alt Hacker NewsI always found this UI pattern a bit odd, because there just aren't that many situations where you want to compare the left side of image A and the right side of image B.
I see it a lot in photography, to show before/after processing - but what you want to be able to quickly compare are the same part of an image with and without the processing applied.
One of the photography tools I make is a LUT viewer/converter - and while I didn't have the slider at first, I guess it's standard enough at this point that people asked for it and I added it.
But I made two additions to it that make it more useful IMO:
- have labels on the left/right top corners, so it's immediately clear which version of the image you're looking at
- click and hold on the image to preview the full unprocessed version; release to revert to the view. That makes it easy to quickly compare the two versions of the same spot of a photo. (similar to what you suggest, but non-latching)
I have a video of it in action here: