Java desktop example: detect retina and scale accordingly

also: zoom in/out buttons

1 files changed, 36 insertions, 5 deletions

diff --git a/platform/java/example/PageCanvas.java b/platform/java/example/PageCanvas.java
index ffe3efc2..bfeca21b 100644
--- a/platform/java/example/PageCanvas.java
+++ b/platform/java/example/PageCanvas.java
@@ -9,6 +9,9 @@ public class PageCanvas extends java.awt.Canvas
 	protected Page page;
 	protected BufferedImage image;
 
+	protected float mScale = 1.0f;
+	private float mRetinaScale = 1.0f;
+
 	public static BufferedImage imageFromPixmap(Pixmap pixmap) {
 		int w = pixmap.getWidth();
 		int h = pixmap.getHeight();
@@ -23,7 +26,7 @@ public class PageCanvas extends java.awt.Canvas
 		Pixmap pixmap = new Pixmap(ColorSpace.DeviceBGR, bbox);
 		pixmap.clear(255);
 		DrawDevice dev = new DrawDevice(pixmap);
-		page.run(dev, new Matrix());
+		page.run(dev, ctm);
 		dev.destroy();
 		BufferedImage image = imageFromPixmap(pixmap);
 		pixmap.destroy();
@@ -37,9 +40,19 @@ public class PageCanvas extends java.awt.Canvas
 		return image;
 	}
 
-	public PageCanvas(Page page_) {
+	public PageCanvas(Page page_, float nativeScale) {
+		mRetinaScale = nativeScale;
+		mScale = mRetinaScale;
 		this.page = page_;
-		image = imageFromPage(page, new Matrix());
+		run();
+	}
+
+	private void run()
+	{
+		Matrix ctm = new Matrix();
+		ctm.scale(mScale);
+		image = imageFromPage(page, ctm);
+		repaint();
 	}
 
 	public Dimension getPreferredSize() {
@@ -54,7 +67,25 @@ public class PageCanvas extends java.awt.Canvas
 		return getPreferredSize();
 	}
 
-	public void paint(Graphics g) {
-		g.drawImage(image, 0, 0, null);
+	public void zoomIn() {
+		mScale += 0.25f;
+		run();
+	}
+
+	public void zoomOut() {
+	    mScale -= 0.25f;
+	    run();
 	}
+
+	public void paint(Graphics g)
+	{
+		float scale = 1.0f;
+		scale = 1/mRetinaScale;
+
+		final Graphics2D g2d = (Graphics2D)g.create(0, 0, image.getWidth(), image.getHeight());
+		g2d.scale(scale, scale);
+		g2d.drawImage(image, 0, 0, null);
+		g2d.dispose();
+	}
+
 }