Wt

Hello Christian,

this is a VERY good catch. No theming is ever applied to the WPanel.

This could be the case for any widget that is set as the WCompositeWidget's implementation. I am however sure I have seen this work for certain other widgets, and am curious as to what the discrepancy is.

Hi Matthias

The Wt- Internal Composite Widgets (like WPanel) work as expected. Because they are a Special Type that is handled in the Theme.

It is different for User Generated Composites.

From what I could figure out, I wrote a Patch, but it really is not a longterm, global solution.

It just targets WBootstrap5Theme, making its apply() function a friend of WCompositeWidget, and in the apply() function, change the widget to the implementation() of the composite Widget.

Breaking SolutionBreaking Solution

class WTheme
{
public:
  class Bootstrap2;
  class Bootstrap3;
  class Bootstrap5;
  ... // rest of class
};

class WTheme::Bootstrap2 : public WTheme
{
  // Bootstrap2 Definition
};
//... others

I made a way better patch...

I added a function to WCompositeWidget to check if the impl_ widget can be cast to a Type:

template <typename T>
bool canCastTo() const {

  if (!impl_) {
    return false; // Cannot cast if no implementation widget exists
  }
      
  // Perform the dynamic_cast and check if it succeeds
  return dynamic_cast<T>(impl_.get()) != nullptr; 
}

There are concepts for the future, and also static_asserts to make sure the type fits. (left out here)

Within the ::apply() functions of the Bootstrap and Css Theme Classes, I added a check to see if it is a composite:

WCompositeWidget *composite = dynamic_cast<WCompositeWidget*>(widget);

auto panel = dynami_cast<WPanel*>(widget);

if(panel || (composite && composite->canCastTo<WPanel*>()))
{
... // Apply Style
}

Updated the ::apply() Function for WCSSTheme as well as Bootstrap 2, 3 & 5

Aparrently my last Patch had Windows Line Endings (CRLF), which failed my own patching...

converting to Linux Line Endings (LF) fixed that ...

Fixed Patch for 4.12.0

With the support for native Style classes, my proposed solution does not work for DateEdit and TimeEdit Implementations anymore