fix: use the better way to fix rendering problems

RtcSurfaceView.swift

@@ -14,23 +14,27 @@ class RtcSurfaceView: UIView {
     private var surface: UIView
     private var canvas: AgoraRtcVideoCanvas
     private weak var channel: AgoraRtcChannel?
-    
+
     override init(frame: CGRect) {
-        surface = UIView(frame: frame)
+        surface = UIView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: frame.size))
         canvas = AgoraRtcVideoCanvas()
         canvas.view = surface
         super.init(frame: frame)
         addSubview(surface)
-        addObserver(self, forKeyPath: "frame", options: .new, context: nil)
+        addObserver(self, forKeyPath: observerForKeyPath(), options: .new, context: nil)
+    }
+
+    func observerForKeyPath() -> String {
+        return "frame"
     }
-    
+
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
-    
+
     deinit {
         canvas.view = nil
-        removeObserver(self, forKeyPath: "frame", context: nil)
+        removeObserver(self, forKeyPath: observerForKeyPath(), context: nil)
     }
 
     func setData(_ engine: AgoraRtcEngineKit, _ channel: AgoraRtcChannel?, _ uid: Int) {
@@ -56,8 +60,10 @@ class RtcSurfaceView: UIView {
     }
 
     private func setupVideoCanvas(_ engine: AgoraRtcEngineKit) {
-        subviews.forEach { $0.removeFromSuperview() }
-        surface = UIView(frame: self.frame)
+        subviews.forEach {
+            $0.removeFromSuperview()
+        }
+        surface = UIView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: bounds.size))
         addSubview(surface)
         canvas.view = surface
         if canvas.uid == 0 {
@@ -88,10 +94,12 @@ class RtcSurfaceView: UIView {
             }
         }
     }
-
-    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
-        if keyPath == "frame" {
-            surface.frame = CGRect(x: 0, y: 0, width: self.frame.width, height: self.frame.height)
+
+    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
+        if keyPath == observerForKeyPath() {
+            if let rect = change?[.newKey] as? CGRect {
+                surface.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: rect.size)
+            }
         }
     }
 }