canvas.py 文件源码

def resetTransforms(self):
        """I want to draw something (eg, string underlines) w.r.t. the default user space.
           Reset the matrix! This should be used usually as follows::

              canv.saveState()
              canv.resetTransforms()
              #...draw some stuff in default space coords...
              canv.restoreState() # go back!
        """
        # we have to adjoin the inverse, since reset is not a basic operation (without save/restore)
        (selfa, selfb, selfc, selfd, selfe, selff) = self._currentMatrix
        det = selfa*selfd - selfc*selfb
        resulta = selfd/det
        resultc = -selfc/det
        resulte = (selfc*selff - selfd*selfe)/det
        resultd = selfa/det
        resultb = -selfb/det
        resultf = (selfe*selfb - selff*selfa)/det
        self.transform(resulta, resultb, resultc, resultd, resulte, resultf)