it is very easy ,it is concerning about font style. the function from menu bar .
but I don't know what you said 显示框后半段没有数字的地方显示仍然为白色
what do you mean ? the background is Black, and the indicting string is white, if no string's location indicates white ? are you afraid of confusion about ?
Use "string's text selection property node" ,it can achieve what you want.
then, convert string to number.
this is the sample attachment. for this case, I think that you would love me more. he he. ^.^
cause this is the simple sample, maybe , there are some bug, Please process it yourself as you need.