Kivy和Matplotlib尝试更新按钮回调上的绘图 [英] Kivy and Matplotlib trying to update plot on button callback

问题描述

我可以使用Kivy和Matplotlib很好地生成2D表面图.我试图在单击按钮时更新Z值.如何实现?

I can generate a 2D surface plot very nicely with Kivy and Matplotlib. I am trying to update the Z values on a button click. How may this be accomplished?

我注意到我可以发出一个plt.clf()来清除绘图，但是执行plt.gcf()来显示当前绘图是无效的.

I noticed that I can issue a plt.clf() which will clear the plot but doing the plt.gcf() to display the current plot doesn't work.

任何建议将不胜感激.

import matplotlib
matplotlib.use('module://kivy.garden.matplotlib.backend_kivy')
from matplotlib.figure import Figure
from numpy import arange, sin, pi
from kivy.app import App

import numpy as np
from matplotlib.mlab import griddata
from kivy.garden.matplotlib.backend_kivy import FigureCanvas,\
                                                NavigationToolbar2Kivy

# from backend_kivy import FigureCanvasKivy as FigureCanvas

from kivy.uix.floatlayout import FloatLayout
from kivy.uix.boxlayout import BoxLayout
from matplotlib.transforms import Bbox
from kivy.uix.button import Button
from kivy.graphics import Color, Line, Rectangle

import matplotlib.pyplot as plt
from matplotlib import cm
from mpl_toolkits.mplot3d import Axes3D

fig, ax = plt.subplots()

X = np.arange(-508, 510, 203.2)
Y = np.arange(-508, 510, 203.2)
X, Y = np.meshgrid(X, Y)

Z = np.random.rand(6, 6)

plt.contourf(X, Y, Z, 100, zdir='z', offset=1.0, cmap=cm.hot)
plt.colorbar()

ax.set_ylabel('Y [mm]')
ax.set_title('NAILS surface')
ax.set_xlabel('X [mm]')

canvas = fig.canvas


def callback(instance):


    fig, ax = plt.subplots()

    X = np.arange(-508, 510, 203.2)
    Y = np.arange(-508, 510, 203.2)
    X, Y = np.meshgrid(X, Y)

    Z = np.random.rand(6, 6)

    plt.contourf(X, Y, Z, 100, zdir='z', offset=1.0, cmap=cm.hot)
    plt.colorbar()

    ax.set_ylabel('Y [mm]')
    ax.set_title('NAILS surface')
    ax.set_xlabel('X [mm]')

    canvas = fig.canvas
    canvas.draw()


class MatplotlibTest(App):
    title = 'Matplotlib Test'

    def build(self):
        fl = BoxLayout(orientation="vertical")
        a = Button(text="press me", height=40, size_hint_y=None)
        a.bind(on_press=callback)

        fl.add_widget(canvas)
        fl.add_widget(a)
        return fl

if __name__ == '__main__':
    MatplotlibTest().run()

推荐答案

您的代码的第45行:

fig, ax = plt.subplots()

创建一个新的图形，从而创建一个新的画布.该画布永远不会添加到BoxLayout，因此也就不会显示.重复使用旧画布可能是一个更好的主意.将回调函数更改为此:

creates a new figure and hence a new canvas. This canvas is never added to the BoxLayout and hence never shown. It's probably a better idea to re-use the old canvas. Change the callback function to this:

def callback(instance):
    # Clear the existing figure and re-use it
    plt.clf()

    X = np.arange(-508, 510, 203.2)
    Y = np.arange(-508, 510, 203.2)
    X, Y = np.meshgrid(X, Y)

    Z = np.random.rand(6, 6)

    plt.contourf(X, Y, Z, 100, zdir='z', offset=1.0, cmap=cm.hot)
    plt.colorbar()

    ax.set_ylabel('Y [mm]')
    ax.set_title('NAILS surface')
    ax.set_xlabel('X [mm]')

    canvas.draw_idle()

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