kevinlinxc

Make your Python user scripts delightful with prompt_toolkit

When writing Python scripts, I ask for user input all the time. This input often has a fixed set of options, those options are usually not fully listed out to the user, the user has to type them out while making no typos, and then we have to do validation afterwards to make sure they picked something valid.

Recently I discovered the prompt_toolkit Python library, which fixes all this.

The library actually has lots of features, but the one that is relevant is this nice dropdown that lets you pick an item from pre-defined options. It saves time for the end-user and the script writer, and it'll delight anyone seeing it for the first time.

kevinlinxc

"""
Manim animation showing morphological dilation. Input image and kernel can be modified and the
output will still look good, although you may need to move/translate it to be viewable.
Mostly written by Claude, I needed to modify it a bit.

`manim -pqh dilation.py`
"""

from manim import *
import numpy as np

kevinlinxc

from PIL import Image, ImageDraw, ImageFont
import cv2
import numpy as np

def get_bounding_rect_area(contour):
    # calculate area using the minimum bounding rectangle instead of whatever cv2.contourArea does
    rect = cv2.minAreaRect(contour)
    width = rect[1][0]
    height = rect[1][1]
    return width * height

kevinlinxc

import cv2
import numpy as np


def nothing(x):
    pass


# Create a black image, a window
img = np.zeros((300, 512, 3), np.uint8)

kevinlinxc

import serial
import serial.tools.list_ports

def get_ports():
    """
    Get a list of available serial ports.
    Returns:
        List of serial ports, or None if no ports are available.
    """
    serial_ports = serial.tools.list_ports.comports()

kevinlinxc

"""Calculate the difference between two GPS coordinates using the Haversine formula"""
from math import radians, cos, sin, sqrt, atan2


def haversine(coord1, coord2):
    # Radius of the Earth in kilometers
    R = 6378.137

    # Converting coordinates from degrees to radians
    lat1, lon1 = radians(coord1[0]), radians(coord1[1])

kevinlinxc

"""
This simple helper script auto-detects the Arduino port.
Saves time because you don't need to check the Arduino IDE/device manager to get the port number each time.
"""
import serial.tools.list_ports


def get_port():
    """
    Get the port name of a connected Arduino if one is connected.

kevinlinxc

import cv2
import numpy

# make a video where each frame is the frame number

writer = cv2.VideoWriter("frame_numbers.mp4", cv2.VideoWriter_fourcc(*"mp4v"), 30, (1920, 1080))

for i in range(6572):
    frame = numpy.zeros((1080, 1920, 3), dtype=numpy.uint8)
    cv2.putText(frame, str(i), (500, 500), cv2.FONT_HERSHEY_SIMPLEX, 10, (255, 255, 255), 2)

kevinlinxc

# pip install pygeodesy
import pygeodesy.sphericalNvector


def intersection_point(lat_long_1, bearing_1, lat_long_2, bearing_2):
    vector1 = pygeodesy.sphericalNvector.LatLon(*lat_long_1)
    vector2 = pygeodesy.sphericalNvector.LatLon(*lat_long_2)
    return vector1.intersection(bearing_1, vector2, bearing_2)

kevinlinxc

Diffing PDFs

Recently, I wanted to find the textual differences between two PDFS, in the same way that you would compare plain text files with Git/GitHub. I wanted the nice side-by-side view too, not just the Git diff terminal output.

Edit: After writing this gist, I realized that https://www.diffchecker.com/pdf-compare/ pretty much does what I want. This was still a fun experiment though.

I tried a few different ways of extracting the text (Tesseract OCR, Copy and Pasting all the text), but eventually I found the best solution for me was a tool called textract, which uses pdftotext under the hood. This did the best job, as it didn't have weird misread symbols like OCR and it didn't have extra nonsense copied by C/P.