Another attempt at fixing Lerp.

Former-commit-id: 48f5e84d6b95756a125ec0ff3adce66530f8a277
Former-commit-id: cc600e84bb3e3a5ae3038811bc466f9b161e6ee8
Former-commit-id: ef0a7b1b98de88cb1ab51634aac379d0132039a2

src/ImageProcessor/Colors/Color.cs

@@ -350,7 +350,7 @@ namespace ImageProcessor
         {
             amount = amount.Clamp(0f, 1f);
 
-            if (Math.Abs(from.A - 1) < Epsilon || Math.Abs(from.A) < Epsilon)
+            if (Math.Abs(from.A - 1) < Epsilon && Math.Abs(to.A - 1) < Epsilon)
             {
                 return from + (to - from) * amount;
             }

src/ImageProcessor/Filters/ColorMatrix/Polaroid.cs

@@ -33,7 +33,13 @@ namespace ImageProcessor.Filters
         protected override void AfterApply(ImageBase source, ImageBase target, Rectangle targetRectangle, Rectangle sourceRectangle)
         {
             new Vignette { Color = new Color(102 / 255f, 34 / 255f, 0) }.Apply(target, target, targetRectangle);
-            new Glow { Color = new Color(1, 153 / 255f, 102 / 255f, .7f) }.Apply(target, target, targetRectangle);
+            new Glow
+            {
+                Color = new Color(1, 153 / 255f, 102 / 255f),
+                RadiusX = target.Width / 4f,
+                RadiusY = target.Width / 4f
+            }
+            .Apply(target, target, targetRectangle);
         }
     }
 }

src/ImageProcessor/Filters/Glow.cs

@@ -49,7 +49,7 @@ namespace ImageProcessor.Filters
                         {
                             float distance = Vector2.Distance(centre, new Vector2(x, y));
                             Color sourceColor = target[x, y];
-                            target[x, y] = Color.Lerp(sourceColor, glowColor, .334f * (1 - distance / maxDistance));
+                            target[x, y] = Color.Lerp(sourceColor, glowColor, .5f * (1 - distance / maxDistance));
                         }
                     });
         }

tests/ImageProcessor.Tests/Processors/Filters/FilterTests.cs

@@ -45,7 +45,7 @@ namespace ImageProcessor.Tests
             { "Hue-180", new Hue(180) },
             { "Hue--180", new Hue(-180) },
             { "BoxBlur", new BoxBlur(10) },
-            {"Vignette", new Vignette()}
+            { "Vignette", new Vignette()}
         };
 
         [Theory]

tests/ImageProcessor.Tests/Processors/ProcessorTestBase.cs

@@ -23,7 +23,7 @@ namespace ImageProcessor.Tests
             "TestImages/Formats/Jpg/Calliphora.jpg",
             //"TestImages/Formats/Jpg/gamma_dalai_lama_gray.jpg", //Perf: Enable for local testing only
             "TestImages/Formats/Bmp/Car.bmp",
-            //"TestImages/Formats/Png/blur.png", //Perf: Enable for local testing only
+            "TestImages/Formats/Png/blur.png", //Perf: Enable for local testing only
             "TestImages/Formats/Png/splash.png",
             "TestImages/Formats/Gif/rings.gif",
             //"TestImages/Formats/Gif/giphy.gif" //Perf: Enable for local testing only