Method center

Lib/idlelib/editor.py:1045–1051

(self, mark="insert")

        return "break"

    def center(self, mark="insert"):
        text = self.text
        top, bot = self.getwindowlines()
        lineno = self.getlineno(mark)
        height = bot - top
        newtop = max(1, lineno - height//2)
        text.yview(float(newtop))

    def getwindowlines(self):
        text = self.text