What Is BlurKit?

BlurKit is an extraordinarily easy to use and performant utility to render real time blur effects in Android.

Perfomance

BlurKit is faster than other blurring libraries due to a number of bitmap retrieval and drawing optimizations. We've been logging benchmarks for the basic high-intensity tasks for a 300dp x 100dp BlurView:

Task	BlurKit time	Avg. time without BlurKit
Retrieve source bitmap	1-2 ms	8-25 ms
Blur and draw to BlurView	1-2 ms	10-50ms

This results in an average work/frame time of 2-4ms, which will be a seamless experience for most users and apps.

Setup

Add BlurKit to the dependencies block of the app level build.gradle:

dependencies {
    implementation 'io.alterac.blurkit:blurkit:1.1.0'
}

Usage

BlurLayout

Add a BlurLayout to your XML layout just like any other view.

<io.alterac.blurkit.BlurLayout
    android:id="@+id/blurLayout"
    android:layout_width="150dp"
    android:layout_height="150dp"/>

In the Main_Activity.java you need to override the onStart() and onStop() methods to include the BlurLayout functionality.

BlurLayout blurLayout;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    blurLayout = findViewById(R.id.blurLayout);
}

@Override
protected void onStart() {
    super.onStart();
    blurLayout.startBlur();
}

@Override
protected void onStop() {
    blurLayout.pauseBlur();
    super.onStop();
}

The layout background will continuously blur the content behind it. If you know your background content will be somewhat static, you can set the layout fps to 0. At any time you can re-blur the background content by calling invalidate() on the BlurLayout.

<io.alterac.blurkit.BlurLayout
    android:id="@+id/blurLayout"
    android:layout_width="150dp"
    android:layout_height="150dp"
    blurkit:blk_fps="0" />

Other attributes you can configure are the blur radius and the downscale factor. Getting these to work together well can take some experimentation. The downscale factor is a performance optimization; the bitmap for the background content will be downsized by this factor before being drawn and blurred.

<io.alterac.blurkit.BlurLayout
    android:id="@+id/blurLayout"
    android:layout_width="150dp"
    android:layout_height="150dp"
    blurkit:blk_blurRadius="12"
    blurkit:blk_downscaleFactor="0.12"
    blurkit:blk_fps="60" />

Creating BlurKit Outside Of A Layout

You can use the BlurKit class which has a few useful blurring utilities. Before using this class outside of a BlurLayout, you need to initialize BlurKit.

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        BlurKit.init(this);
    }
}

You can blur a View, or a Bitmap directly.

// View
BlurKit.getInstance().blur(View src, int radius);

// Bitmap
BlurKit.getInstance().blur(Bitmap src, int radius);

You can also fastBlur a View. This optimizes the view blurring process by allocating a downsized bitmap and using a Matrix with the bitmaps Canvas to prescale the drawing of the view to the bitmap.

BlurKit.getInstance().fastBlur(View src, int radius, float downscaleFactor);

Upcoming Features

• SurfaceView support
• Support for use outside of an Activity (dialogs, etc.)
• Enhance retrieval of background content to only include views drawn behind the BlurLayout.

License

BlurKit is MIT licensed.

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Blurkit is a sister project of CameraKit and maintained by the CameraKit team.