android camerax怎样实现实时滤镜

在Android中使用CameraX库实现实时滤镜，可以通过以下步骤来完成：

1. 添加依赖： 首先，在你的build.gradle文件中添加CameraX和滤镜相关的依赖项。

   dependencies {
       implementation 'androidx.camera:camera-core:1.0.0'
       implementation 'androidx.camera:camera-camera2:1.0.0'
       implementation 'androidx.camera:camera-lifecycle:1.0.0'
       implementation 'androidx.camera:camera-view:1.0.0'
       implementation 'com.google.android.material:material:1.2.1'
       // 如果你需要使用滤镜库，可以添加如Glide或Picasso等库
   }
   

2. 配置CameraX： 在你的Activity或Fragment中，配置CameraX并设置预览视图。

   import androidx.appcompat.app.AppCompatActivity
   import android.os.Bundle
   import androidx.camera.core.CameraSelector
   import androidx.camera.core.ImageAnalysis
   import androidx.camera.core.ImageProxy
   import androidx.camera.core.ImageAnalyzer
   import androidx.camera.core.ImageProxy
   import androidx.camera.lifecycle.ProcessCameraProvider
   import androidx.camera.view.PreviewView
   import kotlinx.coroutines.Dispatchers
   import kotlinx.coroutines.GlobalScope
   import kotlinx.coroutines.launch
   import java.util.concurrent.ExecutorService
   import java.util.concurrent.Executors
   
   class MainActivity : AppCompatActivity() {
   
       private lateinit var cameraProviderFuture: ProcessCameraProvider
       private lateinit var previewView: PreviewView
       private lateinit var imageAnalyzer: ImageAnalyzer
   
       override fun onCreate(savedInstanceState: Bundle?) {
           super.onCreate(savedInstanceState)
           setContentView(R.layout.activity_main)
   
           previewView = findViewById(R.id.previewView)
   
           // 创建一个单线程的ExecutorService用于图像分析
           val executor: ExecutorService = Executors.newSingleThreadExecutor()
   
           // 获取CameraProvider
           cameraProviderFuture = ProcessCameraProvider.getInstance(this)
   
           // 设置预览视图
           previewView.previewViewInfo = PreviewView.PreviewViewInfo.Builder().build()
   
           // 创建图像分析器
           imageAnalyzer = ImageAnalyzer(executor)
   
           // 设置相机选择器
           val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()
   
           // 绑定预览视图和相机提供者
           cameraProviderFuture.addListener({
               val cameraProvider = cameraProviderFuture.get()
               bindPreviewAndImageAnalyzer(cameraProvider)
           }, ContextCompat.getMainExecutor(this))
       }
   
       private fun bindPreviewAndImageAnalyzer(cameraProvider: ProcessCameraProvider) {
           val preview = Preview.Builder().build().also {
               it.setSurfaceProvider(previewView.surfaceProvider)
           }
   
           val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()
   
           val imageAnalyzer = ImageAnalyzer(executor)
   
           val cameraTap = ImageProxy.Builder().build()
   
           cameraProvider.unbindAll()
           cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageAnalyzer, cameraTap)
       }
   }
   

3. 实现图像分析器： 创建一个图像分析器类，用于处理图像并应用滤镜效果。

   import android.renderscript.Allocation
   import android.renderscript.Element
   import android.renderscript.RenderScript
   import android.renderscript.ScriptIntrinsicBlur
   import androidx.camera.core.ImageProxy
   import java.nio.ByteBuffer
   
   class ImageAnalyzer(private val executor: ExecutorService) : ImageAnalysis.Analyzer {
   
       private val rs = RenderScript.create(applicationContext)
       private val inAllocation = Allocation.createFromBitmap(rs, (previewView as PreviewView).image)
       private val outAllocation = Allocation.createFromBitmap(rs, (previewView as PreviewView).image)
       private val scriptIntrinsicBlur = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs))
   
       override fun analyze(imageProxy: ImageProxy) {
           if (imageProxy.image != null) {
               val mediaImage = imageProxy.image!!
               inAllocation.copyFrom(mediaImage)
   
               // 应用滤镜效果
               scriptIntrinsicBlur.setRadius(5f) // 设置模糊半径
               scriptIntrinsicBlur.setInput(inAllocation)
               scriptIntrinsicBlur.forEach(outAllocation)
   
               // 将处理后的图像设置回预览视图
               outAllocation.copyTo(mediaImage)
               imageProxy.image = mediaImage
   
               // 释放资源
               inAllocation.destroy()
               outAllocation.destroy()
           }
   
           imageProxy.close()
       }
   }
   

4. 布局文件： 确保你的布局文件中有一个PreviewView用于显示预览图像。

   <androidx.camera.view.PreviewView
       android:id="@+id/previewView"
       android:layout_width="match_parent"
       android:layout_height="match_parent" />
   

通过以上步骤，你可以在Android中使用CameraX库实现实时滤镜效果。注意，这里的示例使用了RenderScript来进行模糊效果的处理，你可以根据需要替换为其他滤镜效果。