Zfont

A text plugin for the Zdog 3D engine! Renders TrueType fonts via Typr.js | jaames.github.io/zfont

Features | Caveats | Demo | Installation | Usage | API | Zdog.Font | Zdog.Text | Zdog.TextGroup | Todo | Building

Features

* Built on top of Typr.js, which supports a wide range of .ttf and .otf fonts with speed and grace
* Less than 14kB minified and gzipped
* No need to worry about waiting for fonts to load; text automatically pops into existence once the font is ready
* Includes support for multiline text
* Update font, text, color, alignment, etc at any time
* Bonus utilities for measuring text, waiting for font load & more!

Caveats

* You have to provide a .ttf to use yourself; it isn't possible to use system fonts
* Character range is limited to whichever glyphs are supported by your chosen font, and font stacks/fallbacks aren't supported yet

Demo

A live demo can be found here, there's also some more in-depth examples on Codepen!

Installation

$3

``bash
$ npm install zfont --save
`

If you are using a module bundler like Webpack or Rollup, import Zfont into your project:

`javascript
// Using ES6 module syntax
import Zfont from 'zfont';

// Using CommonJS modules
const Zfont = require('zfont');
`

$3

`html

`

When manually including the library like this, it will be globally available on window.Zfont

$3

Development version

Uncompressed at around 75kB, with source comments included

Production version

Minified to 45kB

Then add it to the of your page with a



`

Usage

$3

After both Zdog and Zfont have been imported/downloaded, we need to initialize the Zfont plugin. Once the it's initialized, the Zdog.Font, Zdog.Text and Zdog.TextGroup classes will be available:

`js
Zfont.init(Zdog);
`

$3

(Pssst! If you prefer to dive in, check out the basic demo over on Codepen)

To draw some text in a Zdog scene, first we need to set up a new Zdog.Font object with the .ttf url for our desired font, then we can create a new Zdog.Text object and add it to the illustration like any other shape:

`js
// Initialize Zfont
Zfont.init(Zdog);


// Create a Zdog illustration
let illo = new Zdog.Illustration({
element: '.zdog-canvas'
});

// Set up a font to use
let myFont = new Zdog.Font({
src: './path/to/font.ttf'
});

// Create a text object
// This is just a Zdog.Shape object with a couple of extra parameters!
new Zdog.Text({
addTo: illo,
font: myFont,
value: 'Hey, Zdog!',
fontSize: 64,
color: '#fff'
});

// Animation loop
function animate() {
illo.updateRenderGraph();
requestAnimationFrame(animate);
}
animate();
`

$3

Both Zdog.Text and Zdog.TextGroup support multiline text, by inserting a newline character (\n) wherever you wish to add a line break:

`js
new Zdog.Text({
...
value: 'The quick brown fox\njumps over the\nlazy zdog',
});
`

For better readability you may prefer to use an array of strings for the value option. In this case, each string in the array will be treated as a seperate line of text:

`js
new Zdog.Text({
...
value: [
'The quick brown fox'
'jumps over the',
'lazy zdog'
]
});
`

$3

In most cases you don't have to worry about waiting for fonts to load, as text objects will magically pop into existence once their font is ready to use. However, the plugin also provides a Zdog.waitForFonts() utility function if you need to delay anything until all the fonts in your scene have finished loading.

For example, let's modify the animation loop from the previous example so that it doesn't begin until the fonts are ready:

`js
// Animation loop
function animate() {
illo.updateRenderGraph();
requestAnimationFrame(animate);
}
// Zdog.waitForFonts() returns a Promise which is resolved once all the fonts added to the scene so far have been loaded
Zdog.waitForFonts().then(() => {
// Once the fonts are done, start the animation loop
animate();
})
`

API

$3

Represents a font that can be used by an instance of either Zdog.Text or Zdog.TextGroup.

`js
let font = new Zdog.Font({
src: './path/to/font.ttf'
})
`

#### Options

| Param | Details | Default |
|:-----------|:--------|:--------|
| src | Font URL path. This can be a .ttf or .otf font, check out the Typr.js repo for more details about font support | '' |

#### Methods

##### measureText(text, fontSize)

Get the measurements for the specified string text when rendered at fontSize (measured in pixels), similar to Canvas​Rendering​Context2D.measure​Text().

Returns an object with width, height, descender, ascender.

##### getTextPath(text, fontSize, x=0, y=0, z=0, alignX='left', alignY='bottom')

Returns an array of Zdog path commands for the specified string text, when rendered at fontSize (measured in pixels).

* (x, y, z) is the origin point of the path
* alignX is the horizontal text alignment (equivalent to the CSS text-align property); either "left", "center" or "right".
* alignY is the vertical text alignment; either "top", "middle" or "bottom".

##### waitForLoad()

Returns a Promise which resolves once this font has finished loading.

$3

An object used for rendering text. It inherits everything from the Zdog.Shape class.

`js
new Zdog.Text({
addTo: illo,
font: font,
value: 'Hey, Zdog!',
textAlign: 'center',
textBaseline: 'middle',
color: '#5222ee',
stroke: 1,
})
`

#### Options

Zdog.Text inherits all the options from the Zdog.Shape class, plus a couple of extras:

| Param | Details | Default |
|:-----------|:--------|:--------|
| font | Zdog.Font to use for this text. This is required. | null |
| value | Text string | '' |
| fontSize | Text size, measured in pixels | 64 |
| textAlign| Horizontal text alignment, equivalent to the CSS text-align property. This can be either 'left', 'center' or 'right' | 'left' |
| textBaseline| Vertical text alignment, equivalent to the HTML5 canvas' textBaseline property. This can be either 'top', 'middle' or 'bottom' | 'bottom' |

#### Properties

Zdog.Text inherits all the properties from the Zdog.Shape class, as well as some extras. All of these properties can be updated at any time and the rendered text will update automatically.

##### font

The Zdog.Font instance being used for this text.

##### value

Text value as a string.

##### fontSize

Font size, measured in pixels.

##### textAlign

Horizontal text alignment, equivalent to the CSS text-align property. This can be either 'left', 'center' or 'right'

##### textBaseline

Vertical text alignment, equivalent to the HTML5 canvas' textBaseline property. This can be either 'top', 'middle' or 'bottom'

$3

This class is very similar to Zdog.Text, except it acts as a Zdog.Group instead, and each text glyph is rendered as its own shape. This is helpful for more advanced use-cases where you need control over each character.

`js
new Zdog.TextGroup({
addTo: illo,
font: font,
value: 'Hey, Zdog!',
textAlign: 'center',
color: '#5222ee',
stroke: 2,
})
`

#### Options

Zdog.TextGroup inherits all the options from the Zdog.Group class, plus a few extras:

| Param | Details | Default |
|:-----------|:--------|:--------|
| font | Zdog.Font to use for this text. This is required. | null |
| value | Text string | '' |
| fontSize | Text size, measured in pixels | 64 |
| textAlign| Horizontal text alignment, equivalent to the CSS text-align property. This can be either 'left', 'center' or 'right' | 'left' |
| textBaseline| Vertical text alignment, equivalent to the HTML5 canvas' textBaseline property. This can be either 'top', 'middle' or 'bottom' | 'bottom' |
| color | Text color | #333 |
| fill | Text fill | false |
| stroke | Text stroke | stroke |

#### Properties

Zdog.TextGroup inherits all the properties from the Zdog.Group class, as well as some extras. All of these properties can be updated at any time and the rendered text will update automatically.

##### font

The Zdog.Font instance being used for this text.

##### value

Text value as a string.

##### fontSize

Font size, measured in pixels.

##### textAlign

Horizontal text alignment, equivalent to the CSS text-align property. This can be either 'left', 'center' or 'right'

##### textBaseline

Vertical text alignment, equivalent to the HTML5 canvas' textBaseline property. This can be either 'top', 'middle' or 'bottom'

##### color

Text color, equivalent to Shape.color. Setting this will update the color for all of the group's children.

##### fill

Text fill, equivalent to Shape.fill. Setting this will update the fill for all of the group's children.

##### stroke

Text stroke, equivalent to Shape.stroke. Setting this will update the stroke for all of the group's children.

$3

Returns a Promise which resolves as soon as all the fonts currently added to the scene are loaded and ready for use.

`js
Zdog.waitForFonts().then(function() {
// Do something once the font is ready
}
`

Todo

* Google Fonts & Typekit integration?
* Support for different text directions, e.g. right-to-left
* Support for fallback fonts
* Support for color (SVG) fonts

Building

$3

`bash
$ npm install
`

$3

`bash
$ npm start
`

$3

`bash
$ npm run build
``

----

2019 James Daniel