Python - OpenCV - imread - Displaying Image

Sinjin Forde picture Sinjin Forde · Oct 10, 2013 · Viewed 109.4k times · Source

I am currently working on reading an image and displaying it to a window. I have successfully done this, but upon displaying the image, the window only allows me to see a portion of the full image. I tried saving the image after loading it, and it saved the entire image. So I am fairly certain that it is reading the entire image.

imgFile = cv.imread('1.jpg')

cv.imshow('dst_rt', imgFile)
cv.waitKey(0)
cv.destroyAllWindows()

Image: image

Screenshot: screenshot

Answer

Igonato picture Igonato · Oct 17, 2013

Looks like the image is too big and the window simply doesn't fit the screen. Create window with the cv2.WINDOW_NORMAL flag, it will make it scalable. Then you can resize it to fit your screen like this:

from __future__ import division
import cv2


img = cv2.imread('1.jpg')

screen_res = 1280, 720
scale_width = screen_res[0] / img.shape[1]
scale_height = screen_res[1] / img.shape[0]
scale = min(scale_width, scale_height)
window_width = int(img.shape[1] * scale)
window_height = int(img.shape[0] * scale)

cv2.namedWindow('dst_rt', cv2.WINDOW_NORMAL)
cv2.resizeWindow('dst_rt', window_width, window_height)

cv2.imshow('dst_rt', img)
cv2.waitKey(0)
cv2.destroyAllWindows()

According to the OpenCV documentation CV_WINDOW_KEEPRATIO flag should do the same, yet it doesn't and it's value not even presented in the python module.