export default function (scrawl, el) {Editable header text colorizer and animation effect snippets
Related files:
Purpose: Displays text with an animation of rising bubbles over the text fill
Function input:
Customisation: The snippet can be customised using the following --data-??? CSS custom properties:
--data-text-color - any CSS color string (default: #c213bc')--data-dark-text-color - any CSS color string (default: #fcdeef)--data-outline-color - any CSS color string (default: #f59dcf)--data-dark-outline-color - any CSS color string (default: #f59dcf)--data-outline-width - (unit % of font size) percentage of the font size for text outline width (default: 0.05)--data-bubble-color - any CSS color string (default: #fcdeef)--data-dark-bubble-color - any CSS color string (default: #ed5fb0)--data-bubble-outline-color - any CSS color string (default: #c213bc)--data-dark-bubble-outline-color - any CSS color string (default: #c213bc)--data-bubble-density - the number of bubbles to generate (default: 50)--data-contrast-color - any CSS color string, used when user has set prefers-contrast: more (default: black)--data-dark-contrast-color - any CSS color string, used when user has set prefers-contrast: more (default: white)Function output: a Javascript object will be returned, containing the following attributes
{
element // the Scrawl-canvas wrapper for the DOM element supplied to the function
canvas // the Scrawl-canvas wrapper for the snippet's canvas
animation // the Scrawl-canvas animation object
demolish // remove the snippet from the Scrawl-canvas library
}
import * as scrawl from 'path/to/scrawl-canvas/library';
import mySnippet from './relative/or/absolute/path/to/this/file.js';
let myElements = document.querySelectorAll('.some-class');
myElements.forEach(el => mySnippet(scrawl, el));
Effects on the element:
transparenttransparentexport default function (scrawl, el) {Boilerplate - namespacing
const namespace = el.id;
const name = (val) => `${namespace}-${val}`;Only progress if the supplied element has an id attribute
if (namespace) {Create the snippet for this DOM element
const snippet = scrawl.makeSnippet({
domElement: el,
});Only proceed if the snippet is successfully generated
if (snippet) {Unpack the snippet into the parts we’ll be using
const canvas = snippet.canvas,
animation = snippet.animation,
demolishAction = snippet.demolish,
compStyles = snippet.element.elementComputedStyles;Boilerplate - text processing
const addTextNode = () => {
const shy = document.createTextNode('!');
el.appendChild(shy);
};
const processText = t => {
t = t.replace(/<canvas.*<\/canvas>/gi, '');
t = t.replace(/<button.*<\/button>/gi, '');
if (!t.length) {
addTextNode();
t = '!';
}
return t;
}Boilerplate - demolish/kill functionality
const additionalDemolishActions = [];
snippet.demolish = () => {
additionalDemolishActions.forEach(f => f());
scrawl.purge(namespace);
demolishAction();
};This makes the canvas element’s base cell the default group for everything we create
canvas.setAsCurrentCanvas();Boilerplate - fix for text alignment
const getJustifyLine = (val) => {
if (val === 'justify') return 'space-between';
if (val === 'justify-all') return 'space-around';
if (val === 'match-parent') return 'start';
return val;
};Boilerplate - fix for lineSpacing/lineHeight
const getLineSpacing = () => parseFloat(compStyles.lineHeight) / parseFloat(compStyles.fontSize);Initialize and collect developer-supplied data
const userData = {
direction: compStyles.direction || 'ltr',
fontStretch: compStyles.fontStretch || 'normal',
letterSpacing: compStyles.letterSpacing || '0px',
wordSpacing: compStyles.wordSpacing || '0px',
fontVariantCaps: compStyles.fontVariantCaps || 'normal',
lineAdjustment: compStyles.getPropertyValue('--data-line-adjustment') || '0',
justifyLine: getJustifyLine(compStyles.textAlign),
elBackgroundColor: compStyles.backgroundColor || 'transparent',
textColor: compStyles.getPropertyValue('--data-text-color') || '#c213bc',
darkTextColor: compStyles.getPropertyValue('--data-dark-text-color') || '#fcdeef',
outlineColor: compStyles.getPropertyValue('--data-outline-color') || '#f59dcf',
darkOutlineColor: compStyles.getPropertyValue('--data-dark-outline-color') || '#f59dcf',
bubbleColor: compStyles.getPropertyValue('--data-bubble-color') || '#fcdeef',
darkBubbleColor: compStyles.getPropertyValue('--data-dark-bubble-color') || '#ed5fb0',
bubbleOutlineColor: compStyles.getPropertyValue('--data-bubble-outline-color') || '#c213bc',
darkBubbleOutlineColor: compStyles.getPropertyValue('--data-dark-bubble-outline-color') || '#c213bc',
contrastColor: compStyles.getPropertyValue('--data-contrast-color') || 'black',
darkContrastColor: compStyles.getPropertyValue('--data-dark-contrast-color') || 'white',
outlineWidth: compStyles.getPropertyValue('--data-outline-width') || '0.05',
bubbleDensity: compStyles.getPropertyValue('--data-bubble-density') || '50',
};
const getLineWidth = () => parseFloat(userData.outlineWidth) * parseFloat(compStyles.fontSize);Build the animated bubbles text effect
const fizz = scrawl.makeWheel({
name: name('bubble-template'),
order: 1,
startY: '100%',
handleX: 'center',
handleY: 'center',
fillStyle: userData.bubbleColor,
strokeStyle: userData.bubbleOutlineColor,
lineWidth: getLineWidth() * 0.7,
globalCompositeOperation: 'source-atop',
method: 'none',
});
const bubblesGroup = scrawl.makeGroup({
name: name('bubbles-group'),
});
const tweens = [];
for (let i = 0; i < userData.bubbleDensity; i++) {
const bubble = fizz.clone({
name: name(`bubble-${i}`),
radius: Math.round((Math.random() * (parseFloat(compStyles.fontSize) / 2)) + 4),
startX: `${Math.random() * 100}%`,
noCanvasEngineUpdates: true,
sharedState: true,
method: 'fillThenDraw',
});
bubblesGroup.addArtefacts(bubble);
const myRandom = Math.random();
tweens.push(scrawl.makeTween({
name: name(`bubble-${i}`),
targets: bubble,
duration: Math.round((myRandom * 3000) + 5000),
cycles: 0,
definitions: [{
attribute: 'startY',
start: '100%',
end: '0%',
}, {
attribute: 'scale',
start: 0.3,
end: Math.round((1 - myRandom) * 0.9) + 0.6,
}],
}).run());
}
const template = scrawl.makeBlock({
name: name('template'),
dimensions: ['100%', '100%'],
visibility: false,
});
const label = scrawl.makeEnhancedLabel({
name: name('content'),
layoutTemplate: name('template'),
text: processText(el.innerHTML),
fontString: compStyles.font,
textHandleY: 'alphabetic',
visibility: false,
cacheOutput: false,
direction: userData.direction,
fontStretch: userData.fontStretch,
letterSpacing: userData.letterSpacing,
wordSpacing: userData.wordSpacing,
fontVariantCaps: userData.fontVariantCaps,
lineSpacing: getLineSpacing(),
justifyLine: userData.justifyLine,
fillStyle: userData.textColor,
strokeStyle: userData.outlineColor,
lineWidth: getLineWidth(),
method: 'fillAndDraw',
});Boilerplate - font adjustments
let meta;
const getLineAdjustment = () => {
const size = parseFloat(compStyles.fontSize);
const ratio = size / 100;
return ratio * (meta.alphabeticBaseline + meta.verticalOffset + parseFloat(userData.lineAdjustment));
};
const updateOnFontLoad = () => {
const font = compStyles.fontFamily,
check = scrawl.checkFontIsLoaded(font);
if (check) {
el.style.backgroundColor = 'transparent';
el.style.color = 'transparent';
meta = scrawl.getFontMetadata(font);
const displacement = getLineAdjustment();
template.set({
startY: displacement,
handleY: displacement,
fillStyle: userData.elBackgroundColor,
visibility: true,
});
label.set({ visibility: true });
bubblesGroup.set({ visibility: true });
animation.updateHook('commence');
}
};
animation.updateHook('commence', updateOnFontLoad);Boilerplate user interaction - resizing the browser window
let resizeFlag = true,
lastResize = Date.now();
const resizeChoke = 200;
const setResizeFlag = () => {
resizeFlag = true;
const now = Date.now();Canvases don’t animate when outside of the browser viewport (to save CPU, battery, etc)
if (!animation.isRunning() && now > lastResize + resizeChoke) {
resizeAction();
animation.updateOnce();
lastResize = now;
}
};
const resizeAction = () => {
if (resizeFlag) {
resizeFlag = false;
label.set({ fontString: compStyles.font });
if (meta) {
const displacement = getLineAdjustment();
template.set({
startY: displacement,
handleY: displacement,
});
label.set({
letterSpacing: compStyles.letterSpacing,
wordSpacing: compStyles.wordSpacing,
lineWidth: getLineWidth(),
});
bubblesGroup.setArtefacts({
lineWidth: getLineWidth() * 0.7,
});
}
}
};
animation.updateHook('afterShow', resizeAction);
additionalDemolishActions.push(
scrawl.addNativeListener('resize', setResizeFlag, window),
);Boilerplate user interaction - editing the text
if (el.getAttribute('contenteditable')) {
const updateText = () => {
label.set({ text: processText(el.innerHTML) });
}
const focusText = () => {
el.style.color = 'rgb(0 0 0 / 0.4)';
}
const blurText = () => {
el.style.color = 'transparent';
}
additionalDemolishActions.push(
scrawl.addNativeListener('input', updateText, el),
scrawl.addNativeListener('focus', focusText, el),
scrawl.addNativeListener('blur', blurText, el),
);
}Boilerplate - animation control
if ('static' === compStyles.position) el.style.position = 'relative';
const control = document.createElement('button');
control.style.position = 'absolute';
control.style.fontSize = '12px';
control.style.display = 'block';
control.style.top = '0';
control.style.right = '0';
control.textContent = 'Halt';
control.setAttribute('contenteditable', 'false');
el.appendChild(control);
let isAnimated = true;
const stopStartAction = () => {
isAnimated = !isAnimated;
if (isAnimated) tweens.forEach(t => t.resume());
else tweens.forEach(t => t.halt());
control.textContent = isAnimated ? 'Halt' : 'Play';
};
additionalDemolishActions.push(
scrawl.addNativeListener('click', stopStartAction, control)
);Accessibility
const reduceMotionAction = () => {
if (isAnimated) {
isAnimated = false;
tweens.forEach(t => t.halt());
control.textContent = 'Play';
}
};
const noPreferenceMotionAction = () => {
if (!isAnimated) {
isAnimated = true;
tweens.forEach(t => t.resume());
control.textContent = 'Halt';
}
};
const colorSchemeLightAction = () => {
fizz.set({
fillStyle: userData.bubbleColor,
strokeStyle: userData.bubbleOutlineColor,
});
label.set({
fillStyle: userData.textColor,
strokeStyle: userData.outlineColor,
});
};
const colorSchemeDarkAction = () => {
fizz.set({
fillStyle: userData.darkBubbleColor,
strokeStyle: userData.darkBubbleOutlineColor,
});
label.set({
fillStyle: userData.darkTextColor,
strokeStyle: userData.darkOutlineColor,
});
};
const moreContrastAction = () => {
const prefersDark = canvas.here.prefersDarkColorScheme;
const color = (prefersDark) ? userData.darkContrastColor : userData.contrastColor;
label.set({
fillStyle: color,
method: 'fill',
});
bubblesGroup.set({ visibility: false });
};
const otherContrastAction = () => {
const prefersDark = canvas.here.prefersDarkColorScheme;
const color = (prefersDark) ? userData.darkTextColor : userData.textColor;
label.set({
fillStyle: color,
method: 'fillAndDraw',
});
bubblesGroup.set({ visibility: true });
};
canvas.set({
colorSchemeLightAction,
colorSchemeDarkAction,
moreContrastAction,
otherContrastAction,
reduceMotionAction,
noPreferenceMotionAction,
});Render once, to get everything in place
animation.updateOnce();Return the snippet, so coders can access the snippet’s parts
return snippet;
}
}
return null;
}