[Matplotlib-users] Some beginner questions

[David Aldrich]

Hi

I'm new to Matplotlib and am struggling a bit.

I'm using Matplotlib with the Kivy GUI framework, but that shouldn't be directly relevant.  I want to show a single figure having 4 subplots, each displaying one line.  My code looks like this (simplified):

class CMplGraph():
    pass

    def __init__(self, **kwargs):
        self.create_plot()

    def create_plot(self):
        self.fig, ((self.ax0, self.ax1), (self.ax2, self.ax3)) = plt.subplots(nrows=2, ncols=2)

        self.ax0.set_title("Title_0")
        self.ax1.set_title("Title_1")
        self.ax2.set_title("Title_2")
        self.ax3.set_title("Title_3")
        plt.show()

    def plot(self, plotType, xCoords, yCoords):

        if (plotType == "PLOT_0 "):
            ax = self.ax0
        elif (plotType == " PLOT_1"):
            ax = self.ax1
        elif (plotType == " PLOT_2"):
            ax = self.ax2
        elif (plotType == " PLOT_3"):
            ax = self.ax3
        else:
            raise BadPlotType(plotType)

        # remove previous line
        if len(ax.lines) > 0:
            ax.lines.pop(0)


        plt.draw()
        time.sleep(1)    # Blink

        line = ax.plot(xCoords, yCoords, color='blue')

        canvas = self.fig.canvas
        canvas.draw()

Then my main app can call create_plot() once, followed by plot() whenever it wants to update the displayed data.

This seems to work but I'm not sure I'm doing it correctly.  Here are my questions:


1)      Is it ok that I created axis objects?


2)      Am I removing the previous line correctly?



3)      I would like display to 'blink' between successive calls to plot(). So I put in a 1s sleep after removing the previous line. There should therefore be a flash before the new data is displayed.  But I don't see that blink - the line updates instantaneously.  Why is that?




Best regards

David

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