def unIndentBlock(block):
            currentIndent = blockIndentation(block)

            if currentIndent.endswith('\t'):
                charsToRemove = 1
            elif withSpace:
                charsToRemove = 1 if currentIndent else 0
            else:
                if self.useTabs:
                    charsToRemove = min(spacesCount(currentIndent), self.width)
                else:  # spaces
                    if currentIndent.endswith(self.text()):  # remove indent level
                        charsToRemove = self.width
                    else:  # remove all spaces
                        charsToRemove = min(spacesCount(currentIndent), self.width)

            if charsToRemove:
                cursor = cursorAtSpaceEnd(block)
                cursor.setPosition(cursor.position() - charsToRemove, QTextCursor.KeepAnchor)
                cursor.removeSelectedText()
def setSaSS(self, lenp2, lenp3, lenp1):
        self.lenp2 = lenp2
        self.lenp3 = lenp3
        self.lenp1 = lenp1
        if(self.lenp1 > (self.lenp2 + self.lenp3)):
        #<CAB 夾角為 180 度, 三點共線且 A 介於 BC 之間
            ret = math.pi
        else :
            # <CAB 夾角為 0, 三點共線且 A 不在 BC 之間
            if((self.lenp1 < (self.lenp2 - self.lenp3)) or (self.lenp1 < (self.lenp3 - self.lenp2))):
                ret = 0.0
            else :
            # 透過餘絃定理求出夾角 <CAB 
                ret = math.acos(((self.lenp2 * self.lenp2 + self.lenp3 * self.lenp3) - self.lenp1 * self.lenp1) / (2 * self.lenp2 * self.lenp3))
        return ret