Custom control always paints background in Linux only

[Tony0945]

My custom control paints a grey background on wxGTK 2.9.3 but has no background (correct) on wxMSW 2.9.3. It worked the same on both platforms in 2.8.4, but the application is now using other features that are not available in 2.8. Code for a test app demonstrating the problem is attached as test.zip as are screen shots in Windows (XP) and Linux (Gentoo running Gnome2) both on a desktop PC. Here is the custom control rendering code:

Code: Select all

#include <wx/event.h>
#include <wx/process.h>
#include "MyControl.h"
#include "TestApp.h"
#include <wx/dnd.h>
#include <wx/sizer.h>

#include <wx/app.h>

DECLARE_APP(TestFrmApp);

                        
BEGIN_EVENT_TABLE(MyControl,wxPanel)
    EVT_LEFT_DOWN(MyControl::LeftDown)
    EVT_LEFT_UP(MyControl::LeftUp)
    EVT_MOTION(MyControl::Moving)
    EVT_MOUSE_CAPTURE_LOST(MyControl::MouseCaptureLost)
 
// catch paint events
    EVT_PAINT(MyControl::paintEvent)
 
END_EVENT_TABLE()

MyControl::MyControl(wxWindow * parent,wxBitmap *map, wxString &Label, wxPoint pos,const wxSize& size) : wxPanel(parent,wxID_ANY,pos,size)
{
    mymap = *map;  // make a local copy

    SetForegroundColour(*wxWHITE);

    SetSize(mymap.GetWidth()+50,mymap.GetHeight()+50);

    paintNow();
       
	Move(pos);

//    SetOwnBackgroundColour(*wxLIGHT_GREY);
    
    dragging = false;
    LabelText = Label;
}

MyControl::~MyControl()
{
}

void MyControl::paintEvent(wxPaintEvent & evt)
{   
    wxPaintDC dc(this);
    render(dc);
}

void MyControl::paintNow()
{    
    wxClientDC dc(this);
    render(dc);
}

void MyControl::render(wxDC& dc)
{
    dc.DrawBitmap( mymap, 0, 0, true );
    dc.DrawText(LabelText,0,mymap.GetHeight());
}


void MyControl::LeftDown(wxMouseEvent& event)
{ 
    CaptureMouse();
    dragging = true;
    Xpos = event.GetX();
    Ypos = event.GetY();
}

void MyControl::Moving(wxMouseEvent& event)
{
    if (dragging)
    {
        wxPoint mouseOnScreen = wxGetMousePosition();
        int newx = mouseOnScreen.x - Xpos;
        int newy = mouseOnScreen.y - Ypos;
        this->Move( this->GetParent()->ScreenToClient( wxPoint(newx, newy) ));
    } 
}

void MyControl::LeftUp(wxMouseEvent& event)
{
    // TODO Need code to prevent moving on top of another MyControl
    ReleaseMouse();
    dragging=false;
    Hide();
    Show();
}

void MyControl::MouseCaptureLost(wxMouseCaptureLostEvent& event)
{
    // don't call event.skip
    wxMessageBox("Lost Mouse");
}

[doublemax]

Try adding this to the ctor of the control:

Code: Select all

SetBackgroundStyle( wxBG_STYLE_PAINT );

[Tony0945]

Unfortunately, that rips a hole through not only the Custom Control but through the underlaying Frame into the application beneath. I want the frame's background to show, but not the Panel's. i.e. the panel should be transparent. I tried calling SetBackgroundColour(wx*TRANSPARENT) but that had no effect on wxGTK.

[doublemax]

As i don't work under Linux, i can't help any further. If you don't find a solution, try asking on the mailing list.