How does element picker work?

[AnClark]

Hi, Rui!

I'm porting DrumkV1 to DPF, DISTRHO Plugin Framework. And I encountered a problem:

In official LV2 version, when I pick an element from the element list (the listbox on the left of sample view), sample view and other controllers changes corresponding to the element's params.

But in my implementation, things are not what I wish. No matter how I touch the element list, UI won't change.

So I wonder how does the element list work. Does it relate to features of LV2?

My repo: https://github.com/anclark/drumkv1/tree/dpf-implementation

[rncbc]

it relies on lv2 instance-access, something I guess it's banned on the DPF , last time i've checked, eons ago

[AnClark]

Actually, in DPF, I can use instance-access with DPF_PLUGIN_WANTS_DIRECT_ACCESS activated:

https://github.com/AnClark/drumkv1/blob/5b92448ecd184641bc23eefacb8ca804251eb54b/src/DistrhoPluginInfo.h#L42

---

In your official LV2 implementation (drumkv1_lv2.cpp or drumkv1_lv2ui.cpp), I wonder where the plugin updates the element params.

[AnClark]

Seems that this line relates to that feature:

drumkv1/src/drumkv1_lv2.cpp

Line 823 in 86e159c

drumkv1::setCurrentElementEx(mesg->data.key);

In my implementation, I directly call it in drumkv1_dpf::selectSample(int) in drumkv1_dpf.cpp, like this:

void drumkv1_dpf::selectSample (int key)
{
	fprintf(stderr, ">> Trigger selectSample, key = %d\n", key);
	drumkv1::setCurrentElementEx(key);
}

However, it still does not work as what I wish.