Feature request: download new image only when changing to next wallpaper

[JI Xiang]

I find the current way of separating downloading and changing images a bit unintuitive. I'd like to have a mode in which the app would only download a new image when I explicitly change to the next wallpaper, either automatically or manually. Currently, the app either downloads a lot of images that I don't necessarily want, if I set the download interval to be too frequent; or I easily run out of images to change for when I press "next", if I set the download interval to be too infrequent, and thus end up rotating through all the old images that I had. I usually only change wallpapers once a day.

[Peter Levi (peterlevi)]

This is something I have thought about, and it probably makes sense to have (as the default and only behavior, not as an option). The current configuration in this aspect is unnecessarily complex.

[Peter Levi (peterlevi)]

This becomes a lot more important as we reduce supported sources to just those for which we use rate-limited API keys (as per the policy update http://peterlevi.com/variety/2017/03/changes/).

With Unsplash and Flickr we cannot afford to perform unnecessary downloads.

[Peter Levi (peterlevi)]

Implementation-wise, we need a pre-downloaded queue of several images, as well as download rate-limiting (if user starts scrolling down-down-down-down in a quick manner we should not download each time) - maybe fine-grain limiting rate per minute, per hour, per day.

[Peter Levi (peterlevi)]

Moved to https://github.com/varietywalls/variety/issues/212