Document canvas library

Author: Sainan

docs/Runtime Environment/Canvas.md

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+---
+sidebar_position: 3
+---
+Must be included via `require`.
+
+---
+### `canvas.new`
+Creates a new canvas instance.
+#### Parameters
+1. Width.
+2. Height.
+
+---
+### `canvas.bmp`
+Creates a new canvas instance based on a BMP image.
+#### Parameters
+1. The BMP image as a string.
+
+---
+### `canvas.qrcode`
+Creates a new canvas instance containing a QR code.
+#### Parameters
+1. The string to be encoded.
+2. An optional table of options.
+#### Options
+- "ecl" specifies the error correction level between "low", "medium", "quartile", "high". defaults to "low".
+- "border" specifies the number of pixels around the QR code. defaults to 0.
+- "bg" specifies the background color. defaults to `0x000000` for black.
+- "fg" specifies the background color. defaults to `0xffffff` for white.
+
+```pluto
+local canvas = require "canvas"
+local c = canvas.qrcode("Hello from Pluto!", { fg = 0xffffff, bg = 0x000000 })
+print(c:tobwstring(0xffffff))
+--> █▀▀▀▀▀█ ▄ █▄▄ █▀▀▀▀▀█
+--> █ ███ █ ▄█▄▄█ █ ███ █
+--> █ ▀▀▀ █ ▄▀ █▄ █ ▀▀▀ █
+--> ▀▀▀▀▀▀▀ ▀▄▀▄█ ▀▀▀▀▀▀▀
+--> ▀▀███ ▀███ █▀▀ ▀▄█▄▀▄
+--> █▄▀▄▀█▀█▀▀ ▀█▄▀▄▄██▀ 
+--> ▀▀▀▀▀ ▀ █▀█▀ ▄█▄▄▄  ▀
+--> █▀▀▀▀▀█ ▀  ▀██▀▄ ▄██ 
+--> █ ███ █ █▄ ▄█▄██▄▄ ▄ 
+--> █ ▀▀▀ █ █▄ ▀█▀ ▀▄▄█  
+--> ▀▀▀▀▀▀▀ ▀   ▀ ▀ ▀  ▀ 
+```
+
+---
+### `canvas.get`
+Gets the color of the pixel at the given coordinates.
+#### Parameters
+1. The canvas instance.
+2. The X coordinate.
+3. The Y coordinate.
+#### Returns
+The color as an integer.
+
+---
+### `canvas.set`
+Sets the color of the pixel at the given coordinates.
+#### Parameters
+1. The canvas instance.
+2. The X coordinate.
+3. The Y coordinate.
+4. The color as an integer.
+
+---
+### `canvas.fill`
+Sets every pixel to the given color.
+#### Parameters
+1. The canvas instance.
+2. The color as an integer.
+
+---
+### `canvas.size`
+Get the size of a canvas.
+#### Parameters
+1. The canvas instance.
+#### Returns
+1. Width.
+1. Height.
+
+---
+### `canvas.mulsize`
+Multiplies the size of a canvas.
+#### Parameters
+1. The canvas instance.
+2. The multiplier. Must be 2 or higher.
+
+---
+### `canvas.tobmp`
+Convert a canvas to a BMP image.
+#### Parameters
+1. The canvas instance.
+#### Returns
+A string.
+
+---
+### `canvas.topng`
+Convert a canvas to a PNG image.
+#### Parameters
+1. The canvas instance.
+#### Returns
+A string.
+```pluto
+local { base64, canvas } = require "*"
+local c = new canvas(5, 5)
+c:fill(0xff0000)
+print("data:image/png;base64,"..base64.encode(c:topng()))
+--> data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAW0lEQVQIHQFQAK//AP8AAP8AAP8AAP8AAP8AAAD/AAD/AAD/AAD/AAD/AAAA/wAA/wAA/wAA/wAA/wAAAP8AAP8AAP8AAP8AAP8AAAD/AAD/AAD/AAD/AAD/AAD9fBjo3iScjwAAAABJRU5ErkJggg==
+```
+
+---
+### `canvas.tobwstring`
+Convert a canvas to a black and white unicode string.
+#### Parameters
+1. The canvas instance.
+2. The color to be "white." Any other color will be "black."
+#### Returns
+A string.