Announcing my third #MARCHintosh 2026 project - the MARCHintosh Canvas!
If you're familiar with Reddit's /r/place, pxls space, or Wplace, you’ll know what this is - a shared canvas anyone can place pixels onto in real-time.
Only this time, it's over the venerable AppleTalk protocol, with the public server accessible to anyone on #GlobalTalk :)
Feel free to drop by and leave your mark - available in the usual places (landisk, Blackbird) on BaroNet
Some notes:
- It's in monochrome for now to allow older Macs to join in without bifurcating the canvas into Color vs B&W
- I can adjust the duration of a cooldown timer on the server end, but for now I'm going to assume the latency of GlobalTalk itself will be a good enough limit
- In local testing with multiple machines, the networking likes to get hung up. I have not nailed down what bug is causing this so please be patient if I keep restarting the server and keep an eye out for updates
Alright I found one major cause of hangs and disconnects - I had my idle timer only set to 10 ticks. Essentially this limited the server to 6 requests per second, dropping any requests that came in under 160ms after a previous request. I’ve lowered it to 1 tick, increasing that 10-fold.
And yeah I guess now I have to bite the bullet and rewrite the server to work with interrupt callbacks to improve it further so there is no “dead period” where requests fail.
I’ve applied the same fix to Chat.
As I head for bed at midnight JST, this is the state of the canvas! Thank you everyone who has stopped by, looking forward to seeing what it looks like when I wake up!
The server is saving a snapshot once an hour so hopefully I can put together a time lapse when it's all over.
Day 2 is over and there’s been a bunch more activity!
Are the Windows users taking over? Will the Mac fight back!?? Stay tuned on #GlobalTalk …
@kalleboo I briefly managed to get it to run on A/UX, placed a couple pixels (badly, my mouse is way too sensitive for this), and then it hard froze 😅
Will have to try later in the run on another machine (the 6500's occupied with other things at the moment)... this is neat though!
@kalleboo
my mouse hand is cramped, but I had fun drawing for 20 minutes straight to produce two items: the happy Finder icon, and the working title of your canvas: "TWITCH PAINTS POKÉMON" .
I had to turn the mouse's optical sensitivity all the way down. Even with the FatBits enlargement window, this was a challenge!
I managed to get a screenshot moments before the app crashed with a Type 1 error.
It was very responsive, probably 250-500ms between click and paint. I had Wireshark running the whole time to see how quickly the server ACK'd my pixel drops. There were some blips every few minutes where the pixel would not be painted, but I kept clicking, and eventually the server caught up and (un)painted the pixels I had clicked.
Would you like the packet trace to check for issues? I suspect your UDP data contains coördinates in the Printer Access Protocol.
@theirongiant Thanks!
Really strange crash, getting the status shouldn’t fail unless the window has been closed…
@_the_cloud @theirongiant CanvasWGetState doesn’t touch anything related to the actual Mac WindowPtr, just my internal window information structure with the status of if we’re connected, waiting to place a pixel, etc.
That structure is only released when you’ve actually closed the window (click in goAway or File>Close)
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