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

Question

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

Kotlin Mobile DevelopmentApps/Applications

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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 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.

Azhar

Published on 26-Sep-2020 17:41:14

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