[REQ] Add support for tap-and-drag image zoom

[geominorai]

Describe the problem that needs solving

The current image player on v3.0.0-beta1 only supports pinch zooming but not double-tap or tap-and-drag gestures used in other media player or image gallery apps for one-handed operation and accessibility.

Describe the solution you'd like

Double-tapping should zoom in a fixed amount while tap-and-drag should start and adjust zoom depending on the distance dragged.

These zooming gestures can also apply to the video player, which currently does not support zooming at all.

For reference, please see the image and media player implementation in the Sync for Reddit app.

[geominorai]

That is only double-tap zooming. This requests for tap-and-drag zooming. Here are some examples in other apps:

Sync.Drag.Zooming.mp4

Gallery.Drag.Zooming.mp4

The latter app is open-source: https://github.com/SimpleMobileTools/Simple-Gallery

[jonjomckay]

From what I can find, this isn't yet possible in Flutter.

There is a PR (flutter/flutter#109573) that looks like it adds support for double tap and drag, but it's not merged yet. Once it's merged, I'll try and implement this using those primitives.

[geominorai]

Sounds good, thanks!