We need to know if samples, context switches and messages are present to be
able to correctly calculate thread height. However, if the thread is not
visible, it is not necessary to provide a list of items to draw.
There are various changes involved into making this work:
1. Zone size (zsz) is no longer clamped to the timeline viewport area.
This clamping has to be removed to prevent otherwise uncollapsed zones
from apparently becoming small near the viewport borders. Such a small
zone would then be collapsed, resulting in unwanted popping.
Interesingly, only the CPU zones were clamped before. GPU zones were
not.
2. Iteration over visible zones has to start before the visible timeline
viewport area. Without this some zones that would be otherwise
included in the collapsed area (started by a previous zone) may be
fully visible. This causes child zones to be drawn and produces
unwanted popping. (At this point threshold for continuing collapsed
area is greater than threshold for starting it.)
3. Since the iteration now starts before timeline visible area, it may so
happen that everything found will be in a small slice of timeline that
is outside the screen. To fix this, the end time of last found item is
checked against the viewport start time.
It is always valid to access *(zitend-1), as it is in each case done
after null set check (it == zitend).
Similar but simpler fix was also applied to per-thread call stack samples.
The reasoning is that you want to use the color to see where a zone of
a particular type is placed. When collapsed zones go back to displaying
thread color, you may mistake such region of collapsed zones for something
they aren't.
Namespace shortening was kinda ok for function names produced by MSVC, which
are generally clean looking. However, gcc/clang like to produce function names
which include template arguments, function parameters, return values, etc. In
such cases the old algorithm simply didn't work, because removal of everything
before the last :: could as well happen in midst of function parameters list.
The result was certainly not an usable function name.
With this new approach namespaces are no longer explicitly mentioned and this
functionality is simply called zone name shortening.
The user-selectable options were changed to make the shortening always
enabled, disabled, or to apply as needed. Note that the "as needed" approach
will be dynamic, trying to gradually remove more and more from the name, until
it fits in the requested area.
Current implementation is only the first step into making this work. In this
first step the function parameters are reduced to () and the template
arguments are reduced to <>. This alone greatly improves readability of the
zone names.
The option to reduce namespaces to one letter (i.e. std::tr1::hash would
become s:t:hash) will no longer be present, now or in the future.
