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canvas-txt multiline text on html canvas

Canvas Txt 📐

Transforming Your Canvas with Multiline Magic ✨

NPM NPM NPM

A Miniscule library to render text on HTML5 Canvas with ZERO dependencies

Features

  • Multiline text
  • Auto line breaks
  • Horizontal Align
  • Vertical Align
  • Justify Align
  • Easy Debugging
  • Improved Performance

Demo

See Demo: Here

Install

yarn add canvas-txt

or

npm i canvas-txt

Usage

<canvas id="myCanvas" width="500" height="500"></canvas>

Bundler

import { drawText } from 'canvas-txt'

const c = document.getElementById('myCanvas')
const ctx = c.getContext('2d')

ctx.clearRect(0, 0, 500, 500)

const txt = 'Lorem ipsum dolor sit amet'

const { height } = drawText(ctx, txt, {
  x: 100,
  y: 200,
  width: 200,
  height: 200,
  fontSize: 24,
})

console.log(`Total height = ${height}`)

Node canvas

See Node js demo in ./src/node-test.ts

const { createCanvas } = require('canvas')
const { drawText } = require('canvas-txt')
const fs = require('fs')

// Or
// import { createCanvas } from 'canvas'
// import { drawText } from 'canvas-txt'
// import * as fs from 'fs'

function main() {
  const canvas = createCanvas(400, 400)
  const ctx = canvas.getContext('2d')
  const txt = 'Hello World!'

  const { height } = drawText(ctx, txt, {
    x: 100,
    y: 200,
    width: 200,
    height: 200,
    fontSize: 24,
  })

  // Convert the canvas to a buffer in PNG format
  const buffer = canvas.toBuffer('image/png')
  fs.writeFileSync('output.png', buffer)
  console.log(`Total height = ${height}`)
}

main()

CDN

See fiddle : https://jsfiddle.net/geongeorgek/n5xw3ufj/2/

<script src="//unpkg.com/canvas-txt"></script>
const { drawText, getTextHeight, splitText } = window.canvasTxt
/// ...remaining same

Properties

Properties Default Description
width Required Width of the text box
height Required Height of the text box
x Required X position of the text box
y Required Y position of the text box
debug false Shows the border and align gravity for debugging purposes
align center Text align. Other possible values: left, right
vAlign middle Text vertical align. Other possible values: top, bottom
font Arial Font family of the text
fontSize 14 Font size of the text in px
fontStyle '' Font style, same as css font-style. Examples: italic, oblique 40deg
fontVariant '' Font variant, same as css font-variant. Examples: small-caps, slashed-zero
fontWeight '' Font weight, same as css font-weight. Examples: bold, 100
lineHeight null Line height of the text, if set to null it tries to auto-detect the value
justify false Justify text if true, it will insert spaces between words when necessary.

Methods

import { drawText, splitText, getTextHeight } from 'canvas-txt'
Method Description
drawText(ctx,text, config) To draw the text to the canvas
splitText({ ctx, text, justify, width } To split the text { ctx: CanvasRenderingContext2D, text: string, justify: boolean, width: number }
getTextHeight({ ctx, text, style }) To get the height of the text { ctx: CanvasRenderingContext2D, text: string, style: string (font style we pass to ctx.font) } ctx.font docs