使用Glide实现高斯模糊效果

implementation 'com.github.bumptech.glide:glide:4.7.1'
implementation 'jp.wasabeef:glide-transformations:2.0.1'

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Build;
import android.renderscript.RSRuntimeException;

import androidx.annotation.NonNull;

import com.bumptech.glide.Glide;
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.resource.bitmap.BitmapTransformation;

import java.nio.charset.Charset;
import java.security.MessageDigest;

import jp.wasabeef.glide.transformations.internal.FastBlur;
import jp.wasabeef.glide.transformations.internal.RSBlur;


/**
 * 虚化Transformation
 * 更多效果参考：https://github.com/wasabeef/glide-transformations
 */

public class BlurTransformation extends BitmapTransformation {

  private static String STRING_CHARSET_NAME = "UTF-8";
  private static final String ID = "com.kevin.glidetest.BlurTransformation";
  private static Charset CHARSET = Charset.forName(STRING_CHARSET_NAME);
  private static final byte[] ID_BYTES = ID.getBytes(CHARSET);

  private static int MAX_RADIUS = 25;
  private static int DEFAULT_DOWN_SAMPLING = 1;

  private Context mContext;
  private BitmapPool mBitmapPool;

  private int mRadius;
  private int mSampling;

  public BlurTransformation(Context context) {
    this(context, Glide.get(context).getBitmapPool(), MAX_RADIUS, DEFAULT_DOWN_SAMPLING);
  }

  public BlurTransformation(Context context, BitmapPool pool) {
    this(context, pool, MAX_RADIUS, DEFAULT_DOWN_SAMPLING);
  }

  public BlurTransformation(Context context, BitmapPool pool, int radius) {
    this(context, pool, radius, DEFAULT_DOWN_SAMPLING);
  }

  public BlurTransformation(Context context, int radius) {
    this(context, Glide.get(context).getBitmapPool(), radius, DEFAULT_DOWN_SAMPLING);
  }

  public BlurTransformation(Context context, int radius, int sampling) {
    this(context, Glide.get(context).getBitmapPool(), radius, sampling);
  }

  public BlurTransformation(Context context, BitmapPool pool, int radius, int sampling) {
    mCOntext= context.getApplicationContext();
    mBitmapPool = pool;
    mRadius = radius;
    mSampling = sampling;
  }


  @Override
  protected Bitmap transform(@NonNull BitmapPool pool, @NonNull Bitmap toTransform, int
      outWidth, int outHeight) {
    Bitmap source = toTransform ;

    int width = source.getWidth();
    int height = source.getHeight();
    int scaledWidth = width / mSampling;
    int scaledHeight = height / mSampling;

    Bitmap bitmap = mBitmapPool.get(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888);
    if (bitmap == null) {
      bitmap = Bitmap.createBitmap(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888);
    }

    Canvas canvas = new Canvas(bitmap);
    canvas.scale(1 / (float) mSampling, 1 / (float) mSampling);
    Paint paint = new Paint();
    paint.setFlags(Paint.FILTER_BITMAP_FLAG);
    canvas.drawBitmap(source, 0, 0, paint);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
      try {
        bitmap = RSBlur.blur(mContext, bitmap, mRadius);
      } catch (RSRuntimeException e) {
        bitmap = FastBlur.blur(bitmap, mRadius, true);
      }
    } else {
      bitmap = FastBlur.blur(bitmap, mRadius, true);
    }

    //return BitmapResource.obtain(bitmap, mBitmapPool);
    return bitmap;
  }

  @Override
  public int hashCode() {
    return ID.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    return obj instanceof BlurTransformation;
  }

  @Override
  public void updateDiskCacheKey(MessageDigest messageDigest) {
    messageDigest.update(ID_BYTES);
  }

}

String url="url";
 Glide.with(this).load(url)
 .apply(RequestOptions.bitmapTransform(new BlurTransformation(this,25,3)))
        .into(img);
 //参数用来设置模糊程度