连续循环中的painevent

Question

我有以下代码，在圆的圆周上绘制椭圆，然后在椭圆之间绘制和弦。和弦画得很好，但事件轰炸了我，进入了一个无限循环。

def binomial(i, n):
    return math.factorial(n) / float(
    math.factorial(i) * math.factorial(n - i))

def bernstein(t, i, n):
    return binomial(i, n) * (t ** i) * ((1 - t) ** (n - i))

def bezier(t, points):
    n = len(points) - 1
    x = y = 0
    for i, pos in enumerate(points):
        bern = bernstein(t, i, n)
        x += pos[0] * bern
        y += pos[1] * bern
   return x, y

def bezier_curve_range(n, points):
    for i in xrange(n):
        t = i / float(n - 1)
        yield bezier(t, points)
def getControlPt(x1, y1, x2, y2, t):
    new_px = (1 - t) * x1 + t * x2
    new_py = (1 - t) * y1 + t * y2
    return new_px, new_py

class Temp1(QWidget):
    def __init__(self, c, parent=None):
        super(Temp1, self).__init__(parent)
        self.text = "Hi"
        self.cords = c
    def paintEvent(self, e):
        qp = QPainter(self)
        qp.setPen(Qt.red)
        bluePen = QPen(Qt.blue, 1, Qt.DashLine)
        steps = 10000
        for i in range(15):
            for j in range(15):
              if i == j:
                  continue
              px, py = getControlPt(self.cords[i][0], self.cords[i][1], self.cords[j][0], self.cords[j][1], 0.55)
              px1, py1 = getControlPt(px, py, self.cords[j][0], self.cords[j][1], 0.25)
              px2, py2 = getControlPt(px1, py1, self.cords[j][0], self.cords[j][1], 0.75)
              cp = (self.cords[i], (px, py) , (px1, py1), (px2, py2), self.cords[j])
              oldPoint = cp[0]
              qp.setPen(bluePen)
              for point in bezier_curve_range(steps, cp):
                   qp.drawLine(oldPoint[0], oldPoint[1], point[0], point[1])
                   oldPoint = point


class Temp(QPushButton):
    def __init__(self, x, y, w, h, theta, cords, parent=None):
        super(Temp, self).__init__(parent)
        self.w = w
        self.h = h
        self.x = x
        self.y = y
        self.text = "test"
        self.angle = theta
        self.cords = cords
    def paintEvent(self, e):
        qp = QPainter(self)
        qp.setPen(Qt.red)
        qp.drawEllipse(0, 0, self.w - 2, self.h -2)


class Example(QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.cords = []
        self.initUI()
    def initUI(self):
        self.setWindowTitle('Points')
        self.drawP()

    def drawP(self):
        theta = 2 * np.pi / 15
        for i in range(15):
            angle = theta * (i + 1)
            dx = int(round(400 + 300 * np.cos(angle)))
            dy = int(round(400 + 300 * np.sin(angle)))
            self.cords.append((dx, dy))
        for i in range(15):    
            t = Temp(self.cords[i][0], self.cords[i][1], 45, 20, np.degrees(angle), self.cords, parent=self)
            t.setGeometry(self.cords[i][0], self.cords[i][1] , 45, 20)
        t1 = Temp1(self.cords, parent = self)
        t1.setGeometry(0, 0, 800, 600)

app = QApplication(sys.argv)
ex = Example()
ex.setGeometry(0, 0, 800, 600)
ex.show()
sys.exit(app.exec_())

问题在于Temp1类的painevent函数

Answer 1

如果你将print 'Temp1.paintEvent', e, i, j放入Temp1.paintEvent内嵌套的for循环中，你会发现它没有挂起，它只是很慢，每次你隐藏窗口，然后把它带回来，它必须再次经历整个paintEvent才能真正显示它。如果您耐心等待，该窗口最终会弹出。