(#10, #3) Added unit tests for random gradients, add constants for mi…

…nimum color count/radius.

- Moved random gradient methods to `Gradients.java`

src/main/java/tech/fastj/graphics/util/DrawUtil.java

@@ -4,12 +4,8 @@
 import tech.fastj.engine.FastJEngine;
 import tech.fastj.math.Maths;
 import tech.fastj.math.Pointf;
-import tech.fastj.graphics.Boundary;
 import tech.fastj.graphics.Drawable;
 import tech.fastj.graphics.game.Polygon2D;
-import tech.fastj.graphics.util.gradients.Gradients;
-import tech.fastj.graphics.util.gradients.LinearGradientBuilder;
-import tech.fastj.graphics.util.gradients.RadialGradientBuilder;
 
 import java.awt.Color;
 import java.awt.Font;
@@ -584,48 +580,4 @@ public static Font randomFont() {
 
         return new Font(fontNames[Maths.randomInteger(0, fontNames.length - 1)].getFontName(), font, Maths.randomInteger(1, 256));
     }
-
-    public static LinearGradientPaint randomLinearGradient(Drawable drawable, Boundary start, Boundary end) {
-        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient(drawable, start, end);
-
-        int randomColorCount = Maths.randomInteger(2, 8);
-        for (int i = 0; i < randomColorCount; i++) {
-            linearGradientBuilder.withColor(randomColor());
-        }
-
-        return linearGradientBuilder.build();
-    }
-
-    public static LinearGradientPaint randomLinearGradientWithAlpha(Drawable drawable, Boundary start, Boundary end) {
-        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient(drawable, start, end);
-
-        int randomColorCount = Maths.randomInteger(2, 8);
-        for (int i = 0; i < randomColorCount; i++) {
-            linearGradientBuilder.withColor(randomColorWithAlpha());
-        }
-
-        return linearGradientBuilder.build();
-    }
-
-    public static RadialGradientPaint randomRadialGradient(Drawable drawable) {
-        RadialGradientBuilder radialGradientBuilder = Gradients.radialGradient(drawable);
-
-        int randomColorCount = Maths.randomInteger(2, 8);
-        for (int i = 0; i < randomColorCount; i++) {
-            radialGradientBuilder.withColor(randomColor());
-        }
-
-        return radialGradientBuilder.build();
-    }
-
-    public static RadialGradientPaint randomRadialGradientWithAlpha(Drawable drawable) {
-        RadialGradientBuilder radialGradientBuilder = Gradients.radialGradient(drawable);
-
-        int randomColorCount = Maths.randomInteger(2, 8);
-        for (int i = 0; i < randomColorCount; i++) {
-            radialGradientBuilder.withColor(randomColorWithAlpha());
-        }
-
-        return radialGradientBuilder.build();
-    }
 }

src/main/java/tech/fastj/graphics/util/gradients/Gradients.java

@@ -1,8 +1,10 @@
 package tech.fastj.graphics.util.gradients;
 
+import tech.fastj.math.Maths;
 import tech.fastj.math.Pointf;
 import tech.fastj.graphics.Boundary;
 import tech.fastj.graphics.Drawable;
+import tech.fastj.graphics.util.DrawUtil;
 
 import java.awt.Color;
 import java.awt.GradientPaint;
@@ -14,8 +16,14 @@
 /** Class to streamline working with the {@link GradientPaint} class (and its implementations) within FastJ. */
 public class Gradients {
 
-    /** The amount of colors allowed in a single {@link LinearGradientBuilder} or {@link RadialGradientBuilder}. */
-    public static final int ColorLimit = 8;
+    /** The maximum amount of colors allowed in a single {@link LinearGradientBuilder} or {@link RadialGradientBuilder}. */
+    public static final int MaximumColorCount = 8;
+
+    /** The minimum amount of colors allowed in a single {@link LinearGradientBuilder} or {@link RadialGradientBuilder}. */
+    public static final int MinimumColorCount = 2;
+
+    /** The minimum radius allowed in a single {@link RadialGradientBuilder}, including the value of this constant. */
+    public static final float MinimumRadius = 0.0f;
 
     /**
      * Gets a builder instance for creating a {@link LinearGradientPaint}.
@@ -53,6 +61,156 @@ public static RadialGradientBuilder radialGradient(Pointf center, float radius)
         return RadialGradientBuilder.builder(center, radius);
     }
 
+    /**
+     * Generates a random linear gradient from the specified {@code drawable} and {@code start}/{@code end} values, with
+     * random colors.
+     *
+     * @param drawable The {@link Drawable} to calculate start/end {@code Pointf}s.
+     * @param start    The {@link Boundary} specifying the starting area for the gradient.
+     * @param end      The {@link Boundary} specifying the ending area for the gradient.
+     * @return The randomly generated {@link LinearGradientPaint}.
+     */
+    public static LinearGradientPaint randomLinearGradient(Drawable drawable, Boundary start, Boundary end) {
+        LinearGradientBuilder linearGradientBuilder = linearGradient(drawable, start, end);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            linearGradientBuilder.withColor(DrawUtil.randomColor());
+        }
+
+        return linearGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random linear gradient from the specified {@code drawable} and {@code start}/{@code end} values, with
+     * random colors including random alpha values.
+     *
+     * @param drawable The {@link Drawable} to calculate start/end {@code Pointf}s.
+     * @param start    The {@link Boundary} specifying the starting area for the gradient.
+     * @param end      The {@link Boundary} specifying the ending area for the gradient.
+     * @return The randomly generated {@link LinearGradientPaint}.
+     */
+    public static LinearGradientPaint randomLinearGradientWithAlpha(Drawable drawable, Boundary start, Boundary end) {
+        LinearGradientBuilder linearGradientBuilder = linearGradient(drawable, start, end);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            linearGradientBuilder.withColor(DrawUtil.randomColorWithAlpha());
+        }
+
+        return linearGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random linear gradient from the specified {@code start}/{@code end} values, with random colors.
+     *
+     * @param start The {@link Pointf} specifying the starting area for the gradient.
+     * @param end   The {@link Pointf} specifying the ending area for the gradient.
+     * @return The randomly generated {@link LinearGradientPaint}.
+     */
+    public static LinearGradientPaint randomLinearGradient(Pointf start, Pointf end) {
+        LinearGradientBuilder linearGradientBuilder = linearGradient(start, end);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            linearGradientBuilder.withColor(DrawUtil.randomColor());
+        }
+
+        return linearGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random linear gradient from the specified {@code start}/{@code end} values, with random colors
+     * including random alpha values.
+     *
+     * @param start The {@link Pointf} specifying the starting area for the gradient.
+     * @param end   The {@link Pointf} specifying the ending area for the gradient.
+     * @return The randomly generated {@link LinearGradientPaint}.
+     */
+    public static LinearGradientPaint randomLinearGradientWithAlpha(Pointf start, Pointf end) {
+        LinearGradientBuilder linearGradientBuilder = linearGradient(start, end);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            linearGradientBuilder.withColor(DrawUtil.randomColorWithAlpha());
+        }
+
+        return linearGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random radial gradient from the specified {@code drawable}, with random colors.
+     *
+     * @param drawable The {@link Drawable} specifying the center and radius for the gradient.
+     * @return The randomly generated {@link RadialGradientPaint}.
+     */
+    public static RadialGradientPaint randomRadialGradient(Drawable drawable) {
+        RadialGradientBuilder radialGradientBuilder = radialGradient(drawable);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            radialGradientBuilder.withColor(DrawUtil.randomColor());
+        }
+
+        return radialGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random radial gradient from the specified {@code drawable}, with random colors including random alpha
+     * values.
+     *
+     * @param drawable The {@link Drawable} specifying the center and radius for the gradient.
+     * @return The randomly generated {@link RadialGradientPaint}.
+     */
+    public static RadialGradientPaint randomRadialGradientWithAlpha(Drawable drawable) {
+        RadialGradientBuilder radialGradientBuilder = radialGradient(drawable);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            radialGradientBuilder.withColor(DrawUtil.randomColorWithAlpha());
+        }
+
+        return radialGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random radial gradient from the specified {@code center} and {@code radius} values, with random
+     * colors.
+     *
+     * @param center The {@link Pointf} specifying the centerpoint for the gradient.
+     * @param radius The {@code float} specifying the radius for the gradient.
+     * @return The randomly generated {@link RadialGradientPaint}.
+     */
+    public static RadialGradientPaint randomRadialGradient(Pointf center, float radius) {
+        RadialGradientBuilder radialGradientBuilder = radialGradient(center, radius);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            radialGradientBuilder.withColor(DrawUtil.randomColor());
+        }
+
+        return radialGradientBuilder.build();
+    }
+
+    /**
+     * Generates a random radial gradient from the specified {@code center} and {@code radius} values, with random
+     * colors including random alpha values.
+     *
+     * @param center The {@link Pointf} specifying the centerpoint for the gradient.
+     * @param radius The {@code float} specifying the radius for the gradient.
+     * @return The randomly generated {@link RadialGradientPaint}.
+     */
+    public static RadialGradientPaint randomRadialGradientWithAlpha(Pointf center, float radius) {
+        RadialGradientBuilder radialGradientBuilder = radialGradient(center, radius);
+
+        int randomColorCount = Maths.randomInteger(MinimumColorCount, MaximumColorCount);
+        for (int i = 0; i < randomColorCount; i++) {
+            radialGradientBuilder.withColor(DrawUtil.randomColorWithAlpha());
+        }
+
+        return radialGradientBuilder.build();
+    }
+
     static void samePointfCheck(Pointf start, Pointf end) {
         if (start.equals(end)) {
             throw new IllegalArgumentException(
@@ -74,7 +232,7 @@ static void sameBoundaryCheck(Boundary start, Boundary end) {
     }
 
     static void minimumRadiusValueCheck(float radius) {
-        if (radius <= 0f) {
+        if (radius <= MinimumRadius) {
             throw new IllegalArgumentException("The radius for a gradient must be larger than 0.");
         }
     }
@@ -92,19 +250,19 @@ static void nullColorCheck(Color[] colors) {
     }
 
     static void colorLimitCheck(int count) {
-        if (count >= Gradients.ColorLimit) {
-            throw new IllegalStateException("Gradients cannot contain more than " + Gradients.ColorLimit + " colors.");
+        if (count >= MaximumColorCount) {
+            throw new IllegalStateException("Gradients cannot contain more than " + MaximumColorCount + " colors.");
         }
     }
 
     static void colorLimitCheck(int count, Color[] colors) {
-        if (count + colors.length > Gradients.ColorLimit) {
-            throw new IllegalStateException("Gradients cannot contain more than " + Gradients.ColorLimit + " colors.");
+        if (count + colors.length > MaximumColorCount) {
+            throw new IllegalStateException("Gradients cannot contain more than " + MaximumColorCount + " colors.");
         }
     }
 
     static void minimumColorCheck(int count, Color[] colors) {
-        if (count < 2) {
+        if (count < MinimumColorCount) {
             throw new IllegalStateException(
                     "Gradients must contain at least 2 colors."
                             + System.lineSeparator()

src/main/java/tech/fastj/graphics/util/gradients/LinearGradientBuilder.java

@@ -19,13 +19,13 @@ public class LinearGradientBuilder implements GradientBuilder {
 
     /** Initializes a {@code LinearGradientBuilder}'s internals. */
     LinearGradientBuilder(Drawable drawable, Boundary start, Boundary end) {
-        colors = new Color[Gradients.ColorLimit];
+        colors = new Color[Gradients.MaximumColorCount];
         position(drawable, start, end);
     }
 
     /** Initializes a {@code LinearGradientBuilder}'s internals. */
     LinearGradientBuilder(Pointf start, Pointf end) {
-        colors = new Color[Gradients.ColorLimit];
+        colors = new Color[Gradients.MaximumColorCount];
         position(start, end);
     }
 
@@ -60,7 +60,7 @@ private void position(Pointf start, Pointf end) {
     /**
      * Adds a {@link Color} to the builder to be used in the resulting gradient.
      * <p>
-     * The amount of colors used in a {@link LinearGradientBuilder} cannot exceed {@link Gradients#ColorLimit}.
+     * The amount of colors used in a {@link LinearGradientBuilder} cannot exceed {@link Gradients#MaximumColorCount}.
      *
      * @param color The {@code Color} being added.
      * @return The {@code LinearGradientBuilder}, for method chaining.
@@ -77,7 +77,7 @@ public LinearGradientBuilder withColor(Color color) {
     /**
      * Adds several {@link Color}s to the builder to be used in the resulting gradient.
      * <p>
-     * The amount of colors used in a {@link LinearGradientBuilder} cannot exceed {@link Gradients#ColorLimit}.
+     * The amount of colors used in a {@link LinearGradientBuilder} cannot exceed {@link Gradients#MaximumColorCount}.
      *
      * @param colors The {@code Color}s being added. This parameter must not cause the builder to increase over 8
      *               colors.

src/main/java/tech/fastj/graphics/util/gradients/RadialGradientBuilder.java

@@ -19,13 +19,13 @@ public class RadialGradientBuilder implements GradientBuilder {
 
     /** Initializes a {@code RadialGradientBuilder}'s internals. */
     RadialGradientBuilder(Drawable drawable) {
-        colors = new Color[Gradients.ColorLimit];
+        colors = new Color[Gradients.MaximumColorCount];
         position(drawable);
     }
 
     /** Initializes a {@code RadialGradientBuilder}'s internals. */
     RadialGradientBuilder(Pointf center, float radius) {
-        colors = new Color[Gradients.ColorLimit];
+        colors = new Color[Gradients.MaximumColorCount];
         position(center, radius);
     }
 
@@ -57,7 +57,7 @@ private void position(Pointf center, float radius) {
     /**
      * Adds a {@link Color} to the builder to be used in the resulting gradient.
      * <p>
-     * The amount of colors used in a {@link RadialGradientBuilder} not exceed {@link Gradients#ColorLimit}.
+     * The amount of colors used in a {@link RadialGradientBuilder} not exceed {@link Gradients#MaximumColorCount}.
      *
      * @param color The {@code Color} being added.
      * @return The {@code LinearGradientBuilder}, for method chaining.
@@ -74,7 +74,7 @@ public RadialGradientBuilder withColor(Color color) {
     /**
      * Adds several {@link Color}s to the builder to be used in the resulting gradient.
      * <p>
-     * The amount of colors used in a {@link RadialGradientBuilder} cannot exceed {@link Gradients#ColorLimit}.
+     * The amount of colors used in a {@link RadialGradientBuilder} cannot exceed {@link Gradients#MaximumColorCount}.
      *
      * @param colors The {@code Color}s being added. This parameter must not cause the builder to increase over 8
      *               colors.