BlurKit is an extraordinarily easy to use utility to get live blurring just like on iOS. Built by Dylan McIntyre.

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 your dependencies block:

compile 'com.wonderkiln:blurkit:1.0.0'

You also need to add RenderScript to your app module. Add these lines to the defaultConfig block of your build.gradle.

renderscriptTargetApi 24
renderscriptSupportModeEnabled true

Usage

BlurLayout

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

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:text="BlurKit!"
        android:textColor="@android:color/white" />

</com.wonderkiln.blurkit.BlurLayout>

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.

<com.wonderkiln.blurkit.BlurLayout xmlns:blurkit="http://schemas.android.com/apk/res-auto"
    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.

<com.wonderkiln.blurkit.BlurLayout xmlns:blurkit="http://schemas.android.com/apk/res-auto"
    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" />

Other

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);

Proguard

If you use Proguard, add the following to your proguard-rules.pro:

-keep class com.wonderkiln.blurkit.** { *; }

-dontwarn android.support.v8.renderscript.*
-keepclassmembers class android.support.v8.renderscript.RenderScript {
  native *** rsn*(...);
  native *** n*(...);
}

To Do (incoming!)

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

Credits

Dylan McIntyre

License

BlurKit-Android is MIT licensed.