Improve behaviour of scrolling through a ribbon gallery.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66051 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/ribbon/gallery.h

@@ -69,6 +69,7 @@ public:
     virtual bool Layout();
 
     virtual bool ScrollLines(int lines);
+    bool ScrollPixels(int pixels);
     void EnsureVisible(const wxRibbonGalleryItem* item);
 
 protected:
@@ -84,8 +85,10 @@ protected:
     void OnMouseLeave(wxMouseEvent& evt);
     void OnMouseDown(wxMouseEvent& evt);
     void OnMouseUp(wxMouseEvent& evt);
+    void OnMouseDClick(wxMouseEvent& evt);
     void OnPaint(wxPaintEvent& evt);
     void OnSize(wxSizeEvent& evt);
+    int GetScrollLineSize() const;
 
     virtual wxSize DoGetBestSize() const;
     virtual wxSize DoGetNextSmallerSize(wxOrientation direction,

interface/wx/ribbon/gallery.h

@@ -239,6 +239,18 @@ public:
             direction, @false if it did not scroll.
     */
     virtual bool ScrollLines(int lines);
+    
+    /**
+        Scroll the gallery contents by some fine-grained amount.
+
+        @param pixels
+          Positive values scroll toward the end of the gallery, while negative
+          values scroll toward the start.
+
+        @return @true if the gallery scrolled at least one pixel in the given
+            direction, @false if it did not scroll.
+    */
+    bool ScrollPixels(int pixels);
 
     /**
         Scroll the gallery to ensure that the given item is visible.

src/ribbon/gallery.cpp

@@ -76,6 +76,7 @@ BEGIN_EVENT_TABLE(wxRibbonGallery, wxRibbonControl)
     EVT_LEAVE_WINDOW(wxRibbonGallery::OnMouseLeave)
     EVT_LEFT_DOWN(wxRibbonGallery::OnMouseDown)
     EVT_LEFT_UP(wxRibbonGallery::OnMouseUp)
+    EVT_LEFT_DCLICK(wxRibbonGallery::OnMouseDClick)
     EVT_MOTION(wxRibbonGallery::OnMouseMove)
     EVT_PAINT(wxRibbonGallery::OnPaint)
     EVT_SIZE(wxRibbonGallery::OnSize)
@@ -372,6 +373,15 @@ void wxRibbonGallery::OnMouseUp(wxMouseEvent& evt)
     }
 }
 
+void wxRibbonGallery::OnMouseDClick(wxMouseEvent& evt)
+{
+    // The 2nd click of a double-click should be handled as a click in the
+    // same way as the 1st click of the double-click. This is useful for
+    // scrolling through the gallery.
+    OnMouseDown(evt);
+    OnMouseUp(evt);
+}
+
 void wxRibbonGallery::SetItemClientObject(wxRibbonGalleryItem* itm,
                                           wxClientData* data)
 {
@@ -398,14 +408,31 @@ bool wxRibbonGallery::ScrollLines(int lines)
     if(m_scroll_limit == 0 || m_art == NULL)
         return false;
 
+    return ScrollPixels(lines * GetScrollLineSize());
+}
+
+int wxRibbonGallery::GetScrollLineSize() const
+{
+    if(m_art == NULL)
+        return 32;
+
     int line_size = m_bitmap_padded_size.GetHeight();
     if(m_art->GetFlags() & wxRIBBON_BAR_FLOW_VERTICAL)
         line_size = m_bitmap_padded_size.GetWidth();
-    if(lines < 0)
+
+    return line_size;
+}
+
+bool wxRibbonGallery::ScrollPixels(int pixels)
+{
+    if(m_scroll_limit == 0 || m_art == NULL)
+        return false;
+
+    if(pixels < 0)
     {
         if(m_scroll_amount > 0)
         {
-            m_scroll_amount += lines * line_size;
+            m_scroll_amount += pixels;
             if(m_scroll_amount <= 0)
             {
                 m_scroll_amount = 0;
@@ -418,11 +445,11 @@ bool wxRibbonGallery::ScrollLines(int lines)
             return true;
         }
     }
-    else if(lines > 0)
+    else if(pixels > 0)
     {
         if(m_scroll_amount < m_scroll_limit)
         {
-            m_scroll_amount += lines * line_size;
+            m_scroll_amount += pixels;
             if(m_scroll_amount >= m_scroll_limit)
             {
                 m_scroll_amount = m_scroll_limit;