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/*************************************************************************************
Extended WPF Toolkit
Copyright (C) 2007-2013 Xceed Software Inc.
This program is provided to you under the terms of the Microsoft Public
License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license
For more features, controls, and fast professional support,
pick up the Plus Edition at http://xceed.com/wpf_toolkit
Stay informed: follow @datagrid on Twitter or Like http://facebook.com/datagrids
***********************************************************************************/
using System;
using System.Windows;
using Xceed.Wpf.Toolkit.Core.Utilities;
namespace Xceed.Wpf.Toolkit.Panels
{
internal static class ScrollHelper
{
public static bool ScrollLeastAmount( Rect physViewRect, Rect itemRect, out Vector newPhysOffset )
{
bool scrollNeeded = false;
newPhysOffset = new Vector();
if( physViewRect.Contains( itemRect ) == false )
{
// Check if child is inside the view horizontially.
if( itemRect.Left > physViewRect.Left && itemRect.Right < physViewRect.Right ||
DoubleHelper.AreVirtuallyEqual( itemRect.Left, physViewRect.Left ) == true )
{
newPhysOffset.X = itemRect.Left;
}
// Child is to the left of the view or is it bigger than the view
else if( itemRect.Left < physViewRect.Left || itemRect.Width > physViewRect.Width )
{
newPhysOffset.X = itemRect.Left;
}
// Child is to the right of the view
else
{
newPhysOffset.X = Math.Max( 0, physViewRect.Left + ( itemRect.Right - physViewRect.Right ) );
}
// Check if child is inside the view vertically.
if( itemRect.Top > physViewRect.Top && itemRect.Bottom < physViewRect.Bottom ||
DoubleHelper.AreVirtuallyEqual( itemRect.Top, physViewRect.Top ) == true )
{
newPhysOffset.Y = itemRect.Top;
}
// Child is the above the view or is it bigger than the view
else if( itemRect.Top < physViewRect.Top || itemRect.Height > physViewRect.Height )
{
newPhysOffset.Y = itemRect.Top;
}
// Child is below the view
else
{
newPhysOffset.Y = Math.Max( 0, physViewRect.Top + ( itemRect.Bottom - physViewRect.Bottom ) );
}
scrollNeeded = true;
}
return scrollNeeded;
}
}
}
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