add Java2D/Graphics2D example

examples/graphics2d/README.md

@@ -0,0 +1,9 @@
+# Java2D/Graphics2D drawing example
+
+JWM raster example working with the standard `Java2D/Graphics2D` as a graphics-drawing library.
+
+This example shows some text and an orange circle at the center of the main window.
+
+Requires Java 22+ to compile/run, as it uses FFM
+([Foreign Function & Memory](https://docs.oracle.com/en/java/javase/25/core/foreign-function-and-memory-api.html))
+to access/share the screen pixels' native memory buffers created by JWM.

examples/graphics2d/java/EventFrameGraphics2D.java

@@ -0,0 +1,26 @@
+package io.github.humbleui.jwm.examples;
+
+import java.awt.image.BufferedImage;
+
+import io.github.humbleui.jwm.Event;
+
+/// Frame event for Java2D/Graphics2D graphics-drawing library.
+/// 
+public class EventFrameGraphics2D implements Event {
+
+    private final BufferedImage bufferedImage;
+
+    public EventFrameGraphics2D(BufferedImage bufferedImage) {
+        this.bufferedImage = bufferedImage;
+    }
+
+    public BufferedImage getBufferedImage() {
+        return bufferedImage;
+    }
+
+    @Override
+    public String toString() {
+        return "EventFrameGraphics2D(bufferedImage=" + System.identityHashCode(bufferedImage) + ")";
+    }
+
+}

examples/graphics2d/java/Example.java

@@ -0,0 +1,67 @@
+package io.github.humbleui.jwm.examples;
+
+import io.github.humbleui.jwm.*;
+
+import java.awt.Color;
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
+import java.util.function.Consumer;
+
+/// An example of JWM working with Java2D/Graphics2D as graphics-drawing library.
+/// 
+/// This example shows some text and an orange circle at the center of the main window.
+/// 
+public class Example implements Consumer<Event> {
+
+    private Window window;
+
+    public Example(int width, int height) {
+        window = App.makeWindow();
+        window.setEventListener(this);
+        window.setTitle("JWM with Java2D/Graphics2D Fixed Scale");
+
+        window.setLayer(new LayerRasterGraphics2D());
+
+        window.setWindowSize(width, height);
+        window.setVisible(true);
+    }
+
+    @Override
+    public void accept(Event e) {
+        if (e instanceof EventWindowCloseRequest) {
+            window.close();
+            App.terminate();
+        }
+        else if (e instanceof EventFrameGraphics2D eg) {
+            var image = eg.getBufferedImage();
+            var g2d = image.createGraphics();
+            drawJava2DScene(g2d, image.getWidth(), image.getHeight());
+            g2d.dispose();
+        }
+    }
+
+    private void drawJava2DScene(Graphics2D g2d, int w, int h) {
+        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+
+        // Clear background
+        g2d.setColor(new Color(30, 30, 30));
+        g2d.fillRect(0, 0, w, h);
+
+        // Draw an orange circle
+        int circleSize = Math.min(w, h) / 2;
+        int x = (w - circleSize) / 2;
+        int y = (h - circleSize) / 2;
+
+        g2d.setColor(Color.ORANGE);
+        g2d.fillOval(x, y, circleSize, circleSize);
+
+        // Draw some text
+        g2d.setColor(Color.WHITE);
+        g2d.drawString("Hello from High-DPI Correlated Java2D!", 50, 50);
+    }
+
+    public static void main(String[] args) {
+        App.start(() -> new Example(800, 600));
+    }
+
+}

examples/graphics2d/java/LayerRasterGraphics2D.java

@@ -0,0 +1,47 @@
+package io.github.humbleui.jwm.examples;
+
+import java.awt.image.BufferedImage;
+import java.awt.image.ColorModel;
+import java.awt.image.DataBuffer;
+import java.awt.image.Raster;
+import java.awt.image.SinglePixelPackedSampleModel;
+
+import io.github.humbleui.jwm.LayerRaster;
+
+/// Raster layer implementation for Java2D/Graphics2D graphics-drawing library.
+/// 
+public class LayerRasterGraphics2D extends LayerRaster {
+
+    private BufferedImage renderBuffer;
+
+    @Override
+    public void frame() {
+        // re-initialize the raster buffer if needed
+        initRasterBuffer(getWidth(), getHeight());
+        _window.accept(new EventFrameGraphics2D(renderBuffer));
+        swapBuffers();
+    }
+
+    private void initRasterBuffer(int width, int height) {
+        if (width <= 0 || height <= 0) return;
+
+        // If the buffer size hasn't changed, skip re-allocation
+        if (renderBuffer != null && renderBuffer.getWidth() == width && renderBuffer.getHeight() == height) {
+            return;
+        }
+
+        // Use custom DataBuffer wrapper around the JWM native pixel buffer
+        var nativeDataBuffer = new NativeIntDataBuffer(getPixelsPtr(), width * height);
+
+        // Construct a Custom WritableRaster linking to native memory buffer
+        int[] bandMasks = {0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000}; // RGBA masks
+        var sampleModel = new SinglePixelPackedSampleModel(
+            DataBuffer.TYPE_INT, width, height, width, bandMasks
+        );
+        var raster = Raster.createWritableRaster(sampleModel, nativeDataBuffer, null);
+
+        // Build the BufferedImage for rendering
+        renderBuffer = new BufferedImage(ColorModel.getRGBdefault(), raster, true, null);
+    }
+
+}

examples/graphics2d/java/NativeIntDataBuffer.java

@@ -0,0 +1,33 @@
+package io.github.humbleui.jwm.examples;
+
+import static java.lang.foreign.ValueLayout.JAVA_INT;
+
+import java.awt.image.DataBuffer;
+import java.lang.foreign.MemorySegment;
+
+/// Custom DataBuffer wrapping a native memory segment
+/// as backing data "array".
+/// 
+public class NativeIntDataBuffer extends DataBuffer {
+
+    private final MemorySegment segment;
+
+    public NativeIntDataBuffer(long dataIntPtr, int size) {
+        super(DataBuffer.TYPE_INT, size);
+        this.segment = MemorySegment.ofAddress(dataIntPtr)
+                .reinterpret(size * JAVA_INT.byteSize());
+    }
+
+	@Override
+    public int getElem(int bank, int i) {
+        // Read directly from native memory space
+        return segment.getAtIndex(JAVA_INT, i);
+    }
+
+    @Override
+    public void setElem(int bank, int i, int val) {
+        // Write directly to native memory space
+        segment.setAtIndex(JAVA_INT, i, val);
+    }
+
+}

script/run.py

@@ -56,7 +56,7 @@ def main():
       'examples/dashboard/resources'
     ]
   sources = build_utils.files(f'examples/{args.example}/java/**/*.java')
-  build_utils.javac(sources, f'examples/{args.example}/target/classes', classpath = classpath, release='16')
+  build_utils.javac(sources, f'examples/{args.example}/target/classes', classpath = classpath, release='22')
 
   # run
   subprocess.check_call([