Unable to write text on mouseclick area on Image

问题

I am trying to draw text on Image where the user clicks. Getting this error:

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\Admin\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
  File "C:/Users/Admin/PycharmProjects/ashish/td.py", line 35, in draw_text
    cv2.putText(img, "OpenCV + Jurassic Park!!!", (event.x,event.y), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 255, 0), 2)
TypeError: Expected cv::UMat for argument 'img'

if __name__ == "__main__":
    root = Tk()
    frame = Frame(root, bd=2, relief=SUNKEN)
    canvas = Canvas(frame, bd=0)
    canvas.grid(row=0, column=0, sticky=N+S+E+W)
    frame.pack(fill=BOTH,expand=1)

    #adding the image
    File = filedialog.askopenfilename(parent=root, initialdir="F:/",title='Choose an image.')
    img = ImageTk.PhotoImage(Image.open(File))
    canvas.create_image(0,0,image=img,anchor="nw")

    #function to be called when mouse is clicked
    def draw_text(event):
        cv2.putText(img, "OpenCV + Jurassic Park!!!", (event.x,event.y), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 255, 0), 2)
        cv2.imshow("Text", img)
    #mouseclick event
    canvas.bind("<Button 1>",draw_text)

    root.mainloop()

回答1:

Your img is ImageTK object from tkinter but cv2 is not part of tkinter and cv2.putText doesn't work with ImageTK. It needs something different. cv2 has own function to read image and it creates object which you can use with cv2.putText().

But canvas has function to display text on top of image and you don't need cv2. But it can't be saved in file as image with text.

But Image has function to draw text on image and it can be saved in file.

So finally you don't need cv2.

I use Image.Draw to create object on which I can put text or draw line/square/etc.
After adding text I replace image on canvas.

This method create image with text which you can save in file (img.save())

from tkinter import *
from tkinter import filedialog
from PIL import Image, ImageTk, ImageDraw

# function to be called when mouse is clicked
def draw_text(event):
    global imgtk
    global cv_img

    # create object for drawing
    draw = ImageDraw.Draw(img)
    # put text
    draw.text((event.x,event.y), "ImageDraw + Jurassic Park!!!")

    # replace old image
    canvas.delete(cv_img_id)    
    imgtk = ImageTk.PhotoImage(img)
    cv_img_id = canvas.create_image(0, 0, image=imgtk, anchor="nw")

if __name__ == "__main__":
    root = Tk()

    frame = Frame(root, bd=2, relief=SUNKEN)
    frame.pack(fill=BOTH, expand=1)

    canvas = Canvas(frame, bd=0)
    canvas.grid(row=0, column=0, sticky=N+S+E+W)

    #adding the image
    file = filedialog.askopenfilename(parent=root, initialdir="F:/",title='Choose an image.')
    img = Image.open(file)
    imgtk = ImageTk.PhotoImage(img)
    cv_img_id = canvas.create_image(0, 0, image=imgtk, anchor="nw")

    #mouseclick event
    canvas.bind("<Button 1>", draw_text)

    root.mainloop()

Using canvas.create_text you can put text on top of image which you can move/remove later but it doesn't create image with text which you can save in file.

from tkinter import *
from tkinter import filedialog
from PIL import Image, ImageTk

# function to be called when mouse is clicked
def draw_text(event):
    canvas.create_text((event.x,event.y), text="Canvas + Jurassic Park!!!")

if __name__ == "__main__":
    root = Tk()

    frame = Frame(root, bd=2, relief=SUNKEN)
    frame.pack(fill=BOTH, expand=1)

    canvas = Canvas(frame, bd=0)
    canvas.grid(row=0, column=0, sticky=N+S+E+W)

    #adding the image
    file = filedialog.askopenfilename(parent=root, initialdir="F:/",title='Choose an image.')
    imgtk = ImageTk.PhotoImage(Image.open(file))
    canvas.create_image(0, 0, image=imgtk, anchor="nw")

    #mouseclick event
    canvas.bind("<Button 1>", draw_text)

    root.mainloop()

来源：https://stackoverflow.com/questions/55548811/unable-to-write-text-on-mouseclick-area-on-image

标签

python

tkinter

cv2