Python Matplotlib "ginput" 可以独立于 "zoom to rectangle" 吗?

can Python Matplotlib "ginput" be independent from "zoom to rectangle"?

我正在使用 ginput 沿着时间信号对几个点进行图形选择。有时,当信号太密集时,在选择点之前放大一个区域可能很有用。我的问题是 zoom to rectangle 选项似乎在 ginput 中被考虑在内。

例如,使用此示例代码:

from __future__ import print_function
from pylab import arange, plot, sin, ginput, show
import numpy as np

t = np.linspace(0,25,500)
plot(t, sin(t))
x = ginput(3)
print("clicked",x)
show()

如果我放大信号的一部分,为缩放区域选择所做的点击被计入 ginput...有没有办法避免这种情况并使缩放区域选择独立于ginput ?

由于我没有得到任何答案,而且我找不到太多关于该主题的信息,所以我是这样解决这个问题的:我添加了一个允许用户放大所选区域的前置程序。当该区域适合点选时,用户只需按"Enter"并继续ginput

from __future__ import print_function
from pylab import arange, plot, sin, ginput, show
import matplotlib as plt  
from pylab import *
import numpy as np

def closest_point(vec,val):
    ind = np.where(vec==min(vec,key=lambda x:abs(x-val)))
    return ind[0][0]

t = np.linspace(0,250,5000)
y = sin(t)

fig = plt.figure()
plt.suptitle('chosing points over a possibly dense signal...',fontsize=14)
zoom_ok = False
while not zoom_ok:
    plt.plot(t,y)
    plt.title('1 - click on the two corners of the area to enlarge',fontsize=12)
    zoom = ginput(2,timeout=-1)
    xzoom = np.zeros([0])
    for i in range(2):
        xzoom = np.concatenate((xzoom,[int(closest_point(t,zoom[i][0]))]))  
    temps_zoom = t[xzoom[0]:xzoom[1]]
    dep_zoom = y[xzoom[0]:xzoom[1]]
    plt.clf()
    plt.plot(temps_zoom,dep_zoom,'b')
    plt.title('2 - if zoom ok -> press Enter, otherwise -> mouse click',fontsize=12)
    zoom_ok = plt.waitforbuttonpress()
plt.title('3 - you may now select the points ',fontsize=16)
x = ginput(2,timeout=-1)
plt.show()  

我遇到了同样的问题,我的解决方法是编写一个使用鼠标滚轮进行缩放的函数,这样我就可以在不单击的情况下进行缩放。我从这个页面获得了功能:

Matplotlib plot zooming with scroll wheel

并修改了函数,使其不会缩放到超过原始 x 和 y 限制:

def zoom_factory(ax, max_xlim, max_ylim, base_scale = 2.):
    def zoom_fun(event):
        # get the current x and y limits
        cur_xlim = ax.get_xlim()
        cur_ylim = ax.get_ylim()
        xdata = event.xdata # get event x location
        ydata = event.ydata # get event y location
        if event.button == 'up':
            # deal with zoom in
            scale_factor = 1/base_scale
            x_scale = scale_factor / 2
        elif event.button == 'down':
            # deal with zoom out
            scale_factor = base_scale
            x_scale = scale_factor * 2
        else:
            # deal with something that should never happen
            scale_factor = 1
            print(event.button)
        # set new limits
        new_width = (cur_xlim[1] - cur_xlim[0]) * x_scale
        new_height = (cur_ylim[1] - cur_ylim[0]) * scale_factor

        relx = (cur_xlim[1] - xdata) / (cur_xlim[1] - cur_xlim[0])
        rely = (cur_ylim[1] - ydata) / (cur_ylim[1] - cur_ylim[0])

        if xdata - new_width * (1 - relx) > max_xlim[0]:
            x_min = xdata - new_width * (1 - relx)
        else:
            x_min = max_xlim[0]
        if xdata + new_width * (relx) < max_xlim[1]:
            x_max = xdata + new_width * (relx)
        else:
            x_max = max_xlim[1]
        if ydata - new_height * (1 - rely) > max_ylim[0]:
            y_min = ydata - new_height * (1 - rely)
        else:
            y_min = max_ylim[0]
        if ydata + new_height * (rely) < max_ylim[1]:
            y_max = ydata + new_height * (rely)
        else:
            y_max = max_ylim[1]
        ax.set_xlim([x_min, x_max])
        ax.set_ylim([y_min, y_max])
        ax.figure.canvas.draw()

    fig = ax.get_figure() # get the figure of interest
    # attach the call back
    fig.canvas.mpl_connect('scroll_event',zoom_fun)

    #return the function
    return zoom_fun

所以对于给定的数字:

t = np.linspace(0,250,5000)
y = sin(t)    

fig = figure()
ax = fig.add_subplot(111)
plt.plot(t,y)

max_xlim = ax.get_xlim() # get current x_limits to set max zoom out
max_ylim = ax.get_ylim() # get current y_limits to set max zoom out
f = zoom_factory(ax, max_xlim, max_ylim, base_scale=1.1)
show()

x = ginput(3)

我使用的解决方法是将鼠标按钮参数设置为 None:

plt.ginput(n=0, timeout=0, mouse_add=None, mouse_pop=None, mouse_stop=None)

然后我使用键盘到add/pop/stop。 (要添加一个点,请将鼠标移动到正确的位置并按 Spacebarj 等。使用 Delete 删除最后一个点并使用 Enter 停止。)这样,当我用鼠标使用矩形缩放时,我没有得到不需要的点。

当然,您尝试使用的某些键盘按键可能会产生其他 window/zoom-related 副作用。 (例如 Backspace 会弹出并重置缩放),因此您必须小心。