Android, How to crop circular area from bitmap


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

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:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity"
   android:id="@+id/rl"
   android:padding="16dp"
   android:background="#edf2ea">
   <ImageView
      android:id="@+id/iv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"/>
   <Button
      android:id="@+id/btn"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Circular It"
      android:layout_alignParentBottom="true"
      android:layout_alignParentRight="true"/>
</RelativeLayout>

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

package com.medkart.sample;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout;
public class MainActivity extends AppCompatActivity {
   private Context mContext;
   private Resources mResources;
   private RelativeLayout mRelativeLayout;
   private Button mBTN;
   private ImageView mImageView;
   private Bitmap mBitmap;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      // Get the application context
      mContext = getApplicationContext();
      // Get the Resources
      mResources = getResources();
      // Get the widgets reference from XML layout
      mRelativeLayout = (RelativeLayout) findViewById(R.id.rl);
      mImageView = (ImageView) findViewById(R.id.iv);
      mBTN = (Button) findViewById(R.id.btn);
      // Get the bitmap resource id
      final int bitmapResourceID =R.drawable.flower;
      // Set an image to ImageView
      mImageView.setImageBitmap(BitmapFactory.decodeResource(mResources, bitmapResourceID));
      // Set a click listener for Button widget
      mBTN.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View view) {
            // Get the bitmap from drawable resources
            mBitmap = BitmapFactory.decodeResource(mResources, bitmapResourceID);
            // Create a circular bitmap
            mBitmap = getCircularBitmap(mBitmap);
            // Add a border around circular bitmap
            mBitmap = addBorderToCircularBitmap(mBitmap, 15, Color.WHITE);
            // Add a shadow around circular bitmap
            mBitmap = addShadowToCircularBitmap(mBitmap, 4, Color.LTGRAY);
            // Set the ImageView image as drawable object
            mImageView.setImageBitmap(mBitmap);
         }
      });
   }
   protected Bitmap getCircularBitmap(Bitmap srcBitmap) {
      // Calculate the circular bitmap width with border
      int squareBitmapWidth = Math.min(srcBitmap.getWidth(), srcBitmap.getHeight());
      // Initialize a new instance of Bitmap
      Bitmap dstBitmap = Bitmap.createBitmap (
         squareBitmapWidth, // Width
         squareBitmapWidth, // Height
         Bitmap.Config.ARGB_8888 // Config
      );
      Canvas canvas = new Canvas(dstBitmap);
      // Initialize a new Paint instance
      Paint paint = new Paint();
      paint.setAntiAlias(true);
      Rect rect = new Rect(0, 0, squareBitmapWidth, squareBitmapWidth);
      RectF rectF = new RectF(rect);
      canvas.drawOval(rectF, paint);
      paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
      // Calculate the left and top of copied bitmap
      float left = (squareBitmapWidth-srcBitmap.getWidth())/2;
      float top = (squareBitmapWidth-srcBitmap.getHeight())/2;
      canvas.drawBitmap(srcBitmap, left, top, paint);
      // Free the native object associated with this bitmap.
      srcBitmap.recycle();
      // Return the circular bitmap
      return dstBitmap;
   }
   // Custom method to add a border around circular bitmap
   protected Bitmap addBorderToCircularBitmap(Bitmap srcBitmap, int borderWidth, int borderColor) {
      // Calculate the circular bitmap width with border
      int dstBitmapWidth = srcBitmap.getWidth()+borderWidth*2;
      // Initialize a new Bitmap to make it bordered circular bitmap
      Bitmap dstBitmap = Bitmap.createBitmap(dstBitmapWidth,dstBitmapWidth, Bitmap.Config.ARGB_8888);
      // Initialize a new Canvas instance
      Canvas canvas = new Canvas(dstBitmap);
      // Draw source bitmap to canvas
      canvas.drawBitmap(srcBitmap, borderWidth, borderWidth, null);
      // Initialize a new Paint instance to draw border
      Paint paint = new Paint();
      paint.setColor(borderColor);
      paint.setStyle(Paint.Style.STROKE);
      paint.setStrokeWidth(borderWidth);
      paint.setAntiAlias(true);
      canvas.drawCircle(
         canvas.getWidth() / 2, // cx
         canvas.getWidth() / 2, // cy
         canvas.getWidth()/2 - borderWidth / 2, // Radius
         paint // Paint
      );
      // Free the native object associated with this bitmap.
      srcBitmap.recycle();
      // Return the bordered circular bitmap
      return dstBitmap;
   }
   // Custom method to add a shadow around circular bitmap
   protected Bitmap addShadowToCircularBitmap(Bitmap srcBitmap, int shadowWidth, int shadowColor){
      // Calculate the circular bitmap width with shadow
      int dstBitmapWidth = srcBitmap.getWidth()+shadowWidth*2;
      Bitmap dstBitmap = Bitmap.createBitmap(dstBitmapWidth,dstBitmapWidth, Bitmap.Config.ARGB_8888);
      // Initialize a new Canvas instance
      Canvas canvas = new Canvas(dstBitmap);
      canvas.drawBitmap(srcBitmap, shadowWidth, shadowWidth, null);
      // Paint to draw circular bitmap shadow
      Paint paint = new Paint();
      paint.setColor(shadowColor);
      paint.setStyle(Paint.Style.STROKE);
      paint.setStrokeWidth(shadowWidth);
      paint.setAntiAlias(true);
      // Draw the shadow around circular bitmap
      canvas.drawCircle (
         dstBitmapWidth / 2, // cx
         dstBitmapWidth / 2, // cy
         dstBitmapWidth / 2 - shadowWidth / 2, // Radius
         paint // Paint
      );
      srcBitmap.recycle();
      return dstBitmap;
   }
}

Step 4  − Add the following code to Manifests/AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.medkart.sample">
   <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 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.

raja
Published on 11-Sep-2019 15:04:27
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