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utils/vgui_panel_zoo/ScrollBarDemo.cpp

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//=============================================================================//
+#include "DemoPage.h"
+
+#include <VGUI/IVGui.h>
+
+#include <vgui/IScheme.h>
+#include <vgui_controls/ScrollBar.h>
+#include <vgui_controls/Label.h>
+#include <stdio.h>
+
+using namespace vgui;
+
+//-----------------------------------------------------------------------------
+// A ScrollBar is an class for selecting a numerical value from a range.
+// E.g. in the case of a scrolling text window we use the scroll bar to select
+// what line/char of text display should start at in the text window.
+ 
+// Some terms:
+//   
+//	There are arrow buttons on either end of the scroll bar.
+//  These move the scroll bar 'slider' or 'nob' across the space between the arrows.
+//  The nob moves over a user specified 'range' of numbers.
+//
+//    ----------------------------------------------------
+//    |	/ |..............|         |................ | \ |			
+//    | \ |..............|   nob   |.................| / | 
+//    ----------------------------------------------------
+//
+// In this demo we create a vertical scroll bar that is not attached to anything.
+// We display the current value of the slider nob next to the scroll bar.
+//-----------------------------------------------------------------------------
+class ScrollBarDemo: public DemoPage
+{
+	public:
+		ScrollBarDemo(Panel *parent, const char *name);
+		~ScrollBarDemo();
+
+		void OnSliderMoved();
+		
+	private:
+		ScrollBar *m_pScrollbar;
+		Label *m_pScrollValue;
+
+		DECLARE_PANELMAP();
+};
+
+//-----------------------------------------------------------------------------
+// Purpose: Constructor
+//-----------------------------------------------------------------------------
+ScrollBarDemo::ScrollBarDemo(Panel *parent, const char *name) : DemoPage(parent, name)
+{
+	// A vertical slider
+	m_pScrollbar = new ScrollBar (this, "ASscrollbar", true);
+
+	// Set the position of the bar
+	m_pScrollbar->SetPos(100, 100);
+
+	// Set the size of the bar
+	m_pScrollbar->SetSize (20, 200);
+
+	// Set the size of the bar nob, which is actually proportionally
+	// related to how many lines of info fit into the window the
+	// scroll bar is attatched to vs how many total lines there are.
+	// With a size of 10, the scroll bar value will pass from 0 to 100.
+	m_pScrollbar->SetRangeWindow(10);
+
+	// Set the range of the bar, 
+	// We want our range displayed to go from 0 to 100.
+	// We must take size of the bar nob into account, and set the max to 110.
+	m_pScrollbar->SetRange(0, 110);
+
+	// Set how far the scroll bar slider moves 
+	// when a scroll bar arrow button is pressed
+	m_pScrollbar->SetButtonPressedScrollValue(5);
+
+	// Set the starting value of the bar nob.
+	// This will put the nob at the top of the vertical scroll bar.
+	m_pScrollbar->SetValue(0);
+
+	// Finally we create a little label to tell us what the current value
+	// of the scroll bar is. 
+	// We will update it every time the slider is moved.
+	m_pScrollValue = new Label (this, "ScrollBarValue", "0");
+
+	// Stick the label next to the scroll bar.
+	m_pScrollValue->SetPos(130, 100);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Destructor
+//-----------------------------------------------------------------------------
+ScrollBarDemo::~ScrollBarDemo()
+{
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Respond to movement of the scroll bar nob by updating the label's
+// text with the current value of the scrollbar.
+//-----------------------------------------------------------------------------
+void ScrollBarDemo::OnSliderMoved()
+{
+	char number[6];
+	sprintf (number, "%d", m_pScrollbar->GetValue());
+	m_pScrollValue->SetText(number);
+}
+
+//-----------------------------------------------------------------------------
+// Purpose: Message map
+//-----------------------------------------------------------------------------
+MessageMapItem_t ScrollBarDemo::m_MessageMap[] =
+{
+	MAP_MESSAGE( ScrollBarDemo, "ScrollBarSliderMoved", OnSliderMoved ),
+};
+IMPLEMENT_PANELMAP(ScrollBarDemo, Panel);
+
+
+Panel* ScrollBarDemo_Create(Panel *parent)
+{
+	return new ScrollBarDemo(parent, "ScrollBarDemo");
+}
+