How to crop a circular area from bitmap in Android using Kotlin?

This example demonstrates how to crop a circular area from bitmap in Android using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project, and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="#edf2ea"    android:padding="8dp"    tools:context=".MainActivity">    <ImageView       android:id="@+id/iv"       android:layout_width="match_parent"       android:layout_height="500dp"       android:layout_centerInParent="true" />    <Button       android:id="@+id/btn"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignParentEnd="true"       android:layout_alignParentBottom="true"       android:text="Crop It" /> </RelativeLayout> 

Step 3 − Add the following code to src/MainActivity.kt

import android.graphics.* import android.os.Bundle import android.widget.Button import android.widget.ImageView import androidx.appcompat.app.AppCompatActivity import kotlin.math.min class MainActivity : AppCompatActivity() {    lateinit var button: Button    lateinit var imageView: ImageView    lateinit var bitmap: Bitmap    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"       imageView = findViewById(R.id.iv)       button = findViewById(R.id.btn)       // Get the bitmap resource id       // Get the bitmap resource id       val bitmapResourceID: Int = R.drawable.image       // Set an image to ImageView       // Set an image to ImageView       imageView.setImageBitmap(BitmapFactory.decodeResource(resources, bitmapResourceID))       // Set a click listener for Button widget       // Set a click listener for Button widget       button.setOnClickListener {          bitmap = BitmapFactory.decodeResource(resources, bitmapResourceID)          // Create a circular bitmap          bitmap = getCircularBitmap(bitmap)          imageView.setImageBitmap(bitmap)       }    }    private fun getCircularBitmap(srcBitmap: Bitmap?): Bitmap {       val squareBitmapWidth = min(srcBitmap!!.width, srcBitmap.height)       // Initialize a new instance of Bitmap       // Initialize a new instance of Bitmap       val dstBitmap = Bitmap.createBitmap(          squareBitmapWidth,  // Width          squareBitmapWidth,  // Height          Bitmap.Config.ARGB_8888 // Config       )       val canvas = Canvas(dstBitmap)       // Initialize a new Paint instance       // Initialize a new Paint instance       val paint = Paint()       paint.isAntiAlias = true       val rect = Rect(0, 0, squareBitmapWidth, squareBitmapWidth)       val rectF = RectF(rect)       canvas.drawOval(rectF, paint)       paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)       // Calculate the left and top of copied bitmap       // Calculate the left and top of copied bitmap       val left = ((squareBitmapWidth - srcBitmap.width) / 2).toFloat()       val top = ((squareBitmapWidth - srcBitmap.height) / 2).toFloat()       canvas.drawBitmap(srcBitmap, left, top, paint)       // Free the native object associated with this bitmap.       // Free the native object associated with this bitmap.       srcBitmap.recycle()       // Return the circular bitmap       // Return the circular bitmap       return dstBitmap    } }

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11">    <application       android:allowBackup="true"       android:icon="@mipmap/ic_launcher"       android:label="@string/app_name"       android:roundIcon="@mipmap/ic_launcher_round"       android:supportsRtl="true"       android:theme="@style/AppTheme">       <activity android:name=".MainActivity">          <intent-filter>             <action android:name="android.intent.action.MAIN" />             <category android:name="android.intent.category.LAUNCHER" />          </intent-filter>       </activity>    </application> </manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from the android studio, open one of your project's activity files and click the Run icon  from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen.

Click here to download the project code.