Android中Canvas、Paint、Path的总结

Canvas(画布):

canvas.translate(canvas.getWidth()/2,500);//将画布的坐标原点进行平移
canvas.drawCircle(0,0,10,mPaint);//圆心坐标、半径、画笔对象
canvas.save();//保存Canvas状态，save后可以调用Canvas的平移、放缩、旋转、错切、裁剪等操作

 

canvas.drawText("hzk",0,0,wPaint);//以(0,0)为起点先上写文字

 

...
wPaint.setTextAlign(Paint.Align.CENTER);
...

canvas.drawText("hzk",0,0,wPaint);//这样文字就会居中显示了

 

 

RectF rectF=new RectF(-50,-100,50,100);
canvas.drawRect(rectF,circlePaint);//画矩形，并在图中居中

 

各参数的含义如下图： 

下面的图引自：https://blog.youkuaiyun.com/dingzj2000/article/details/61651259

 

画扇形

int w=canvas.getWidth();
canvas.drawCircle(0,0,w/3,cPaint);
circlePaint.setColor(getResources().getColor(R.color.test));//改变画笔颜色为橘色
RectF rectF=new RectF(-w/3,-w/3,w/3,w/3);//这里的矩形是用来规定圆所在范围
canvas.drawArc(rectF,0,60,true,cPaint);//范围,起始度数,顺时针扫过的度数,画笔对象

Path(路径):

Path path=new Path();
path.addArc(new RectF(0,0,150,150),0,180);//绘制弧形区域

Paint(画笔)