Paint-滤镜

以黑白为例，附常见效果过滤器。

目标效果： black&white.gif

代码：
自定义View：

public class MyView extends View {


    private Bitmap mBitmap;
    private Paint mPaint;
    private ColorMatrixColorFilter mColorMatrixColorFilter;
    public static final float colorMatrix[] = {
        0.8f, 1.6f, 0.2f, 0, -163.9f,
        0.8f, 1.6f, 0.2f, 0, -163.9f,
        0.8f, 1.6f, 0.2f, 0, -163.9f,
        0, 0, 0, 1.0f, 0};

    public MyView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mPaint = new Paint();
        mBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.black_widow);
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mPaint.setColorFilter(mColorMatrixColorFilter);
        canvas.drawBitmap(mBitmap, 0,0, mPaint);
    }

    public void bianbianbian(){
        if (mColorMatrixColorFilter == null){
            mColorMatrixColorFilter = new ColorMatrixColorFilter(colorMatrix);
        }else{
            mColorMatrixColorFilter = null;
        }
        invalidate();
    }

}

Activity：

public class MainActivity extends Activity {


    MyView myView;
    Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myView = findViewById(R.id.myView);
        button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myView.bianbianbian();
            }
        });
    }
}

完事。

---

贴出常见效果过滤器：

    // 黑白
    public static final float colormatrix_heibai[] = {
            0.8f, 1.6f, 0.2f, 0, -163.9f,
            0.8f, 1.6f, 0.2f, 0, -163.9f,
            0.8f, 1.6f, 0.2f, 0, -163.9f,
            0, 0, 0, 1.0f, 0};
    // 怀旧
    public static final float colormatrix_huajiu[] = {
            0.2f, 0.5f, 0.1f, 0, 40.8f,
            0.2f, 0.5f, 0.1f, 0, 40.8f,
            0.2f, 0.5f, 0.1f, 0, 40.8f,
            0, 0, 0, 1, 0};
    // 哥特
    public static final float colormatrix_gete[] = {
            1.9f, -0.3f, -0.2f, 0, -87.0f,
            -0.2f, 1.7f, -0.1f, 0, -87.0f,
            -0.1f, -0.6f, 2.0f, 0, -87.0f,
            0, 0, 0, 1.0f, 0};
    // 淡雅
    public static final float colormatrix_danya[] = {
            0.6f, 0.3f, 0.1f, 0, 73.3f,
            0.2f, 0.7f, 0.1f, 0, 73.3f,
            0.2f, 0.3f, 0.4f, 0, 73.3f,
            0, 0, 0, 1.0f, 0};
    // 蓝调
    public static final float colormatrix_landiao[] = {
            2.1f, -1.4f, 0.6f, 0.0f, -71.0f,
            -0.3f, 2.0f, -0.3f, 0.0f, -71.0f,
            -1.1f, -0.2f, 2.6f, 0.0f, -71.0f,
            0.0f, 0.0f, 0.0f, 1.0f, 0.0f};
    // 光晕
    public static final float colormatrix_guangyun[] = {
            0.9f, 0, 0, 0, 64.9f,
            0, 0.9f, 0, 0, 64.9f,
            0, 0, 0.9f, 0, 64.9f,
            0, 0, 0, 1.0f, 0};
    // 梦幻
    public static final float colormatrix_menghuan[] = {
            0.8f, 0.3f, 0.1f, 0.0f, 46.5f,
            0.1f, 0.9f, 0.0f, 0.0f, 46.5f,
            0.1f, 0.3f, 0.7f, 0.0f, 46.5f,
            0.0f, 0.0f, 0.0f, 1.0f, 0.0f};
    // 酒红
    public static final float colormatrix_jiuhong[] = {
            1.2f, 0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.9f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.8f, 0.0f, 0.0f,
            0, 0, 0, 1.0f, 0};
    // 胶片
    public static final float colormatrix_fanse[] = {
            -1.0f, 0.0f, 0.0f, 0.0f, 255.0f,
            0.0f, -1.0f, 0.0f, 0.0f, 255.0f,
            0.0f, 0.0f, -1.0f, 0.0f, 255.0f,
            0.0f, 0.0f, 0.0f, 1.0f, 0.0f};
    // 湖光掠影
    public static final float colormatrix_huguang[] = {
            0.8f, 0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.9f, 0.0f, 0.0f,
            0, 0, 0, 1.0f, 0};
    // 褐片
    public static final float colormatrix_hepian[] = {
            1.0f, 0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.8f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.8f, 0.0f, 0.0f,
            0, 0, 0, 1.0f, 0};
    // 复古
    public static final float colormatrix_fugu[] = {
            0.9f, 0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.8f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.5f, 0.0f, 0.0f,
            0, 0, 0, 1.0f, 0};
    // 泛黄
    public static final float colormatrix_huan_huang[] = {
            1.0f, 0.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
            0.0f, 0.0f, 0.5f, 0.0f, 0.0f,
            0, 0, 0, 1.0f, 0};
    // 传统
    public static final float colormatrix_chuan_tong[] = {
            1.0f, 0.0f, 0.0f, 0, -10f,
            0.0f, 1.0f, 0.0f, 0, -10f,
            0.0f, 0.0f, 1.0f, 0, -10f,
            0, 0, 0, 1, 0};
    // 胶片2
    public static final float colormatrix_jiao_pian[] = {
            0.71f, 0.2f, 0.0f, 0.0f, 60.0f,
            0.0f, 0.94f, 0.0f, 0.0f, 60.0f,
            0.0f, 0.0f, 0.62f, 0.0f, 60.0f,
            0, 0, 0, 1.0f, 0};

    // 锐色
    public static final float colormatrix_ruise[] = {
            4.8f, -1.0f, -0.1f, 0, -388.4f,
            -0.5f, 4.4f, -0.1f, 0, -388.4f,
            -0.5f, -1.0f, 5.2f, 0, -388.4f,
            0, 0, 0, 1.0f, 0};
    // 清宁
    public static final float colormatrix_qingning[] = {
            0.9f, 0, 0, 0, 0,
            0, 1.1f, 0, 0, 0,
            0, 0, 0.9f, 0, 0,
            0, 0, 0, 1.0f, 0};
    // 浪漫
    public static final float colormatrix_langman[] = {
            0.9f, 0, 0, 0, 63.0f,
            0, 0.9f, 0, 0, 63.0f,
            0, 0, 0.9f, 0, 63.0f,
            0, 0, 0, 1.0f, 0};
    // 夜色
    public static final float colormatrix_yese[] = {
            1.0f, 0.0f, 0.0f, 0.0f, -66.6f,
            0.0f, 1.1f, 0.0f, 0.0f, -66.6f,
            0.0f, 0.0f, 1.0f, 0.0f, -66.6f,
            0.0f, 0.0f, 0.0f, 1.0f, 0.0f};