@chemicalluck/canvas-txt
v4.2.1
Published
Render multiline textboxes in HTML5 canvas with auto line breaks and better alignment system
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A Miniscule library to render text on HTML5 Canvas with ZERO dependencies
Features
- [x] Multiline text
- [x] Auto line breaks
- [x] Horizontal Align
- [x] Vertical Align
- [x] Justify Align
- [x] Easy Debugging
- [x] 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
|
| drawStyle
| fill
| Text draw style. Other possible values: outline
|
| 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 |