Glide blur transformation

BlurTransformation.kt

import android.content.Context
import android.graphics.Bitmap
import android.renderscript.Allocation
import android.renderscript.Element
import android.renderscript.RenderScript
import android.renderscript.ScriptIntrinsicBlur
import com.bumptech.glide.load.Key
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool
import com.bumptech.glide.load.resource.bitmap.BitmapTransformation
import java.security.MessageDigest


class BlurTransformation(context: Context) : BitmapTransformation() {
    
    private val renderScript = RenderScript.create(context)

    override fun transform(pool: BitmapPool, toTransform: Bitmap, outWidth: Int, outHeight: Int): Bitmap {
        val blurredBitmap = toTransform.copy(Bitmap.Config.ARGB_8888, true)

        val input = Allocation.createFromBitmap(
            renderScript,
            blurredBitmap,
            Allocation.MipmapControl.MIPMAP_FULL,
            Allocation.USAGE_SHARED
        )
        val output = Allocation.createTyped(renderScript, input.type)

        with(ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript))) {
            setInput(input)
            setRadius(25f)
            forEach(output)
        }

        output.copyTo(blurredBitmap)

        return blurredBitmap
    }

    override fun updateDiskCacheKey(messageDigest: MessageDigest) {
        messageDigest.update(ID_BYTES)
    }

    companion object {
        private const val ID = "ru.napoleonit.youfix.lib.glide.BlurTransformation"
        private val ID_BYTES = ID.toByteArray(Key.CHARSET)
    }
}