I loved tixy when I first discovered it a few years ago so created this https://www.mathsuniverse.com/tixy (with permission from the original author) with puzzles to solve on the tixy grid. I use it with my computer science students who get really into it.
I was blown away by the little functions at first and I too made a clone to experiment with calculang [1].
I added an evaluation feature (F9) so you can select sub-expressions and see what they do, which was helpful to figure out some patterns (video in [2])
What's wrong with that statement? It has historically and traditionally been true for raster displays, even if there do exist ways to use standard Cartesian-style coordinates with a computer.
There top left has usually been (0, 0) for hardware pixel coordinates (although even then there’s plenty of exceptions, e.g. mode 13h scrolling) but as a blanket statement about computer graphics in general it’s misleading.
I'm struggling to see the problem with this statement, other than maybe to add in the word "usually". My students will know of graphs in maths where the origin is always bottom left. When working with HTML canvas and every other computer graphics situation I've worked in, it's top left instead.
"PostScript uses a coordinate system where the origin is at the bottom-left corner of the page, with the x-axis increasing to the right and the y-axis increasing upwards."
Oscilloscopes use middle-left.
Unreal engine and SketchUp use Screen middle with xy increasing to the right.
in AutoCAD, the user coordinate system is 1/3 of the screen to the left for the origin, with X increasing to the right, and Y increasing upwards.
Almost all raster displays, and memory based programs assume top left, because that is how it was done first - counter intuitive.
It it not counter intuitive and the decision extends far earlier than the first displays.
A raster image onscreen is displayed in the order that the data appears when written down. It stands to reason that a data depiction should be in the same orientation as the display orientation. Displays were created by people who read from left to right, top to bottom. If the displays did not follow that order. images would be flipped or rotated when displayed in a data form.
The first pixel written to the display is in the top left because we read from the top left. If writers of another language had have popularised the text, perhaps things might have been different.
