/gui/kernel/qguiapplication_p.h

@@ -200,6 +200,7 @@ public:
     static Qt::MouseButtons tabletState;
     static QWindow *tabletPressTarget;
     static QWindow *currentMouseWindow;
+    static QWindow *currentMousePressWindow;
     static Qt::ApplicationState applicationState;
 
 #ifndef QT_NO_CLIPBOARD

src/gui/kernel/qwindow.cpp

@@ -1599,6 +1599,8 @@ void QWindow::destroy()
         QGuiApplicationPrivate::focus_window = parent();
     if (QGuiApplicationPrivate::currentMouseWindow == this)
         QGuiApplicationPrivate::currentMouseWindow = parent();
+    if (QGuiApplicationPrivate::currentMousePressWindow == this)
+        QGuiApplicationPrivate::currentMousePressWindow = parent();
     if (QGuiApplicationPrivate::tabletPressTarget == this)
         QGuiApplicationPrivate::tabletPressTarget = parent();
 

src/platformsupport/eglconvenience/qeglplatformcursor.cpp

@@ -43,6 +43,7 @@
 
 #include "qeglplatformcursor_p.h"
 #include "qeglplatformintegration_p.h"
+#include "qeglplatformscreen_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -56,7 +57,7 @@ QT_BEGIN_NAMESPACE
 
 QEGLPlatformCursor::QEGLPlatformCursor(QPlatformScreen *screen)
     : m_visible(true),
-      m_screen(screen),
+      m_screen(static_cast<QEGLPlatformScreen *>(screen)),
       m_program(0),
       m_vertexCoordEntry(0),
       m_textureCoordEntry(0),
@@ -300,6 +301,7 @@ void QEGLPlatformCursor::setPos(const QPoint &pos)
     const QRect oldCursorRect = cursorRect();
     m_cursor.pos = pos;
     update(oldCursorRect | cursorRect());
+    m_screen->handleCursorMove(m_cursor.pos);
 }
 
 void QEGLPlatformCursor::pointerEvent(const QMouseEvent &event)
@@ -309,6 +311,7 @@ void QEGLPlatformCursor::pointerEvent(const QMouseEvent &event)
     const QRect oldCursorRect = cursorRect();
     m_cursor.pos = event.screenPos().toPoint();
     update(oldCursorRect | cursorRect());
+    m_screen->handleCursorMove(m_cursor.pos);
 }
 
 void QEGLPlatformCursor::paintOnScreen()

src/platformsupport/eglconvenience/qeglplatformcursor_p.h

@@ -54,6 +54,7 @@ QT_BEGIN_NAMESPACE
 
 class QOpenGLShaderProgram;
 class QEGLPlatformCursor;
+class QEGLPlatformScreen;
 
 class QEGLPlatformCursorDeviceListener : public QObject
 {
@@ -127,7 +128,7 @@ private:
     } m_cursorAtlas;
 
     bool m_visible;
-    QPlatformScreen *m_screen;
+    QEGLPlatformScreen *m_screen;
     QOpenGLShaderProgram *m_program;
     int m_vertexCoordEntry;
     int m_textureCoordEntry;

src/platformsupport/eglconvenience/qeglplatformscreen.cpp

@@ -32,6 +32,8 @@
 ****************************************************************************/
 
 #include "qeglplatformscreen_p.h"
+#include <QtGui/qwindow.h>
+#include <qpa/qwindowsysteminterface.h>
 #include <QtPlatformSupport/private/qopenglcompositor_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -45,7 +47,8 @@ QT_BEGIN_NAMESPACE
  */
 
 QEGLPlatformScreen::QEGLPlatformScreen(EGLDisplay dpy)
-    : m_dpy(dpy)
+    : m_dpy(dpy),
+      m_pointerWindow(0)
 {
 }
 
@@ -54,4 +57,41 @@ QEGLPlatformScreen::~QEGLPlatformScreen()
     QOpenGLCompositor::destroy();
 }
 
+void QEGLPlatformScreen::handleCursorMove(const QPoint &pos)
+{
+    const QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
+    const QList<QOpenGLCompositorWindow *> windows = compositor->windows();
+
+    // Generate enter and leave events like a real windowing system would do.
+    if (windows.isEmpty())
+        return;
+
+    // First window is always fullscreen.
+    if (windows.count() == 1) {
+        QWindow *window = windows[0]->sourceWindow();
+        if (m_pointerWindow != window) {
+            m_pointerWindow = window;
+            QWindowSystemInterface::handleEnterEvent(window, window->mapFromGlobal(pos), pos);
+        }
+        return;
+    }
+
+    QWindow *enter = 0, *leave = 0;
+    for (int i = windows.count() - 1; i >= 0; --i) {
+        QWindow *window = windows[i]->sourceWindow();
+        const QRect geom = window->geometry();
+        if (geom.contains(pos)) {
+            if (m_pointerWindow != window) {
+                leave = m_pointerWindow;
+                m_pointerWindow = window;
+                enter = window;
+            }
+            break;
+        }
+    }
+
+    if (enter && leave)
+        QWindowSystemInterface::handleEnterLeaveEvent(enter, leave, enter->mapFromGlobal(pos), pos);
+}
+
 QT_END_NAMESPACE

src/platformsupport/eglconvenience/qeglplatformscreen_p.h

@@ -46,6 +46,7 @@
 //
 
 #include <QtCore/QList>
+#include <QtCore/QPoint>
 #include <QtCore/qtextstream.h>
 #include <qpa/qplatformscreen.h>
 #include <EGL/egl.h>
@@ -53,6 +54,7 @@
 QT_BEGIN_NAMESPACE
 
 class QOpenGLContext;
+class QWindow;
 class QEGLPlatformWindow;
 
 class QEGLPlatformScreen : public QPlatformScreen
@@ -63,8 +65,11 @@ public:
 
     EGLDisplay display() const { return m_dpy; }
 
+    void handleCursorMove(const QPoint &pos);
+
 private:
     EGLDisplay m_dpy;
+    QWindow *m_pointerWindow;
 };
 
 QT_END_NAMESPACE