Though we display the frame delay as milliseconds, it is actually stored
as unsigned centiseconds in GIF. This means that displaying milliseconds
can be misleading since we round every value to tens and it also means
that 10ms is the lower delay allowed. This limitation is in the GIF
format.
Other animation formats may not have this limitation and we try and keep
consistent export UIs. Also the layer tagging for animation uses "ms"
syntax. So I just keep the delay entry as ms, but sets a lower allowed
value and makes it "snaps to ticks" (i.e. snaps to 10 ms increments).
Finally I add a tooltip to the field saying "GIF supports hundredths of
a second precision."
Hopefully this should make things clearer and not mislead people about
what the GIF format allows.
Add an 'As Animation' toggle to the GIF export options. If checked,
the GIF will be written as an animation. Only enable it on images with
more than on layer though. Add the new GIFSaveVals as_animation member
last so we don't break gimp_get_data() of old data. The fix moves the
GIF options fetching to *before* gimp_export_image(). If as-animation,
we simply pass GIMP_EXPORT_CAN_HANDLE_LAYERS to capabilities so the
layers are kept.
