Add tests, corners not working properly for some reason

Terminal.Gui/TextEffects/New/GradientFill.cs

@@ -17,15 +17,19 @@ public class GradientFill : IFill
 
     public GradientFill (Rectangle area, Gradient gradient, Gradient.Direction direction)
     {
-        _map = 
+        _map =
             gradient.BuildCoordinateColorMapping (area.Height, area.Width, direction)
-            .ToDictionary(
-                (k)=> new Point(k.Key.Column,k.Key.Row),
-                (v)=> new Terminal.Gui.Color (v.Value.R, v.Value.G, v.Value.B));
+            .ToDictionary (
+                (k) => new Point (k.Key.Column, k.Key.Row),
+                (v) => new Terminal.Gui.Color (v.Value.R, v.Value.G, v.Value.B));
     }
 
     public Terminal.Gui.Color GetColor (Point point)
     {
-        return _map [point];
+        if (_map.TryGetValue (point, out var color))
+        {
+            return color;
+        }
+        return new Terminal.Gui.Color (0, 0, 0); // Default to black if point not found
     }
-}
+}

UICatalog/Scenarios/TextEffectsScenario.cs

@@ -24,6 +24,7 @@ public class TextEffectsScenario : Scenario
         {
             Width = Dim.Fill(),
             Height = Dim.Fill (),
+            Title = "Text Effects Scenario"
         };
 
         w.Loaded += (s, e) =>
@@ -34,7 +35,11 @@ public class TextEffectsScenario : Scenario
         };
         w.SizeChanging += (s,e)=>
         {
-            SetupGradientLineCanvas (w, e.Size);
+            if(e.Size.HasValue)
+            {
+                SetupGradientLineCanvas (w, e.Size.Value);
+            }
+            
             // TODO: Does not work
             //SetupGradientLineCanvas (tabView, tabView.Frame.Size);
         };
@@ -87,14 +92,14 @@ public class TextEffectsScenario : Scenario
     }
 
 
-    private void SetupGradientLineCanvas (View w, Size? size)
+    private void SetupGradientLineCanvas (View w, Size size)
     {
-        GetAppealingGradientColors (out var stops, out var steps);
+        GetAppealingGradientColors (size, out var stops, out var steps);
 
         var g = new Gradient (stops, steps);
 
         var fore = new GradientFill (
-            new Rectangle (0, 0, size.Value.Width, size.Value.Height), g, Gradient.Direction.Diagonal);
+            new Rectangle (0, 0, size.Width, size.Height), g, Gradient.Direction.Diagonal);
         var back = new SolidFill (new Terminal.Gui.Color (ColorName.Black));
 
         w.LineCanvas.Fill = new FillPair (
@@ -102,7 +107,7 @@ public class TextEffectsScenario : Scenario
             back);
     }
 
-    private void GetAppealingGradientColors (out List<Color> stops, out List<int> steps)
+    private void GetAppealingGradientColors (Size size, out List<Color> stops, out List<int> steps)
     {
         // Define the colors of the gradient stops with more appealing colors
         stops = new List<Color>
@@ -114,8 +119,11 @@ public class TextEffectsScenario : Scenario
             Color.FromRgb(255, 0, 128)     // Bright Pink
         };
 
-        // Define the number of steps between each color for smoother transitions
-        steps = new List<int> { 15, 15, 15, 15 }; // 15 steps between each color
+            // Calculate the number of steps based on the size
+            int maxSteps = Math.Max (size.Width, size.Height);
+
+            // Define the number of steps between each color for smoother transitions
+            steps = new List<int> { maxSteps / 4, maxSteps / 4, maxSteps / 4, maxSteps / 4 };
     }
 }
 

UnitTests/TextEffects/New/GradientFillTests.cs

@@ -0,0 +1,111 @@
+namespace Terminal.Gui.TextEffects.Tests;
+
+public class GradientFillTests
+{
+    private Gradient _gradient;
+
+    public GradientFillTests ()
+    {
+        // Define the colors of the gradient stops
+        var stops = new List<Color>
+        {
+            Color.FromRgb(255, 0, 0),    // Red
+            Color.FromRgb(0, 0, 255)     // Blue
+        };
+
+        // Define the number of steps between each color
+        var steps = new List<int> { 10 }; // 10 steps between Red -> Blue
+
+        _gradient = new Gradient (stops, steps, loop: false);
+    }
+
+    [Fact]
+    public void TestGradientFillCorners ()
+    {
+        var area = new Rectangle (0, 0, 10, 10);
+        var gradientFill = new GradientFill (area, _gradient, Gradient.Direction.Diagonal);
+
+        // Test the corners
+        var topLeft = new Point (0, 0);
+        var topRight = new Point (area.Width - 1, 0);
+        var bottomLeft = new Point (0, area.Height - 1);
+        var bottomRight = new Point (area.Width - 1, area.Height - 1);
+
+        var topLeftColor = gradientFill.GetColor (topLeft);
+        var topRightColor = gradientFill.GetColor (topRight);
+        var bottomLeftColor = gradientFill.GetColor (bottomLeft);
+        var bottomRightColor = gradientFill.GetColor (bottomRight);
+
+        // Validate the colors at the corners
+        Assert.NotNull (topLeftColor);
+        Assert.NotNull (topRightColor);
+        Assert.NotNull (bottomLeftColor);
+        Assert.NotNull (bottomRightColor);
+
+        // Expected colors
+        var expectedTopLeftColor = new Terminal.Gui.Color (255, 0, 0); // Red
+        var expectedBottomRightColor = new Terminal.Gui.Color (0, 0, 255); // Blue
+
+        Assert.Equal (expectedTopLeftColor, topLeftColor);
+        Assert.Equal (expectedBottomRightColor, bottomRightColor);
+
+        // Additional checks can be added to verify the exact expected colors if known
+        Console.WriteLine ($"Top-left: {topLeftColor}");
+        Console.WriteLine ($"Top-right: {topRightColor}");
+        Console.WriteLine ($"Bottom-left: {bottomLeftColor}");
+        Console.WriteLine ($"Bottom-right: {bottomRightColor}");
+    }
+
+    [Fact]
+    public void TestGradientFillColorTransition ()
+    {
+        var area = new Rectangle (0, 0, 10, 10);
+        var gradientFill = new GradientFill (area, _gradient, Gradient.Direction.Diagonal);
+
+        for (int row = 0; row < area.Height; row++)
+        {
+            int previousRed = 255;
+            int previousBlue = 0;
+
+            for (int col = 0; col < area.Width; col++)
+            {
+                var point = new Point (col, row);
+                var color = gradientFill.GetColor (point);
+
+                // Ensure color is not null
+                Assert.NotNull (color);
+
+                // Check if the current color is 'more blue' and 'less red' as it goes right and down
+                Assert.True (color.R <= previousRed, $"Failed at ({col}, {row}): {color.R} > {previousRed}");
+                Assert.True (color.B >= previousBlue, $"Failed at ({col}, {row}): {color.B} < {previousBlue}");
+
+                // Update the previous color values for the next iteration
+                previousRed = color.R;
+                previousBlue = color.B;
+            }
+        }
+
+        for (int col = 0; col < area.Width; col++)
+        {
+            int previousRed = 255;
+            int previousBlue = 0;
+
+            for (int row = 0; row < area.Height; row++)
+            {
+                var point = new Point (col, row);
+                var color = gradientFill.GetColor (point);
+
+                // Ensure color is not null
+                Assert.NotNull (color);
+
+                // Check if the current color is 'more blue' and 'less red' as it goes right and down
+                Assert.True (color.R <= previousRed, $"Failed at ({col}, {row}): {color.R} > {previousRed}");
+                Assert.True (color.B >= previousBlue, $"Failed at ({col}, {row}): {color.B} < {previousBlue}");
+
+                // Update the previous color values for the next iteration
+                previousRed = color.R;
+                previousBlue = color.B;
+            }
+        }
+    }
+}