Allow OpenSkyNetwork DB, OpenAIP and OurAirports DB stuctures to be
shared by different plugins, to speed up loading.
Perform map anti-aliasing on the whole map, rather than just info boxes,
to improve rendering speed when there are many items. Add map
multisampling as a preference.
Add plotting of airspaces, airports, navaids on Map feature.
Add support for polylines and polygons to be plotted on Map feature.
Add support for images to 2D Map feature.
Add distance and name filters to Map feature.
Filter map items when zoomed out or if off screen, to improve rendering
performance.
Add UK DAB, FM and AM transmitters to Map feature.
Use labelless maps for 2D transmit maps in Map feature (same as in ADS-B
demod).
screen when screen orientation changes.
Add DialPopup to allow dials to adjusted with a slider, which is easier
on touchscreens.
Add TableTapAndHold to support table context menus on touchscreens.
Add sizeToContents in ChannelGUI and FeatureGUI, called when widget is
rolled, so we can remove resizing code from all of the individual
channels and features.
In RollupContents, use minimumSizeHint for calculated size, so that
minimumWidth can come from .ui file.
In DeviceGUI::sizeToContents(), call adjustSize(), so Device GUIs start
out at minimum needed size (which should restore appearance prior to
last patch).
In stackSubWindows, use available space for channels if no
spectrum/features present.
In stackSubWindows, fix spectrum from being sized too big, resulting in
scroll bars appearing.
Reset user-defined channel width in stackSubWindows, when channels are
removed.
Don't stack maximized windows.
There's one hack in Channel/FeatureGUI::maximizeWindow(). It seems that
when maximimzing a window, QOpenGLWidgets aren't always paint properly
immediately afterwards, so the code forces an additional update. I can't
see why the first call to paintGL doesn't work.
