From 06385ce83bcfd57ac82e2f5ca4d9575fe1f1649f Mon Sep 17 00:00:00 2001
From: Romain Vimont <rom@rom1v.com>
Date: Sun, 10 Nov 2024 16:21:59 +0100
Subject: [PATCH] Reimplement lock orientation using transforms

Reimplement the --lock-video-orientation feature using affine
transforms.

Fixes #4011 <https://github.com/Genymobile/scrcpy/issues/4011>
PR #5455 <https://github.com/Genymobile/scrcpy/pull/5455>
---
 .../genymobile/scrcpy/video/ScreenCapture.java   | 11 +++++++++++
 .../com/genymobile/scrcpy/video/VideoFilter.java | 16 ++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java b/server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java
index 79d4974d..bc0f825a 100644
--- a/server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java
+++ b/server/src/main/java/com/genymobile/scrcpy/video/ScreenCapture.java
@@ -35,6 +35,7 @@ public class ScreenCapture extends SurfaceCapture {
     private final int displayId;
     private int maxSize;
     private final Rect crop;
+    private int lockVideoOrientation;
 
     private DisplayInfo displayInfo;
     private Size videoSize;
@@ -64,6 +65,7 @@ public class ScreenCapture extends SurfaceCapture {
         assert displayId != Device.DISPLAY_ID_NONE;
         this.maxSize = options.getMaxSize();
         this.crop = options.getCrop();
+        this.lockVideoOrientation = options.getLockVideoOrientation();
     }
 
     @Override
@@ -136,6 +138,11 @@ public class ScreenCapture extends SurfaceCapture {
         Size displaySize = displayInfo.getSize();
         setSessionDisplaySize(displaySize);
 
+        if (lockVideoOrientation == Device.LOCK_VIDEO_ORIENTATION_INITIAL) {
+            // The user requested to lock the video orientation to the current orientation
+            lockVideoOrientation = displayInfo.getRotation();
+        }
+
         VideoFilter filter = new VideoFilter(displaySize);
 
         if (crop != null) {
@@ -143,6 +150,10 @@ public class ScreenCapture extends SurfaceCapture {
             filter.addCrop(crop, transposed);
         }
 
+        if (lockVideoOrientation != Device.LOCK_VIDEO_ORIENTATION_UNLOCKED) {
+            filter.addLockVideoOrientation(lockVideoOrientation, displayInfo.getRotation());
+        }
+
         transform = filter.getInverseTransform();
         videoSize = filter.getOutputSize().limit(maxSize).round8();
     }
diff --git a/server/src/main/java/com/genymobile/scrcpy/video/VideoFilter.java b/server/src/main/java/com/genymobile/scrcpy/video/VideoFilter.java
index 5a52231f..2d570446 100644
--- a/server/src/main/java/com/genymobile/scrcpy/video/VideoFilter.java
+++ b/server/src/main/java/com/genymobile/scrcpy/video/VideoFilter.java
@@ -66,4 +66,20 @@ public class VideoFilter {
         transform = AffineMatrix.reframe(x, y, w, h).multiply(transform);
         size = new Size(crop.width(), crop.height());
     }
+
+    public void addRotation(int ccwRotation) {
+        if (ccwRotation == 0) {
+            return;
+        }
+
+        transform = AffineMatrix.rotateOrtho(ccwRotation).multiply(transform);
+        if (ccwRotation % 2 != 0) {
+            size = size.rotate();
+        }
+    }
+
+    public void addLockVideoOrientation(int lockVideoOrientation, int displayRotation) {
+        int ccwRotation = (4 + lockVideoOrientation - displayRotation) % 4;
+        addRotation(ccwRotation);
+    }
 }