utility to capture result of on-screen paintingjb8u112-b622

1 files changed, 47 insertions, 0 deletions

diff --git a/idea/java/tests/src/ScreenPaintingCaptor.java b/idea/java/tests/src/ScreenPaintingCaptor.java
new file mode 100644
index 0000000000..26347a3b43
--- /dev/null
+++ b/idea/java/tests/src/ScreenPaintingCaptor.java
@@ -0,0 +1,47 @@
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.util.function.Consumer;
+import javax.swing.*;
+
+public class ScreenPaintingCaptor {
+    public static BufferedImage capture(int width, int height, Consumer<Graphics2D> painter) throws Exception {
+        JFrame[] f = new JFrame[1];
+        Point[] p = new Point[1];
+        SwingUtilities.invokeAndWait(() -> {
+            f[0] = new JFrame();
+            JComponent c = new MyComponent(painter);
+            f[0].add(c);
+            c.setSize(width + 2, height + 2);
+            f[0].setSize(width + 100, height + 100); // giving some space for frame border effects, e.g. rounded frame
+            c.setLocation(50, 50);
+            f[0].setVisible(true);
+            p[0]= c.getLocationOnScreen();
+        });
+        Robot r = new Robot();
+        while (!Color.black.equals(r.getPixelColor(p[0].x, p[0].y))) {
+            Thread.sleep(100);
+        }
+        BufferedImage i = r.createScreenCapture(new Rectangle(p[0].x + 1, p[0].y + 1, width, height));
+        SwingUtilities.invokeAndWait(f[0]::dispose);
+        return i;
+    }
+
+    private static class MyComponent extends JComponent {
+        private final Consumer<Graphics2D> painter;
+
+        private MyComponent(Consumer<Graphics2D> painter) {
+            this.painter = painter;
+        }
+
+        @Override
+        protected void paintComponent(Graphics g) {
+            g.translate(1, 1);
+            Shape savedClip = g.getClip();
+            g.clipRect(0, 0, getWidth() - 2, getHeight() - 2);
+            painter.accept((Graphics2D)g);
+            g.setClip(savedClip);
+            g.setColor(Color.black);
+            g.drawRect(-1, -1, getWidth() - 1, getHeight() - 1);
+        }
+    }
+}