Add a visible clicks option to mtplot

When running the robot touch firmware test suite, it's not uncommon for
the robot to accidentally click the pad while performing a gesture.
When this happens it can cause unexpected results as well as clearing
the display.  Since the logs of the gestures include an image from
mtplot, something that might be useful is having a visual indicator on
the plot that shows where the fingers were when clicks happened.  This
way we can set up the robotic touch firmware test to collect its images
from mtplot using the new -s flag and if something goes wrong we'll be
able to see it and react accordingly.

BUG=chromium:342433
TEST=I ran mtplot -c0 -s1 and the clicks were marked with little
rectanges.  Without the -s1 flag everything was normal

Change-Id: Ic67775cc9dbbf73858d1d7c9051ea6d8145bc6c4
Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/185674
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
1 file changed