Keep screen awake,WIP: freeze stream

app/build.gradle

@@ -11,7 +11,7 @@ android {
         minSdk 26
         targetSdk 33
         versionCode 1
-        versionName "1.0"
+        versionName "1.0.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/java/com/polar/mirror/FreezeController.java

@@ -0,0 +1,124 @@
+package com.polar.mirror;
+
+import static androidx.core.content.ContextCompat.getMainExecutor;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.Camera;
+import android.graphics.ImageFormat;
+import android.graphics.Matrix;
+import android.media.Image;
+import android.util.Log;
+import android.view.View;
+import android.widget.ImageView;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.OptIn;
+import androidx.camera.core.CameraSelector;
+import androidx.camera.core.ExperimentalGetImage;
+import androidx.camera.core.ImageCapture;
+import androidx.camera.core.ImageCaptureException;
+import androidx.camera.core.ImageProxy;
+import androidx.camera.lifecycle.ProcessCameraProvider;
+import androidx.camera.view.PreviewView;
+import androidx.lifecycle.LifecycleOwner;
+
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+
+import java.io.File;
+import java.nio.ByteBuffer;
+
+/**
+ * Controls freezing camera view
+ */
+public class FreezeController {
+    private static final String TAG = "FreezeController";
+    private final FloatingActionButton mFreezeButton;
+    private final PreviewView mCameraView;
+    private final ImageView mFreezeView;
+    private final ImageCapture mImageCapture;
+    private final Context mContext;
+    private boolean mCameraFrozen = false;
+
+    FreezeController(Context context, FloatingActionButton freezeButton, PreviewView cameraView,
+                     ImageView freezeView){
+        mFreezeButton = freezeButton;
+        mCameraView = cameraView;
+        mFreezeView = freezeView;
+        mContext = context;
+        mImageCapture = new ImageCapture.Builder()
+                .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
+                .build();
+    }
+
+    /**
+     * Should be called when camera is ready
+     * @param provider camera provider
+     * @param lcOwner lifecycle owner used for binding camera usecases
+     */
+    public void onCameraInitialized(ProcessCameraProvider provider, LifecycleOwner lcOwner){
+        CameraSelector cameraSelector = new CameraSelector.Builder()
+                .requireLensFacing(CameraSelector.LENS_FACING_FRONT)
+                .build();
+        provider.bindToLifecycle(lcOwner, cameraSelector, mImageCapture);
+        Log.d(TAG, "completed onCameraInitialized");
+    }
+
+
+    private void setFrozenImage(){
+        mImageCapture.takePicture(getMainExecutor(mContext),
+                new ImageCapture.OnImageCapturedCallback() {
+
+                    @Override
+                    @SuppressLint("UnsafeOptInUsageError")
+                    public void onCaptureSuccess(@NonNull ImageProxy imageProxy){
+                        Log.i(TAG, "Capture success");
+                        Image image = imageProxy.getImage();
+                        if(image == null){
+                            Log.e(TAG, "Image is null");
+                            return;
+                        }
+                        int format = image.getFormat();
+                        if(format != ImageFormat.JPEG){
+                            Log.e(TAG, "Expected JPEG format, got format " + format);
+                            return;
+                        }
+                        ByteBuffer buffer = image.getPlanes()[0].getBuffer();
+                        byte[] bytes = new byte[buffer.remaining()];
+                        buffer.get(bytes);
+                        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
+                        Matrix matrix = new Matrix();
+                        matrix.postRotate(270);
+                        bitmap = Bitmap.createBitmap(
+                                bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true
+                        );
+                        mFreezeView.setImageBitmap(bitmap);
+                        imageProxy.close();
+                    }
+
+                    @Override
+                    public void onError(@NonNull ImageCaptureException exception) {
+                        Log.e(TAG, "Can not capture image");
+                        exception.printStackTrace();
+                    }
+                });
+    }
+
+    /**
+     * Toggles camera freeze
+     */
+    public void toggleFreeze(){
+        if(mCameraFrozen){
+            mFreezeView.setVisibility(View.GONE);
+            mCameraView.setVisibility(View.VISIBLE);
+            mCameraFrozen = false;
+        } else {
+            setFrozenImage();
+            mCameraView.setVisibility(View.GONE);
+            mFreezeView.setVisibility(View.VISIBLE);
+            mCameraFrozen = true;
+        }
+    }
+}

app/src/main/java/com/polar/mirror/MainActivity.java

@@ -12,14 +12,15 @@
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
+import android.widget.ImageView;
 
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 
 import java.util.concurrent.ExecutionException;
 
 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
     private PreviewView mCameraView;
-    private boolean mCameraFrozen = false;
+    private FreezeController mFreezeController;
     private final static String TAG = "MainActivity";
 
     @Override
@@ -30,6 +31,14 @@ protected void onCreate(Bundle savedInstanceState) {
         setupView();
 
         mCameraView = findViewById(R.id.preview_view);
+
+        //Initialize freeze controller
+        FloatingActionButton freezeButton = findViewById(R.id.freeze_button);
+        ImageView freezeView = findViewById(R.id.stop_view);
+        mFreezeController = new FreezeController(this, freezeButton, mCameraView,
+                freezeView);
+
+        //Start camera
         try {
             startCamera();
         } catch (ExecutionException | InterruptedException e) {
@@ -94,6 +103,7 @@ private void startCamera() throws ExecutionException, InterruptedException {
                     .build();
             cameraProvider.unbindAll();
             cameraProvider.bindToLifecycle((LifecycleOwner)this, cameraSelector, preview);
+            mFreezeController.onCameraInitialized(cameraProvider, (LifecycleOwner)this);
         } catch (Exception e) {
             e.printStackTrace();
         }
@@ -103,13 +113,7 @@ private void startCamera() throws ExecutionException, InterruptedException {
      * Toggles camera freeze mode
      */
     private void toggleCameraFreeze(){
-        if(!mCameraFrozen) {
-            mCameraView.setVisibility(View.GONE);
-            mCameraFrozen = true;
-        } else {
-            mCameraView.setVisibility(View.VISIBLE);
-            mCameraFrozen = false;
-        }
+        mFreezeController.toggleFreeze();
     }
 
     @Override

app/src/main/res/layout/activity_main.xml

@@ -4,13 +4,21 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
+    android:keepScreenOn="true"
     tools:context=".MainActivity">
 
     <androidx.camera.view.PreviewView
         android:id="@+id/preview_view"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />
 
+    <ImageView
+        android:id="@+id/stop_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:scaleType="centerCrop"
+        android:contentDescription="@string/stop_view_desc" />
+
     <include layout="@layout/action_panel" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values/strings.xml

@@ -2,4 +2,5 @@
     <string name="app_name">Mirror</string>
     <string name="exit">Exit app</string>
     <string name="freeze">Freeze</string>
+    <string name="stop_view_desc">Image displaying stop-frame</string>
 </resources>