Add explicit double type marker on values.

Flip the sign on distance to match the correct behavior.

src/Avalonia.Visuals/Animation/CrossFade.cs

@@ -38,11 +38,11 @@ namespace Avalonia.Animation
                     new Setter
                     {
                         Property = Visual.OpacityProperty,
-                        Value = 0.0
+                        Value = 0d
                     }
                 )
                 {
-                    Cue = new Cue(1.0)
+                    Cue = new Cue(1d)
                 }
             };
             _fadeInAnimation = new Animation
@@ -52,11 +52,11 @@ namespace Avalonia.Animation
                     new Setter
                     {
                         Property = Visual.OpacityProperty,
-                        Value = 0.0
+                        Value = 0d
                     }
                 )
                 {
-                    Cue = new Cue(0.0)
+                    Cue = new Cue(0d)
                 }
             };
             _fadeOutAnimation.Duration = _fadeInAnimation.Duration = duration;

src/Avalonia.Visuals/Animation/PageSlide.cs

@@ -86,22 +86,22 @@ namespace Avalonia.Animation
                         new Setter
                         {
                             Property = translateProperty,
-                            Value = 0.0
+                            Value = 0d
                         }
                     )
                     {
-                        Cue = new Cue(0.0)
+                        Cue = new Cue(0d)
                     },
                     new KeyFrame
                     (
                         new Setter
                         {
                             Property = translateProperty,
-                            Value = forward ? -distance : distance
+                            Value = forward ? distance : -distance
                         }
                     )
                     {
-                        Cue = new Cue(1.0)
+                        Cue = new Cue(1d)
                     }
                 };
                 animation.Duration = Duration;
@@ -123,18 +123,18 @@ namespace Avalonia.Animation
                         }
                     )
                     {
-                        Cue = new Cue(0.0)
+                        Cue = new Cue(0d)
                     },
                     new KeyFrame
                     (
                         new Setter
                         {
                             Property = translateProperty,
-                            Value = 0.0
+                            Value = 0d
                         }
                     )
                     {
-                        Cue = new Cue(1.0)
+                        Cue = new Cue(1d)
                     },
                 };
                 animation.Duration = Duration;