feat(video): add custom zoom controls

close #1159

android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt

@@ -122,6 +122,7 @@ class ExoPlayerCore(private val activity: Activity) : Player.Listener {
   private var surfaceContainer: FrameLayout? = null
   private var videoAspectContainer: AspectRatioFrameLayout? = null
   private var subtitleView: SubtitleView? = null
+  private var videoZoomScale: Float = 1.0f
   private var assHandler: AssHandler? = null
   private var overlayLayoutListener: ViewTreeObserver.OnGlobalLayoutListener? = null
   private var lastVideoSize: VideoSize? = null
@@ -1193,18 +1194,26 @@ class ExoPlayerCore(private val activity: Activity) : Player.Listener {
     val containerHeight = contentView.height
     if (containerWidth == 0 || containerHeight == 0) return
 
-    // In cover/stretch modes subtitles stay at container size so they never get
-    // cropped or distorted. In letterbox mode they follow the video rect so they
-    // anchor to the bottom of the video (matching MPV's default sub positioning).
+    // In cover/stretch/zoomed-in modes subtitles stay at container size so they
+    // never get cropped. In letterbox mode they follow the visible video rect.
     val isLetterbox = videoAspectContainer?.resizeMode == AspectRatioFrameLayout.RESIZE_MODE_FIT
     val (subWidth, subHeight) = if (isLetterbox) {
       val videoAspect = (videoWidth * pixelRatio) / videoHeight
       val containerAspect = containerWidth.toFloat() / containerHeight
-      if (videoAspect > containerAspect) {
+      val (baseWidth, baseHeight) = if (videoAspect > containerAspect) {
         containerWidth to (containerWidth / videoAspect).toInt()
       } else {
         (containerHeight * videoAspect).toInt() to containerHeight
       }
+      if (videoZoomScale < 0.999f) {
+        val zoomedWidth = ((baseWidth * videoZoomScale).toInt()).coerceAtLeast(1)
+        val zoomedHeight = ((baseHeight * videoZoomScale).toInt()).coerceAtLeast(1)
+        zoomedWidth to zoomedHeight
+      } else if (videoZoomScale > 1.001f) {
+        containerWidth to containerHeight
+      } else {
+        baseWidth to baseHeight
+      }
     } else {
       containerWidth to containerHeight
     }
@@ -1235,6 +1244,21 @@ class ExoPlayerCore(private val activity: Activity) : Player.Listener {
     }
   }
 
+  fun setVideoZoom(scale: Double) {
+    if (disposing) return
+    val clamped = scale.coerceIn(0.5, 2.0).toFloat()
+    activity.runOnUiThread {
+      videoZoomScale = clamped
+      videoAspectContainer?.scaleX = clamped
+      videoAspectContainer?.scaleY = clamped
+      lastVideoSize?.let { vs ->
+        if (vs.width > 0 && vs.height > 0) {
+          updateSubtitleViewSize(vs.width, vs.height, vs.pixelWidthHeightRatio)
+        }
+      }
+    }
+  }
+
   private fun emitTrackList() {
     val player = exoPlayer ?: return
     val tracks = player.currentTracks

android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerPlugin.kt

@@ -148,6 +148,7 @@ class ExoPlayerPlugin :
       }
       "setSubtitleStyle" -> handleSetSubtitleStyle(call, result)
       "setBoxFitMode" -> handleSetBoxFitMode(call, result)
+      "setVideoZoom" -> handleSetVideoZoom(call, result)
       "setDvConversionMode" -> handleSetDvConversionMode(call, result)
       "observeProperty" -> handleObserveProperty(call, result)
       "setMpvProperty" -> handleSetMpvProperty(call, result)
@@ -550,6 +551,22 @@ class ExoPlayerPlugin :
     } ?: result.success(null)
   }
 
+  private fun handleSetVideoZoom(call: MethodCall, result: MethodChannel.Result) {
+    val scale = call.argument<Number>("scale")?.toDouble()
+    if (scale == null) {
+      result.error("INVALID_ARGS", "Missing 'scale'", null)
+      return
+    }
+    if (usingMpvFallback) {
+      result.success(null)
+      return
+    }
+    activity?.runOnUiThread {
+      playerCore?.setVideoZoom(scale)
+      result.success(null)
+    } ?: result.success(null)
+  }
+
   private fun handleSetDvConversionMode(call: MethodCall, result: MethodChannel.Result) {
     val mode = call.argument<String>("mode")
     if (mode == null) {