Opencv & PyGi : how to display an image read by opencv

Question

I want to display an image in PyGi, the image is read first by opencv. But,it fails.

from gi.repository import Gtk, GdkPixbuf
import cv2
import numpy as np
window = Gtk.Window()
image = Gtk.Image()
image.show()
window.add(image)
window.show_all()
im = cv2.imread("file.bmp")
a = np.ndarray.tostring(img)
h, w, d = img.shape
p = GdkPixbuf.Pixbuf.new_from_data(a,GdkPixbuf.Colorspace.RGB, False, 8, w, h, w*3, None, None)
image.set_from_pixbuf(p)
Gtk.main()

But the result is a black image. Moreover, if I loop around a set of files (multiple .bmp files from a directory), I got coredump (suspecting GdkPixbuf.Pixbuf.new_from_data)

Is it the proper way to have opencv & PyGi interacting ? I managed to use opencv with Tkinter, but I fail to use it with PyGi.

Answer 1

You can try using GdkPixbuf.PixbufLoader:

loader = GdkPixbuf.PixbufLoader()
loader.write(img)
loader.close()
pixbuf = loader.get_pixbuf()
image = Gtk.Image.new_from_pixbuf(pixbuf)

Answer 2

This actually worked just fine for me. Perhaps the issue in your case was the two different variables ' im ' (in which you are reading the CV image) and ' img ' (the one that you are converting to string)?

Here is a simplified code that worked for me in displaying a video frame from camera:

# OpenCV image:
cap = cv2.VideoCapture(0)
ret, img = cap.read()
# Gtk Image:
img_gtk = Gtk.Image()
# Do other things such as attaching the 'img_gtk' to a window/grid...

# Convert and display:
h, w, d = img.shape
pixbuf = GdkPixbuf.Pixbuf.new_from_data  (img.tostring(), GdkPixbuf.Colorspace.RGB, False, 8, w, h, w*3, None, None)
img_gtk.set_from_pixbuf (pixbuf)
img_gtk.show()