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bk138 / gromit-mpx

Gromit-MPX is an on-screen annotation tool that works with any Unix desktop environment under X11 as well as Wayland.
GNU General Public License v2.0
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Unlimited (100x) undo buffer with compression #201

Closed pascal-niklaus closed 7 months ago

pascal-niklaus commented 8 months ago

This (small) PR implements LZ4 compression of the undo buffers.

LZ4 compression/decompression is very fast, and with the drawings I tested, achieves a compression down to 1.5-2.5% of the original buffer. Hence, this allows for a very deep undo buffer without significant memory penalty. I have fixed it at 100 which for practical purposes is unlimited.

The entire logic of the undo system remains unaltered.

The only difference is that swap_surface includes a compression/decompression step.

The undo buffers are only allocated once they are needed, and they are successively grown when this is necessary.

pascal-niklaus commented 8 months ago

Sorry, I have parts in the PR that were not meant to be in there. Not sure how this happens. I will tidy this up now...