Dual Boot
If the device has one copy of a different OS—i.e. anything but elementary OS in our case—and they choose to dual boot, we must let them choose the amount of storage to give the new OS.
Note that "Other OS" in this design should be replaced with the other OS's name if we can get it.
The size scale is also inverted, meaning it starts from the right (in LTR languages). This is handy for a few reasons: the value of the scale is just the value of how much space we should make for the new OS; the "fill level" of the scale is how large the new OS could be, and automatically constrains the scale to that value so we don't make it too big; the filled-in part of the scale is directly correlated with the accent-colored label of the new OS; the new OS goes on the right, visually reinforcing that the old OS is already on the disk and the new OS will be effectively appended on.
The new amount reserved for each partition as well as the resulting free space live updates when moving the scale. The scale is also constrained to keep it from being sized too small (using the minimum required size of the install).
- Manual input with an entry? I'm not convinced this is needed for most people, and if someone wants super nitpicky control, they can always use Custom…
- Should we clamp to GB, MB, or…? I think displaying it as GB will be good for most people, but could be convinced to show 12.52 GB or whatever. How finicky do we want to get?