Unable to use fitz with python 3.8

I use pymupdf to automatically sign my document. But the package name is pymupdf even the warning is that “fitz”  is not installed. If come across an error message like import fitz File “/home/phsamuel/p3/lib/python3.10/site-packages/fitz/__init__.py”, line 1, in <module> from frontend import * File “/home/phsamuel/p3/lib/python3.10/site-packages/frontend/__init__.py”, line 1, in <module> from .events import * File “/home/phsamuel/p3/lib/python3.10/site-packages/frontend/events/__init__.py”, line…

Create trackbar example in OpenCV

I was not aware that OpenCV has a built-in slider, I usually use cvui for that. But for simple application, the built-in function is more handy import cv2 cap=cv2.VideoCapture(0) low_H=99 high_H=125 def on_low_H_thresh_trackbar(var): global low_H low_H=var def on_high_H_thresh_trackbar(var): global high_H high_H=var cv2.namedWindow(‘frame’) cv2.createTrackbar(‘Low H’,’frame’,low_H,255,on_low_H_thresh_trackbar) cv2.createTrackbar(‘High H’,’frame’,high_H,255,on_high_H_thresh_trackbar) while True: ret, frame=cap.read() color=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV) frame=cv2.inRange(color,(low_H,0,0),(high_H,255,255)) cv2.imshow(‘frame’,frame) if cv2.waitKey(50)…

OpenCV and QT on 22.04

I got error Could not load the Qt platform plugin “xcb” in “” even though it was found Even following this did not solve the problem. But it seems that going headless works. That is, pip uninstall opencv-python pip install opencv-python-headless

hotkey for taking screenshots

Suddenly Ubuntu does not show the window of how to deal with a screenshot after taking one. It still was not solved. But I guess it is better to just add “Ctrl” to grab a shot.  

No bold math in latex

I got this “bug” for a long time and ignored it. Eventually it seems like coming from \renewcommand{\sfdefault}{cmss} which I am not sure where I copied from. This seems to set sans font to cmss, which probably doesn’t bold math.  

Canvas API pagination

Canvas API’s pagination is mentioned here but is not really very well-documented. For example, r.links[‘last’] may not exist. Therefore a solution as below suggested here may not work while r.links[‘current’][‘url’] != r.links[‘last’][‘url’]:    r = requests.get(r.links[‘next’][‘url’], headers=headers)    raw = r.json()    for question in raw:        data_set.append(question) Instead, I changed it a little bit…

Muting Discord server

The tooltip for muting a channel explains that it prevents unread indicators and notifications unless you’re mentioned. If you want it not to show anything even if you’re mentioned, click on the server name in the upper left and change your notification settings to “nothing” for that channel.

Office 365 online no equation editor

As title, it wasted me an hour to figure that out. The information online is very confusing. In particular, they describe how to insert equations for office 365. And never even footnote that the “web-version” does not have that feature. Microsoft Office Web vs Desktop Apps: What is the Difference?