一.PhotoView

在这里插入图片描述

1.倒入依赖

implementation ‘com.github.chrisbanes:PhotoView:2.0.0’

2.项目gradle添加maven仓库

allprojects {
    repositories {
        google()
        jcenter()
        //Bmob的maven仓库地址，必须填写
        maven {
            url "https://raw.github.com/bmob/bmob-android-sdk/master"
        }
        maven {
            url "https://jitpack.io"
        }


    }
}

3.布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".matrix.PhotoViewActivity">
    <com.github.chrisbanes.photoview.PhotoView
        android:id="@+id/photo_view"
        android:layout_width="match_parent"
        android:src="@drawable/erha"
        android:layout_height="match_parent"></com.github.chrisbanes.photoview.PhotoView>

</LinearLayout>

二.Matrix矩阵

Matrix 就是矩阵的意思，我们通常使用它进行一些图片的变化操作
平移、缩放、旋转、错切、水印等效果
Matrix 三种动作 pre 、post 、set
1.pre代表之前有操作，乖乖排队
2.post代表插队到第一个
3.set代表设置，替换之前所有

核心代码：

		matrix.reset();
        matrix.preTranslate(100, 100);//平移
        matrix.preScale(2,2);//缩放
        matrix.preRotate(45);//旋转
        matrix.preSkew(0,1);//扭曲
        invalidate();

全部代码：

public class MyView extends View {
    private Paint paint;
    private Matrix matrix;

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

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initPaint();
    }

    private void initPaint() {
        paint = new Paint();
        matrix = new Matrix();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pao);
        canvas.drawBitmap(bitmap, matrix, paint);
    }

    public void change() {
        matrix.reset();
        matrix.preTranslate(100, 100);//平移
        matrix.preScale(2,2);//缩放
        matrix.preRotate(45);//旋转
        matrix.preSkew(0,1);//扭曲
        invalidate();
    }

}

public class Main4Activity extends AppCompatActivity {
    @BindView(R.id.myview)
    MyView myview;
    @BindView(R.id.change)
    Button change;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main4);
        ButterKnife.bind(this);
    }
    @OnClick({R.id.change})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.change:
                myview.change();
                break;

        }
    }
}