用matplotlib在图像上单击之间绘制线

Question

我试图允许用户右键单击一次图像，然后再一次，然后该程序将从第一个单击到第二个。

然而，我现在拥有的，看似随机地将行插入我的图像中。它们弹出，它们远不及我的点击次数，并且具有随机的长度和角度。

我是Python的初学者，绝对是matplotlib，因此，任何帮助都将不胜感激。以下是我的代码，相关区域标记为＃s：

from pymouse import PyMouse
import matplotlib.pyplot as plt
import matplotlib.lines as lines
import numpy

im1 = plt.imread('xexample1.PNG')
im2 = plt.imread('xexample2.PNG')
im3 = plt.imread('xexample3.PNG')
data_images = [im1,im2,im3]

index = 0
ax = plt.gca()
fig = plt.gcf()
plt.imshow(data_images[index])

linepoints = numpy.array([])
print linepoints


#on click event- print x,y coords
def onclick(event):
   # if event.xdata != None and event.ydata != None:
    plot = numpy.asarray(data_images[index])
    if event.button == 1:            
        print("IMAGE: %d" %index, event.xdata, event.ydata,(plot[event.xdata][event.ydata])*255)
######################################################################
    if event.button == 3:
        global linepoints
        x = event.xdata
        y = event.ydata
        tup1 = [(x, y)]
        linepoints = numpy.append(linepoints, x)
        linepoints = numpy.append(linepoints, y)
        if numpy.size(linepoints) == 4:
           # print "full"
            #l1 = lines.Line2D([linepoints[0], linepoints[1]], [linepoints[2],linepoints[3]], transform=fig.transFigure, figure=plt)
            #fig.canvas.draw()
            plt.plot((linepoints[0], linepoints[1]), (linepoints[2], linepoints[3]), '-')
            print linepoints
            linepoints = numpy.array([])

        print linepoints
       # plt.show()
######################################################################
def toggle_images(event):
    global index

    if event.key == 'x':
        index += 1
        if index < len(data_images) and index >= 0:
            plt.imshow(data_images[index])
            plt.draw()
        else:
            #plt.close()
            print 'out of range'
            index -= 1

    if event.key == 'z':
        index -= 1
        if index < len(data_images) and index >= 0:
            plt.imshow(data_images[index])
            plt.draw()
        else:
            #plt.close()
            print 'out of range'
            index += 1
plt.imshow(data_images[index])
plt.connect('key_press_event',toggle_images)
cid = fig.canvas.mpl_connect('button_press_event', onclick)
plt.show()

Answer 1

我创建了下面附上的穿着的版本，但最终只有一个非常小的错误：

plt.plot((linepoints[0], linepoints[1]), (linepoints[2], linepoints[3]), '-')

需要：

plt.plot((linepoints[0], linepoints[2]), (linepoints[1], linepoints[3]), '-')

即您的第一（索引0）和第三（索引2）值是x值，第二个值（索引1）和第四（索引3）是y值，现在您实际上是在绘制(x0,y0),(x1,y1)而不是(x0,x1),(y0,y1)

我的最小示例：

import matplotlib.pyplot as plt
import numpy
plt.close('all')
fake_img = numpy.random.random((10,10))
plt.imshow(fake_img, interpolation='none')
ax  = plt.gca()
fig = plt.gcf()
linepoints = numpy.array([])
def onclick(event):
    if event.button == 3:
        global linepoints
        x = event.xdata
        y = event.ydata
        linepoints = numpy.append(linepoints, x)
        linepoints = numpy.append(linepoints, y)
        if numpy.size(linepoints) == 4:
            plt.plot((linepoints[0], linepoints[2]), (linepoints[1], linepoints[3]), '-')
            linepoints = numpy.array([])
            plt.show()
cid = fig.canvas.mpl_connect('button_press_event', onclick)
plt.show()