feat(ui): add preview API for camerax CameraViewFinder

core/src/main/java/io/github/thibaultbee/streampack/core/streamers/DefaultCameraStreamer.kt

@@ -55,7 +55,7 @@ fun DefaultCameraStreamer(
  * @param internalEndpoint the [IEndpointInternal] implementation
  */
 open class DefaultCameraStreamer(
-    private val context: Context,
+    context: Context,
     audioSourceInternal: IAudioSourceInternal?,
     internalEndpoint: IEndpointInternal = DynamicEndpoint(context)
 ) : DefaultStreamer(

core/src/main/java/io/github/thibaultbee/streampack/core/streamers/DefaultStreamer.kt

@@ -61,7 +61,7 @@ import java.util.concurrent.Executors
  * @param dispatcher the [CoroutineDispatcher] to execute suspendable methods. For test only. Do not change.
  */
 open class DefaultStreamer(
-    private val context: Context,
+    protected val context: Context,
     protected val audioSourceInternal: IAudioSourceInternal?,
     protected val videoSourceInternal: IVideoSourceInternal?,
     protected val endpointInternal: IEndpointInternal = DynamicEndpoint(context),
@@ -79,7 +79,7 @@ open class DefaultStreamer(
     // Keep configurations
     private var _audioConfig: AudioConfig? = null
     private var _videoConfig: VideoConfig? = null
-    
+
     override val audioConfig: AudioConfig?
         get() = _audioConfig
 

gradle/libs.versions.toml

@@ -1,5 +1,6 @@
 [versions]
 agp = "8.5.2"
+guava = "33.3.1-android"
 videoApiClient = "1.5.7"
 androidxActivity = "1.9.2"
 androidxAppcompat = "1.7.0"
@@ -26,6 +27,7 @@ srtdroid = "1.8.3"
 junitKtx = "1.2.1"
 
 [libraries]
+guava = { module = "com.google.guava:guava", version.ref = "guava" }
 video-api-client = { module = "video.api:android-api-client", version.ref = "videoApiClient" }
 android-gradle = { module = "com.android.tools.build:gradle", version.ref = "agp" }
 android-material = { module = "com.google.android.material:material", version.ref = "material" }

ui/build.gradle.kts

@@ -21,4 +21,5 @@ dependencies {
     implementation(libs.androidx.lifecycle.runtime)
     implementation(libs.androidx.camera.viewfinder.view)
     implementation(libs.androidx.core.ktx)
+    implementation(libs.guava)
 }

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

@@ -0,0 +1,115 @@
+package io.github.thibaultbee.streampack.ui.views
+
+import android.content.Context
+import android.hardware.camera2.CameraCharacteristics
+import android.util.Size
+import android.view.Surface
+import androidx.camera.impl.utils.futures.FutureCallback
+import androidx.camera.impl.utils.futures.Futures
+import androidx.camera.viewfinder.CameraViewfinder
+import androidx.camera.viewfinder.CameraViewfinderExt.requestSurface
+import androidx.camera.viewfinder.surface.ViewfinderSurfaceRequest
+import androidx.camera.viewfinder.surface.populateFromCharacteristics
+import androidx.core.content.ContextCompat
+import io.github.thibaultbee.streampack.core.streamers.interfaces.ICameraCallbackStreamer
+import io.github.thibaultbee.streampack.core.streamers.interfaces.ICameraCoroutineStreamer
+import io.github.thibaultbee.streampack.core.streamers.interfaces.startPreview
+import io.github.thibaultbee.streampack.core.utils.extensions.getCameraCharacteristics
+
+/**
+ * Start preview on a [CameraViewfinder]
+ *
+ * @param viewfinder The [CameraViewfinder] to set as preview
+ * @param previewSize The size of the preview
+ * @return The [ViewfinderSurfaceRequest] used to set the preview. Use it to call [ViewfinderSurfaceRequest.markSurfaceSafeToRelease] after [stopPreview].
+ */
+suspend fun ICameraCoroutineStreamer.startPreview(
+    viewfinder: CameraViewfinder,
+    previewSize: Size
+): ViewfinderSurfaceRequest {
+    val request = setPreview(viewfinder, previewSize)
+    startPreview()
+    return request
+}
+
+/**
+ * Set preview on a [CameraViewfinder]
+ *
+ * @param viewfinder The [CameraViewfinder] to set as preview
+ * @param previewSize The size of the preview
+ * @return The [ViewfinderSurfaceRequest] used to set the preview. Use it to call [ViewfinderSurfaceRequest.markSurfaceSafeToRelease].
+ */
+suspend fun ICameraCoroutineStreamer.setPreview(
+    viewfinder: CameraViewfinder,
+    previewSize: Size
+): ViewfinderSurfaceRequest {
+    val builder = ViewfinderSurfaceRequest.Builder(previewSize)
+    val cameraCharacteristics = viewfinder.context.getCameraCharacteristics(camera)
+    val request = builder.populateFromCharacteristics(cameraCharacteristics).build()
+    setPreview(viewfinder.requestSurface(request))
+    return request
+}
+
+/**
+ * Start preview on a [CameraViewfinder]
+ *
+ * @param viewfinder The [CameraViewfinder] to set as preview
+ * @param previewSize The size of the preview
+ * @return The [ViewfinderSurfaceRequest] used to set the preview. Use it to call [ViewfinderSurfaceRequest.markSurfaceSafeToRelease] after [stopPreview].
+ */
+fun ICameraCallbackStreamer.startPreview(
+    viewfinder: CameraViewfinder,
+    previewSize: Size
+): ViewfinderSurfaceRequest {
+    val cameraCharacteristics = viewfinder.context.getCameraCharacteristics(camera)
+    return executeSurfaceRequest(
+        viewfinder.context,
+        viewfinder,
+        previewSize,
+        cameraCharacteristics
+    ) {
+        startPreview(it)
+    }
+}
+
+/**
+ * Set preview on a [CameraViewfinder].
+ *
+ * @param viewfinder The [CameraViewfinder] to set as preview
+ * @param previewSize The size of the preview
+ * @return The [ViewfinderSurfaceRequest] used to set the preview. Use it to call [ViewfinderSurfaceRequest.markSurfaceSafeToRelease].
+ */
+fun ICameraCallbackStreamer.setPreview(
+    viewfinder: CameraViewfinder,
+    previewSize: Size
+): ViewfinderSurfaceRequest {
+    val cameraCharacteristics = viewfinder.context.getCameraCharacteristics(camera)
+    return executeSurfaceRequest(
+        viewfinder.context,
+        viewfinder,
+        previewSize,
+        cameraCharacteristics
+    ) { setPreview(it) }
+}
+
+private fun executeSurfaceRequest(
+    context: Context,
+    viewfinder: CameraViewfinder,
+    previewSize: Size,
+    cameraCharacteristics: CameraCharacteristics,
+    block: (Surface) -> Unit
+): ViewfinderSurfaceRequest {
+    val builder = ViewfinderSurfaceRequest.Builder(previewSize)
+    val request = builder.populateFromCharacteristics(cameraCharacteristics).build()
+    val surfaceListenableFuture = viewfinder.requestSurfaceAsync(request)
+    Futures.addCallback(surfaceListenableFuture, object : FutureCallback<Surface> {
+        override fun onSuccess(result: Surface?) {
+            result?.let { block(it) }
+        }
+
+        override fun onFailure(t: Throwable) { /* something went wrong */
+        }
+    }, ContextCompat.getMainExecutor(context))
+
+    return request
+}