screenshot plugin: fix to paint client ui from EDT

Fix deadlock between the game thread and the EDT

runelite-client/src/main/java/net/runelite/client/plugins/screenshot/ScreenshotPlugin.java

@@ -40,6 +40,7 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.lang.reflect.InvocationTargetException;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.time.LocalDate;
@@ -51,6 +52,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import javax.imageio.ImageIO;
 import javax.inject.Inject;
+import javax.swing.SwingUtilities;
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.extern.slf4j.Slf4j;
@@ -524,7 +526,23 @@ public class ScreenshotPlugin extends Plugin
 			return;
 		}
 
-		Consumer<Image> screenshotConsumer = image ->
+		Consumer<Image> imageCallback = (img) ->
+		{
+			// This callback is on the game thread, move to executor thread
+			executor.submit(() -> takeScreenshot(fileName, img));
+		};
+
+		if (config.displayDate())
+		{
+			screenshotOverlay.queueForTimestamp(imageCallback);
+		}
+		else
+		{
+			drawManager.requestNextFrameListener(imageCallback);
+		}
+	}
+
+	private void takeScreenshot(String fileName, Image image)
 	{
 		BufferedImage screenshot = config.includeFrame()
 			? new BufferedImage(clientUi.getWidth(), clientUi.getHeight(), BufferedImage.TYPE_INT_ARGB)
@@ -538,7 +556,14 @@ public class ScreenshotPlugin extends Plugin
 		if (config.includeFrame())
 		{
 			// Draw the client frame onto the screenshot
-				clientUi.paint(graphics);
+			try
+			{
+				SwingUtilities.invokeAndWait(() -> clientUi.paint(graphics));
+			}
+			catch (InterruptedException | InvocationTargetException e)
+			{
+				log.warn("unable to paint client UI on screenshot", e);
+			}
 
 			// Evaluate the position of the game inside the frame
 			final Point canvasOffset = clientUi.getCanvasOffset();
@@ -572,8 +597,6 @@ public class ScreenshotPlugin extends Plugin
 
 		playerFolder.mkdirs();
 
-			executor.execute(() ->
-			{
 		try
 		{
 			File screenshotFile = new File(playerFolder, fileName + ".png");
@@ -593,17 +616,6 @@ public class ScreenshotPlugin extends Plugin
 		{
 			log.warn("error writing screenshot", ex);
 		}
-			});
-		};
-
-		if (config.displayDate())
-		{
-			screenshotOverlay.queueForTimestamp(screenshotConsumer);
-		}
-		else
-		{
-			drawManager.requestNextFrameListener(screenshotConsumer);
-		}
 	}
 
 	/**

runelite-client/src/main/java/net/runelite/client/ui/ClientUI.java

@@ -543,6 +543,7 @@ public class ClientUI
 	 */
 	public void paint(final Graphics graphics)
 	{
+		assert SwingUtilities.isEventDispatchThread() : "paint must be called on EDT";
 		frame.paint(graphics);
 	}