Restore SEBPatch

SafeExamBrowser.UserInterface.Shared/Utilities/VisualExtensions.cs

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+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System.Windows;
+using System.Windows.Interop;
+using System.Windows.Media;
+
+namespace SafeExamBrowser.UserInterface.Shared.Utilities
+{
+	/// <summary>
+	/// WPF works with device-independent pixels. These methods are required to transform
+	/// such values to their absolute, device-specific pixel values and vice versa.
+	/// 
+	/// Source: https://stackoverflow.com/questions/3286175/how-do-i-convert-a-wpf-size-to-physical-pixels
+	/// </summary>
+	public static class VisualExtensions
+	{
+		public static Vector TransformToPhysical(this Visual visual, double x, double y)
+		{
+			var matrix = default(Matrix);
+			var source = PresentationSource.FromVisual(visual);
+
+			if (source != null)
+			{
+				matrix = source.CompositionTarget.TransformToDevice;
+			}
+			else
+			{
+				using (var newSource = new HwndSource(new HwndSourceParameters()))
+				{
+					matrix = newSource.CompositionTarget.TransformToDevice;
+				}
+			}
+
+			return matrix.Transform(new Vector(x, y));
+		}
+
+		public static Vector TransformFromPhysical(this Visual visual, double x, double y)
+		{
+			var matrix = default(Matrix);
+			var source = PresentationSource.FromVisual(visual);
+
+			if (source != null)
+			{
+				matrix = source.CompositionTarget.TransformFromDevice;
+			}
+			else
+			{
+				using (var newSource = new HwndSource(new HwndSourceParameters()))
+				{
+					matrix = newSource.CompositionTarget.TransformFromDevice;
+				}
+			}
+
+			return matrix.Transform(new Vector(x, y));
+		}
+	}
+}