scroll when cursor is outside of viewport during selection

2 files changed, 38 insertions, 6 deletions

diff --git a/dw/fltkviewport.cc b/dw/fltkviewport.cc
index 19e28854..2dcc199b 100644
--- a/dw/fltkviewport.cc
+++ b/dw/fltkviewport.cc
@@ -275,7 +275,9 @@ int FltkViewport::handle (int event)
       break;
 
    case FL_DRAG:
-      if (dragScrolling && Fl::event_button() == FL_MIDDLE_MOUSE) {
+      if (Fl::event_inside(this))
+         Fl::remove_timeout(selectionScroll);
+      if (dragScrolling) {
          scroll(dragX - Fl::event_x(), dragY - Fl::event_y());
          dragX = Fl::event_x();
          dragY = Fl::event_y();
@@ -286,6 +288,11 @@ int FltkViewport::handle (int event)
       } else if (horScrolling) {
          hscrollbar->handle(event);
          return 1;
+      } else if (!Fl::event_inside(this)) {
+         mouse_x = Fl::event_x();
+         mouse_y = Fl::event_y();
+         if (!Fl::has_timeout(selectionScroll, this))
+            Fl::add_timeout(0.025, selectionScroll, this);
       }
       break;
 
@@ -294,6 +301,7 @@ int FltkViewport::handle (int event)
       break;
 
    case FL_RELEASE:
+      Fl::remove_timeout(selectionScroll);
       if (Fl::event_button() == FL_MIDDLE_MOUSE) {
          setCursor (core::style::CURSOR_DEFAULT);
       } else if (verScrolling) {
@@ -310,10 +318,6 @@ int FltkViewport::handle (int event)
       mouse_y = Fl::event_y();
       positionChanged();
       break;
-
-   case FL_LEAVE:
-      mouse_x = mouse_y = -1;
-      break;
    }
 
    return FltkWidgetView::handle (event);
@@ -332,7 +336,8 @@ void FltkViewport::setCanvasSize (int width, int ascent, int descent)
  */
 void FltkViewport::positionChanged ()
 {
-   if (mouse_x != -1 && dragScrolling == false)
+   if (!dragScrolling && mouse_x >= x() && mouse_x < x()+w() && mouse_y >= y()
+       && mouse_y < y()+h())
       (void)theLayout->motionNotify (this,
                                      translateViewXToCanvasX (mouse_x),
                                      translateViewYToCanvasY (mouse_y),
@@ -425,6 +430,30 @@ void FltkViewport::scroll (core::ScrollCommand cmd)
    }
 }
 
+/*
+ * Scrolling in response to selection where the cursor is outside the view.
+ */
+void FltkViewport::selectionScroll ()
+{
+   int dx = 0, dy = 0;
+
+   if (mouse_x < x())
+      dx = -hscrollbar->linesize ();
+   else if (mouse_x >= x() + w())
+      dx = hscrollbar->linesize ();
+   if (mouse_y < y())
+      dy = -vscrollbar->linesize ();
+   else if (mouse_y >= y() + h())
+      dy = vscrollbar->linesize ();
+   scroll (dx, dy);
+}
+
+void FltkViewport::selectionScroll (void *data)
+{
+   ((FltkViewport *)data)->selectionScroll ();
+   Fl::repeat_timeout(0.025, selectionScroll, data);
+}
+
 void FltkViewport::setViewportSize (int width, int height,
                                     int hScrollbarThickness,
                                     int vScrollbarThickness)
diff --git a/dw/fltkviewport.hh b/dw/fltkviewport.hh
index 3df1dccb..1569a7d8 100644
--- a/dw/fltkviewport.hh
+++ b/dw/fltkviewport.hh
@@ -39,6 +39,9 @@ private:
    static void hscrollbarCallback (Fl_Widget *hscrollbar, void *viewportPtr);
    static void vscrollbarCallback (Fl_Widget *vscrollbar, void *viewportPtr);
 
+   void selectionScroll();
+   static void selectionScroll(void *vport);
+
    void updateCanvasWidgets (int oldScrollX, int oldScrollY);
    static void draw_area (void *data, int x, int y, int w, int h);