BackedPanel.cpp

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//
//  BackedPanel.cpp
//  Audacity
//
//  Created by Paul Licameli on 5/7/16.
//
//
 
 
#include "BackedPanel.h"
 
BackedPanel::BackedPanel(wxWindow * parent, wxWindowID id,
            const wxPoint & pos,
            const wxSize & size,
            long style)
: wxPanelWrapper(parent, id, pos, size, style)
, mBacking{ std::make_unique<wxBitmap>(1, 1, 24) }
{
   // Preinit the backing DC and bitmap so routines that require it will
   // not cause a crash if they run before the panel is fully initialized.
   mBackingDC.SelectObject(*mBacking);
}
 
BackedPanel::~BackedPanel()
{
   if (mBacking)
      mBackingDC.SelectObject( wxNullBitmap );
}
 
wxDC &BackedPanel::GetBackingDC()
{
   return mBackingDC;
}
 
wxDC &BackedPanel::GetBackingDCForRepaint()
{
   if (mResizeBacking)
   {
      // Reset
      mResizeBacking = false;
 
      ResizeBacking();
   }
 
   return mBackingDC;
}
 
void BackedPanel::ResizeBacking()
{
   if (mBacking)
      mBackingDC.SelectObject(wxNullBitmap);
 
   wxSize sz = GetClientSize();
   mBacking = std::make_unique<wxBitmap>();
   // Bug 2040 - Avoid 0 x 0 bitmap when minimized.
   mBacking->Create(std::max(sz.x,1), std::max(sz.y,1),24); //, *dc);
   mBackingDC.SelectObject(*mBacking);
}
 
void BackedPanel::RepairBitmap(wxDC &dc, wxCoord x, wxCoord y, wxCoord width, wxCoord height)
{
   dc.Blit(x, y, width, height, &mBackingDC, x, y);
}
 
void BackedPanel::DisplayBitmap(wxDC &dc)
{
   if( mBacking ) 
      RepairBitmap(dc, 0, 0, mBacking->GetWidth(), mBacking->GetHeight());
}
 
void BackedPanel::OnSize(wxSizeEvent & event)
{
   // Tell OnPaint() to recreate the backing bitmap
   mResizeBacking = true;
   event.Skip();
   // Refresh the entire area.  Really only need to refresh when
   // expanding...is it worth the trouble?
   Refresh();
}
 
BEGIN_EVENT_TABLE(BackedPanel, wxPanelWrapper)
   EVT_SIZE(BackedPanel::OnSize)
END_EVENT_TABLE()