refactor(*): add listener for camera zoom

Author: ThibaultBee

core/src/main/java/io/github/thibaultbee/streampack/core/elements/sources/video/camera/CameraSettings.kt

@@ -73,6 +73,7 @@ import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import java.util.concurrent.CancellationException
+import java.util.concurrent.CopyOnWriteArrayList
 import java.util.concurrent.atomic.AtomicLong
 
 
@@ -684,6 +685,8 @@ class CameraSettings internal constructor(
         protected val characteristics: CameraCharacteristics,
         protected val cameraSettings: CameraSettings
     ) {
+        private val listeners: CopyOnWriteArrayList<OnZoomChangedListener> = CopyOnWriteArrayList()
+
         abstract val availableRatioRange: Range<Float>
         internal abstract suspend fun getCropSensorRegion(): Rect
 
@@ -709,6 +712,20 @@ class CameraSettings internal constructor(
             }
         }
 
+        fun addListener(listener: OnZoomChangedListener) {
+            listeners.add(listener)
+        }
+
+        fun removeListener(listener: OnZoomChangedListener) {
+            listeners.remove(listener)
+        }
+
+        protected fun notifyZoomListeners(zoomRatio: Float) {
+            listeners.forEach {
+                it.onZoomChanged(zoomRatio)
+            }
+        }
+
         class CropScalerRegionZoom internal constructor(
             characteristics: CameraCharacteristics,
             cameraSettings: CameraSettings
@@ -732,15 +749,20 @@ class CameraSettings internal constructor(
             override suspend fun setZoomRatio(zoomRatio: Float) {
                 mutex.withLock {
                     val clampedValue = zoomRatio.clamp(availableRatioRange)
+                    if (clampedValue == persistentZoomRatio) {
+                        return@withLock
+                    }
+                    persistentZoomRatio = clampedValue
+
                     currentCropRect = getCropRegion(
                         characteristics,
                         clampedValue
                     )
                     cameraSettings.set(
                         CaptureRequest.SCALER_CROP_REGION, currentCropRect
                     )
-                    cameraSettings.applyRepeatingSession()
-                    persistentZoomRatio = clampedValue
+                    cameraSettings.applyRepeatingSessionSync()
+                    notifyZoomListeners(clampedValue)
                 }
             }
 
@@ -800,10 +822,14 @@ class CameraSettings internal constructor(
             }
 
             override suspend fun setZoomRatio(zoomRatio: Float) {
+                if (zoomRatio == getZoomRatio()) {
+                    return
+                }
                 cameraSettings.set(
                     CaptureRequest.CONTROL_ZOOM_RATIO, zoomRatio.clamp(availableRatioRange)
                 )
                 cameraSettings.applyRepeatingSession()
+                notifyZoomListeners(zoomRatio)
             }
 
             override suspend fun getCropSensorRegion(): Rect {
@@ -826,6 +852,18 @@ class CameraSettings internal constructor(
                 }
             }
         }
+
+        /**
+         * Listener for zoom change.
+         */
+        interface OnZoomChangedListener {
+            /**
+             * Called when the zoom ratio changes.
+             *
+             * @param zoomRatio the zoom ratio
+             */
+            fun onZoomChanged(zoomRatio: Float)
+        }
     }
 
 

demos/camera/src/main/java/io/github/thibaultbee/streampack/app/ui/main/PreviewFragment.kt

@@ -34,6 +34,7 @@ import io.github.thibaultbee.streampack.app.R
 import io.github.thibaultbee.streampack.app.databinding.MainFragmentBinding
 import io.github.thibaultbee.streampack.app.utils.DialogUtils
 import io.github.thibaultbee.streampack.app.utils.PermissionManager
+import io.github.thibaultbee.streampack.core.elements.sources.video.camera.CameraSettings
 import io.github.thibaultbee.streampack.core.interfaces.IStreamer
 import io.github.thibaultbee.streampack.core.interfaces.IWithVideoSource
 import io.github.thibaultbee.streampack.core.streamers.lifecycle.StreamerViewModelLifeCycleObserver
@@ -182,15 +183,17 @@ class PreviewFragment : Fragment(R.layout.main_fragment) {
     private fun inflateStreamerPreview(streamer: IWithVideoSource) {
         val preview = binding.preview
         // Set camera settings button when camera is started
-        preview.listener = object : PreviewView.Listener {
+        preview.listener = object : PreviewView.PreviewListener {
             override fun onPreviewStarted() {
                 Log.i(TAG, "Preview started")
             }
+        }
 
-            override fun onZoomRationOnPinchChanged(zoomRatio: Float) {
-                previewViewModel.onZoomRationOnPinchChanged()
+        preview.setZoomListener(object : CameraSettings.Zoom.OnZoomChangedListener {
+            override fun onZoomChanged(zoomRatio: Float) {
+                previewViewModel.onZoomChanged()
             }
-        }
+        })
 
         // Wait till streamer exists to set it to the SurfaceView.
         lifecycleScope.launch {

demos/camera/src/main/java/io/github/thibaultbee/streampack/app/ui/main/PreviewViewModel.kt

@@ -247,7 +247,7 @@ class PreviewViewModel(private val application: Application) : ObservableViewMod
         }
     }
 
-    fun onZoomRationOnPinchChanged() {
+    fun onZoomChanged() {
         notifyPropertyChanged(BR.zoomRatio)
     }
 

ui/ui/src/main/java/io/github/thibaultbee/streampack/ui/views/PreviewView.kt

@@ -35,6 +35,7 @@ import androidx.camera.viewfinder.core.ScaleType
 import androidx.camera.viewfinder.core.ViewfinderSurfaceRequest
 import androidx.camera.viewfinder.core.populateFromCharacteristics
 import io.github.thibaultbee.streampack.core.elements.sources.video.IPreviewableSource
+import io.github.thibaultbee.streampack.core.elements.sources.video.camera.CameraSettings
 import io.github.thibaultbee.streampack.core.elements.sources.video.camera.CameraSettings.FocusMetering.Companion.DEFAULT_AUTO_CANCEL_DURATION_MS
 import io.github.thibaultbee.streampack.core.elements.sources.video.camera.ICameraSource
 import io.github.thibaultbee.streampack.core.elements.sources.video.camera.extensions.getCameraCharacteristics
@@ -108,9 +109,11 @@ class PreviewView @JvmOverloads constructor(
         }
 
     /**
-     * The [Listener] to listen to specific view events.
+     * The [PreviewListener] to listen to specific view events.
      */
-    var listener: Listener? = null
+    var listener: PreviewListener? = null
+
+    private var zoomListener: CameraSettings.Zoom.OnZoomChangedListener? = null
 
     private var touchUpEvent: MotionEvent? = null
 
@@ -176,12 +179,46 @@ class PreviewView @JvmOverloads constructor(
                         }
                         if (newVideoSource is IPreviewableSource) {
                             attachToStreamerIfReady(true)
+                            zoomListener?.let {
+                                registerZoomListener(it)
+                            }
                         }
                     }
                 }
         }
     }
 
+    /**
+     * Sets the [CameraSettings.Zoom.OnZoomChangedListener] to listen to zoom changes.
+     *
+     * @param listener the [CameraSettings.Zoom.OnZoomChangedListener] to listen to zoom changes.
+     */
+    fun setZoomListener(listener: CameraSettings.Zoom.OnZoomChangedListener?) {
+        if (listener == null) {
+            unregisterZoomListener()
+        } else {
+            registerZoomListener(listener)
+        }
+        zoomListener = listener
+    }
+
+    private fun registerZoomListener(listener: CameraSettings.Zoom.OnZoomChangedListener) {
+        val source = streamer?.videoInput?.sourceFlow?.value
+        if (source is ICameraSource) {
+            source.settings.zoom.addListener(listener)
+        }
+    }
+
+    private fun unregisterZoomListener() {
+        zoomListener?.let {
+            val source = streamer?.videoInput?.sourceFlow?.value
+            if (source is ICameraSource) {
+                source.settings.zoom.removeListener(it)
+            }
+        }
+    }
+
+
     /**
      * Sets the [IWithVideoSource] to preview.
      *
@@ -504,7 +541,6 @@ class PreviewView @JvmOverloads constructor(
                     mutex.withLock {
                         val zoom = source.settings.zoom
                         zoom.onPinch(scaleFactor)
-                        listener?.onZoomRationOnPinchChanged(zoom.getZoomRatio())
                     }
                 }
                 return true
@@ -518,7 +554,7 @@ class PreviewView @JvmOverloads constructor(
     /**
      * A listener for the [PreviewView].
      */
-    interface Listener {
+    interface PreviewListener {
         /**
          * Called when the preview is started.
          */
@@ -528,12 +564,6 @@ class PreviewView @JvmOverloads constructor(
          * Called when the preview failed to start.
          */
         fun onPreviewFailed(t: Throwable) {}
-
-        /**
-         * Called when the zoom ratio is changed.
-         * @param zoomRatio the new zoom ratio
-         */
-        fun onZoomRationOnPinchChanged(zoomRatio: Float) {}
     }
 
     /**