canvas-console

canvas-console

Console/terminal style drawing to an HTML canvas

Example

Install, usage etc

npm install canvas-console

const CanvasConsole = require( 'canvas-console' )

const randInt = exclMax => Math.floor( Math.random() * exclMax )

const container = document.querySelector( '.container' )

CanvasConsole( container )
.then( canvasConsole => {
  const { width, height, putChar } = canvasConsole

  const drawRandom = () => {
    for( let vY = 0; vY < height; vY++ ){
      for( let vX = 0; vX < width; vX++ ){
        const ch = randInt( 256 )
        const fore = randInt( 16 )
        const back = randInt( 16 )

        putChar( ch, vX, vY, fore, back )
      }
    }

    requestAnimationFrame( drawRandom )
  }

  drawRandom()
})

API

CanvasConsole

A function that takes a parent container and optional options (options described below) and returns a promise containing the API

The container should have a width and height

The canvas will fill as much of the container as possible, and automatically handle resizing the viewport

The API currently provides only putChar:

putChar

( ch: string | number, column: number, row: number, fore: RgbaTuple | number = 7, back: RgbaTuple | number = 0 ) => void

ch

A single character string or a number

If a single character string, it uses the sprite from the spritesheet with the same index as the code point of the character eg 'A' will use the sprite with the index 65

If a number, it uses the sprite with this index

column

The column in which to draw the character

row

The row in which to draw the character

fore

The foreground color to use when drawing the character - this can either be an index into the palette, or an RGBA tuple array, eg [ 0, 127, 255, 255 ]

back

The background color to use when drawing the character - this can either be an index into the palette, or an RGBA tuple array, eg [ 0, 127, 255, 255 ]

Options

interface Options {
  spriteSize?: Size,
  viewSize?: Size,
  palette?: Palette,
  spriteSource?: string,
  useCleanScaling?: boolean
}

spriteSize

The size of the sprites in your sprite sheet

default:

{
  "width": 8,
  "height": 16
}

viewSize

The size of the terminal in text columns and rows

default:

{
  "width": 80,
  "height": 25
}

palette

The palette to use

default:

[
  [ 0, 0, 0, 255 ],
  [ 0, 0, 170, 255 ],
  [ 0, 170, 0, 255 ],
  [ 0, 170, 170, 255 ],
  [ 170, 0, 0, 255 ],
  [ 170, 0, 170, 255 ],
  [ 170, 85, 0, 255 ],
  [ 170, 170, 170, 255 ],
  [ 85, 85, 85, 255 ],
  [ 85, 85, 255, 255 ],
  [ 85, 255, 85, 255 ],
  [ 85, 255, 255, 255 ],
  [ 255, 85, 85, 255 ],
  [ 255, 85, 255, 255 ],
  [ 255, 255, 85, 255 ],
  [ 255, 255, 255, 255 ]
]

The palette can have as few or many colors as you like

The palette is optional, you can just pass RGBA tuples eg [ 0, 127, 255, 255 ] to putChar if you prefer

spriteSource

The source uri for your spritesheet

Defaults to a data URI of the following image:

The spritesheet can be arranged in any number of columns and rows so long as they line up according to the spriteSize

useCleanScaling

Defaults to true

If true, the console will only be scaled up in clean multiples of the spriteSize

If false, the console will fill as much of the parent container as possible