New API for drag and drop

Let the compositor implementation keep all the GUI state.

Change-Id: I73a865fa3407340276d6765e10378b8e23a76fe2
Reviewed-by: Jørgen Lind <jorgen.lind@theqtcompany.com>

4 files changed, 87 insertions, 23 deletions

diff --git a/examples/wayland/qwindow-compositor/compositorwindow.cpp b/examples/wayland/qwindow-compositor/compositorwindow.cpp
index b08a5b2a5..f59017824 100644
--- a/examples/wayland/qwindow-compositor/compositorwindow.cpp
+++ b/examples/wayland/qwindow-compositor/compositorwindow.cpp
@@ -52,8 +52,7 @@
 CompositorWindow::CompositorWindow()
     : m_backgroundTexture(0)
     , m_compositor(0)
-    , m_moveState(false)
-    , m_resizeState(false)
+    , m_grabState(NoGrab)
 {
 }
 
@@ -61,6 +60,7 @@ void CompositorWindow::setCompositor(WindowCompositor *comp) {
     m_compositor = comp;
     connect(m_compositor, &WindowCompositor::startMove, this, &CompositorWindow::startMove);
     connect(m_compositor, &WindowCompositor::startResize, this, &CompositorWindow::startResize);
+    connect(m_compositor, &WindowCompositor::dragStarted, this, &CompositorWindow::startDrag);
     connect(m_compositor, &WindowCompositor::frameOffset, this, &CompositorWindow::setFrameOffset);
 }
 
@@ -125,6 +125,8 @@ WindowCompositorView *CompositorWindow::viewAt(const QPointF &point)
 {
     WindowCompositorView *ret = 0;
     Q_FOREACH (WindowCompositorView *view, m_compositor->views()) {
+        if (view == m_dragIconView)
+            continue;
         QPointF topLeft = view->position();
         QWaylandSurface *surface = view->surface();
         QRectF geo(topLeft, surface->size());
@@ -136,16 +138,23 @@ WindowCompositorView *CompositorWindow::viewAt(const QPointF &point)
 
 void CompositorWindow::startMove()
 {
-    m_moveState = true;
+    m_grabState = MoveGrab;
 }
 
 void CompositorWindow::startResize(int edge)
 {
     m_initialSize = m_mouseView->surface()->size();
-    m_resizeState = true;
+    m_grabState = ResizeGrab;
     m_resizeEdge = edge;
 }
 
+void CompositorWindow::startDrag(WindowCompositorView *dragIcon)
+{
+    m_grabState = DragGrab;
+    m_dragIconView = dragIcon;
+    m_compositor->raise(dragIcon);
+}
+
 void CompositorWindow::setFrameOffset(const QPoint &offset)
 {
     if (m_mouseView)
@@ -161,11 +170,10 @@ void CompositorWindow::mousePressEvent(QMouseEvent *e)
         if (!m_mouseView)
             return;
 
-        if (m_mouseView && (e->modifiers() == Qt::AltModifier ||
-                            e->modifiers() == Qt::MetaModifier)) {
-            //start move
-            m_moveState = true;
-        }
+        if (e->modifiers() == Qt::AltModifier || e->modifiers() == Qt::MetaModifier)
+            m_grabState = MoveGrab; //start move
+        else
+            m_compositor->raise(m_mouseView);
         m_initialMousePos = e->localPos();
         m_mouseOffset = e->localPos() - m_mouseView->position();
 
@@ -180,28 +188,45 @@ void CompositorWindow::mouseReleaseEvent(QMouseEvent *e)
     if (!mouseGrab())
         sendMouseEvent(e, m_mouseView);
     if (e->buttons() == Qt::NoButton) {
+        if (m_grabState == DragGrab) {
+            WindowCompositorView *view = viewAt(e->localPos());
+            m_compositor->handleDrag(view, e);
+        }
         m_mouseView = 0;
-        m_moveState = false;
-        m_resizeState = false;
+        m_grabState = NoGrab;
     }
 }
 
 void CompositorWindow::mouseMoveEvent(QMouseEvent *e)
 {
-    if (mouseGrab()) {
-        if (m_moveState) {
-            m_mouseView->setPosition(e->localPos() - m_mouseOffset);
-            update();
-        } else if (m_resizeState) {
-            QPoint delta = (e->localPos() - m_initialMousePos).toPoint();
-            m_compositor->handleResize(m_mouseView, m_initialSize, delta, m_resizeEdge);
-        }
-    } else {
+    switch (m_grabState) {
+    case NoGrab: {
         WindowCompositorView *view = m_mouseView ? m_mouseView.data() : viewAt(e->localPos());
         sendMouseEvent(e, view);
         if (!view)
             setCursor(Qt::ArrowCursor);
     }
+        break;
+    case MoveGrab: {
+        m_mouseView->setPosition(e->localPos() - m_mouseOffset);
+        update();
+    }
+        break;
+    case ResizeGrab: {
+        QPoint delta = (e->localPos() - m_initialMousePos).toPoint();
+        m_compositor->handleResize(m_mouseView, m_initialSize, delta, m_resizeEdge);
+    }
+        break;
+    case DragGrab: {
+        WindowCompositorView *view = viewAt(e->localPos());
+        m_compositor->handleDrag(view, e);
+        if (m_dragIconView) {
+            m_dragIconView->setPosition(e->localPos());
+            update();
+        }
+    }
+        break;
+    }
 }
 
 void CompositorWindow::sendMouseEvent(QMouseEvent *e, WindowCompositorView *target)
diff --git a/examples/wayland/qwindow-compositor/compositorwindow.h b/examples/wayland/qwindow-compositor/compositorwindow.h
index 4e6a25f74..720db5bc7 100644
--- a/examples/wayland/qwindow-compositor/compositorwindow.h
+++ b/examples/wayland/qwindow-compositor/compositorwindow.h
@@ -72,11 +72,14 @@ protected:
 private slots:
     void startMove();
     void startResize(int edge);
+    void startDrag(WindowCompositorView *dragIcon);
     void setFrameOffset(const QPoint &offset);
 
 private:
+    enum GrabState { NoGrab, MoveGrab, ResizeGrab, DragGrab };
+
     WindowCompositorView *viewAt(const QPointF &point);
-    bool mouseGrab() const { return m_moveState || m_resizeState; }
+    bool mouseGrab() const { return m_grabState != NoGrab ;}
     void drawBackground();
     void sendMouseEvent(QMouseEvent *e, WindowCompositorView *target);
 
@@ -85,12 +88,12 @@ private:
     QOpenGLTexture *m_backgroundTexture;
     WindowCompositor *m_compositor;
     QPointer<WindowCompositorView> m_mouseView;
-    bool m_moveState;
-    bool m_resizeState;
+    GrabState m_grabState;
     QSize m_initialSize;
     int m_resizeEdge;
     QPointF m_mouseOffset;
     QPointF m_initialMousePos;
+    WindowCompositorView *m_dragIconView;
 };
 
 QT_END_NAMESPACE
diff --git a/examples/wayland/qwindow-compositor/windowcompositor.cpp b/examples/wayland/qwindow-compositor/windowcompositor.cpp
index 761c6387d..951aadf07 100644
--- a/examples/wayland/qwindow-compositor/windowcompositor.cpp
+++ b/examples/wayland/qwindow-compositor/windowcompositor.cpp
@@ -47,6 +47,7 @@
 #include <QtWaylandCompositor/QWaylandOutputSpace>
 #include <QtWaylandCompositor/QWaylandShellSurface>
 #include <QtWaylandCompositor/qwaylandinput.h>
+#include <QtWaylandCompositor/qwaylanddrag.h>
 
 #include <QDebug>
 
@@ -87,6 +88,7 @@ void WindowCompositor::create()
 
     connect(this, &QWaylandCompositor::surfaceCreated, this, &WindowCompositor::onSurfaceCreated);
     connect(defaultInputDevice(), &QWaylandInputDevice::cursorSurfaceRequest, this, &WindowCompositor::adjustCursorSurface);
+    connect(defaultInputDevice()->drag(), &QWaylandDrag::dragStarted, this, &WindowCompositor::startDrag);
 }
 
 void WindowCompositor::onSurfaceCreated(QWaylandSurface *surface)
@@ -218,3 +220,32 @@ void WindowCompositor::handleResize(WindowCompositorView *target, const QSize &i
     QSize newSize = shellSurface->sizeForResize(initialSize, delta, edges);
     shellSurface->sendConfigure(newSize, edges);
 }
+
+void WindowCompositor::startDrag()
+{
+    QWaylandDrag *currentDrag = defaultInputDevice()->drag();
+    Q_ASSERT(currentDrag);
+    WindowCompositorView *iconView = findView(currentDrag->icon());
+
+    emit dragStarted(iconView);
+}
+
+void WindowCompositor::handleDrag(WindowCompositorView *target, QMouseEvent *me)
+{
+    QPointF pos = me->localPos();
+    QWaylandSurface *surface = 0;
+    if (target) {
+        pos -= target->position();
+        surface = target->surface();
+    }
+    QWaylandDrag *currentDrag = defaultInputDevice()->drag();
+    currentDrag->dragMove(surface, pos);
+    if (me->buttons() == Qt::NoButton)
+        currentDrag->drop();
+}
+
+void WindowCompositor::raise(WindowCompositorView *view)
+{
+    m_views.removeOne(view);
+    m_views.append(view);
+}
diff --git a/examples/wayland/qwindow-compositor/windowcompositor.h b/examples/wayland/qwindow-compositor/windowcompositor.h
index 55d964cab..1b5329d89 100644
--- a/examples/wayland/qwindow-compositor/windowcompositor.h
+++ b/examples/wayland/qwindow-compositor/windowcompositor.h
@@ -81,9 +81,11 @@ public:
     void endRender();
 
     QList<WindowCompositorView*> views() const { return m_views; }
+    void raise(WindowCompositorView *view);
 
     void handleMouseEvent(QWaylandView *target, QMouseEvent *me);
     void handleResize(WindowCompositorView *target, const QSize &initialSize, const QPoint &delta, int edge);
+    void handleDrag(WindowCompositorView *target, QMouseEvent *me);
 
 protected:
     void adjustCursorSurface(QWaylandSurface *surface, int hotspotX, int hotspotY);
@@ -91,6 +93,7 @@ protected:
 signals:
     void startMove();
     void startResize(int edge);
+    void dragStarted(WindowCompositorView *dragIcon);
     void frameOffset(const QPoint &offset);
 
 private slots:
@@ -100,6 +103,8 @@ private slots:
     void viewSurfaceDestroyed();
     void onStartResize(QWaylandInputDevice *inputDevice, QWaylandShellSurface::ResizeEdge edges);
 
+    void startDrag();
+
     void triggerRender();
 
     void onSurfaceCreated(QWaylandSurface *surface);