在 Matplotlib 中像 Google 财经图表一样制作动画？

Question

我刚刚开始尝试使用 Matplotlib 的动画功能来生成 Google Finance 的图表。

我结合了在项目网站上找到的两个示例（可拖动矩形练习，api 示例代码：date_demo.py）并对它们进行了一些调整以得出代码列在底部。

虽然看起来还不错，但我希望顶部图表（主）随着底部图表（从）选择的移动而动态更新，而不仅仅是在释放底部选择时。我该怎么做？我尝试将 self.rect.figure.canvas.draw() 位移至 on_motion 方法，但它似乎干扰了 blit 内容，因为底部选择获胜无法正确渲染。

因此，我认为解决方案是为底部图表（即 blit-ing 位）执行智能动画，而顶部图表则完全重新绘制。问题是，我可以重新绘制任何内容的唯一方法是重新绘制整个画布，这将包括底部图表。我确实找到了 matplotlib.axes 的 draw() 方法，但我无法让它工作。正如我上面所说，最好我只想重新绘制顶部图表，同时以巧妙的方式对底部图表进行位图传输。有谁知道该怎么做？

到目前为止，这是我的代码。请原谅代码，有点乱。

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.background = None
        self.xMax = xMax
        self.xMin = xMin
        self.master = master
    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
        self.rect.set_animated(True)
        canvas.draw()
        self.background = canvas.copy_from_bbox(self.rect.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
        canvas.restore_region(self.background)
        self.master.set_xlim(self.rect.get_x(), self.rect.get_x() + 92)
        axes.draw_artist(self.rect)
        canvas.blit(axes.bbox)
    def on_release(self, event):        
        if DraggableRectangle.lock is not self: return
        self.press = None
        DraggableRectangle.lock = None
        self.rect.set_animated(False)
        self.background = None
        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()

Answer 1

今天早上我有机会处理这个问题（过去三天我们遭遇了第二场暴风雪）。你是对的，如果你尝试在 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 blit 线。

试试这个代码：

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()