Redone (generic) wxComboCtrl background painting and handling. The 'actual' wxWindow background colour is now largely ignored and overridden to refer the text-area's background colour instead (as is usually the case with controls like this). Base 'transparent' background is now only painted when double-buffered rendering is required, and otherwise delegated to the system, as appropriate. This should significantly improve control's appearance and compliancy with GTK+ and OS X themes and custom backgrounds.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67255 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/combo.h

@@ -445,6 +445,9 @@ public:
     // Return true if Create has finished
     bool IsCreated() const { return m_iFlags & wxCC_IFLAG_CREATED ? true : false; }
 
+    // Need to override to return text area background colour
+    wxColour GetBackgroundColour() const;
+
     // common code to be called on popup hide/dismiss
     void OnPopupDismiss(bool generateEvent);
 
@@ -671,6 +674,9 @@ protected:
     wxRect                  m_tcArea;
     wxRect                  m_btnArea;
 
+    // Colour of the the text area, in case m_text is NULL
+    wxColour                m_tcBgCol;
+
     // current button state (uses renderer flags)
     int                     m_btnState;
 

include/wx/generic/combo.h

@@ -31,6 +31,8 @@
 
 #endif
 
+#include "wx/dcbuffer.h"
+
 extern WXDLLIMPEXP_DATA_CORE(const char) wxComboBoxNameStr[];
 
 class WXDLLIMPEXP_CORE wxGenericComboCtrl : public wxComboCtrlBase
@@ -96,6 +98,21 @@ protected:
     virtual WXHWND GetEditHWND() const { return NULL; }
 #endif
 
+    // For better transparent background rendering
+    virtual bool HasTransparentBackground()
+    {
+        #if wxALWAYS_NATIVE_DOUBLE_BUFFER
+          #ifdef __WXGTK__
+            // Sanity check for GTK+
+            return IsDoubleBuffered();
+          #else
+            return true;
+          #endif
+        #else
+            return false;
+        #endif
+    }
+
     // Mandatory virtuals
     virtual void OnResize();
 

src/common/combocmn.cpp

@@ -1071,10 +1071,10 @@ wxComboCtrlBase::CreateTextCtrl(int style)
 
 void wxComboCtrlBase::OnThemeChange()
 {
-    // Leave the default bg on the Mac so the area used by the focus ring will
+    // Because wxComboCtrl has transparent parts on most platforms, we
-    // be the correct colour and themed brush.  Instead we'll use
+    // don't want to touch the actual background colour. Instead, we just
-    // wxSYS_COLOUR_WINDOW in the EVT_PAINT handler as needed.
+    // usually re-obtain m_tcBgCol here.
-#ifndef __WXMAC__
+
 #if defined(__WXMSW__) || defined(__WXGTK__)
     wxVisualAttributes vattrs = wxComboBox::GetClassDefaultAttributes();
 #else
@@ -1083,17 +1083,19 @@ void wxComboCtrlBase::OnThemeChange()
     vattrs.colBg = wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW);
 #endif
 
+    if ( !m_hasBgCol )
+        m_tcBgCol = vattrs.colBg;
+
+#ifndef __WXMAC__
     // Only change the colours if application has not specified
     // custom ones.
     if ( !m_hasFgCol )
     {
         SetOwnForegroundColour(vattrs.colFg);
-        m_hasFgCol = false;
     }
-    if ( !m_hasBgCol )
+    if ( !HasTransparentBackground() )
     {
-        SetOwnBackgroundColour(vattrs.colBg);
+        SetOwnBackgroundColour(GetParent()->GetBackgroundColour());
-        m_hasBgCol = false;
     }
 #endif // !__WXMAC__
 }
@@ -1477,15 +1479,21 @@ bool wxComboCtrlBase::SetForegroundColour(const wxColour& colour)
 }
 
 bool wxComboCtrlBase::SetBackgroundColour(const wxColour& colour)
-{
-    if ( wxControl::SetBackgroundColour(colour) )
 {
     if ( m_text )
         m_text->SetBackgroundColour(colour);
+    m_tcBgCol = colour;
+    m_hasBgCol = true;
     return true;
 }
-    return false;
+
+wxColour wxComboCtrlBase::GetBackgroundColour() const
+{
+    if ( m_text )
+        return m_text->GetBackgroundColour();
+    return m_tcBgCol;
 }
+
 // ----------------------------------------------------------------------------
 // painting
 // ----------------------------------------------------------------------------
@@ -1644,7 +1652,9 @@ void wxComboCtrlBase::DrawButton( wxDC& dc, const wxRect& rect, int flags )
             return;
 
         // Need to clear button background even if m_btn is present
-        if ( flags & Button_PaintBackground )
+        if ( (flags & Button_PaintBackground) &&
+                (!HasTransparentBackground() ||
+                 !(m_iFlags & wxCC_IFLAG_BUTTON_OUTSIDE)) )
         {
             wxColour bgCol;
 

src/generic/combog.cpp

@@ -201,8 +201,10 @@ bool wxGenericComboCtrl::Create(wxWindow *parent,
     // Add keyboard input handlers for main control and textctrl
     InstallInputHandlers();
 
-    // Set background
+    // Set background style for double-buffering, when needed
-    SetBackgroundStyle( wxBG_STYLE_CUSTOM ); // for double-buffering
+    // (cannot use when system draws background automatically)
+    if ( !HasTransparentBackground() )
+        SetBackgroundStyle( wxBG_STYLE_PAINT );
 
     // SetInitialSize should be called last
     SetInitialSize(size);
@@ -238,11 +240,19 @@ void wxGenericComboCtrl::OnResize()
 
 void wxGenericComboCtrl::OnPaintEvent( wxPaintEvent& WXUNUSED(event) )
 {
-    wxSize sz = GetClientSize();
+    // Determine wxDC to use based on need to double-buffer or
-    wxAutoBufferedPaintDC dc(this);
+    // use system-generated transparent background portions
+    wxDC* dcPtr;
+    if ( HasTransparentBackground() )
+        dcPtr = new wxPaintDC(this);
+    else
+        dcPtr = new wxAutoBufferedPaintDC(this);
+    wxDC& dc = *dcPtr;
 
-    const wxRect& rectb = m_btnArea;
+    wxSize sz = GetClientSize();
-    wxRect rect = m_tcArea;
+    const wxRect& butRect = m_btnArea;
+    wxRect tcRect = m_tcArea;
+    wxRect fullRect(0, 0, sz.x, sz.y);
 
     // artificial simple border
     if ( m_widthCustomBorder )
@@ -256,10 +266,10 @@ void wxGenericComboCtrl::OnPaintEvent( wxPaintEvent& WXUNUSED(event) )
         dc.SetPen( pen1 );
 
         // area around both controls
-        wxRect rect2(0,0,sz.x,sz.y);
+        wxRect rect2(fullRect);
         if ( m_iFlags & wxCC_IFLAG_BUTTON_OUTSIDE )
         {
-            rect2 = m_tcArea;
+            rect2 = tcRect;
             if ( customBorder == 1 )
             {
                 rect2.Inflate(1);
@@ -282,44 +292,49 @@ void wxGenericComboCtrl::OnPaintEvent( wxPaintEvent& WXUNUSED(event) )
         dc.DrawRectangle(rect2);
     }
 
-#ifndef __WXMAC__  // see note in OnThemeChange
+    // Clear the main background if the system doesn't do it by itself
-    wxColour winCol = GetBackgroundColour();
+    if ( !HasTransparentBackground() &&
-#else
+         (tcRect.x > 0 || tcRect.y > 0) )
-    wxColour winCol = wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW);
+    {
-#endif
+        wxColour winCol = GetParent()->GetBackgroundColour();
         dc.SetBrush(winCol);
         dc.SetPen(winCol);
 
-    //wxLogDebug(wxT("hei: %i tcy: %i tchei: %i"),GetClientSize().y,m_tcArea.y,m_tcArea.height);
+        dc.DrawRectangle(fullRect);
-    //wxLogDebug(wxT("btnx: %i tcx: %i tcwid: %i"),m_btnArea.x,m_tcArea.x,m_tcArea.width);
+    }
-
-    // clear main background
-    dc.DrawRectangle(rect);
 
     if ( !m_btn )
     {
         // Standard button rendering
-        DrawButton(dc,rectb);
+        DrawButton(dc, butRect);
     }
 
     // paint required portion on the control
-    if ( (!m_text || m_widthCustomPaint) )
+    if ( !m_text || m_widthCustomPaint )
     {
         wxASSERT( m_widthCustomPaint >= 0 );
 
+        // Clear the text-control area background
+        wxColour tcCol = GetBackgroundColour();
+        dc.SetBrush(tcCol);
+        dc.SetPen(tcCol);
+        dc.DrawRectangle(tcRect);
+
         // this is intentionally here to allow drawed rectangle's
         // right edge to be hidden
         if ( m_text )
-            rect.width = m_widthCustomPaint;
+            tcRect.width = m_widthCustomPaint;
 
         dc.SetFont( GetFont() );
 
-        dc.SetClippingRegion(rect);
+        dc.SetClippingRegion(tcRect);
         if ( m_popupInterface )
-            m_popupInterface->PaintComboControl(dc,rect);
+            m_popupInterface->PaintComboControl(dc, tcRect);
         else
-            wxComboPopup::DefaultPaintComboControl(this,dc,rect);
+            wxComboPopup::DefaultPaintComboControl(this, dc, tcRect);
     }
+
+    delete dcPtr;
 }
 
 void wxGenericComboCtrl::OnMouseEvent( wxMouseEvent& event )