[wxperl-users] ScrolledWindow drawing (was Re: wxPerl Standard Selection Dialogs )

[Mark D. <mar...@zn...>]

Mark Dootson wrote:

> 
> I shall test wrapping DoPrepareDC and post a diff a little later. If you are on MSWin, I will have incorporated changes in PPMs too.
> 

Or maybe not!

I have wrapped DoPrepareDC and that works fine. It still doesn't really solve the issue though:

Within wxWidgets itself, there is a hack used to make OnDraw work.
The base class for ScrolledWindow checks if any handler of a wxPaintEvent in a derived class actually did anything.

If it didn't, the base class still calls its own handler for the event.
That handler does the following.

wxPaintDC dc(m_win);
DoPrepareDC(dc);
OnDraw(dc);

note: the problem here is that the base class DoPrepareDC is called - NOT any DoPrepareDC in any derived class.

Gnash.

So, for now, to do what I suggested in the earlier post, you would do as follows. 
(You don't actually need a separate OnDraw sub anymore of course)

sub new {
    .......
    .......
    EVT_PAINT( $self, \&OnPaint );
    $self->set_user_scale(0.5,0.5);
    .......
    .......
}

sub OnPaint {
    my ($self, $event) = @_;
    $event->Skip(1);
    my $dc = Wx::PaintDC->new($self);
    $self->PrepareDC( $dc );
    $self->OnDraw($dc);
}

sub OnDraw {
    my($self, $dc) = @_;
    ...........
    ...........
}

sub PrepareDC {
    my ($self, $dc) = @_;
    $self->SUPER::PrepareDC( $dc );
    $dc->SetUserScale( $self->get_user_scale() );
}

sub get_user_scale {
    my ($self) = @_;
    return @{ $self->{_user_scale} };
}

sub set_user_scale {
    my ($self, $scalex, $scaley) = @_;
    $self->{_user_scale} = [ $scalex, $scaley ];
}

---------------------------------------------------

It would be nice to have wxPerl act like the C wxWidgets docs suggest so I'll not post a diff for DoPrepareDC. 
To make that work would mean installing a default wxPaintEvent handler for wxScrolledWindow in wxPerl.

Regards

Mark