# Pixel Canvas

> ⚠️ **Experimental — generated with no human supervision** by the daily MCP pipeline to exercise gno tooling. Not audited. See [r/moul/x/daily](https://github.com/moul/gno-contracts/blob/main/r/moul/x/daily/README.md).

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A shared 16x16 canvas. Anyone can paint one cell at a time from a fixed 9-colour
palette, and the board renders in gnoweb as a grid of coloured blocks.

Painting is **last-write-wins** — that's the point of a shared canvas. Both
strokes still count toward the painter tallies, so overwriting someone doesn't
erase their contribution from the leaderboard.

```
Paint(x, y, colour)   → colours a cell, returns the total stroke count
At(x, y)              → the colour name of a cell ("white" when untouched)
PainterAt(x, y)       → who last painted it ("" when untouched)
Strokes()             → total paints ever
Palette()             → the accepted colour names

/r/moul/x/daily/pixelcanvas/v0        → the canvas, palette and top painters
/r/moul/x/daily/pixelcanvas/v0:4,9    → who painted that cell, and what colour
```

Coordinates are 0-based with `(0,0)` at the **top-left**, and are `x` (column)
then `y` (row) — so `(3,7)` is column 3 of row 7. Colour names are matched
case- and space-insensitively.

Palette: `white`, `red`, `orange`, `yellow`, `green`, `blue`, `purple`,
`brown`, `black`.

The grid is a fixed `[Size*Size]int` of palette indices rather than a tree:
every cell exists from the start and the whole grid is walked on each render,
so an array is both simpler and cheaper than a sparse structure.

Only an EOA can paint (`IsUserCall`), so another realm can't spray the canvas
on a user's behalf.

Built for gno 0.9. Live on both testnets (agent address):

- sapphire — https://sapphire.testnets.gno.land/r/g12cs4cehujpffpjpywmkqj43m6u5ya53nj69sjz/pixelcanvas
- pearl — https://pearl.testnets.gno.land/r/g12cs4cehujpffpjpywmkqj43m6u5ya53nj69sjz/pixelcanvas

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Part of **[moul/gno-contracts](https://github.com/moul/gno-contracts)** — moul's versioned gno.land contracts. See the repository for the full catalog, build/test tooling, and usage.

**Dependency graph:**

![gno.land/r/moul/x/daily/pixelcanvas/v0 dependency graph](https://raw.githubusercontent.com/moul/gno-contracts/main/_assets/gno.land/r/moul/x/daily/pixelcanvas/v0/deps.png)

> 🧪 **Highly experimental — potentially vibe-coded.** Not audited; may break, change, or be removed at any time. Do not use with anything of value. Full disclaimer: [DISCLAIMER](https://github.com/moul/gno-contracts/blob/main/DISCLAIMER.md).

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