Canvas.drawCircle()方法中半径参数的单位是多少？
是像素吗？还是蘸？
http://developer.android.com/reference/android/graphics/Canvas.html#drawCircle（float，float，浮动，android.graphics.Paint）
我试着查看源代码，看看是否能得到任何想法，但该方法只是一个包装器，文档中没有指定任何内容。
如官方文档中所述：
When you're writing an application in which you would like to perform specialized drawing and/or control the animation of graphics, you should do so by drawing through a Canvas. A Canvas works for you as a pretense, or interface, to the actual surface upon which your graphics will be drawn — it holds all of your "draw" calls. Via the Canvas, your drawing is actually performed upon an underlying Bitmap, which is placed into the window.
根据定义，位图使用像素，而不使用其他像素作为其单位。
因此，所有的drawXYZ()方法都在px中。