Doug Baldwin wrote:
>
> On May 15, 2008, at 11:05 AM, Diego A. Fons wrote:
>
>> Like Theodore I'm using gtkmm. This is an extrac of the code which
>> doesn't work:
>> void Plotter::on_realize( void )
>> {
>> // Create the GDK window
>> refGdkWindow = Gdk::Window::create(get_window(), &attributes,
>> GDK_WA_X | GDK_WA_Y);
>>
>> // Create Cairo context
>> Cairo::RefPtr<Cairo::Context> cr =
>> refGdkWindow->create_cairo_context();
>> }
>>
>>
>> bool Plotter::on_expose_event( GdkEventExpose* event )
>> {
>> // ... Use cr to do some drawing
>> }
>>
>> Both cr and refGdkWindow are members of the class Plotter....
>
> Isn't variable cr local to Plotter::on_realize in the above? Even
> if you declare a similarly-named variable in the class, I'm pretty
> sure the declaration in the on_realize method will shadow the class
> member. You might get the result you want if you drop the declaration
> from the statement that saves the context in cr, i.e., change the
> second half of Plotter::on_realize to...
>
> // Create Cairo context
> cr = refGdkWindow->create_cairo_context();
>
My mistake!
That's what i meant:
void Plotter::on_realize( void )
{
// Create the GDK window
refGdkWindow = Gdk::Window::create(get_window(), &attributes,
GDK_WA_X | GDK_WA_Y);
// Create Cairo context
cr = refGdkWindow->create_cairo_context();
// cr is a private member of the class
}
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