mouse coordinates seem to be off using version 4.5 or higher
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- Python
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Description
Actual behaviour
opencv version 4.4.0 seams to be still ok, but somewhere for later versions mouse reading coordinates seems to be off, is that true? Not sure what version it starts but latest 4.6 or 4.7 for sure
It could be tested in code below. It is a 2x2 image, so with mouse increase the size of the window. It should print proper mouse coordinates while hoovering with mouse over image. But latest opencv versions show proper value only for top , left quadrant for a pixel
Steps to reproduce
import numpy as np
import cv2
print(f'OpenCV version {cv2.__version__}')
img = np.zeros((2,2,3), np.uint8)
img[0, 0] = (0, 0, 255)
img[1, 0] = (0, 255, 0)
img[0, 1] = (255, 0, 0)
def mouseAction(event,x,y,flags,param=None):
print(x,y)
cv2.namedWindow('image', cv2.WINDOW_NORMAL)
cv2.setWindowProperty('image',cv2.WND_PROP_FULLSCREEN, cv2.WINDOW_NORMAL)
cv2.setMouseCallback('image', mouseAction)
cv2.imshow('image', img)
cv2.waitKey(0)
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the supplied Python reproducer and compare its mouse coordinates under OpenCV 4.4.0 and the later versions named in the issue. Trace whether the mismatch belongs to the Python package or the underlying window and mouse-callback behavior; done means a confirmed version boundary, expected coordinates, and a reproducible diagnosis.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- opencv, python
- Domain
- computer-vision
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100