Introduce VideoConstraints

Group video constraints into a dedicated class. For now it only contains
the `alignment` field; additional constraints will be added in further
commits.

PR #6766 <https://github.com/Genymobile/scrcpy/pull/6766>

server/src/main/java/com/genymobile/scrcpy/device/Size.java

@@ -1,5 +1,7 @@
 package com.genymobile.scrcpy.device;
 
+import com.genymobile.scrcpy.video.VideoConstraints;
+
 import android.graphics.Rect;
 
 import java.util.Objects;
@@ -29,7 +31,9 @@ public final class Size {
         return new Size(height, width);
     }
 
-    public Size constrain(int maxSize, int alignment) {
+    public Size constrain(int maxSize, VideoConstraints constraints) {
+        int alignment = constraints.getAlignment();
+
         assert maxSize >= 0 : "Max size may not be negative";
         assert alignment > 0 : "Alignment must be positive";
         assert (alignment & (alignment - 1)) == 0 : "Alignment must be a power-of-two";

server/src/main/java/com/genymobile/scrcpy/video/CameraCapture.java

@@ -149,7 +149,7 @@ public class CameraCapture extends SurfaceCapture {
         filter.addAngle(angle);
 
         transform = filter.getInverseTransform();
-        videoSize = filter.getOutputSize().constrain(maxSize, getAlignment());
+        videoSize = filter.getOutputSize().constrain(maxSize, getVideoConstraints());
     }
 
     private static String selectCamera(String explicitCameraId, CameraFacing cameraFacing) throws CameraAccessException, ConfigurationException {

server/src/main/java/com/genymobile/scrcpy/video/NewDisplayCapture.java

@@ -134,7 +134,7 @@ public class NewDisplayCapture extends SurfaceCapture {
         filter.addAngle(angle);
 
         Size outputSize = filter.getOutputSize();
-        Size filteredSize = outputSize.constrain(maxSize, getAlignment());
+        Size filteredSize = outputSize.constrain(maxSize, getVideoConstraints());
         if (!filteredSize.equals(outputSize)) {
             filter.addResize(filteredSize);
         }

server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java

@@ -97,7 +97,7 @@ public class ScreenCapture extends SurfaceCapture {
         filter.addAngle(angle);
 
         transform = filter.getInverseTransform();
-        videoSize = filter.getOutputSize().constrain(maxSize, getAlignment());
+        videoSize = filter.getOutputSize().constrain(maxSize, getVideoConstraints());
     }
 
     @Override

server/src/main/java/com/genymobile/scrcpy/video/SurfaceCapture.java

@@ -17,7 +17,7 @@ public abstract class SurfaceCapture {
     }
 
     private CaptureListener listener;
-    private int alignment;
+    private VideoConstraints constraints;
 
     /**
      * Notify the listener that the capture has been invalidated (for example, because its size changed, or due to a manual user request).
@@ -29,9 +29,9 @@ public abstract class SurfaceCapture {
     /**
      * Called once before the first capture starts.
      */
-    public final void init(CaptureListener listener, int alignment) throws ConfigurationException, IOException {
+    public final void init(CaptureListener listener, VideoConstraints constraints) throws ConfigurationException, IOException {
         this.listener = listener;
-        this.alignment = alignment;
+        this.constraints = constraints;
         init();
     }
 
@@ -83,13 +83,11 @@ public abstract class SurfaceCapture {
     }
 
     /**
-     * Return the video alignment
-     * <p>
-     * This a power-of-2 value that the video width and height must be multiples of.
+     * Return the video constraints.
      *
-     * @return the video alignment
+     * @return the video constraints
      */
-    protected int getAlignment() {
-        return alignment;
+    protected VideoConstraints getVideoConstraints() {
+        return constraints;
     }
 }

server/src/main/java/com/genymobile/scrcpy/video/SurfaceEncoder.java

@@ -67,8 +67,9 @@ public class SurfaceEncoder implements AsyncProcessor {
             alignment = minSizeAlignment;
             Ln.d("Actual video size alignment: " + alignment + "px");
         }
+        VideoConstraints constraints = new VideoConstraints(alignment);
 
-        capture.init(reset, alignment);
+        capture.init(reset, constraints);
 
         try {
             boolean alive;

server/src/main/java/com/genymobile/scrcpy/video/VideoConstraints.java

@@ -0,0 +1,22 @@
+package com.genymobile.scrcpy.video;
+
+public class VideoConstraints {
+    private final int alignment;
+
+    public VideoConstraints(int alignment) {
+        assert alignment > 0 : "Alignment must be positive";
+        assert (alignment & (alignment - 1)) == 0 : "Alignment must be a power-of-two";
+        this.alignment = alignment;
+    }
+
+    /**
+     * Return the video alignment.
+     * <p>
+     * This a power-of-2 value that the video width and height must be multiples of.
+     *
+     * @return the video alignment
+     */
+    public int getAlignment() {
+        return alignment;
+    }
+}

server/src/test/java/com/genymobile/scrcpy/device/SizeTest.java

@@ -1,35 +1,42 @@
 package com.genymobile.scrcpy.device;
 
+import com.genymobile.scrcpy.video.VideoConstraints;
+
 import org.junit.Assert;
 import org.junit.Test;
 
 public class SizeTest {
+
+    private VideoConstraints createVideoConstraints(int alignment) {
+        return new VideoConstraints(alignment);
+    }
+
     @Test
     public void testConstrainSize() {
         Size size = new Size(207, 209);
 
-        Assert.assertEquals(size, size.constrain(0, 1));
-        Assert.assertEquals(new Size(208, 210), size.constrain(0, 2));
-        Assert.assertEquals(new Size(208, 208), size.constrain(0, 4));
+        Assert.assertEquals(size, size.constrain(0, createVideoConstraints(1)));
+        Assert.assertEquals(new Size(208, 210), size.constrain(0, createVideoConstraints(2)));
+        Assert.assertEquals(new Size(208, 208), size.constrain(0, createVideoConstraints(4)));
 
-        Size s = size.constrain(208, 2);
+        Size s = size.constrain(208, createVideoConstraints(2));
         Assert.assertEquals(208, s.getHeight());
         Assert.assertTrue(s.getWidth() >= 206 && s.getWidth() <= 208 && s.getWidth() % 2 == 0);
 
-        Assert.assertEquals(new Size(207 * 208 / 209, 208), size.constrain(208, 2));
-        Assert.assertEquals(new Size(208, 208), size.constrain(208, 4));
+        Assert.assertEquals(new Size(207 * 208 / 209, 208), size.constrain(208, createVideoConstraints(2)));
+        Assert.assertEquals(new Size(208, 208), size.constrain(208, createVideoConstraints(4)));
     }
 
     @Test
     public void testConstrainSizeUnchanged() {
         Size size = new Size(256, 512);
 
-        Assert.assertEquals(size, size.constrain(0, 1));
-        Assert.assertEquals(size, size.constrain(512, 1));
-        Assert.assertEquals(size, size.constrain(515, 1));
-        Assert.assertEquals(size, size.constrain(512, 16));
-        Assert.assertEquals(size, size.constrain(515, 16));
-        Assert.assertEquals(size, size.constrain(0, 16));
-        Assert.assertEquals(size, size.constrain(4096, 16));
+        Assert.assertEquals(size, size.constrain(0, createVideoConstraints(1)));
+        Assert.assertEquals(size, size.constrain(512, createVideoConstraints(1)));
+        Assert.assertEquals(size, size.constrain(515, createVideoConstraints(1)));
+        Assert.assertEquals(size, size.constrain(512, createVideoConstraints(16)));
+        Assert.assertEquals(size, size.constrain(515, createVideoConstraints(16)));
+        Assert.assertEquals(size, size.constrain(0, createVideoConstraints(16)));
+        Assert.assertEquals(size, size.constrain(4096, createVideoConstraints(16)));
     }
 }