关于Canvas.drawText中xy位置问题
问：canvas.drawText("3", x, y, paint); x和y是指画得时候数字3中心的坐标吗？还是左上角的坐标？
x答：默认是‘3’这个字符的左边在屏幕的位置，如果设置了paint.setTextAlign(Paint.Align.CENTER);那就是字符的中心，y是指定这个字符baseline在屏幕上的位置。
public void drawText (String text, float x, float y, Paint paint)
Since: API Level 1 Draw the text, with origin at (x,y), using the specified paint.
The origin is interpreted based on the Align setting in the paint.
Parameters
text The text to be drawn
x The x-coordinate of the origin of the text being drawn
y The y-coordinate of the origin of the text being drawn
paint The paint used for the text (e.g. color, size, style)
