(#10) integrate "position" method into linear gradient constructor

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

@@ -586,7 +586,7 @@ public static Font randomFont() {
     }
 
     public static LinearGradientPaint randomLinearGradient(Drawable drawable, Boundary start, Boundary end) {
-        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient().position(drawable, start, end);
+        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient(drawable, start, end);
 
         int randomColorCount = Maths.randomInteger(2, 8);
         for (int i = 0; i < randomColorCount; i++) {
@@ -597,7 +597,7 @@ public static LinearGradientPaint randomLinearGradient(Drawable drawable, Bounda
     }
 
     public static LinearGradientPaint randomLinearGradientWithAlpha(Drawable drawable, Boundary start, Boundary end) {
-        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient().position(drawable, start, end);
+        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient(drawable, start, end);
 
         int randomColorCount = Maths.randomInteger(2, 8);
         for (int i = 0; i < randomColorCount; i++) {

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

@@ -80,8 +80,7 @@ private static Polygon2D[] parsePsdf(String fileLocation) {
                         break;
                     }
                     case "lg": { // set paint as LinearGradientPaint
-                        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient();
-                        linearGradientBuilder.position(
+                        LinearGradientBuilder linearGradientBuilder = Gradients.linearGradient(
                                 new Pointf(
                                         Float.parseFloat(tokens[1]),
                                         Float.parseFloat(tokens[2])

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

@@ -1,5 +1,9 @@
 package tech.fastj.graphics.util.gradients;
 
+import tech.fastj.math.Pointf;
+import tech.fastj.graphics.Boundary;
+import tech.fastj.graphics.Drawable;
+
 import java.awt.GradientPaint;
 import java.awt.LinearGradientPaint;
 import java.awt.RadialGradientPaint;
@@ -15,8 +19,17 @@ public class Gradients {
      *
      * @return A {@link LinearGradientPaint} builder.
      */
-    public static LinearGradientBuilder linearGradient() {
-        return LinearGradientBuilder.builder();
+    public static LinearGradientBuilder linearGradient(Drawable drawable, Boundary start, Boundary end) {
+        return LinearGradientBuilder.builder(drawable, start, end);
+    }
+
+    /**
+     * Gets a builder instance for creating a {@link LinearGradientPaint}.
+     *
+     * @return A {@link LinearGradientPaint} builder.
+     */
+    public static LinearGradientBuilder linearGradient(Pointf start, Pointf end) {
+        return LinearGradientBuilder.builder(start, end);
     }
 
     /**

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

@@ -8,6 +8,7 @@
 import java.awt.Color;
 import java.awt.LinearGradientPaint;
 import java.util.Arrays;
+import java.util.Objects;
 
 /** A builder class for creating {@link LinearGradientPaint} objects. */
 public class LinearGradientBuilder implements GradientBuilder {
@@ -19,8 +20,15 @@ public class LinearGradientBuilder implements GradientBuilder {
     private int count;
 
     /** Initializes a {@code LinearGradientBuilder}'s internals. */
-    LinearGradientBuilder() {
+    LinearGradientBuilder(Drawable drawable, Boundary start, Boundary end) {
         colors = new Color[Gradients.ColorLimit];
+        position(drawable, start, end);
+    }
+
+    /** Initializes a {@code LinearGradientBuilder}'s internals. */
+    LinearGradientBuilder(Pointf start, Pointf end) {
+        colors = new Color[Gradients.ColorLimit];
+        position(start, end);
     }
 
     /**
@@ -30,9 +38,8 @@ public class LinearGradientBuilder implements GradientBuilder {
      * @param drawable The basis for what the {@code start} and {@code end} end positions evaluate to.
      * @param start    The starting boundary to create the gradient from.
      * @param end      The ending boundary to create the gradient from.
-     * @return The {@code LinearGradientBuilder}, for method chaining.
      */
-    public LinearGradientBuilder position(Drawable drawable, Boundary start, Boundary end) {
+    private void position(Drawable drawable, Boundary start, Boundary end) {
         if (start.equals(end)) {
             FastJEngine.error(
                     GradientBuilder.GradientCreationError,
@@ -46,18 +53,15 @@ public LinearGradientBuilder position(Drawable drawable, Boundary start, Boundar
 
         this.from = drawable.getBound(start);
         this.to = drawable.getBound(end);
-
-        return this;
     }
 
     /**
      * Sets the starting and ending points for the builder, based on the provided {@link Pointf} values.
      *
      * @param start The {@code Pointf} defining the starting point of the gradient.
      * @param end   The {@code Pointf} defining the ending point of the gradient.
-     * @return The {@code LinearGradientBuilder}, for method chaining.
      */
-    public LinearGradientBuilder position(Pointf start, Pointf end) {
+    private void position(Pointf start, Pointf end) {
         if (start.equals(end)) {
             FastJEngine.error(
                     GradientBuilder.GradientCreationError,
@@ -71,14 +75,12 @@ public LinearGradientBuilder position(Pointf start, Pointf end) {
 
         this.from = start;
         this.to = end;
-
-        return this;
     }
 
     /**
      * Adds a {@link Color} to the builder to be used in the resulting gradient.
      * <p>
-     * The amount of colors used in a {@link LinearGradientBuilder} not exceed {@link Gradients#ColorLimit}.
+     * The amount of colors used in a {@link LinearGradientBuilder} cannot exceed {@link Gradients#ColorLimit}.
      *
      * @param color The {@code Color} being added.
      * @return The {@code LinearGradientBuilder}, for method chaining.
@@ -95,6 +97,37 @@ public LinearGradientBuilder withColor(Color color) {
         return this;
     }
 
+    /**
+     * 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}.
+     *
+     * @param colors The {@code Color}s being added. This parameter must not cause the builder to increase over 8
+     *               colors.
+     * @return The {@code LinearGradientBuilder}, for method chaining.
+     */
+    public LinearGradientBuilder withColors(Color... colors) {
+        if (count == Gradients.ColorLimit) {
+            FastJEngine.error(GradientBuilder.GradientCreationError,
+                    new IllegalStateException("Gradients cannot contain more than " + Gradients.ColorLimit + " colors.")
+            );
+        }
+
+        if (Arrays.stream(colors).anyMatch(Objects::isNull)) {
+            FastJEngine.error(GradientBuilder.GradientCreationError,
+                    new IllegalStateException(
+                            "Gradients cannot contain null color values."
+                                    + System.lineSeparator()
+                                    + "Colors: " + Arrays.toString(colors)
+                    )
+            );
+        }
+
+        System.arraycopy(colors, count, this.colors, 0, count + colors.length);
+        count += colors.length;
+        return this;
+    }
+
     /**
      * Creates a new {@link LinearGradientPaint} object, using the data provided by other method calls.
      *
@@ -122,7 +155,16 @@ public LinearGradientPaint build() {
      *
      * @return The {@code LinearGradientBuilder} instance.
      */
-    static LinearGradientBuilder builder() {
-        return new LinearGradientBuilder();
+    static LinearGradientBuilder builder(Pointf start, Pointf end) {
+        return new LinearGradientBuilder(start, end);
+    }
+
+    /**
+     * Gets a new instance of a {@link LinearGradientBuilder}.
+     *
+     * @return The {@code LinearGradientBuilder} instance.
+     */
+    static LinearGradientBuilder builder(Drawable drawable, Boundary start, Boundary end) {
+        return new LinearGradientBuilder(drawable, start, end);
     }
 }

src/test/java/unittest/testcases/graphics/util/LinearGradientTests.java

@@ -48,8 +48,7 @@ void checkCreateLinearGradient_withTwoRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .build();
@@ -91,8 +90,7 @@ void checkCreateLinearGradient_withThreeRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)
@@ -136,8 +134,7 @@ void checkCreateLinearGradient_withFourRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3, randomColor4}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)
@@ -183,8 +180,7 @@ void checkCreateLinearGradient_withFiveRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3, randomColor4, randomColor5}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)
@@ -232,8 +228,7 @@ void checkCreateLinearGradient_withSixRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3, randomColor4, randomColor5, randomColor6}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)
@@ -284,8 +279,7 @@ void checkCreateLinearGradient_withSevenRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3, randomColor4, randomColor5, randomColor6, randomColor7}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)
@@ -338,8 +332,7 @@ void checkCreateLinearGradient_withEightRandomColors_usingRandomLocations() {
                 new Color[]{randomColor1, randomColor2, randomColor3, randomColor4, randomColor5, randomColor6, randomColor7, randomColor8}
         );
 
-        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient()
-                .position(randomStartingPoint, randomEndingPoint)
+        LinearGradientPaint actualLinearGradientPaint = Gradients.linearGradient(randomStartingPoint, randomEndingPoint)
                 .withColor(randomColor1)
                 .withColor(randomColor2)
                 .withColor(randomColor3)

src/test/java/unittest/testcases/graphics/util/PsdfUtilTests.java

@@ -49,8 +49,7 @@ class PsdfUtilTests {
             new Pointf(85f, 25f)
     };
     private static final Polygon2D expectedHouseRoof = new Polygon2D(expectedHouseRoofMesh);
-    private static final LinearGradientPaint expectedHouseRoofGradient = Gradients.linearGradient()
-            .position(expectedHouseRoof, Boundary.TopLeft, Boundary.BottomRight)
+    private static final LinearGradientPaint expectedHouseRoofGradient = Gradients.linearGradient(expectedHouseRoof, Boundary.TopLeft, Boundary.BottomRight)
             .withColor(Color.blue)
             .withColor(Color.cyan)
             .withColor(Color.yellow)