Tkinter 中未显示选择区域

Question

我正在开发一个应用程序，它允许用户根据他们的选择缩放图表的一部分。我能够得到初始的 x, y 坐标(x0, y0) 以及最终的 x, y 坐标(x1, y1)。但完全不知道为什么选择区域没有出现。

from Tkinter import *
matplotlib.use('TkAgg')
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

root = Tk()
graph = Figure(figsize=(5,4), dpi=100)
ax = graph.add_subplot(111)
plot = ax.plot([1,2,3,4],[5,6,2,8])
canvas = FigureCanvasTkAgg(graph, master=root)
canvas.show()
canvas.get_tk_widget().grid(column=2, row=1, rowspan=2, sticky=(N, S, E, W))

class Zoom(object):
    def __init__(self):
        self.graph = Figure(figsize=(5,4), dpi=100)
        self.ax = graph.add_subplot(111)
        self.rect = ax.patch
        self.rect.set_facecolor('green')
        self.ax.plot([1,2,3,4],[5,6,2,8])
        self.is_pressed = False
        self.x0 = None
        self.y0 = None
        self.x1 = None
        self.y1 = None
        self.aid = graph.canvas.mpl_connect('button_press_event', self.on_press)
        self.bid = graph.canvas.mpl_connect('button_release_event', self.on_release)
        self.cid = graph.canvas.mpl_connect('motion_notify_event', self.on_motion)

    def on_press(self, event):
        print 'press'
        self.is_pressed = True
        self.x0 = event.xdata
        self.y0 = event.ydata
        print(self.x1, self.x0)
        print(self.y1, self.y0)

    def on_motion(self, event):
        if self.is_pressed is True:
            print 'panning'
            self.x1 = event.xdata
            self.y1 = event.ydata
            print(self.x1, self.x0)
            print(self.y1, self.y0)
            self.rect.set_width(self.x1 - self.x0)
            self.rect.set_height(self.y1 - self.y0)
            self.rect.set_xy((self.x0, self.y0))
            self.rect.set_linestyle('dashed')
            self.ax.figure.canvas.draw()

    def on_release(self, event):
        print 'release'
        self.is_pressed = False
        self.x1 = event.xdata
        self.y1 = event.ydata
        print(self.x1, self.x0)
        print(self.y1, self.y0)
        self.rect.set_width(self.x1 - self.x0)
        self.rect.set_height(self.y1 - self.y0)
        self.rect.set_xy((self.x0, self.y0))
        self.rect.set_linestyle('solid')
        self.ax.figure.canvas.draw()

my_object = Zoom()
root.mainloop()

我从这个问题中得到了帮助Matplotlib: draw a selection area in the shape of a rectangle with the mouse 我得到的输出是

press
(0.0, 1.4007056451612905)
(0.0, 6.9296116504854366)

panning
(1.4007056451612905, 1.4007056451612905)
(6.8932038834951452, 6.9296116504854366)
panning
(None, 1.4007056451612905)
(None, 6.9296116504854366)
panning
(None, 1.4007056451612905)
(None, 6.9296116504854366)

release
(None, 1.4007056451612905)
(None, 6.9296116504854366)

Answer 1

它对我有用：

from Tkinter import *
from matplotlib.figure import *
import matplotlib

matplotlib.use('TkAgg')
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg

root = Tk()
graph = Figure(figsize=(5,4), dpi=100)
ax = graph.add_subplot(111)
plot = ax.plot([1,2,3,4],[5,6,2,8])
canvas = FigureCanvasTkAgg(graph, master=root)
canvas.show()
canvas.get_tk_widget().grid(column=2, row=1, rowspan=2, sticky=(N, S, E, W))

class Zoom(object):
    def __init__(self):
        self.graph = Figure(figsize=(5,4), dpi=100)
        self.ax = graph.add_subplot(111)

        # should be Rectangle((0,0),0,0)
        self.rect = Rectangle((10,10),100,100)
        self.ax.add_patch(self.rect)

        self.ax.plot([1,2,3,4],[5,6,2,8])
        self.is_pressed = False
        self.x0 = 0.0
        self.y0 = 0.0
        self.x1 = 0.0
        self.y1 = 0.0
        self.aid = graph.canvas.mpl_connect('button_press_event', self.on_press)
        self.bid = graph.canvas.mpl_connect('button_release_event', self.on_release)
        self.cid = graph.canvas.mpl_connect('motion_notify_event', self.on_motion)

    def on_press(self, event):
        self.is_pressed = True
        if event.xdata is not None and event.ydata is not None:
            self.x0, self.y0 = event.xdata, event.ydata

            print 'press:', self.x0, self.y0

            # only remove old rectangle
            self.rect.set_width(0)
            self.rect.set_height(0)
            self.rect.set_xy((self.x0, self.y0))
            self.ax.figure.canvas.draw()

            # color and linestyle for future motion 
            self.rect.set_facecolor('red')
            self.rect.set_linestyle('dashed')

    def on_motion(self, event):
        if self.is_pressed:
            if event.xdata is not None and event.ydata is not None:
                self.x1, self.y1 = event.xdata, event.ydata
                self.rect.set_width(self.x1 - self.x0)
                self.rect.set_height(self.y1 - self.y0)
                self.rect.set_xy((self.x0, self.y0))
                self.ax.figure.canvas.draw()
                print 'rect:', self.x0, self.y0, self.x1, self.y1, (self.x1-self.x0), (self.y1-self.y0)

    def on_release(self, event):
        self.is_pressed = False
        print 'release:', event.xdata, event.ydata

        # change only color and linestyle

        #self.rect.set_width(self.x1 - self.x0)
        #self.rect.set_height(self.y1 - self.y0)
        #self.rect.set_xy((self.x0, self.y0))

        self.rect.set_facecolor('blue')
        self.rect.set_linestyle('solid')
        self.ax.figure.canvas.draw()

my_object = Zoom()
root.mainloop()

Answer 2

您需要随着事件的变化更新这些：

def on_motion(self, event):
    if self.is_pressed is True:
        self.x1 = event.xdata
        self.y1 = event.ydata
        self.rect.set_width(1)
        self.rect.set_height(1)
        self.rect.set_xy((2.5, 5))
        self.rect.set_linestyle('dashed')
        self.ax.figure.canvas.draw()

def on_release(self, event):
    print 'release'
    self.is_pressed = False
    self.x1 = event.xdata
    self.y1 = event.ydata
    self.rect.set_width(1)
    self.rect.set_height(1)
    self.rect.set_xy((2.5, 5))
    self.rect.set_linestyle('solid')
    self.ax.figure.canvas.draw()

他们将在坐标 (2.5, 5) 处不断绘制一个固定大小的矩形，宽度和高度为 1。

与您正在查看的类似问题的问题类似。

    def on_press(self, event):
        print('press')
        self.is_pressed = True
        self.x0 = event.xdata
        self.y0 = event.ydata

    def on_motion(self, event):
        self.x1, self.y1 = event.xdata, event.ydata
        if (self.is_pressed is True and
                self.x1 is not None and
                self.y1 is not None):
            self.rect.set_width(self.x1 - self.x0)
            self.rect.set_height(self.y1 - self.y0)
            self.rect.set_xy((self.x0, self.y0))
            self.rect.set_linestyle('dashed')
            self.ax.figure.canvas.draw()

    def on_release(self, event):
        print('release')
        self.is_pressed = False
        self.x1, self.y1 = event.xdata, event.ydata
        try:
            self.rect.set_width(self.x1 - self.x0)
            self.rect.set_height(self.y1 - self.y0)
            self.rect.set_xy((self.x0, self.y0))
        except TypeError:
            if (self.x1 is None or self.y1 is None):
                return
            else:
                raise
        self.rect.set_linestyle('solid')
        self.ax.figure.canvas.draw()

请注意，矩形尺寸取自事件。我添加了警卫以防止事件无法正确解释坐标的事故。

---

@furas 在 cmets 中提出了一个很好的观点，将坐标初始化为浮点数是个好主意。

    self.x0 = 0.0
    self.y0 = 0.0
    self.x1 = 0.0
    self.y1 = 0.0