fix: normalize VideoFrame rotation to 0, 90, 180 or 270

webrtc-javafx/src/test/java/dev/onvoid/webrtc/client/javafx/VideoViewTest.java

@@ -143,6 +143,22 @@ void mirrors() throws Exception {
 		assertTrue(paint(view).getPixelReader().getColor(8, 24).getBrightness() > 0.75);
 	}
 
+	@Test
+	void anyRotationMultiple() throws Exception {
+		// A rotation outside 0..270 is shown as its equal inside it.
+		assertSamePixels(rotated(270), rotated(-90));
+		assertSamePixels(rotated(90), rotated(450));
+
+		// Sideways, a 4:3 picture in a 4:3 view leaves bars on the sides.
+		VideoView view = sized(64, 48);
+		view.accept(frame(64, 48, 128, 128, -90));
+		presented(view);
+
+		Image painted = paint(view);
+		assertEquals(Color.BLACK, painted.getPixelReader().getColor(2, 24));
+		assertGray(painted.getPixelReader().getColor(32, 24));
+	}
+
 	@Test
 	void showsRemoteVideo() throws Exception {
 		SignalingPair link = Signaling.loopback();
@@ -219,11 +235,24 @@ private static <T> T onFx(Callable<T> action) throws Exception {
 		return result.get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
 	}
 
+	/** What a 64x48 view paints of a 64x48 two-tone frame with the given rotation. */
+	private Image rotated(int rotation) throws Exception {
+		VideoView view = sized(64, 48);
+		view.accept(frame(64, 48, 16, 235, rotation));
+		presented(view);
+
+		return paint(view);
+	}
+
+	private static VideoFrame frame(int width, int height, int left, int right) {
+		return frame(width, height, left, right, 0);
+	}
+
 	/**
 	 * A frame whose left half has luma {@code left} and right half {@code right}, with
 	 * neutral chroma.
 	 */
-	private static VideoFrame frame(int width, int height, int left, int right) {
+	private static VideoFrame frame(int width, int height, int left, int right, int rotation) {
 		NativeI420Buffer buffer = NativeI420Buffer.allocate(width, height);
 		ByteBuffer y = buffer.getDataY();
 
@@ -236,7 +265,7 @@ private static VideoFrame frame(int width, int height, int left, int right) {
 		fill(buffer.getDataU());
 		fill(buffer.getDataV());
 
-		return new VideoFrame(buffer, System.nanoTime());
+		return new VideoFrame(buffer, rotation, System.nanoTime());
 	}
 
 	private static void fill(ByteBuffer plane) {
@@ -245,6 +274,18 @@ private static void fill(ByteBuffer plane) {
 		}
 	}
 
+	private static void assertSamePixels(Image expected, Image actual) {
+		assertEquals((int) expected.getWidth(), (int) actual.getWidth());
+		assertEquals((int) expected.getHeight(), (int) actual.getHeight());
+
+		for (int y = 0; y < (int) expected.getHeight(); y++) {
+			for (int x = 0; x < (int) expected.getWidth(); x++) {
+				assertEquals(expected.getPixelReader().getArgb(x, y), actual.getPixelReader().getArgb(x, y),
+						"Pixel " + x + "," + y);
+			}
+		}
+	}
+
 	private static void assertGray(Color color) {
 		assertNotNull(color);
 		assertTrue(Math.abs(color.getRed() - color.getGreen()) < 0.04 && Math.abs(color.getGreen() - color.getBlue()) < 0.04

webrtc/src/main/java/dev/onvoid/webrtc/media/video/VideoFrame.java

@@ -32,7 +32,7 @@ public class VideoFrame implements RefCounted {
 	/** The underlying frame buffer. */
 	public final VideoFrameBuffer buffer;
 
-	/** Rotation of the frame in degrees. */
+	/** Clockwise rotation of the frame in degrees: 0, 90, 180 or 270. */
 	public final int rotation;
 
 	/** Timestamp of the frame in nanoseconds. */
@@ -55,7 +55,9 @@ public VideoFrame(VideoFrameBuffer buffer, long timestampNs) {
 	 * Creates a new VideoFrame with the specified buffer, rotation and timestamp.
 	 *
 	 * @param buffer      The video frame buffer containing the actual frame data.
-	 * @param rotation    The rotation of the frame in degrees (must be a multiple of 90).
+	 * @param rotation    The clockwise rotation of the frame in degrees (must be a multiple of 90).
+	 *                    Any multiple is taken, and kept as its equal in 0, 90, 180 or 270, so that
+	 *                    -90 and 450 are stored as 270 and 90.
 	 * @param timestampNs The timestamp of the frame in nanoseconds.
 	 *
 	 * @throws IllegalArgumentException If buffer is null or rotation is not a multiple of 90.
@@ -69,7 +71,7 @@ public VideoFrame(VideoFrameBuffer buffer, int rotation, long timestampNs) {
 		}
 
 		this.buffer = buffer;
-		this.rotation = rotation;
+		this.rotation = ((rotation % 360) + 360) % 360;
 		this.timestampNs = timestampNs;
 	}
 

webrtc/src/test/java/dev/onvoid/webrtc/client/VideoViewTests.java

@@ -16,6 +16,7 @@
 
 package dev.onvoid.webrtc.client;
 
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -80,6 +81,22 @@ void mirrors() {
 		assertTrue(brightness(paint(view).getRGB(8, 24)) > 192);
 	}
 
+	@Test
+	void anyRotationMultiple() {
+		// A rotation outside 0..270 is shown as its equal inside it.
+		assertArrayEquals(rotated(270), rotated(-90));
+		assertArrayEquals(rotated(90), rotated(450));
+
+		// Sideways, a 4:3 picture in a 4:3 view leaves bars on the sides.
+		VideoView view = new VideoView();
+		view.setSize(64, 48);
+		view.accept(frame(64, 48, 128, 128, -90));
+
+		BufferedImage painted = paint(view);
+		assertEquals(Color.BLACK, new Color(painted.getRGB(2, 24)));
+		assertGray(new Color(painted.getRGB(32, 24)));
+	}
+
 	@Test
 	void showsRemoteVideo() throws Exception {
 		Peer[] peers = pair();
@@ -112,11 +129,24 @@ void showsRemoteVideo() throws Exception {
 		assertEquals(320, snapshot.getWidth());
 	}
 
+	/** The pixels a 64x48 view paints of a 64x48 two-tone frame with the given rotation. */
+	private static int[] rotated(int rotation) {
+		VideoView view = new VideoView();
+		view.setSize(64, 48);
+		view.accept(frame(64, 48, 16, 235, rotation));
+
+		return paint(view).getRGB(0, 0, 64, 48, null, 0, 64);
+	}
+
+	private static VideoFrame frame(int width, int height, int left, int right) {
+		return frame(width, height, left, right, 0);
+	}
+
 	/**
 	 * A frame whose left half has luma {@code left} and right half {@code right}, with
 	 * neutral chroma.
 	 */
-	private static VideoFrame frame(int width, int height, int left, int right) {
+	private static VideoFrame frame(int width, int height, int left, int right, int rotation) {
 		NativeI420Buffer buffer = NativeI420Buffer.allocate(width, height);
 		ByteBuffer y = buffer.getDataY();
 
@@ -129,7 +159,7 @@ private static VideoFrame frame(int width, int height, int left, int right) {
 		fill(buffer.getDataU());
 		fill(buffer.getDataV());
 
-		return new VideoFrame(buffer, System.nanoTime());
+		return new VideoFrame(buffer, rotation, System.nanoTime());
 	}
 
 	private static void fill(ByteBuffer plane) {