Android学习------使用RenderScript ,ScriptIntrinsicBlur实现高斯模糊

android新增了android.support.v8.renderscript支持库，提供了高斯模糊的实现。
参考自：
https://developer.android.google.cn/guide/topics/renderscript/compute.html#using-rs-from-java
http://stackoverflow.com/questions/2067955/fast-bitmap-blur-for-android-sdk

Setup 1

在你的build.gradle中添加

  defaultConfig {
        (...)

        renderscriptTargetApi 18
        renderscriptSupportModeEnabled true

        (...)
    }

Java code

public class MainActivity extends AppCompatActivity {
    private final static String TAG = "MainActivity";
    private ImageView img;
    private Button btn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        img = (ImageView) findViewById(R.id.img);
        btn = (Button) findViewById(R.id.btn);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final BitmapFactory.Options options = new BitmapFactory.Options();
                options.inSampleSize = 8;
                Bitmap blurTemplate = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher, options);
                RenderScript rs = RenderScript.create(MainActivity.this);
                final Allocation input = Allocation.createFromBitmap(rs, blurTemplate);
                final Allocation output = Allocation.createTyped(rs, input.getType());
                final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
                script.setRadius(8f);
                script.setInput(input);
                script.forEach(output);
                output.copyTo(blurTemplate);
                img.setImageBitmap(blurTemplate);

            }
        });

    }
}

注意在解码图片的时候可能会发生OOM

xml code

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
>

    <ImageView
        android:id="@+id/img"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:src="@mipmap/ic_launcher"
        />

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/img"
        android:text="start bulr"
        android:textAllCaps="false"
        />
</RelativeLayout>

demo演示：