Sylvain Lesage

Download the shape of a country

Input: draw points on image

Canvas equality by value

Input: Draw an arrow on an image

Calibrate a Three.js camera using fSpy

Hello fSpy

Main Colors from Image

Colors palette from image

Can I Use Media Fragments?

Hello Cloudinary Upload

Color by number

Pixel-art or Voronoi image tesselation

Hello pixelit

Input: draw a box on image

Extended drawImage

drawImage respects canvas transparency

CSS object-fit formulas

object-fit

Every Other Pixel Is A Line

Fake video player

Async image loading, and CORS

Preload a list of images

Image placeholder

Image cover

Identify images with deterministic UUID

Perspective rectifier - example

Perspective rectifier

Image

This is not a completely fair comparison: isCanvasEqual repeatedly allocaes a typed array, while isDataURLEqual allows for memoizing the Data URL. 

Also, as you alluded at between the lines earlier: when two canvases are equal isCanvasEqual needs to compare *all* pixels, whereas a lot of browsers have some form of optimization for string comparisons IIRC (because they're immutable, a pointer comparison often suffices under the hood when they're equal). So performance metrics will also vary depending on whether the canvases are expected to be equal - if we expect isCanvasEqual to bail early *and* get rid of the typed array allocation it might still beat isDataUrlEqual

Hold up, I'll write a fork with a third comparison point (like, isFloat64Equal, or something).

Job van der Zwan

(just noticed that you mentioned the worst-case in the last paragraphs below, somehow missed that before, sorry)

Here's what I got so far:

https://observablehq.com/d/37d1bf292f23ccb6

I think there's something wrong with how I adapted the benchmarking code, because the array-comparison comes out faster in all cases on my laptop, which makes no sense: it should be equally slow to isCanvasEqual for the N=1 case, no?

(ended up using Uint32 because Float64 doesn't work due to NaN values)

Thanks a lot! It's a great improvement! I merged your contribution and added attribution.

Glad to be useful! But now the overal narrative of the writing is a bit confusing, since it doesn't take into account the new function yet 😅

You're right. I added some text in the performance section. It's not the best notebook of the year, but the information is here for the interested reader.