talk-end-of-procrastination/js/controllers/pointer.js

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/**
* Handles hiding of the pointer/cursor when inactive.
*/
export default class Pointer {
constructor( Reveal ) {
this.Reveal = Reveal;
// Throttles mouse wheel navigation
this.lastMouseWheelStep = 0;
// Is the mouse pointer currently hidden from view
this.cursorHidden = false;
// Timeout used to determine when the cursor is inactive
this.cursorInactiveTimeout = 0;
this.onDocumentCursorActive = this.onDocumentCursorActive.bind( this );
this.onDocumentMouseScroll = this.onDocumentMouseScroll.bind( this );
}
/**
* Called when the reveal.js config is updated.
*/
configure( config, oldConfig ) {
if( config.mouseWheel ) {
document.addEventListener( 'DOMMouseScroll', this.onDocumentMouseScroll, false ); // FF
document.addEventListener( 'mousewheel', this.onDocumentMouseScroll, false );
}
else {
document.removeEventListener( 'DOMMouseScroll', this.onDocumentMouseScroll, false ); // FF
document.removeEventListener( 'mousewheel', this.onDocumentMouseScroll, false );
}
// Auto-hide the mouse pointer when its inactive
if( config.hideInactiveCursor ) {
document.addEventListener( 'mousemove', this.onDocumentCursorActive, false );
document.addEventListener( 'mousedown', this.onDocumentCursorActive, false );
}
else {
this.showCursor();
document.removeEventListener( 'mousemove', this.onDocumentCursorActive, false );
document.removeEventListener( 'mousedown', this.onDocumentCursorActive, false );
}
}
/**
* Shows the mouse pointer after it has been hidden with
* #hideCursor.
*/
showCursor() {
if( this.cursorHidden ) {
this.cursorHidden = false;
this.Reveal.getRevealElement().style.cursor = '';
}
}
/**
* Hides the mouse pointer when it's on top of the .reveal
* container.
*/
hideCursor() {
if( this.cursorHidden === false ) {
this.cursorHidden = true;
this.Reveal.getRevealElement().style.cursor = 'none';
}
}
destroy() {
this.showCursor();
document.removeEventListener( 'DOMMouseScroll', this.onDocumentMouseScroll, false );
document.removeEventListener( 'mousewheel', this.onDocumentMouseScroll, false );
document.removeEventListener( 'mousemove', this.onDocumentCursorActive, false );
document.removeEventListener( 'mousedown', this.onDocumentCursorActive, false );
}
/**
* Called whenever there is mouse input at the document level
* to determine if the cursor is active or not.
*
* @param {object} event
*/
onDocumentCursorActive( event ) {
this.showCursor();
clearTimeout( this.cursorInactiveTimeout );
this.cursorInactiveTimeout = setTimeout( this.hideCursor.bind( this ), this.Reveal.getConfig().hideCursorTime );
}
/**
* Handles mouse wheel scrolling, throttled to avoid skipping
* multiple slides.
*
* @param {object} event
*/
onDocumentMouseScroll( event ) {
if( Date.now() - this.lastMouseWheelStep > 1000 ) {
this.lastMouseWheelStep = Date.now();
let delta = event.detail || -event.wheelDelta;
if( delta > 0 ) {
this.Reveal.next();
}
else if( delta < 0 ) {
this.Reveal.prev();
}
}
}
}