问题
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:
Screenshot:
回答1:
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.
回答2:
This can help you
namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
imshow( "Display window", image ); // Show our image inside it.
回答3:
In openCV whenever you try to display an oversized image or image bigger than your display resolution you get the cropped display. It's a default behaviour.
In order to view the image in the window of your choice openCV encourages to use named window. Please refer to namedWindow documentation
The function namedWindow creates a window that can be used as a placeholder for images and trackbars. Created windows are referred to by their names.
cv.namedWindow(name, flags=CV_WINDOW_AUTOSIZE)
where each window is related to image container by the name arg, make sure to use same name
eg:
import cv2
frame = cv2.imread('1.jpg')
cv2.namedWindow("Display 1")
cv2.resizeWindow("Display 1", 300, 300)
cv2.imshow("Display 1", frame)
来源：https://stackoverflow.com/questions/19285562/python-opencv-imread-displaying-image