Android项目实战（五十七）：Glide 高斯模糊效果

compile 'jp.wasabeef:glide-transformations:2.0.1'

//加载背景，
            Glide.with(MusicPlayerActivity.this)
                    .load(service.getImageUri())
                    .dontAnimate()
                    .error(R.drawable.no_music_rotate_img)
                    // 设置高斯模糊,模糊程度(最大25)  缩放比例
                    .bitmapTransform(new BlurTransformation(this, 14, 3))
                    .into(allBg);

Glide.with(context)
                .load(url)
                .apply(RequestOptions.bitmapTransform(new BlurTransformation(25,8)))
                .into(view);                        

BlurTransformation 类源码：

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.support.annotation.NonNull;

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

import java.security.MessageDigest;

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

public class BlurTransformation extends BitmapTransformation {

    private static final int VERSION = 1;
    private static final String ID = "BlurTransformation." + VERSION;

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

    private int radius;
    private int sampling;

    public BlurTransformation() {
        this(MAX_RADIUS, DEFAULT_DOWN_SAMPLING);
    }

    public BlurTransformation(int radius) {
        this(radius, DEFAULT_DOWN_SAMPLING);
    }

    public BlurTransformation(int radius, int sampling) {
        this.radius = radius;
        this.sampling = sampling;
    }

    @Override
    protected Bitmap transform(@NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
        int width = toTransform.getWidth();
        int height = toTransform.getHeight();
        int scaledWidth = width / sampling;
        int scaledHeight = height / sampling;

        Bitmap bitmap = pool.get(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(bitmap);
        canvas.scale(1 / (float) sampling, 1 / (float) sampling);
        Paint paint = new Paint();
        paint.setFlags(Paint.FILTER_BITMAP_FLAG);
        canvas.drawBitmap(toTransform, 0, 0, paint);
        bitmap = FastBlur.blur(bitmap, radius, true);

        return bitmap;
    }

    @Override public String toString() {
        return "BlurTransformation(radius=" + radius + ", sampling=" + sampling + ")";
    }

    @Override public boolean equals(Object o) {
        return o instanceof BlurTransformation &&
                ((BlurTransformation) o).radius == radius &&
                ((BlurTransformation) o).sampling == sampling;
    }

    @Override public int hashCode() {
        return ID.hashCode() + radius * 1000 + sampling * 10;
    }

    @Override public void updateDiskCacheKey(@NonNull MessageDigest messageDigest) {
        messageDigest.update((ID + radius + sampling).getBytes(CHARSET));
    }
}