Question

我试图让一些eventlisteners工作，而且在课堂上似乎没有做任何事情 - 甚至没有打印信息：

from pylab import *
from cmath import *

class integrator:

    def __init__(self, func, fig):
        self.debug = False
        self.pressed = False
        self.firstPt = None
        self.lastPt = None
        self.isum = 0
        cid = fig.canvas.mpl_connect('button_press_event', self.onclick)
        fig.canvas.mpl_connect('motion_notify_event', self.onmove)
        fig.canvas.mpl_connect('button_release_event', self.onUp)

    #def plotpt(self, z, mark=','):
        #ax.plot(z.real, z.imag, 'k'+mark)#black point.
        #try:
            #result = eval(func)
            #if debug:
                #print 'result',result
            #ax.plot(result.real, result.imag, 'r'+mark)#red result point.
        #except ZeroDivisionError:
            #print "Undefined/infinite (/0) at", z

    def onclick(self, event):
        self.lastPt = event.xdata + 1j*event.ydata
        self.firstPt = self.lastPt
        self.isum = 0
        print 'button=%d, x=%d, y=%d, xdata=%f, ydata=%f'%(
            event.button, event.x, event.y, event.xdata, event.ydata)

    def onmove(self, event):
        if event.xdata is not None and event.ydata is not None and lastPt is not None :
            print event.xdata, event.ydata
            pt = event.xdata + 1j*event.ydata
            diff = abs(pt - lastPt)
            z = lastPt
            nth = eval(func)
            z = pt
            nxt = eval(func)
            part = (nth+nxt)/2 * diff
            print nth,nxt,diff
            isum += part


    def onUp(self, event):
        print 'UP button=%d, x=%d, y=%d, xdata=%f, ydata=%f'%(
            event.button, event.x, event.y, event.xdata, event.ydata)
        print "From",self.firstPt,"to",self.lastPt,"along f(z) =",func,':'
        print self.isum


print "Note: phase(z) is argument, z.conjugate() is conj, z.real, z.imag are re/im parts."
func = raw_input('f(z)=')
fig = plt.figure("Complex function f(z)="+func)
ax = fig.add_subplot(1,1,1)
ax.set_xbound(-3,3)
ax.set_ybound(-3,3)
#ax.plot(np.random.rand(10))
fig.set_label('F(z)='+func)

plt.draw()

integrator(func, fig)

plt.draw()
show()#looks like nothing after this line runs.

在我进入课堂之前至少部分工作：这里至少会打印出一些东西，但是找不到你在屏幕上点击并拖动的任何曲线的复杂曲线积分（总是说它是0）：

from pylab import *
from cmath import *

debug = False
pressed = False
firstPt = None
lastPt = None
isum = 0

def plotpt(z, mark=','):
    ax.plot(z.real, z.imag, 'k'+mark)#black point.
    try:
        result = eval(func)
        if debug:
            print 'result',result
        ax.plot(result.real, result.imag, 'r'+mark)#red result point.
    except ZeroDivisionError:
        print "Undefined/infinite (/0) at", z

def onclick(event):
    lastPt = event.xdata + 1j*event.ydata
    firstPt = lastPt
    isum = 0
    print 'button=%d, x=%d, y=%d, xdata=%f, ydata=%f'%(
        event.button, event.x, event.y, event.xdata, event.ydata)

def onmove(event):
    if event.xdata is not None and event.ydata is not None and lastPt is not None :
        print event.xdata, event.ydata
        pt = event.xdata + 1j*event.ydata
        diff = abs(pt - lastPt)
        z = lastPt
        nth = eval(func)
        z = pt
        nxt = eval(func)
        part = (nth+nxt)/2 * diff
        print nth,nxt,diff
        isum += part


def onUp(event):
    print 'UP button=%d, x=%d, y=%d, xdata=%f, ydata=%f'%(
        event.button, event.x, event.y, event.xdata, event.ydata)
    print "From",firstPt,"to",lastPt,"along f(z) =",func,':'
    print isum


print "Note: phase(z) is argument, z.conjugate() is conj, z.real, z.imag are re/im parts."
func = raw_input('f(z)=')
fig = plt.figure("Complex function f(z)="+func)
ax = fig.add_subplot(1,1,1)
ax.set_xbound(-3,3)
ax.set_ybound(-3,3)
#ax.plot(np.random.rand(10))
fig.set_label('F(z)='+func)

plt.draw()

cid = fig.canvas.mpl_connect('button_press_event', onclick)
fig.canvas.mpl_connect('motion_notify_event', onmove)
fig.canvas.mpl_connect('button_release_event', onUp)

plt.draw()
show()#looks like nothing after this line runs.

Answer 1

这段代码存在很多问题，但是关于为什么在显示绘图窗口之后没有发生任何事情的问题，答案很简单：

您需要保留对所使用对象的引用。

这意味着，您需要将类实例存储在变量

中

integ = integrator(func, fig)

您还需要将事件处理程序存储在类变量

中

self.cid = fig.canvas.mpl_connect('button_press_event', self.onclick)
self.cid2 = fig.canvas.mpl_connect('motion_notify_event', self.onmove)
self.cid3 = fig.canvas.mpl_connect('button_release_event', self.onUp)

在课堂上使用时，为什么我的matplotlib事件不会被触发？

1 个答案: