参考：https://blog.csdn.net/harvic880925/article/details/51010839

1.基本属性

2.特殊属性

• setStrokeCap(Paint.Cap cap)线帽

        Paint paint = new Paint();
        paint.setStrokeWidth(80);
        paint.setAntiAlias(true);
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);

        paint.setStrokeCap(Paint.Cap.BUTT);
        canvas.drawLine(100,200,400,200,paint);
        paint.setStrokeCap(Paint.Cap.SQUARE);
        canvas.drawLine(100,400,400,400,paint);
        paint.setStrokeCap(Paint.Cap.ROUND);
        canvas.drawLine(100,600,400,600,paint);

        //垂直画出x=100这条线
        paint.reset();
        paint.setStrokeWidth(2);
        paint.setColor(Color.RED);
        canvas.drawLine(100,100,100,800,paint);
        canvas.drawLine(400,100,400,800,paint);

加上线帽后头尾都多了一帽子

• setStrokeJoin(Paint.Join join)线段连接样式
  Paint paint = new Paint();
  paint.setStrokeWidth(8);
  paint.setColor(Color.GREEN);
  paint.setStyle(Paint.Style.STROKE);

    Path path = new Path();
    path.moveTo(100,600);
    path.lineTo(400,100);
    path.lineTo(700,600);
  
    canvas.drawPath(path,paint);
  
    paint.setColor(Color.RED);
    paint.setPathEffect(new CornerPathEffect(100));
    canvas.drawPath(path,paint);
  
    paint.setColor(Color.LTGRAY);
    paint.setPathEffect(new CornerPathEffect(300));
    canvas.drawPath(path,paint);
  

        Paint paint = new Paint();
        paint.setStrokeWidth(100);
        paint.setColor(Color.BLACK);
        paint.setStyle(Paint.Style.STROKE);
        paint.setAntiAlias(true);

        Path path  = new Path();
        path.moveTo(100,200);
        path.lineTo(400,200);
        path.lineTo(400,400);
        paint.setStrokeJoin(Paint.Join.MITER);
        canvas.drawPath(path,paint);

        path.moveTo(100,500);
        path.lineTo(400,500);
        path.lineTo(400,700);
        paint.setStrokeJoin(Paint.Join.ROUND);
        canvas.drawPath(path,paint);

        path.moveTo(100,800);
        path.lineTo(400,800);
        path.lineTo(400,1000);
        paint.setStrokeJoin(Paint.Join.BEVEL);
        canvas.drawPath(path,paint);

分别为MITER,ROUND,BEVEL

分别为MITER,ROUND,BEVEL,转角不为90的情况

• setPathEffect(PathEffect effect)路径样式

Path shape:表示印章路径，比如我们下面示例中的三角形加右上角一个点；
float advance：表示两个印章路径间的距离,很容易理解，印章间距离越大，间距就越大。
float phase：路径绘制偏移距离，与上面DashPathEffect中的float phase参数意义相同
Style style：表示在遇到转角时，如何操作印章以使转角平滑过渡，取值有：Style.ROTATE，Style.MORPH，Style.TRANSLATE;Style.ROTATE表示通过旋转印章来过渡转角；Style.MORPH表示通过变形印章来过渡转角；Style.TRANSLATE表示通过位移来过渡转角

        Path path = new Path();
        path.moveTo(100,600);
        path.lineTo(400,100);
        path.lineTo(700,600);

        canvas.drawPath(path,paint);

        paint.setColor(Color.RED);
        paint.setPathEffect(new CornerPathEffect(100));
        canvas.drawPath(path,paint);

        paint.setColor(Color.LTGRAY);
        paint.setPathEffect(new CornerPathEffect(300));
        canvas.drawPath(path,paint);

CornerPathEffect圆形拐角

        Path path = new Path();
        path.moveTo(100,600);
        path.lineTo(300,100);
        path.lineTo(600,600);

        canvas.drawPath(path,paint);
        paint.setColor(Color.RED);

        //使用DashPathEffect画线段
        paint.setPathEffect(new DashPathEffect(new float[]{20,10,100,100},0));
        canvas.translate(20,0);
        canvas.drawPath(path,paint);

        //画同一条线段,偏移值为15
        paint.setPathEffect(new DashPathEffect(new float[]{20,10,50,100},15));
        paint.setColor(Color.BLACK);
        canvas.translate(20,0);
        canvas.drawPath(path,paint);

DashPathEffect虚线段

        Paint paint = getPaint();
        Path path = getPath();
//第一条原生Path
        canvas.drawPath(path,paint);
//第二条Path
        canvas.translate(0,200);
        paint.setPathEffect(new DiscretePathEffect(2,5));
        canvas.drawPath(path,paint);
//第三条Path
        canvas.translate(0,200);
        paint.setPathEffect(new DiscretePathEffect(6,5));
        canvas.drawPath(path,paint);
//第四条Path
        canvas.translate(0,200);
        paint.setPathEffect(new DiscretePathEffect(6,15));
        canvas.drawPath(path,paint);

DiscretePathEffect离散路径效应

        Paint paint = getPaint();
        Path path = new Path();
//画出原始路径
        path.moveTo(100,600);
        path.lineTo(400,100);
        path.lineTo(700,600);
        canvas.drawPath(path,paint);

//构建印章路径
        Path stampPath  = new Path();
        stampPath.moveTo(0,20);
        stampPath.lineTo(10,0);
        stampPath.lineTo(20,20);
        stampPath.close();
        stampPath.addCircle(0,0,3, Path.Direction.CCW);

//使用印章路径效果
        canvas.translate(0,100);
        paint.setPathEffect(new PathDashPathEffect(stampPath,35,0, PathDashPathEffect.Style.TRANSLATE));
        canvas.drawPath(path,paint);

PathDashPathEffect印章路径效果

       //画原始路径
        Paint paint = getPaint();
        Path path = getPath();
        canvas.drawPath(path,paint);

//仅应用圆角特效的路径
        canvas.translate(0,200);
        CornerPathEffect cornerPathEffect = new CornerPathEffect(100);
        paint.setPathEffect(cornerPathEffect);
        canvas.drawPath(path,paint);

//仅应用虚线特效的路径
        canvas.translate(0,200);
        DashPathEffect dashPathEffect = new DashPathEffect(new float[]{2,5,10,10},0);
        paint.setPathEffect(dashPathEffect);
        canvas.drawPath(path,paint);

//利用ComposePathEffect先应用圆角特效,再应用虚线特效
        canvas.translate(0,200);
        ComposePathEffect composePathEffect = new ComposePathEffect(dashPathEffect,cornerPathEffect);
        paint.setPathEffect(composePathEffect);
        canvas.drawPath(path,paint);

//利用SumPathEffect,分别将圆角特效应用于原始路径,然后将生成的两条特效路径合并
        canvas.translate(0,200);
        paint.setStyle(Paint.Style.STROKE);
        SumPathEffect sumPathEffect = new SumPathEffect(cornerPathEffect,dashPathEffect);
        paint.setPathEffect(sumPathEffect);
        canvas.drawPath(path,paint);

ComposePathEffect和SumPathEffect

3.字体相关

4.图像处理和measure测量相关