在matplotlib中添加新的导航模式

Question

我正在写一个wx/matplotlib的应用程序，但在给matplotlib的导航工具栏添加新工具时遇到了很大的困难。

简单来说，我想添加一些选择工具（比如框选、套索等），这些工具可以切换控制子图的鼠标模式。不过到目前为止，我还没有找到什么简单的方法来实现这个功能。

不过，我刚发现了一个看起来可能有用的函数：http://matplotlib.sourceforge.net/api/axes_api.html?highlight=set_navigate_mode#matplotlib.axes.Axes.set_navigate_mode

可惜的是，正如警告所说的，这个函数并没有真正帮到我。

有没有人知道该怎么做？下面是一个简化的例子，展示了我目前的进展。书签图标用来代替我的套索图标，并且为了简洁起见，我去掉了套索的功能。

import wx
from matplotlib.patches import Rectangle
from matplotlib.widgets import Lasso
from matplotlib.figure import Figure
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg
from matplotlib.backends.backend_wxagg import NavigationToolbar2WxAgg as NavigationToolbar

class ScatterPanel(FigureCanvasWxAgg):
    '''
    Contains the guts for drawing scatter plots.
    '''
    def __init__(self, parent, **kwargs):
        self.figure = Figure()
        FigureCanvasWxAgg.__init__(self, parent, -1, self.figure, **kwargs)
        self.canvas = self.figure.canvas
        self.SetMinSize((100,100))
        self.figure.set_facecolor((1,1,1))
        self.figure.set_edgecolor((1,1,1))
        self.canvas.SetBackgroundColour('white')

        self.subplot = self.figure.add_subplot(111)
        self.navtoolbar = None
        self.lasso = None
        self.redraw()

        self.canvas.mpl_connect('button_press_event', self.on_press)
        self.canvas.mpl_connect('button_release_event', self.on_release)

    def lasso_callback(self, verts):
        pass

    def on_press(self, evt):
        if evt.button == 1:
            if self.canvas.widgetlock.locked(): 
                return
            if evt.inaxes is None: 
                return
            if self.navtoolbar.mode == 'lasso':
                self.lasso = Lasso(evt.inaxes, (evt.xdata, evt.ydata), self.lasso_callback)
                self.canvas.widgetlock(self.lasso)

    def on_release(self, evt):
        # Note: lasso_callback is not called on click without drag so we release
        #   the lock here to handle this case as well.
        if evt.button == 1:
            if self.lasso:
                self.canvas.draw_idle()
                self.canvas.widgetlock.release(self.lasso)
                self.lasso = None
        else:
            self.show_popup_menu((evt.x, self.canvas.GetSize()[1]-evt.y), None)

    def redraw(self):
        self.subplot.clear()
        self.subplot.scatter([1,2,3],[3,1,2])

    def toggle_lasso_tool(self, evt):
        if evt.Checked():
            self.navtoolbar.mode = 'lasso'
            #self.subplot.set_navigate_mode('lasso')
            # Cheat: untoggle the zoom and pan tools
            self.navtoolbar.ToggleTool(self.navtoolbar._NTB2_ZOOM, False)
            self.navtoolbar.ToggleTool(self.navtoolbar._NTB2_PAN, False)
        else: 
            self.navtoolbar.mode = ''
            self.lasso = None
            #self.subplot.set_navigate_mode('')

    def get_toolbar(self):
        if not self.navtoolbar:
            self.navtoolbar = NavigationToolbar(self.canvas)
            self.navtoolbar.DeleteToolByPos(6)
            ID_LASSO_TOOL = wx.NewId()
            lasso = self.navtoolbar.InsertSimpleTool(5, ID_LASSO_TOOL, 
                            wx.ArtProvider.GetBitmap(wx.ART_ADD_BOOKMARK),
                            isToggle=True)
            self.navtoolbar.Realize()
            self.navtoolbar.Bind(wx.EVT_TOOL, self.toggle_lasso_tool, id=ID_LASSO_TOOL)
        return self.navtoolbar

if __name__ == "__main__":
    app = wx.PySimpleApp()
    f = wx.Frame(None, size=(600,600))
    p = ScatterPanel(f)
    f.SetToolBar(p.get_toolbar())            
    f.Show()
    app.MainLoop()

谢谢，

亚当

Answer 1

这是一个改进版的 MyNavToolbar。主要需要注意的是新增了一个 add_user_tool 方法。我在 __init__ 里面调用了它，但你可能更想在 MyNavToolbar 类外部调用它。这样一来，你就可以为不同的图表类型添加不同的工具。

class MyNavToolbar(NavigationToolbar2WxAgg):
    """wx/mpl NavToolbar hack with an additional tools user interaction.
    This class is necessary because simply adding a new togglable tool to the
    toolbar won't (1) radio-toggle between the new tool and the pan/zoom tools.
    (2) disable the pan/zoom tool modes in the associated subplot(s).
    """
    def __init__(self, canvas):
        super(NavigationToolbar2WxAgg, self).__init__(canvas)
        self.pan_tool  = self.FindById(self._NTB2_PAN)
        self.zoom_tool = self.FindById(self._NTB2_ZOOM)
        self.Bind(wx.EVT_TOOL, self.on_toggle_pan_zoom, self.zoom_tool)
        self.Bind(wx.EVT_TOOL, self.on_toggle_pan_zoom, self.pan_tool)

        self.user_tools = {}   # user_tools['tool_mode'] : wx.ToolBarToolBase

        self.InsertSeparator(5)
        self.add_user_tool('lasso', 6, icons.lasso_tool.ConvertToBitmap(), True, 'Lasso')
        self.add_user_tool('gate', 7, icons.gate_tool.ConvertToBitmap(), True, 'Gate')

    def add_user_tool(self, mode, pos, bmp, istoggle=True, shortHelp=''):
        """Adds a new user-defined tool to the toolbar.
        mode -- the value that MyNavToolbar.get_mode() will return if this tool 
                is toggled on
        pos -- the position in the toolbar to add the icon
        bmp -- a wx.Bitmap of the icon to use in the toolbar
        isToggle -- whether or not the new tool toggles on/off with the other 
                    togglable tools
        shortHelp -- the tooltip shown to the user for the new tool
        """
        tool_id = wx.NewId()
        self.user_tools[mode] = self.InsertSimpleTool(pos, tool_id, bmp,
                            isToggle=istoggle, shortHelpString=shortHelp)
        self.Bind(wx.EVT_TOOL, self.on_toggle_user_tool, self.user_tools[mode])

    def get_mode(self):
        """Use this rather than navtoolbar.mode
        """
        for mode, tool in self.user_tools.items():
            if tool.IsToggled():
                return mode
        return self.mode

    def untoggle_mpl_tools(self):
        """Hack city: Since I can't figure out how to change the way the 
        associated subplot(s) handles mouse events: I generate events to turn
        off whichever tool mode is enabled (if any). 
        This function needs to be called whenever any user-defined tool 
        (eg: lasso) is clicked.
        """
        if self.pan_tool.IsToggled():
            wx.PostEvent(
                self.GetEventHandler(), 
                wx.CommandEvent(wx.EVT_TOOL.typeId, self._NTB2_PAN)
            )
            self.ToggleTool(self._NTB2_PAN, False)
        elif self.zoom_tool.IsToggled():
            wx.PostEvent(
                self.GetEventHandler(),
                wx.CommandEvent(wx.EVT_TOOL.typeId, self._NTB2_ZOOM)
            )
            self.ToggleTool(self._NTB2_ZOOM, False)

    def on_toggle_user_tool(self, evt):
        """user tool click handler.
        """
        if evt.Checked():
            self.untoggle_mpl_tools()
            #untoggle other user tools
            for tool in self.user_tools.values():
                if tool.Id != evt.Id:
                    self.ToggleTool(tool.Id, False)

    def on_toggle_pan_zoom(self, evt):
        """Called when pan or zoom is toggled. 
        We need to manually untoggle user-defined tools.
        """
        if evt.Checked():
            for tool in self.user_tools.values():
                self.ToggleTool(tool.Id, False)
        # Make sure the regular pan/zoom handlers get the event
        evt.Skip()

    def reset_history(self):
        """More hacky junk to clear/reset the toolbar history.
        """
        self._views.clear()
        self._positions.clear()
        self.push_current()

Answer 2

好了，这就是了，虽然看起来不太好，但能用。我就让文档字符串来解释吧，这个东西已经浪费了我太多时间。

import wx
from matplotlib.patches import Rectangle
from matplotlib.widgets import Lasso
from matplotlib.figure import Figure
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg
from matplotlib.backends.backend_wxagg import NavigationToolbar2WxAgg

class MyNavToolbar(NavigationToolbar2WxAgg):
    """wx/mpl NavToolbar hack with an additional tools user interaction.
    This class is necessary because simply adding a new togglable tool to the
    toolbar won't (1) radio-toggle between the new tool and the pan/zoom tools.
    (2) disable the pan/zoom tool modes in the associated subplot(s).
    """
    ID_LASSO_TOOL = wx.NewId()
    def __init__(self, canvas):
        super(NavigationToolbar2WxAgg, self).__init__(canvas)

        self.pan_tool  = self.FindById(self._NTB2_PAN)
        self.zoom_tool = self.FindById(self._NTB2_ZOOM)

        self.lasso_tool = self.InsertSimpleTool(5, self.ID_LASSO_TOOL, 
                            wx.ArtProvider.GetBitmap(wx.ART_ADD_BOOKMARK),
                            isToggle=True)
        self.Bind(wx.EVT_TOOL, self.on_toggle_lasso_tool, self.lasso_tool)
        self.Bind(wx.EVT_TOOL, self.on_toggle_pan_zoom, self.zoom_tool)
        self.Bind(wx.EVT_TOOL, self.on_toggle_pan_zoom, self.pan_tool)

    def get_mode(self):
        """Use this rather than navtoolbar.mode
        """
        if self.lasso_tool.IsToggled():
            return 'lasso'
        else:
            return self.mode

    def untoggle_mpl_tools(self):
        """Hack city: Since I can't figure out how to change the way the 
        associated subplot(s) handles mouse events: I generate events to turn
        off whichever tool mode is enabled (if any). 
        This function needs to be called whenever any user-defined tool 
        (eg: lasso) is clicked.
        """
        if self.pan_tool.IsToggled():
            wx.PostEvent(
                self.GetEventHandler(), 
                wx.CommandEvent(wx.EVT_TOOL.typeId, self._NTB2_PAN)
            )
            self.ToggleTool(self._NTB2_PAN, False)
        elif self.zoom_tool.IsToggled():
            wx.PostEvent(
                self.GetEventHandler(),
                wx.CommandEvent(wx.EVT_TOOL.typeId, self._NTB2_ZOOM)
            )
            self.ToggleTool(self._NTB2_ZOOM, False)

    def on_toggle_lasso_tool(self, evt):
        """Lasso tool handler.
        """
        if evt.Checked():
            self.untoggle_mpl_tools()

    def on_toggle_pan_zoom(self, evt):
        """Called when pan or zoom is toggled. 
        We need to manually untoggle user-defined tools.
        """
        if evt.Checked():
            self.ToggleTool(self.ID_LASSO_TOOL, False)
        # Make sure the regular pan/zoom handlers get the event
        evt.Skip()

class ScatterPanel(FigureCanvasWxAgg):
    """Contains the guts for drawing scatter plots.
    """
    def __init__(self, parent, **kwargs):
        self.figure = Figure()
        FigureCanvasWxAgg.__init__(self, parent, -1, self.figure, **kwargs)
        self.canvas = self.figure.canvas
        self.SetMinSize((100,100))
        self.figure.set_facecolor((1,1,1))
        self.figure.set_edgecolor((1,1,1))
        self.canvas.SetBackgroundColour('white')

        self.subplot = self.figure.add_subplot(111)
        self.navtoolbar = None
        self.lasso = None
        self.redraw()

        self.canvas.mpl_connect('button_press_event', self.on_press)
        self.canvas.mpl_connect('button_release_event', self.on_release)

    def lasso_callback(self, verts):
        pass

    def on_press(self, evt):
        """canvas mousedown handler
        """
        if evt.button == 1:
            if self.canvas.widgetlock.locked(): 
                return
            if evt.inaxes is None: 
                return
            if self.navtoolbar and self.navtoolbar.get_mode() == 'lasso':
                self.lasso = Lasso(evt.inaxes, (evt.xdata, evt.ydata), self.lasso_callback)
                self.canvas.widgetlock(self.lasso)

    def on_release(self, evt):
        """canvas mouseup handler
        """
        # Note: lasso_callback is not called on click without drag so we release
        #   the lock here to handle this case as well.
        if evt.button == 1:
            if self.lasso:
                self.canvas.draw_idle()
                self.canvas.widgetlock.release(self.lasso)
                self.lasso = None
        else:
            self.show_popup_menu((evt.x, self.canvas.GetSize()[1]-evt.y), None)

    def redraw(self):
        self.subplot.clear()
        self.subplot.scatter([1,2,3],[3,1,2])

    def get_toolbar(self):
        if not self.navtoolbar:
            self.navtoolbar = MyNavToolbar(self.canvas)
            self.navtoolbar.Realize()
        return self.navtoolbar

if __name__ == "__main__":
    app = wx.PySimpleApp()
    f = wx.Frame(None, size=(600,600))
    p = ScatterPanel(f)
    f.SetToolBar(p.get_toolbar())            
    f.Show()
    app.MainLoop()