C++builder中的内存DC

  TCanvas * c;  TRect r;  r = TRect(0, 0, 18, 18);  c = new  TCanvas;  c->Handle = CreateCompatibleDC(Canvas->Handle);//创建兼容的内存DC  SelectObject(c->Handle, CreateCompatibleBitmap(Canvas->Handle, 18, 18));//绑定到位图，并选中  c->Pen->Color = clGreen;//在TCanvas画图  c->Brush->Color = clRed;  c->FillRect(r);  this->Canvas->CopyRect(r, c, r);//将图形复制出来，到指定的目标画上去  delete c;