Introduce PositionMapper

Extract the function that converts coordinates from video space to
display space into a separate component.

It only requires the specific data it uses and does not need a full
ScreenInfo object (although it can be created from a ScreenInfo
instance).

PR #5370 <https://github.com/Genymobile/scrcpy/pull/5370>

server/src/main/java/com/genymobile/scrcpy/control/PositionMapper.java

@@ -0,0 +1,48 @@
+package com.genymobile.scrcpy.control;
+
+import com.genymobile.scrcpy.device.Point;
+import com.genymobile.scrcpy.device.Position;
+import com.genymobile.scrcpy.device.Size;
+import com.genymobile.scrcpy.video.ScreenInfo;
+
+import android.graphics.Rect;
+
+public final class PositionMapper {
+
+    private final Size videoSize;
+    private final Rect contentRect;
+    private final int coordsRotation;
+
+    public PositionMapper(Size videoSize, Rect contentRect, int videoRotation) {
+        this.videoSize = videoSize;
+        this.contentRect = contentRect;
+        this.coordsRotation = reverseRotation(videoRotation);
+    }
+
+    public static PositionMapper from(ScreenInfo screenInfo) {
+        // ignore the locked video orientation, the events will apply in coordinates considered in the physical device orientation
+        Size videoSize = screenInfo.getUnlockedVideoSize();
+        return new PositionMapper(videoSize, screenInfo.getContentRect(), screenInfo.getVideoRotation());
+    }
+
+    private static int reverseRotation(int rotation) {
+        return (4 - rotation) % 4;
+    }
+
+    public Point map(Position position) {
+        // reverse the video rotation to apply the events
+        Position devicePosition = position.rotate(coordsRotation);
+
+        Size clientVideoSize = devicePosition.getScreenSize();
+        if (!videoSize.equals(clientVideoSize)) {
+            // The client sends a click relative to a video with wrong dimensions,
+            // the device may have been rotated since the event was generated, so ignore the event
+            return null;
+        }
+
+        Point point = devicePosition.getPoint();
+        int convertedX = contentRect.left + point.getX() * contentRect.width() / videoSize.getWidth();
+        int convertedY = contentRect.top + point.getY() * contentRect.height() / videoSize.getHeight();
+        return new Point(convertedX, convertedY);
+    }
+}

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

@@ -1,8 +1,8 @@
 package com.genymobile.scrcpy.device;
 
 import com.genymobile.scrcpy.AndroidVersions;
+import com.genymobile.scrcpy.control.PositionMapper;
 import com.genymobile.scrcpy.util.Ln;
-import com.genymobile.scrcpy.video.ScreenInfo;
 import com.genymobile.scrcpy.wrappers.ClipboardManager;
 import com.genymobile.scrcpy.wrappers.DisplayControl;
 import com.genymobile.scrcpy.wrappers.InputManager;
@@ -10,7 +10,6 @@ import com.genymobile.scrcpy.wrappers.ServiceManager;
 import com.genymobile.scrcpy.wrappers.SurfaceControl;
 import com.genymobile.scrcpy.wrappers.WindowManager;
 
-import android.graphics.Rect;
 import android.os.Build;
 import android.os.IBinder;
 import android.os.SystemClock;
@@ -33,34 +32,17 @@ public final class Device {
     public static final int LOCK_VIDEO_ORIENTATION_UNLOCKED = -1;
     public static final int LOCK_VIDEO_ORIENTATION_INITIAL = -2;
 
-    private final AtomicReference<ScreenInfo> screenInfo = new AtomicReference<>(); // set by the ScreenCapture instance
+    private final AtomicReference<PositionMapper> positionMapper = new AtomicReference<>(); // set by the ScreenCapture instance
 
     public Point getPhysicalPoint(Position position) {
         // it hides the field on purpose, to read it with atomic access
         @SuppressWarnings("checkstyle:HiddenField")
-        ScreenInfo screenInfo = this.screenInfo.get();
-        if (screenInfo == null) {
+        PositionMapper positionMapper = this.positionMapper.get();
+        if (positionMapper == null) {
             return null;
         }
 
-        // ignore the locked video orientation, the events will apply in coordinates considered in the physical device orientation
-        Size unlockedVideoSize = screenInfo.getUnlockedVideoSize();
-
-        int reverseVideoRotation = screenInfo.getReverseVideoRotation();
-        // reverse the video rotation to apply the events
-        Position devicePosition = position.rotate(reverseVideoRotation);
-
-        Size clientVideoSize = devicePosition.getScreenSize();
-        if (!unlockedVideoSize.equals(clientVideoSize)) {
-            // The client sends a click relative to a video with wrong dimensions,
-            // the device may have been rotated since the event was generated, so ignore the event
-            return null;
-        }
-        Rect contentRect = screenInfo.getContentRect();
-        Point point = devicePosition.getPoint();
-        int convertedX = contentRect.left + point.getX() * contentRect.width() / unlockedVideoSize.getWidth();
-        int convertedY = contentRect.top + point.getY() * contentRect.height() / unlockedVideoSize.getHeight();
-        return new Point(convertedX, convertedY);
+        return positionMapper.map(position);
     }
 
     public static String getDeviceName() {
@@ -72,8 +54,8 @@ public final class Device {
         return displayId == 0 || Build.VERSION.SDK_INT >= AndroidVersions.API_29_ANDROID_10;
     }
 
-    public void setScreenInfo(ScreenInfo screenInfo) {
-        this.screenInfo.set(screenInfo);
+    public void setPositionMapper(PositionMapper positionMapper) {
+        this.positionMapper.set(positionMapper);
     }
 
     public static boolean injectEvent(InputEvent inputEvent, int displayId, int injectMode) {

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

@@ -1,6 +1,7 @@
 package com.genymobile.scrcpy.video;
 
 import com.genymobile.scrcpy.AndroidVersions;
+import com.genymobile.scrcpy.control.PositionMapper;
 import com.genymobile.scrcpy.device.ConfigurationException;
 import com.genymobile.scrcpy.device.Device;
 import com.genymobile.scrcpy.device.DisplayInfo;
@@ -132,7 +133,8 @@ public class ScreenCapture extends SurfaceCapture {
             }
         }
 
-        device.setScreenInfo(screenInfo);
+        PositionMapper positionMapper = PositionMapper.from(screenInfo);
+        device.setPositionMapper(positionMapper);
     }
 
     @Override