createPlot.ax1.text(xMid, yMid, txtString)
createPlot.ax1 是表示： ax1 是函数 createPlot 的一个属性，这个可以在函数里面定义也可以在函数定义后加入也可以
example：
def fun():
fun.x =1
当你在python的命令窗口下，运行一次fun()后，x 就是 fun()的一个属性，你在命令窗口下输入
fun.x 后面会显示 1
也可以 在 函数定义完后加入 属性 如 fun.y = 2,在使用 dir(fun)，你就会发现fun有 x,y 这两个属性
subplot：
|
Keyword |
Description |
|
loc |
a location code |
|
prop |
the font property (matplotlib.font_manager.FontProperties 对象) eg song_font = matplotlib.font_manager.FontProperties(fname='simsun.ttc', size=8) |
|
fontsize |
the font size (和prop互斥，不可同时使用) |
|
markerscale |
the relative size of legend markers vs. original |
|
numpoints |
the number of points in the legend for line |
|
scatterpoints |
the number of points in the legend for scatter plot |
|
scatteryoffsets |
a list of yoffsets for scatter symbols in legend |
|
frameon |
if True, draw a frame around the legend. If None, use rc |
|
fancybox |
if True, draw a frame with a round fancybox. If None, use rc |
|
shadow |
if True, draw a shadow behind legend |
|
ncol |
number of columns |
|
borderpad |
the fractional whitespace inside the legend border |
|
labelspacing |
the vertical space between the legend entries |
|
handlelength |
the length of the legend handles |
|
handleheight |
the length of the legend handles |
|
handletextpad |
the pad between the legend handle and text |
|
borderaxespad |
the pad between the axes and legend border |
|
columnspacing |
the spacing between columns |
|
title |
the legend title |
|
bbox_to_anchor |
the bbox that the legend will be anchored. |
|
bbox_transform |
the transform for the bbox. transAxes if None. |