Prep mouse event handler to indicate dragging started

Change-Id: Icdb865e511047b166767ca9e87e808c308ad7643
Reviewed-on: https://gerrit.libreoffice.org/53324
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>

include/sfx2/sidebar/DeckTitleBar.hxx

@@ -31,6 +31,7 @@ public:
                  const std::function<void()>& rCloserAction);
 
     void SetCloserVisible(const bool bIsCloserVisible);
+    tools::Rectangle GetDragArea() const;
 
     virtual void DataChanged(const DataChangedEvent& rEvent) override;
 

include/sfx2/sidebar/SidebarController.hxx

@@ -164,6 +164,8 @@ public:
     void FadeIn();
     void FadeOut();
 
+    tools::Rectangle GetDeckDragArea() const;
+
 private:
     SidebarController(
         SidebarDockingWindow* pParentWindow,

include/sfx2/sidebar/SidebarDockingWindow.hxx

@@ -39,6 +39,9 @@ public:
     virtual bool EventNotify(NotifyEvent& rEvent) override;
     virtual bool Close() override;
 
+    void SetReadyToDrag( bool bStartDrag ) { mbIsReadyToDrag = bStartDrag; }
+    bool IsReadyToDrag() const { return mbIsReadyToDrag; }
+
     using SfxDockingWindow::Close;
 
 protected:
@@ -51,6 +54,7 @@ protected:
 
 private:
     ::rtl::Reference<sfx2::sidebar::SidebarController> mpSidebarController;
+    bool mbIsReadyToDrag;
 
     void DoDispose();
 };

sfx2/source/sidebar/DeckTitleBar.cxx

@@ -18,6 +18,7 @@
  */
 
 #include <sfx2/sidebar/DeckTitleBar.hxx>
+#include <sfx2/sidebar/SidebarDockingWindow.hxx>
 #include <sfx2/sidebar/Theme.hxx>
 #include <sfx2/sfxresid.hxx>
 #include <sfx2/strings.hrc>
@@ -81,6 +82,15 @@ tools::Rectangle DeckTitleBar::GetTitleArea (const tools::Rectangle& rTitleBarBo
         rTitleBarBox.Bottom());
 }
 
+tools::Rectangle DeckTitleBar::GetDragArea() const
+{
+    Image aGripImage (Theme::GetImage(Theme::Image_Grip));
+    return tools::Rectangle(0,0,
+               aGripImage.GetSizePixel().Width() + gaLeftGripPadding + gaRightGripPadding,
+               aGripImage.GetSizePixel().Height()
+    );
+}
+
 void DeckTitleBar::PaintDecoration(vcl::RenderContext& rRenderContext, const tools::Rectangle& /*rTitleBarBox*/)
 {
    Image aImage (Theme::GetImage(Theme::Image_Grip));

sfx2/source/sidebar/SidebarController.cxx

@@ -1340,6 +1340,17 @@ void SidebarController::FadeIn()
         mpSplitWindow->FadeIn();
 }
 
+tools::Rectangle SidebarController::GetDeckDragArea() const
+{
+    tools::Rectangle aRect;
+
+    VclPtr<DeckTitleBar> pTitleBar = mpCurrentDeck->GetTitleBar();
+    if ( pTitleBar)
+        aRect = pTitleBar->GetDragArea();
+
+    return aRect;
+}
+
 void SidebarController::frameAction(const css::frame::FrameActionEvent& rEvent)
 {
     if (rEvent.Frame == mxFrame)

sfx2/source/sidebar/SidebarDockingWindow.cxx

@@ -23,6 +23,7 @@
 #include <sfx2/bindings.hxx>
 #include <sfx2/dispatch.hxx>
 #include <tools/link.hxx>
+#include <tools/gen.hxx>
 
 using namespace css;
 using namespace css::uno;
@@ -116,6 +117,17 @@ bool SidebarDockingWindow::EventNotify(NotifyEvent& rEvent)
     if (MouseNotifyEvent::KEYINPUT == nType)
         return true;
 
+    if ( MouseNotifyEvent::MOUSEBUTTONDOWN == nType)
+    {
+        const MouseEvent *mEvt = rEvent.GetMouseEvent();
+        if (mEvt->IsLeft())
+        {
+            tools::Rectangle aGrip = mpSidebarController->GetDeckDragArea();
+            if ( aGrip.IsInside( mEvt->GetPosPixel() ) )
+                SetReadyToDrag( true );
+        }
+    }
+
     return SfxDockingWindow::EventNotify(rEvent);
 }