Fix events for infinite symbols

[Esteban82]

Intro

The description about the coda phase in the events documentation mentions:

" You may also wish for symbols to disappear completely after they reach their end time (we call this period the coda), or perhaps remain visible but faded, shrunk, or darkened."

Also, at the end of the -M section, it says:

Optionally, for finite-duration events that should remain visible for all times after their event end time has been reached you must append +c (for coda) to set the corresponding terminal value during the coda. If +c is not given then the defaults are 0 (intensity), 0 (size), 100 (transparency) and 0 (value), meaning the symbols are not plotted unless you change these attributes with one or more +c modifiers (one per directive).

This implies that symbols without a defined duration (infinite) shouldn’t reach the coda phase. However, currently, this is what is happening (as seen in animation #8607 and animation 08).

This also means that I have to define the symbol properties via the coda phase modifiers (-M+c). In fact, I must include these modifiers to make the symbols visible (e.g., like -Mt+c0), because the default behavior is for them to become invisible.

Proposed Fix

I made a fix to address this issue. The problem was (I believe) that only events with finite duration could reach the normal phase. So, in this PR, I remove that condition. I tested it on my PC (with the same script from the previous link) and got this animation, which looks fine to me:

Tutorial_1_Test.mp4

I think this solution is better because now the symbols at the end retain the properties defined by -Sc and -G (without the -M+c modification). This means the code could be simplified:

gmt events violet.t -T${MOVIE_COL0} -Sc2c -W1p -Gblueviolet
gmt events blue.t   -T${MOVIE_COL0} -Sc2c -W1p -Gblue   -Ms1.5 -Mi1 -Mt -Es+r0.25
gmt events green.t  -T${MOVIE_COL0} -Sc2c -W1p -Ggreen  -Ms1.5 -Mi1 -Mt -Es+r0.25+d0.25
gmt events yellow.t -T${MOVIE_COL0} -Sc2c -W1p -Gyellow -Ms1.5 -Mi1 -Mt -Es+r0.25+p0.25
gmt events orange.t -T${MOVIE_COL0} -Sc2c -W1p -Gorange -Ms1.5 -Mi1 -Mt -Es+r0.25+p0.25+d0.25
gmt events red.t    -T${MOVIE_COL0} -Sc2c -W1p -Gred    -Ms1.5 -Mi1 -Mt -Es+r0.25+p0.25+d0.25+f0.25

I also try the original animation made by Paul (WED-A_Vid_1.sh) and I got the same animation.

[joa-quim]

I can't say that I fully understand the issue but I've not worked with animations for quite some time. But you do, so I trust that this is an improvement.

[Esteban82]

I am quite confident that it is an imporvement necessary. I am confident (although a little less so) that the modification I made to the code is the correct one. But I guess if it is wrong, we will figure it out. My tests were fine.

[Esteban82]

This PR affects the output of this test (test/psevents/events.sh (Failed)).
I have to see how to update that.