在opencv Python中拖动鼠标绘制一条线并获取线的端点坐标

Posted 2023-03-16

【中文标题】在opencv Python中拖动鼠标绘制一条线并获取线的端点坐标

【英文标题】：Drag mouse to draw a line and get cordinates of end points of line in opencv Python

【发布时间】：2017-07-11 04:57:21

【问题描述】：

我需要在图像中画一条线，以便我单击 pt1 并拖动到 pt2。所以结果会显示一条线，我也得到了 pt1 和 pt2 的坐标。我目前正在使用两次单独的鼠标单击来绘制一条带有以下代码的线

import numpy as np
import cv2

def get_points(im):
    # Set up data to send to mouse handler
    data = 
    data['im'] = im.copy()
    data['points'] = []

    # Set the callback function for any mouse event
    cv2.imshow("Image", im)
    cv2.setMouseCallback("Image", mouse_handler, data)
    cv2.waitKey(0)

    # Convert array to np.array
    points = np.vstack(data['points']).astype(float)

    return points

def mouse_handler(event, x, y, flags, data):

    if event == cv2.EVENT_LBUTTONDOWN:
        cv2.circle(data['im'], (x, y), 3, (0, 0, 255), 5, 16);
        cv2.imshow("Image", data['im']);
        if len(data['points']) < 2: # This can be changed for more or less points
            data['points'].append([x, y])


# Running the code
img = cv2.imread('image.jpg', 0)
pts = get_points(img)
cv2.line(img, (pts[0][0], pts[0][1]), (pts[1][0], pts[1][1]), (0,0,0), 2)
cv2.imshow('Image', img)
cv2.waitKey(0)

它有效，但不能解决我的问题。我希望它从 pt1 向下拖动到 pt2 并自己画一条线，而不是我使用点击获得​​点然后画线。因此，例如，左下图是我当前的实现，但我想像右图中那样做

提前感谢您的建议。

【参考方案1】：

也可以使用其他事件。

这是一个快速的肮脏解决方案：

import numpy as np
import cv2

btn_down = False

def get_points(im):
    # Set up data to send to mouse handler
    data = 
    data['im'] = im.copy()
    data['lines'] = []

    # Set the callback function for any mouse event
    cv2.imshow("Image", im)
    cv2.setMouseCallback("Image", mouse_handler, data)
    cv2.waitKey(0)

    # Convert array to np.array in shape n,2,2
    points = np.uint16(data['lines'])

    return points, data['im']

def mouse_handler(event, x, y, flags, data):
    global btn_down

    if event == cv2.EVENT_LBUTTONUP and btn_down:
        #if you release the button, finish the line
        btn_down = False
        data['lines'][0].append((x, y)) #append the seconf point
        cv2.circle(data['im'], (x, y), 3, (0, 0, 255),5)
        cv2.line(data['im'], data['lines'][0][0], data['lines'][0][1], (0,0,255), 2)
        cv2.imshow("Image", data['im'])

    elif event == cv2.EVENT_MOUSEMOVE and btn_down:
        #thi is just for a ine visualization
        image = data['im'].copy()
        cv2.line(image, data['lines'][0][0], (x, y), (0,0,0), 1)
        cv2.imshow("Image", image)

    elif event == cv2.EVENT_LBUTTONDOWN and len(data['lines']) < 2:
        btn_down = True
        data['lines'].insert(0,[(x, y)]) #prepend the point
        cv2.circle(data['im'], (x, y), 3, (0, 0, 255), 5, 16)
        cv2.imshow("Image", data['im'])


# Running the code
img = cv2.imread('C://image.jpg', 1)
pts, final_image = get_points(img)
cv2.imshow('Image', final_image)
print pts
cv2.waitKey(0)

如果这是您的想法，请告诉我。