page = arthur o'dwyer – stuff mostly about c++

url = https://quuxplusone.github.io/blog analysed @ 2021-11-14 04:15 UTC

image-processing pretty-pictures web
Via Hacker News : You may know that you can reverse a string by first reversing the order of the words in the string, then reversing the characters in each word. (So
hello world
becomes
world hello
, and then we recursively reverse each word to get
dlrow olleh
.) Well, it turns out you can do the same kind of thing in two dimensions: to rotate an image by 90 degrees, you can just rotate the order of the quadrants, and then recursively rotate each quadrant.