Add feedback to Workspace to drop tabs on it

src/app/ui/main_window.cpp

@@ -247,6 +247,17 @@ void MainWindow::onActiveViewChange()
   configureWorkspaceLayout();
 }
 
+bool MainWindow::onIsModified(Tabs* tabs, TabView* tabView)
+{
+  if (DocumentView* docView = dynamic_cast<DocumentView*>(tabView)) {
+    Document* document = docView->getDocument();
+    return document->isModified();
+  }
+  else {
+    return false;
+  }
+}
+
 void MainWindow::onSelectTab(Tabs* tabs, TabView* tabView)
 {
   if (!tabView)
@@ -286,15 +297,16 @@ void MainWindow::onMouseOverTab(Tabs* tabs, TabView* tabView)
   }
 }
 
-bool MainWindow::onIsModified(Tabs* tabs, TabView* tabView)
+void MainWindow::onFloatingTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos)
 {
-  if (DocumentView* docView = dynamic_cast<DocumentView*>(tabView)) {
-    Document* document = docView->getDocument();
-    return document->isModified();
-  }
-  else {
-    return false;
-  }
+  m_workspace->setDropViewPreview(pos);
+}
+
+DropTabResult MainWindow::onDropTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos)
+{
+  m_workspace->removeDropViewPreview(pos);
+  m_workspace->dropViewAt(pos, dynamic_cast<WorkspaceView*>(tabView));
+  return DropTabResult::IGNORE;
 }
 
 void MainWindow::configureWorkspaceLayout()

src/app/ui/main_window.h

@@ -74,11 +74,13 @@ namespace app {
     void popTimeline();
 
     // TabsDelegate implementation.
+    bool onIsModified(Tabs* tabs, TabView* tabView) override;
     void onSelectTab(Tabs* tabs, TabView* tabView) override;
     void onCloseTab(Tabs* tabs, TabView* tabView) override;
     void onContextMenuTab(Tabs* tabs, TabView* tabView) override;
     void onMouseOverTab(Tabs* tabs, TabView* tabView) override;
-    bool onIsModified(Tabs* tabs, TabView* tabView) override;
+    void onFloatingTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos) override;
+    DropTabResult onDropTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos) override;
 
   protected:
     bool onProcessMessage(ui::Message* msg) override;

src/app/ui/tabs.cpp

@@ -250,6 +250,9 @@ bool Tabs::onProcessMessage(Message* msg)
               createFloatingTab(m_selected);
 
             m_floatingOverlay->moveOverlay(mousePos - m_dragOffset);
+
+            if (m_delegate)
+              m_delegate->onFloatingTab(this, m_selected->view, mousePos);
           }
           else {
             justDocked = m_floatingTab;
@@ -332,8 +335,13 @@ bool Tabs::onProcessMessage(Message* msg)
 
         releaseMouse();
 
-        if (m_isDragging)
+        if (m_isDragging) {
+          if (m_delegate)
+            m_delegate->onDropTab(this, m_selected->view,
+              mouseMsg->position());
+
           stopDrag();
+        }
 
         if (m_clickedCloseButton) {
           m_clickedCloseButton = false;

src/app/ui/tabs.h

@@ -41,11 +41,20 @@ namespace app {
     virtual TabIcon getTabIcon() = 0;
   };
 
+  enum class DropTabResult {
+    IGNORE,
+    DOCKED_IN_OTHER_PLACE,
+  };
+
   // Interface used to control notifications from the Tabs widget.
   class TabsDelegate {
   public:
+
     virtual ~TabsDelegate() { }
 
+    // Returns true if the tab represent a modified document.
+    virtual bool onIsModified(Tabs* tabs, TabView* tabView) = 0;
+
     // Called when the user selected the tab with the left mouse button.
     virtual void onSelectTab(Tabs* tabs, TabView* tabView) = 0;
 
@@ -59,7 +68,9 @@ namespace app {
     // mouse just leave all tabs)
     virtual void onMouseOverTab(Tabs* tabs, TabView* tabView) = 0;
 
-    virtual bool onIsModified(Tabs* tabs, TabView* tabView) = 0;
+    // Called when the user is dragging a tab outside the Tabs bar.
+    virtual void onFloatingTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos) = 0;
+    virtual DropTabResult onDropTab(Tabs* tabs, TabView* tabView, const gfx::Point& pos) = 0;
   };
 
   // Tabs control. Used to show opened documents.

src/app/ui/workspace.cpp

@@ -30,6 +30,7 @@ Workspace::Workspace()
   : Widget(kGenericWidget)
   , m_tabsBar(nullptr)
   , m_activeView(nullptr)
+  , m_dropPreview(false)
 {
   SkinTheme* theme = static_cast<SkinTheme*>(getTheme());
   setBgColor(theme->colors.workspace());
@@ -100,4 +101,58 @@ void Workspace::onPaint(PaintEvent& ev)
   ev.getGraphics()->fillRect(getBgColor(), getClientBounds());
 }
 
+void Workspace::onResize(ui::ResizeEvent& ev)
+{
+  setBoundsQuietly(ev.getBounds());
+
+  gfx::Rect cpos = getChildrenBounds();
+
+  // Preview to drop tabs in workspace
+  if (m_dropPreview && cpos.contains(m_dropPos)) {
+    int left = ABS(cpos.x - m_dropPos.x);
+    int top = ABS(cpos.y - m_dropPos.y);
+    int right = ABS(cpos.x + cpos.w - m_dropPos.x);
+    int bottom = ABS(cpos.y + cpos.h - m_dropPos.y);
+    int threshold = 32*guiscale();
+    if (threshold > cpos.w/2) threshold = cpos.w/2;
+    if (threshold > cpos.h/2) threshold = cpos.h/2;
+
+    if (left < threshold && left < right && left < top && left < bottom) {
+      cpos.x += threshold;
+      cpos.w -= threshold;
+    }
+    else if (top < threshold && top < left && top < right && top < bottom) {
+      cpos.y += threshold;
+      cpos.h -= threshold;
+    }
+    else if (right < threshold && right < left && right < top && right < bottom) {
+      cpos.w -= threshold;
+    }
+    else if (bottom < threshold && bottom < left && bottom < top && bottom < right) {
+      cpos.h -= threshold;
+    }
+  }
+
+  for (Widget* child : getChildren())
+    child->setBounds(cpos);
+}
+
+void Workspace::setDropViewPreview(const gfx::Point& pos)
+{
+  m_dropPos = pos;
+  m_dropPreview = true;
+
+  layout();
+}
+
+void Workspace::removeDropViewPreview(const gfx::Point& pos)
+{
+  m_dropPreview = false;
+  layout();
+}
+
+void Workspace::dropViewAt(const gfx::Point& pos, WorkspaceView* view)
+{
+}
+
 } // namespace app

src/app/ui/workspace.h

@@ -40,15 +40,23 @@ namespace app {
     WorkspaceView* activeView();
     void setActiveView(WorkspaceView* view);
 
+    // Drop views into workspace
+    void setDropViewPreview(const gfx::Point& pos);
+    void removeDropViewPreview(const gfx::Point& pos);
+    void dropViewAt(const gfx::Point& pos, WorkspaceView* view);
+
     Signal0<void> ActiveViewChanged;
 
   protected:
     void onPaint(ui::PaintEvent& ev) override;
+    void onResize(ui::ResizeEvent& ev) override;
 
   private:
     Tabs* m_tabsBar;
     WorkspaceViews m_views;
     WorkspaceView* m_activeView;
+    bool m_dropPreview;
+    gfx::Point m_dropPos;
   };
 
 } // namespace app