Android -----paint cap join 理解 ,paint画笔形状设置
引自:http://www.2cto.com/kf/201501/370215.html
网上查了很多资料,对paint的里面的枚举类cap join讲的不是很透彻。在这里自己做一个比较深入的研究。
首先说Cap,比较形象的解释就是 用来控制我们的画笔在离开画板时候留下的最后一点图形,比如矩形,圆形等。不懂?那接着往下看。
先看看源码:
/** * The Cap specifies the treatment for the beginning and ending of * stroked lines and paths. The default is BUTT. */ public enum Cap { /** * The stroke ends with the path, and does not project beyond it. */ BUTT (0), /** * The stroke projects out as a semicircle, with the center at the * end of the path. */ ROUND (1), /** * The stroke projects out as a square, with the center at the end * of the path. */ SQUARE (2); private Cap(int nativeInt) { this.nativeInt = nativeInt; } final int nativeInt; }
和Cap类似,看源码也就看出了默认是MITER,其他具体形状还是难以理解。接着看图:
MITER | ![]() |
ROUND | ![]() |
BEVEL | ![]() |
上表就是三种样式的区别,区别明显,在此不再赘述。
引用:
* setStrokeCap(Paint.Cap cap); * 当画笔样式为STROKE或FILL_OR_STROKE时,设置笔刷的图形样式,如圆形样式 * Cap.ROUND,或方形样式Cap.SQUARE * * setSrokeJoin(Paint.Join join); * 设置绘制时各图形的结合方式,如平滑效果等
paint 默认画笔为矩形,即如果要用圆形画笔,则在paint定义里面加上
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
如果想要从圆形切换成矩形需要
paint.setStrokeJoin(Paint.Join.MITER);
paint.setStrokeCap(Paint.Cap.SQUARE);
主要是下面一句