在Matplotlib中像Google财经图表一样动画？

Question

我刚刚开始使用Matplotlib的动画功能来制作Google财经图表。

我结合了我在项目网站上发现的两个例子（Draggable rectangle exercise，api example code: date_demo.py），并稍微调整了一下，以便列出底部列出的代码。

虽然看起来并不太糟糕，但我希望顶部图表（主）更新动态，因为底部图表（从属）选择被移动，而不仅仅是在底部选择被释放时。我怎样才能做到这一点？我试图将self.rect.figure.canvas.draw()位移到on_motion方法，但它似乎会干扰blit的东西，因为底部选择将无法正确呈现。

所以我认为解决方案是对底部图表进行智能动画，即blit-ing位，而顶部图表只是完全重新绘制。问题是，我可以重绘任何东西的唯一方法是重新绘制整个画布，这将包括底部图表。我找到了draw()的{​​{1}}方法，但我无法让它工作。正如我上面所说，最好是我想重新绘制顶部图表，而底部图表则是巧妙的方式。有谁知道怎么做？

到目前为止，这是我的代码。请原谅代码，这有点不整洁。

matplotlib.axes

Answer 1

今天早上我有机会参加这个活动（过去3天我们有第二场暴风雪）。你是对的，如果你试图在on_motion中重绘整个图形，它会弄乱黄色矩形的动画。关键是还要在主子​​图上显示线。

尝试使用此代码：

import datetime
import numpy as np
import sys
import time
import wx
import matplotlib
from matplotlib.figure import Figure 
import matplotlib.dates as mdates
import matplotlib.ticker as mtickers
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas
import matplotlib.patches as mpatches

class DraggableRectangle:
    lock = None
    def __init__(self, rect, master, xMin, xMax):       
        self.rect = rect        
        self.press = None
        self.slave_background = None
        self.master_background = None
        self.xMax = xMax
        self.xMin = xMin
        self.master = master
        self.master_line, = self.master.get_lines()

    def connect(self):      
        self.cidpress = self.rect.figure.canvas.mpl_connect('button_press_event', self.on_press)
        self.cidrelease = self.rect.figure.canvas.mpl_connect('button_release_event', self.on_release)
        self.cidmotion = self.rect.figure.canvas.mpl_connect('motion_notify_event', self.on_motion)

    def on_press(self, event):      
        if event.inaxes != self.rect.axes: return
        if DraggableRectangle.lock is not None: return
        contains, attrd = self.rect.contains(event)
        if not contains: return     
        x0, y0 = self.rect.xy
        self.press = x0, y0, event.xdata, event.ydata
        DraggableRectangle.lock = self
        canvas = self.rect.figure.canvas
        axes = self.rect.axes

        # set up our animated elements
        self.rect.set_animated(True)
        self.master_line.set_animated(True) 
        self.master.xaxis.set_visible(False) #we are not animating this

        canvas.draw()

        # backgrounds for restoring on animation
        self.slave_background = canvas.copy_from_bbox(self.rect.axes.bbox)
        self.master_background = canvas.copy_from_bbox(self.master.axes.bbox)

        axes.draw_artist(self.rect)
        canvas.blit(axes.bbox)

    def on_motion(self, event):
        if DraggableRectangle.lock is not self: return
        if event.inaxes != self.rect.axes: return
        x0, y0, xpress, ypress = self.press
        dx = event.xdata - xpress
        dy = 0
        if x0+dx > self.xMax:
            self.rect.set_x(self.xMax)
        elif x0+dx < self.xMin:
            self.rect.set_x(self.xMin)
        else:
            self.rect.set_x(x0+dx)
        self.rect.set_y(y0+dy)
        canvas = self.rect.figure.canvas
        axes = self.rect.axes

        # restore backgrounds
        canvas.restore_region(self.slave_background)
        canvas.restore_region(self.master_background)

        # set our limits for animated line
        self.master.set_xlim(self.rect.get_x(), self.rect.get_x() + 92)

        # draw yellow box
        axes.draw_artist(self.rect)
        canvas.blit(axes.bbox)

        #draw line
        self.master.axes.draw_artist(self.master_line)
        canvas.blit(self.master.axes.bbox)  

    def on_release(self, event):        
        if DraggableRectangle.lock is not self: return
        self.press = None
        DraggableRectangle.lock = None

        # unanimate rect and lines
        self.rect.set_animated(False)
        self.master_line.set_animated(False)

        self.slave_background = None
        self.master_background = None

        # redraw whole figure
        self.master.xaxis.set_visible(True)
        self.rect.figure.canvas.draw()

    def disconnect(self):
        self.rect.figure.canvas.mpl_disconnect(self.cidpress)
        self.rect.figure.canvas.mpl_disconnect(self.cidrelease)
        self.rect.figure.canvas.mpl_disconnect(self.cidmotion)

class MplCanvasFrame(wx.Frame): 
    def __init__(self):
        wx.Frame.__init__(self, None, wx.ID_ANY, title='First Chart', size=(800, 700))
        datafile = matplotlib.get_example_data('goog.npy')
        r = np.load(datafile).view(np.recarray)
        datesFloat = matplotlib.dates.date2num(r.date)
        figure = Figure()
        xMaxDatetime = r.date[len(r.date)-1]
        xMinDatetime = r.date[0]
        xMaxFloat = datesFloat[len(datesFloat)-1]
        xMinFloat = datesFloat[0]
        yMin = min(r.adj_close) // 5 * 5
        yMax = (1 + max(r.adj_close) // 5) * 5      
        master = figure.add_subplot(211)
        master.plot(datesFloat, r.adj_close)
        master.xaxis.set_minor_locator(mdates.MonthLocator())
        master.xaxis.set_major_locator(mdates.MonthLocator(bymonth=(1,4,7,10)))
        master.xaxis.set_major_formatter(mdates.DateFormatter('%b-%y'))
        master.set_xlim(datesFloat[120], datesFloat[120]+92)
        master.yaxis.set_minor_locator(mtickers.MultipleLocator(50))
        master.yaxis.set_major_locator(mtickers.MultipleLocator(100))
        master.set_ylim(yMin, yMax)
        master.set_position([0.05,0.20,0.92,0.75])
        master.xaxis.grid(True, which='minor')
        master.yaxis.grid(True, which='minor')
        slave = figure.add_subplot(212, yticks=[]) 
        slave.plot(datesFloat, r.adj_close)
        slave.xaxis.set_minor_locator(mdates.MonthLocator())
        slave.xaxis.set_major_locator(mdates.YearLocator())
        slave.xaxis.set_major_formatter(mdates.DateFormatter('%b-%y'))
        slave.set_xlim(xMinDatetime, xMaxDatetime)
        slave.set_ylim(yMin, yMax)
        slave.set_position([0.05,0.05,0.92,0.10])
        rectangle = mpatches.Rectangle((datesFloat[120], yMin), 92, yMax-yMin, facecolor='yellow', alpha = 0.4)     
        slave.add_patch(rectangle)
        canvas = FigureCanvas(self, -1, figure)
        drag = DraggableRectangle(rectangle, master, xMinFloat, xMaxFloat - 92)
        drag.connect()

app = wx.PySimpleApp() 
frame = MplCanvasFrame()
frame.Show(True) 
app.MainLoop()