//Canvas和Paint初步使用：
	//自定义一个类，继承View
	//在构造方法中创建一个画笔
	//在onDraw方法中，可以获得一个画布

	//画笔API
	Paint paint = new Paint();
	paint.setAntiAlias(true); //抗锯齿
	paint.setStyle(Paint.Style.FILL); //填充
	paint.setStyle(Paint.Style.STROKE); //描边
	paint.setStyle(Paint.Style.FILL_AND_STROKE); //填充并描边
	paint.setStrokeWidth(5); //画笔宽度
	paint.setColor(ColorUtil.WHITE); //画笔颜色
	paint.setStrokeCap(Paint.Cap.ROUND); //圆角线头
	paint.setColorFilter(new LightingColorFilter(ColorUtil.LIGHT_BLUE, 0)); //设置颜色过滤器

	//画布API
	//基本操作
	canvas.drawARGB(0x99, 0xFF, 0xFF, 0x00); //画布染色
	canvas.drawColor(ColorUtil.LIGHT_BLUE, PorterDuff.Mode.ADD); //画布染色（颜色混合）
	canvas.drawPoint(100, 100, paint); //画点
	canvas.drawLine(100, 100, 400, 400, paint); //画线
	canvas.drawLines(new float[]{0, 0, 600, 600}, paint); //画线
	canvas.drawLines(new float[]{200, 200, 700, 400, 200, 300, 700, 400}, 0, 8, paint); //画多条线
	canvas.drawRect(100, 100, 600, 600, paint); //画矩形
	canvas.drawRoundRect(100, 100, 600, 600, 20, 20, paint); //画圆角矩形
	canvas.drawCircle(350, 350, 250, paint); //画圆
	canvas.drawOval(100, 100, 600, 300, paint); //画椭圆
	canvas.drawArc(100, 100, 600, 600, 0, -90, false, paint); //画弧
	canvas.drawBitmap(bitmap, 300, 300, paint); //画位图
	canvas.drawBitmap(bitmap, new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()), new Rect(0, 0, 800, 400), paint); //画位图，第一个Rect指定绘制范围，第二个Rect指定绘制位置
	//画任意几何线条
	Path path = new Path();
	path.addArc(200, 200, 400, 400, -225, 225);
	path.arcTo(400, 200, 600, 400, -180, 225, false);
	path.lineTo(400, 542);
	canvas.drawPath(path, paint);
	//通过Picture绘制
	//Picture对象不存储实际像素，只保存绘制过程
	Picture picture = new Picture();
	Canvas c = picture.beginRecording(400, 400);
	c.drawLine(100, 100, 400, 400, paint);
	picture.endRecording();
	canvas.drawPicture(picture);
	canvas.drawPicture(picture, new Rect(0, 0, 400, 400));
	//通过PictureDrawable绘制
	PictureDrawable pd = new PictureDrawable(picture);
	pd.setBounds(new Rect(0, 0, 400, 400));
	pd.draw(canvas);
	//绘制文字
	paint.setTextSize(ViewUtil.toPx(getContext(), 60));
	paint.setTypeface(FontUtil.getTypeface(this, FontUtil.Font.LIBIAN));
	canvas.drawText("Hello", 300, 300, paint); //左下角坐标
	//沿着指定路径绘制文字
	Path path = new Path();
	path.addArc(200, 200, 400, 400, -225, 225);
	path.arcTo(400, 200, 600, 400, -180, 225, false);
	path.lineTo(400, 542);
	paint.setTextSize(ViewUtil.toPx(getContext(), 20));
	paint.setTypeface(Typeface.create(Typeface.MONOSPACE, Typeface.NORMAL));
	canvas.drawPath(path, paint);
	canvas.drawTextOnPath("Hello Hello Hello", path, 300, 300, paint);
	//通过Color清空画布
	canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
	//通过Paint清空画布
	paint.setColor(Color.TRANSPARENT);
	paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));