使用Glide实现图片高斯模糊效果

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1.引入依赖

  implementation 'com.github.bumptech.glide:glide:4.7.1'
  annotationProcessor 'com.github.bumptech.glide:compiler:4.7.1'
  implementation 'jp.wasabeef:glide-transformations:2.0.1'        //高斯模糊

2.自定义BlurTransformation继承BitmapTransformation

 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 = toTrstansform;

        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);
    }
}

3.使用

//设置ImageView背景
Glide.with(context).load(url).apply(bitmapTransform(new BlurTransformation(context,radius,sampling)).into(imageview)；

//设置viewGroup背景

Glide.with(context).load(url).apply(RequestOptions.bitmapTransform(new BlurTransformation(context, radius, sampling))).into(new SimpleTarget<Drawable>() {
    @Override
    public void onResoureReady(@NonNull Drawable resource, @Nullable Transition<? super Drawable> transition) {
       viewGroup.setBackground(resource);
       }
    });

4.出现的错误 使用Transformation库自带的BlurTransformation设置背景时，会出现下列错误：

java.lang.AbstractMethodError: abstract method "void com.bumptech.glide.load.Key.updateDiskCacheKe