Saturday, October 25, 2014

Being busy without being ugly

wxBusyInfo is one of the classes that it is actually best not to use at all, because it blocks the program UI without allowing to dismiss it, so it is hardly user-friendly and usually performing the long-running operation in a separate thread and providing some way to display its progress and cancelling it in the main GUI thread is strongly advised.

However sometimes doing it is too difficult or maybe even impossible if you are using third-party libraries and in this case wxBusyInfo provides a very simple way to at least indicate that the program is busy, using it is as easy as creating an object on the stack:


wxBusyInfo wait("Working, please wait...", parent);


Unfortunately, traditionally, it was not just very simple, but very ugly as well, as can be seen on this screenshot:

After the recent changes, you can show to the user something more presentable (especially if you use a decent icon):
and with only slightly more effort:

wxBusyInfo info
(
    wxBusyInfoFlags()
      .Parent(parent)
      .Icon(wxArtProvider::GetIcon(wxART_PRINT))
      .Title("<b>Printing your document</b>")
      .Text("Please wait...")
      .Foreground(*wxWHITE)
      .Background(*wxBLACK)
      .Transparency(4*wxALPHA_OPAQUE/5)
);


As you can see, now it's possible to specify quite a few more attributes than just the unadorned message:
  • There can be an optional icon in the top part of the window.
  • Message is now split in the "text" and "title" parts, with the latter shown in bigger font by default.
  • Both text and title can contain markup.
  • Background and foreground colours can be specified.
  • Finally, the window can be made partly transparent.
To avoid passing all these parameters directly to wxBusyInfo constructor as one unintelligible jumble, a new helper class wxBusyInfoFlags was added to allow specifying them all by names and to make it simple to add more attributes later than needed.

So while the initial advice to avoid the use of wxBusyInfo in the first place remains valid, you can at least make it less ugly now if you do have to use it.
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