#include <CtrlLib/CtrlLib.h>

using namespace Upp;

// arbitrary custom Ctrl
struct MyCtrl : public ParentCtrl{
	Label l;
	MyCtrl(){
		Add(l.HSizePos(10,10).VSizePos(5,5));
		l.SetFrame(InsetFrame());
	}
	virtual void SetData(const Value& data){
		l.SetText(AsString(data));
	}
};

struct App : public TopWindow {
	typedef App CLASSNAME;
	Array<MyCtrl> ctrls;
	ScrollBar sb;
	int height;
	App() {
		//initialize
		Title("Test").Sizeable();
		SetRect(0, 0, 120, 400);
		height = 40;
		
		//populate
		for(int i = 0; i < 12; i++){
			ctrls.Add() <<= "Widget #"+IntStr(i);
			Add(ctrls[i].HSizePos().TopPos(height*i, height));
		}
		
		//set up scrollbar
		sb.Vert().AutoHide().SetTotal(ctrls.GetCount() * height);
		sb.WhenScroll = THISBACK(Scroll);
		AddFrame(sb);
	}
	void Scroll() {
		//update position
		int pos = sb.Get();
		for(int i = 0; i < ctrls.GetCount(); i++){
			ctrls[i].TopPos(height*i - pos, height);
		}
	}

	virtual void Layout() {
		//window was resized, adjust scrollbar
		sb.SetPage(GetSize().cy);
	}

	virtual bool Key(dword key, int) {
		// pass key event to scrollbar
		return sb.VertKey(key);
	}
};

GUI_APP_MAIN{
	App().Run();
};