Tkinter is not good for setting individual pixels. If you want to move rectangles or ovals though (a small oval will look like a pixel, but it doesn't scale for updating a whole image).
def update(x,y):
canvas.delete('all')
canvas.create_rectangle(x-1,y-1,x+1,y+1)
You can, of course, be more judicious, saving the return value of the rectangle and then only clear the appropriate elements. Or you can move existing elements directly as Bryan points out. As he explains elsewhere Tkinter of course, supports drawing images, ovals, and a slew of other things. Here's a canonical source edit: that is old and not canoncial This one's slightly better For a general source on animating with a timer loop, here's Bryan agian
Bryan also noted that you can work with pixels directly You can do that with PhotoImage.
Array-Like Pixel Access Without Graphical Extensions
A robust module like pygame will be the most scalable option. However, I've had success (in educational settings only) writing graphics engines by modifying the elements of a numpy array and then displaying it as an image (you also need this link to display the images).
This lets you do pixel level modifications; since it's relatively trivial to write C-extensions that modify numpy arrays, you can prototype fast image processing doing custom manipulations. While I've written whole graphics engines using just tkinter this way, again I can only reccomend it for educational purposes.
Otherwise, just bite the bullet and pull in openGl or pygame. You'll save yourself a ton of time in the long run.
Summary
- Very simple animations can be done right in tkinter
- For educational purposes, you can do arbitrary graphics with numpy and tkinter
- For rhobust animations, check out a full library (openGl, matplotlib, pygame) that suits your needs (graphical rendering, statistical graphing, game development, etc.)