matplotlib绘制鼠标的十字光标（自定义方式，官方实例）

最新推荐文章于 2023-12-07 13:33:03 发布

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最新推荐文章于 2023-12-07 13:33:03 发布 · 2w 阅读

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文章标签：

#matplotlib #十字光标 #数据捕捉 #事件 #鼠标

本文介绍了如何使用matplotlib的Cursor类创建自定义交互式十字光标，包括基础实现、优化的blitting技术和捕捉数据点的实现。通过实例展示了如何提高绘制效率并实现精确数据定位。

matplotlib在widgets模块提供Cursor类用于支持十字光标的生成。另外官方还提供了自定义十字光标的实例。

`widgets`模块`Cursor`类源码

class Cursor(AxesWidget):
    """
    A crosshair cursor that spans the axes and moves with mouse cursor.

    For the cursor to remain responsive you must keep a reference to it.

    Parameters
    ----------
    ax : `matplotlib.axes.Axes`
        The `~.axes.Axes` to attach the cursor to.
    horizOn : bool, default: True
        Whether to draw the horizontal line.
    vertOn : bool, default: True
        Whether to draw the vertical line.
    useblit : bool, default: False
        Use blitting for faster drawing if supported by the backend.

    Other Parameters
    ----------------
    **lineprops
        `.Line2D` properties that control the appearance of the lines.
        See also `~.Axes.axhline`.

    Examples
    --------
    See :doc:`/gallery/widgets/cursor`.
    """

    def __init__(self, ax, horizOn=True, vertOn=True, useblit=False,
                 **lineprops):
        AxesWidget.__init__(self, ax)

        self.connect_event('motion_notify_event', self.onmove)
        self.connect_event('draw_event', self.clear)

        self.visible = True
        self.horizOn = horizOn
        self.vertOn = vertOn
        self.useblit = useblit and self.canvas.supports_blit

        if self.useblit:
            lineprops['animated'] = True
        self.lineh = ax.axhline(ax.get_ybound()[0], visible=False, **lineprops)
        self.linev = ax.axvline(ax.get_xbound()[0], visible=False, **lineprops)

        self.background = None
        self.needclear = False

    def clear(self, event):
        """Internal event handler to clear the cursor."""
        if self.ignore(event):
            return
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)
        self.linev.set_visible(False)
        self.lineh.set_visible(False)
        
    def onmove(self, event):
        """Internal event handler to draw the cursor when the mouse moves."""
        if self.ignore(event):
            return
        if not self.canvas.widgetlock.available(self):
            return
        if event.inaxes != self.ax:
            self.linev.set_visible(False)
            self.lineh.set_visible(False)

            if self.needclear:
                self.canvas.draw()
                self.needclear = False
            return
        self.needclear = Tr