Tianpok/image arena background

docs/uml-diagrams/plantuml_class_diagram.puml

@@ -50,7 +50,8 @@ legend right
   interfaces such as TurnProcessor and WaveManager
   Observer - BattleEventPublisher + BattleEventListener
   Factory - BattleSetupFactory and CombatantFactory
-  SRP - ArenaScenePanel, ArenaSceneModel, ArenaSceneRenderer
+  SRP - ArenaScenePanel, ArenaSceneModel, ArenaSceneRenderer,
+  ArenaBackgroundRenderer
   Boundary-Control - UI classes delegate battle flow to
   BattleController and BattleEngine
 endlegend
@@ -760,10 +761,18 @@ package "UI LAYER - Swing GUI boundary/control" {
   }
 
   class ArenaSceneRenderer <<boundary>> {
+    - backgroundRenderer: ArenaBackgroundRenderer
     - fighterRenderer: FighterSpriteRenderer
     ~ render(g: Graphics2D, model: ArenaSceneModel, width: int, height: int, now: long): void
   }
 
+  class ArenaBackgroundRenderer <<boundary>> {
+    {static} ~ BACKGROUND_RESOURCE: String
+    - source: BufferedImage
+    - scaledBackground: BufferedImage
+    ~ render(g: Graphics2D, width: int, height: int): void
+  }
+
   class ArenaSceneLoop <<control>> {
     - tickCallback: Runnable
     - tickTimer: Timer
@@ -1053,6 +1062,7 @@ ArenaScenePanel "1" *-- "1" ArenaSceneRenderer
 ArenaScenePanel "1" *-- "1" ArenaSceneLoop
 ArenaSceneModel "1" o-- "0..*" FighterSpriteDto : sprites
 ArenaSceneModel "1" *-- "0..*" FloatingText : floatingTexts
+ArenaSceneRenderer "1" o-- "1" ArenaBackgroundRenderer
 ArenaSceneRenderer "1" *-- "1" FighterSpriteRenderer
 FighterBodyRenderer <|.. WarriorBodyRenderer
 FighterBodyRenderer <|.. WizardBodyRenderer

src/main/java/sc2002/turnbased/ui/gui/view/ArenaBackgroundRenderer.java

@@ -0,0 +1,109 @@
+package sc2002.turnbased.ui.gui.view;
+
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UncheckedIOException;
+import java.util.Objects;
+
+import javax.imageio.ImageIO;
+
+final class ArenaBackgroundRenderer {
+    static final String BACKGROUND_RESOURCE = "/sc2002/turnbased/ui/gui/assets/arena-background.png";
+
+    private final BufferedImage source;
+    private BufferedImage scaledBackground;
+    private int scaledWidth;
+    private int scaledHeight;
+
+    ArenaBackgroundRenderer() {
+        this(loadResource(BACKGROUND_RESOURCE));
+    }
+
+    ArenaBackgroundRenderer(BufferedImage source) {
+        this.source = Objects.requireNonNull(source, "source");
+        if (source.getWidth() <= 0 || source.getHeight() <= 0) {
+            throw new IllegalArgumentException("Background image must have positive dimensions.");
+        }
+    }
+
+    void render(Graphics2D g, int width, int height) {
+        Objects.requireNonNull(g, "g");
+        if (width <= 0 || height <= 0) {
+            return;
+        }
+        g.drawImage(scaledBackground(width, height), 0, 0, null);
+    }
+
+    private BufferedImage scaledBackground(int width, int height) {
+        if (scaledBackground == null || width != scaledWidth || height != scaledHeight) {
+            scaledBackground = createScaledBackground(width, height);
+            scaledWidth = width;
+            scaledHeight = height;
+        }
+        return scaledBackground;
+    }
+
+    private BufferedImage createScaledBackground(int width, int height) {
+        BufferedImage target = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+        Graphics2D backgroundGraphics = target.createGraphics();
+        try {
+            backgroundGraphics.setRenderingHint(
+                RenderingHints.KEY_INTERPOLATION,
+                RenderingHints.VALUE_INTERPOLATION_BILINEAR
+            );
+            backgroundGraphics.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
+            SourceCrop crop = coverCrop(width, height);
+            backgroundGraphics.drawImage(
+                source,
+                0,
+                0,
+                width,
+                height,
+                crop.x(),
+                crop.y(),
+                crop.x() + crop.width(),
+                crop.y() + crop.height(),
+                null
+            );
+        } finally {
+            backgroundGraphics.dispose();
+        }
+        return target;
+    }
+
+    private SourceCrop coverCrop(int width, int height) {
+        int sourceWidth = source.getWidth();
+        int sourceHeight = source.getHeight();
+        double sourceRatio = sourceWidth / (double) sourceHeight;
+        double targetRatio = width / (double) height;
+        if (sourceRatio > targetRatio) {
+            int cropWidth = Math.max(1, (int) Math.round(sourceHeight * targetRatio));
+            int cropX = (sourceWidth - cropWidth) / 2;
+            return new SourceCrop(cropX, 0, cropWidth, sourceHeight);
+        }
+        int cropHeight = Math.max(1, (int) Math.round(sourceWidth / targetRatio));
+        int cropY = (sourceHeight - cropHeight) / 2;
+        return new SourceCrop(0, cropY, sourceWidth, cropHeight);
+    }
+
+    private static BufferedImage loadResource(String resourceName) {
+        try (InputStream inputStream = ArenaBackgroundRenderer.class.getResourceAsStream(resourceName)) {
+            if (inputStream == null) {
+                throw new IllegalStateException("Missing arena background resource: " + resourceName);
+            }
+            BufferedImage image = ImageIO.read(inputStream);
+            if (image == null) {
+                throw new IllegalStateException("Unreadable arena background resource: " + resourceName);
+            }
+            return image;
+        } catch (IOException exception) {
+            throw new UncheckedIOException("Unable to load arena background resource: " + resourceName, exception);
+        }
+    }
+
+    private record SourceCrop(int x, int y, int width, int height) {
+    }
+}

src/main/java/sc2002/turnbased/ui/gui/view/ArenaSceneRenderer.java

@@ -5,103 +5,34 @@
 import java.awt.Color;
 import java.awt.Composite;
 import java.awt.Font;
-import java.awt.GradientPaint;
 import java.awt.Graphics2D;
-import java.awt.Polygon;
 import java.awt.RenderingHints;
-import java.awt.geom.Path2D;
+import java.util.Objects;
 
 final class ArenaSceneRenderer {
     private static final long FLOATING_TEXT_NANOS = 1_000_000_000L;
 
+    private final ArenaBackgroundRenderer backgroundRenderer;
     private final FighterSpriteRenderer fighterRenderer = new FighterSpriteRenderer();
 
+    ArenaSceneRenderer() {
+        this(new ArenaBackgroundRenderer());
+    }
+
+    ArenaSceneRenderer(ArenaBackgroundRenderer backgroundRenderer) {
+        this.backgroundRenderer = Objects.requireNonNull(backgroundRenderer, "backgroundRenderer");
+    }
+
     void render(Graphics2D g, ArenaSceneModel model, int width, int height, long now) {
         g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
         g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
-        drawBackground(g, width, height);
+        backgroundRenderer.render(g, width, height);
         drawTargetPath(g, model);
         drawSprites(g, model);
         drawFloatingTexts(g, model, now);
         drawOverlay(g, model, width);
     }
 
-    private void drawBackground(Graphics2D g, int width, int height) {
-        int floorTop = floorTop(height);
-        g.setPaint(new GradientPaint(0, 0, new Color(34, 107, 124), 0, height, new Color(232, 86, 76)));
-        g.fillRect(0, 0, width, height);
-
-        g.setColor(new Color(255, 210, 99, 185));
-        g.fillOval(width - 178, 48, 86, 86);
-
-        drawMountain(g, -40, floorTop - 160, 270, new Color(60, 102, 91));
-        drawMountain(g, 190, floorTop - 145, 270, new Color(55, 84, 93));
-        drawMountain(g, 470, floorTop - 152, 300, new Color(63, 105, 81));
-        drawForest(g, width, floorTop);
-        drawRuins(g, width, floorTop);
-
-        g.setPaint(new GradientPaint(0, floorTop, new Color(58, 69, 58), 0, height, new Color(34, 48, 45)));
-        g.fillRect(0, floorTop, width, height - floorTop);
-
-        g.setColor(new Color(88, 116, 91, 140));
-        for (int x = -40; x < width + 90; x += 86) {
-            g.fillRoundRect(x, floorTop + 22, 58, 18, 8, 8);
-            g.fillRoundRect(x + 28, floorTop + 116, 74, 22, 8, 8);
-        }
-        g.setColor(new Color(18, 29, 31, 90));
-        for (int y = floorTop + 30; y < height; y += 48) {
-            g.drawLine(0, y, width, y - 26);
-        }
-    }
-
-    private void drawMountain(Graphics2D g, int x, int baseY, int size, Color color) {
-        Polygon mountain = new Polygon();
-        mountain.addPoint(x, baseY + size);
-        mountain.addPoint(x + size / 2, baseY);
-        mountain.addPoint(x + size, baseY + size);
-        g.setColor(color);
-        g.fillPolygon(mountain);
-        g.setColor(new Color(235, 238, 214, 88));
-        Polygon cap = new Polygon();
-        cap.addPoint(x + size / 2, baseY);
-        cap.addPoint(x + size / 2 - 32, baseY + 70);
-        cap.addPoint(x + size / 2 + 12, baseY + 48);
-        cap.addPoint(x + size / 2 + 42, baseY + 86);
-        g.fillPolygon(cap);
-    }
-
-    private void drawForest(Graphics2D g, int width, int floorTop) {
-        int horizon = floorTop - 40;
-        for (int x = -20; x < width + 60; x += 42) {
-            int height = 54 + Math.floorMod(x * 13, 48);
-            g.setColor(new Color(34, 78, 57, 180));
-            Path2D tree = new Path2D.Double();
-            tree.moveTo(x, horizon);
-            tree.lineTo(x + 20, horizon - height);
-            tree.lineTo(x + 42, horizon);
-            tree.closePath();
-            g.fill(tree);
-            g.setColor(new Color(50, 63, 48, 190));
-            g.fillRect(x + 18, horizon - 10, 8, 18);
-        }
-    }
-
-    private void drawRuins(Graphics2D g, int width, int floorTop) {
-        int base = floorTop - 26;
-        Color stoneColor = new Color(74, 77, 72, 155);
-        Color stripeColor = new Color(120, 58, 58, 150);
-        for (int x = 44; x < width; x += 245) {
-            g.setColor(stoneColor);
-            g.fillRect(x, base - 94, 26, 94);
-            g.setColor(stoneColor);
-            g.fillRect(x + 76, base - 118, 28, 118);
-            g.setColor(stoneColor);
-            g.fillRect(x - 10, base - 120, 128, 18);
-            g.setColor(stripeColor);
-            g.fillRect(x + 24, base - 108, 50, 12);
-        }
-    }
-
     private void drawTargetPath(Graphics2D g, ArenaSceneModel model) {
         FighterSpriteDto player = model.playerSprite();
         FighterSpriteDto target = model.currentSelectedEnemySprite();
@@ -159,10 +90,6 @@ private void drawOverlay(Graphics2D g, ArenaSceneModel model, int width) {
         }
     }
 
-    private static int floorTop(int height) {
-        return (int) (height * 0.55);
-    }
-
     private static String fitText(Graphics2D g, String text, int maxWidth) {
         if (g.getFontMetrics().stringWidth(text) <= maxWidth) {
             return text;

src/test/java/sc2002/turnbased/ui/gui/view/ArenaBackgroundRendererTest.java

@@ -0,0 +1,50 @@
+package sc2002.turnbased.ui.gui.view;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.io.InputStream;
+
+import javax.imageio.ImageIO;
+
+import org.junit.jupiter.api.Test;
+
+class ArenaBackgroundRendererTest {
+    private static final byte[] PNG_SIGNATURE = new byte[] {
+        (byte) 0x89,
+        'P',
+        'N',
+        'G',
+        '\r',
+        '\n',
+        0x1A,
+        '\n'
+    };
+
+    @Test
+    void packagesBackgroundAsPngResource() throws IOException {
+        try (InputStream inputStream = ArenaBackgroundRenderer.class.getResourceAsStream(
+            ArenaBackgroundRenderer.BACKGROUND_RESOURCE
+        )) {
+            assertNotNull(inputStream);
+            assertArrayEquals(PNG_SIGNATURE, inputStream.readNBytes(PNG_SIGNATURE.length));
+        }
+    }
+
+    @Test
+    void decodesPackagedBackgroundResource() throws IOException {
+        try (InputStream inputStream = ArenaBackgroundRenderer.class.getResourceAsStream(
+            ArenaBackgroundRenderer.BACKGROUND_RESOURCE
+        )) {
+            assertNotNull(inputStream);
+            BufferedImage image = ImageIO.read(inputStream);
+
+            assertNotNull(image);
+            assertTrue(image.getWidth() > 0);
+            assertTrue(image.getHeight() > 0);
+        }
+    }
+}