* Enable HW dithering on supported devices (Clara HD, Forma; Oasis 2, PW4)
* FileManager and co. (where appropriate, i.e., when covers are shown)
* Book Status
* Reader, where appropriate:
* CRe: on pages whith image content (for over 7.5% of the screen area, should hopefully leave stuff like bullet points or small scene breaks alone).
* Other engines: on user-request (in the gear tab of the bottom menu), via the new "Dithering" knob (will only appear on supported devices).
* ScreenSaver
* ImageViewer
* Minimize repaints when flash_ui is enabled (by, almost everywhere, only repainting the flashing element, and not the toplevel window which hosts it).
(The first pass of this involved fixing a few Button instances whose show_parent was wrong, in particular, chevrons in the FM & TopMenu).
* Hunted down a few redundant repaints (unneeded setDirty("all") calls),
either by switching the widget to nil when only a refresh was needed, and not a repaint,
or by passing the appropritate widget to setDirty.
(Note to self: Enable *verbose* debugging to catch broken setDirty calls via its post guard).
There were also a few instances of 'em right behind a widget close.
* Don't repaint the underlying widget when initially showing TopMenu & ConfigDialog.
We unfortunately do need to do it when switching tabs, because of their variable heights.
* On Kobo, disabled the extra and completely useless full refresh before suspend/reboot/poweroff, as well as on resume. No more double refreshes!
* Fix another debug guard in Kobo sysfs_light
* Switch ImageWidget & ImageViewer mostly to "ui" updates, which will be better suited to image content pretty much everywhere, REAGL or not.
PS: (Almost 💯 commits! :D)
This widget is used to configure the natural light on KA1/H2O2. It
allows the user to set the gain/offset values for white/red/green, as
well as the exponent used in the formula.
Numbers can be changed via screen keyboard or through the plus/minus
buttons next to the numbers (holding the buttons will in/decrase with
smaller steps). Changes are applied immediately, but will only be set
permanently if 'OK' is pressed. If 'Cancel' is pressed, the new values
are discarded and the old ones restored. Also, pressing 'OK' will save
these values in the koreader settings file (there's no support for
changing these values in Nickel, so there's nothing to sync to its
config file). The 'Restore Default' button will install the original
defaults that were derived from Nickel's behavior.
This widget is meant to be called from the frontlight widget and is
placed at the top, so that the frontlight widget can still be used to
test the current values (see next commit).
