mPaint =new Paint();
mPaint.setColor(Color.RED); //设置颜色
mPaint.setARGB(255,255,255,0); //设置透明度颜色
mPaint.setAntiAlias(true); //这是抗锯齿
mPaint.setStyle(Paint.Style.STROKE); //描边效果 STROKE FILL FILL_AND_STROKE
mPaint.setStrokeWidth(4); //设置边框宽度
mPaint.setStrokeCap(Paint.Cap.ROUND); //圆角效果 默认BUTT 圆角ROUND 方角SQUARE
mPaint.setStrokeJoin(Paint.Join.BEVEL); //拐角效果 默认 MITER尖角 ROUND圆角 BEVEL缺角
mPaint.setShader(new SweepGradient(200,200,Color.RED,Color.BLUE)); //设置渐变渲染器
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.ADD)); //设置图层混合模式
mPaint.setColorFilter(new LightingColorFilter(0x00ffff,0x000000)); //设置颜色过滤器
mPaint.setFilterBitmap(true); //设置双线性过滤 像素间过度效果更加平滑，不会出现马赛克块
//画笔遮罩滤镜，传入度数和样式
mPaint.setMaskFilter(new BlurMaskFilter(10,BlurMaskFilter.Blur.NORMAL));
mPaint.setTextScaleX(2); //设置文本缩放倍数
mPaint.setTextSize(38); //设置字体大小
mPaint.setTextAlign(Paint.Align.LEFT); //设置文本对齐方式
mPaint.setUnderlineText(true); //设置下划线
String str ="Android高级工程师";
Rect rect =new Rect();
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect
float measureSize =mPaint.measureText(str); //获取文本宽度
Paint.FontMetrics metrics =mPaint.getFontMetrics(); //获取字体度量对象
float ascent = metrics.ascent; //字符最高点到baseline的推荐距离
float top = metrics.top; //字符最高点到baseline的最大距离
float descent = metrics.descent; //字符最低点到baseline的推荐距离
float bottom = metrics.bottom; //字符最低点到baseline的最大距离
float leading = metrics.leading; //行间距，即ascent到descent的距离
