Switching to a new converter to avoid memory leaks (#1683)

Added unit tests for the converter.
Enabled InternalsVisibleTo to support testing internal converters.

Author: Keboo

MaterialDesignThemes.Wpf.Tests/Converters/FloatingHintTransformConverterTests.cs

@@ -0,0 +1,48 @@
+using System.Collections.Generic;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Media;
+using MaterialDesignThemes.Wpf.Converters;
+using Xunit;
+
+namespace MaterialDesignThemes.Wpf.Tests.Converters
+{
+    public class FloatingHintTransformConverterTests
+    {
+        public static IEnumerable<object[]> InvalidParameters =>
+            new[] 
+            {
+                new object[] {null, null},
+                new object[] {1.0, null},
+                new object[] {null, new Point()},
+                new object[] {DependencyProperty.UnsetValue, new Point()},
+                new object[] {1.0, DependencyProperty.UnsetValue},
+            };
+
+        [StaTheory]
+        [MemberData(nameof(InvalidParameters))]
+        public void WhenParametersAreNotSetItReturnsIdentity(object scale, object offset)
+        {
+            var converter = new FloatingHintTransformConverter();
+
+            var result = converter.Convert(new[] { scale, offset }, typeof(Transform), null, CultureInfo.CurrentUICulture);
+
+            Assert.Equal(Transform.Identity, result);
+        }
+
+        [StaTheory]
+        [InlineData(2.0, 3.0, 4.0)]
+        [InlineData(1.5, 2.0, 3.0)]
+        public void WhenParametersAreSpecifiedItReturnsScaleTransform(double scale, double x, double y)
+        {
+            var converter = new FloatingHintTransformConverter();
+
+            var result = (TranslateTransform)converter.Convert(new object[] { scale, new Point(x, y) }, typeof(Transform), null, CultureInfo.CurrentUICulture);
+
+            Assert.Equal(scale * x, result.X);
+            Assert.Equal(scale * y, result.Y);
+        }
+    }
+
+    
+}

MaterialDesignThemes.Wpf/Converters/FloatingHintTransformConverter.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+using System.Windows.Media;
+
+namespace MaterialDesignThemes.Wpf.Converters
+{
+    internal class FloatingHintTransformConverter : IMultiValueConverter
+    {
+        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (values?.Length == 2 &&
+                values[0] is double scale &&
+                values[1] is Point floatingOffset)
+            {
+                return new TranslateTransform 
+                {
+                    X = scale * floatingOffset.X,
+                    Y = scale * floatingOffset.Y
+                };
+            }
+            return Transform.Identity;
+        }
+
+        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

MaterialDesignThemes.Wpf/Properties/AssemblyInfo.cs

@@ -1,4 +1,4 @@
-using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Windows;
 using System.Windows.Markup;
@@ -22,11 +22,13 @@
 //[assembly: NeutralResourcesLanguage("en-US", UltimateResourceFallbackLocation.Satellite)]
 
 
-[assembly:ThemeInfo(
+[assembly: ThemeInfo(
     ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
-                             //(used if a resource is not found in the page, 
-                             // or application resource dictionaries)
+                                     //(used if a resource is not found in the page, 
+                                     // or application resource dictionaries)
     ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
-                                      //(used if a resource is not found in the page, 
-                                      // app, or any theme specific resource dictionaries)
+                                              //(used if a resource is not found in the page, 
+                                              // app, or any theme specific resource dictionaries)
 )]
+
+[assembly: InternalsVisibleTo("MaterialDesignThemes.Wpf.Tests")]

MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.SmartHint.xaml

@@ -7,7 +7,7 @@
     <converters:BooleanToVisibilityConverter x:Key="BoolToVisConverter"/>
     <converters:BooleanToVisibilityConverter x:Key="InverseBoolToVisConverter" TrueValue="Collapsed" FalseValue="Visible"/>
     <converters:RangePositionConverter x:Key="RangePositionConverter"/>
-    <converters:MathMultipleConverter x:Key="TranslateConverter" Operation="Multiply"/>
+    <converters:FloatingHintTransformConverter x:Key="FloatingHintTransformConverter" />
     <system:Double x:Key="NoContentFloatingScale">1.0</system:Double>
     <SineEase x:Key="AnimationEasingFunction" EasingMode="EaseOut"/>
 
@@ -126,7 +126,7 @@
                                         VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
                                         Opacity="{TemplateBinding HintOpacity}"
                                         IsHitTestVisible="False"
-                                        IsTabStop="False"                                        
+                                        IsTabStop="False"
                                         RenderTransformOrigin="0,1">
                                     <ContentControl.Tag>
                                         <system:Double>0.0</system:Double>
@@ -152,22 +152,10 @@
                                         </TransformGroup>
                                     </ContentControl.LayoutTransform>
                                     <ContentControl.RenderTransform>
-                                        <TransformGroup>
-                                            <TranslateTransform>
-                                                <TranslateTransform.X>
-                                                    <MultiBinding Converter="{StaticResource TranslateConverter}">
-                                                        <Binding Path="Scale" ElementName="ScaleHost"/>
-                                                        <Binding Path="FloatingOffset.X" RelativeSource="{RelativeSource TemplatedParent}"/>
-                                                    </MultiBinding>
-                                                </TranslateTransform.X>
-                                                <TranslateTransform.Y>
-                                                    <MultiBinding Converter="{StaticResource TranslateConverter}">
-                                                        <Binding Path="Scale" ElementName="ScaleHost"/>
-                                                        <Binding Path="FloatingOffset.Y" RelativeSource="{RelativeSource TemplatedParent}"/>
-                                                    </MultiBinding>
-                                                </TranslateTransform.Y>
-                                            </TranslateTransform>
-                                        </TransformGroup>
+                                        <MultiBinding Converter="{StaticResource FloatingHintTransformConverter}">
+                                            <Binding Path="Scale" ElementName="ScaleHost"/>
+                                            <Binding Path="FloatingOffset" RelativeSource="{RelativeSource TemplatedParent}"/>
+                                        </MultiBinding>
                                     </ContentControl.RenderTransform>
                                 </ContentControl>
                             </Grid>
@@ -177,5 +165,5 @@
             </Trigger>
         </Style.Triggers>
     </Style>
-    
+
 </ResourceDictionary>