Hi,
so far splash-screens, keyboard-shortcuts and fader/dials were discussed.
We've learned knowing the audience is important.
I'd like to bring in a few more aspects that have an (underestimated)
impact on usability:
-font size
to select a sensible default size some information must be assumed, like
screen size, resolution/DPI and viewing distance.
programs like libreoffice show that it's possible to display a font (size
given in points) the same on different systems (like in printing preview).
reasons for a small font size include "otherwise text won't fit on screen"
and "it's not too small, i can still read it".
an example of a too small font was posted on #ardour recently,
http://i.imgur.com/nmorHgV.png
would you ever read that text?
-color contrast
this sounds simple but isn't always that. some color combinations are
irritating, others aren't working for people with reduced color vision
("color-blind").
if we assume a percentage of (any) audience has reduced color vision, we
could ask a specialist if a color set works (i.e. an affected person).
-consistency
handling the same "thing" the same way throughout the program. this
includes naming, widget operation style, meaning of indications etc.
is the ok button always on the left or right of the cancel button etc.
this helps to make the program more clear for the user.
isn't it ironic that we have the screen+mouse+keyboard scenario since
decades and still there is no single true model or consensus for the
perfect screen dial.
best regards
Thomas