First-class movie creation mode

[Debilski]

Please do not yet merge. The new code as well as the surrounding old Tk code needs some more polishing.

This adds the highly sought-after (#531, https://github.com/ASPP/pelita/issues/524#issuecomment-424395032) ‘automatic replay movie creation mode’ to Pelita, which uses Tk’s Canvas.postscript function to write a postscript representation. As the generated postscript depends on what is shown on the screen, this mode also activates a few changes in the UI representation.

1. The canvas size will be resized such that each square has a size of 24x24 (open for discussion),
2. the status part of the UI will be hidden during the replay as it cannot be transformed to Postscript (it is not a Canvas) and hiding it makes some of the calculations needed for proper resizing easier.

Usage:

$ pelita --dump replay.json --null   # I think we should rename --dump though
...
$ pelita --replay replay.json --snapshot-folder my_replay/
$ ninja -C my_replay/
$ vlc my_replay/movie.mp4

For personal convenience, I am creating a ninja.build automatically. Not strictly needed since we are only expected to convert it once (except for testing, where it is useful) and a bash script should do just fine. But parallelisation is nice. :)

Current drawbacks:

• The snapshot mode creates two ps files. For the header and the game canvas. Both of them need to be converted to a png with Image Magic with proper settings to have the right amount of anti-aliasing.
• The status bar is missing. So e.g. the name of the layout is not shown.
• It is not clear which font will be used, so it is potentially very ugly looking.
• The first few frames should not be snapshotted (at least not before the game knows the names of the teams).
• ffmpeg needs to know the output dimensions and introduces some further rescaling.
• If the game window is resized during snapshotting, things will get weird.
• Creating the movie has to be done with external tools.

[codecov-io]

Codecov Report

Merging #542 into master will decrease coverage by 0.62%. The diff coverage is 2.12%.

@@            Coverage Diff             @@
##           master     #542      +/-   ##
==========================================
- Coverage   62.87%   62.24%   -0.63%     
==========================================
  Files          33       33              
  Lines        4611     4656      +45     
==========================================
- Hits         2899     2898       -1     
- Misses       1712     1758      +46

Impacted Files	Coverage Δ
pelita/scripts/pelita_main.py	0% <0%> (ø)	:arrow_up:
pelita/ui/tk_viewer.py	0% <0%> (ø)	:arrow_up:
pelita/ui/tk_canvas.py	0% <0%> (ø)	:arrow_up:
pelita/scripts/pelita_tkviewer.py	0% <0%> (ø)	:arrow_up:
pelita/libpelita.py	51.95% <33.33%> (-0.38%)	:arrow_down:
pelita/player/RandomExplorerPlayer.py	84.21% <0%> (-5.27%)	:arrow_down:

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[Debilski]

• Converting on macOS is really slow…

[Debilski]

Currently I would much prefer looking into a solution that just uses a Qt interface (or we hand-craft a direct-to-png writer) and directly saves the canvas to png. Converting ps to png takes maybe 10 seconds per frame which is far too much time.

[Debilski]

Let’s go full svg. It looks very all right and is quite fast to export (ie. not noticeable). That means we can export it already while the tournament is running.

[Debilski]

Additional open idea: Do we actually need mp4 video files? Maybe an animated Javascript canvas is the better solution for presenting the matches after the tournament anyway. Obviously low priority.

[codecov-commenter]

Codecov Report

Merging #542 (088bfaa) into main (98d4810) will decrease coverage by 0.07%. The diff coverage is 40.00%.

@@            Coverage Diff             @@
##             main     #542      +/-   ##
==========================================
- Coverage   85.39%   85.32%   -0.08%     
==========================================
  Files          21       21              
  Lines        2301     2303       +2     
==========================================
  Hits         1965     1965              
- Misses        336      338       +2     

Impacted Files	Coverage Δ
pelita/game.py	86.06% <40.00%> (-0.48%)	:arrow_down:

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