A plugin for Reveal.js allowing to highlight the current mouse position with a spotlight.

It is off by default and you can trigger it with a keyboard press.

I use "Aplic Wireless Mini Air Mouse" as presenter

Copy the file spotlight.js into the plugin folder of your reveal.js presentation, i.e. plugin/spotlight.

Add the plugin to the dependencies in your presentation, as below.

Reveal.initialize({
	// ...
	dependencies: [
		// ... 		
		{ src: 'plugin/spotlight/spotlight.js' },
		// ... 
	]
});

The plugin can be configured by providing a spotlight option containing an object i.e. with size and other configuration items within the reveal.js initialization options. By default spotlight is toggled by mouse down event. There is no cursor visible by default. You can switch from 'presentation mode' to 'normal mode' by pressing the 'p' key. But you can change this default behaviour.

Reveal.initialize({
	// ...
	spotlight: {

			// size of the spotlight
			size: 60,
			
			// true: Locks the mouse pointer inside the presentation
			// there is by design (Pointer Lock API) no spotlightCursor and presentingCursor 
			// displayed regardless of the configured values 
			lockPointerInsideCanvas: false,

			// toggle spotlight by holding down the mouse key
			toggleSpotlightOnMouseDown: true,

			// the keyCode pressed and held to turn on spotlight, disabled when set to false
			// Problems with this config? Maybe your touchpad is disabled on keypress? 
			spotlightOnKeyPressAndHold: false,

			// choose the cursor when spotlight is on. Maybe "crosshair"?
			spotlightCursor: 'none',

			// choose the cursor when spotlight is off and in presentation mode. Maybe "default"?
			presentingCursor: 'none', 

			// true: initially in presentation mode, will also be ture if this is not set and toggleSpotlightOnMouseDown is true
			initialPresentationMode: true,

			// true: disable selecting in presentation mode
			disablingUserSelect: true,

			// set to a number as transition duration in ms to enable fade in and out, disabled when set to false
			fadeInAndOut: 100,

			// enable pointer mode
			useAsPointer: false,

			// pointer color (If pointer mode enabled)
			pointerColor: 'red'
	},
	keyboard: {	
			// alternative to toggleSpotlightOnMouseDown: 
			// toggle spotlight by pressing key 'c'
			67: function() { RevealSpotlight.toggleSpotlight() },

			// enter/leave presentation mode by pressing key 'p'
			80: function() { 
				RevealSpotlight.togglePresentationMode(); 
			},
	},
	// ...	

Default: 60

Configure the size of the spotlight

Default: false

true: Locks the mouse pointer inside the presentation. Press Esc to undo the lock.

This is very useful especially when you present with a Presenter or a Wireless Air Mouse. Furthermore helpful if you have two screens (i.e. Beamer and Laptopscreen)

This feature relies on the experimental Browser Feature PointerLock

There is by design (Pointer Lock API) no spotlightCursor and presentingCursor displayed regardless of the configured values

Default: true

Toggle spotlight by holding down the mouse key. And switching to the cursor provided by the configuration item presentingCursor, if configuration item presentingCursorOnlyVisibleWhenSpotlightVisible is true.

Default: false

false: disabled

keyCode: if this keycode is pressed and held, spotlight is turned on. After releasing the keycode spotlight is turned off

Problems with this config? Maybe your touchpad is disabled on keypress?

Default: none

Set the cursor value when presentation mode is toggled by togglePresentationMode(). Maybe "default"?

Default: none

Set the cursor value when spotlight is displayed. Maybe "crosshair"?

Default: Points to value of toggleSpotlightOnMouseDown

true: starts directly in presentationmode

Default: true

true: disable selecting in presentation mode

Default: false

false: disable fade in and out

number: transition duration in ms to enable fade in and out

Default: false

Enables a mode where the screen is not dimmed and you can use the mouse as a pointer. While using this option it makes sense to reduce the size to 6

Default: red

Defines the pointer color if configuration item useAsPointer is true.

Example:

RevealSpotlight.toggleSpotlight();

If the spotlight is on, it turns it off. If the spotlight is off, it turns it on.

Example:

RevealSpotlight.togglePresentationMode();

If presentation mode is on, it turns it off and set the cursor to normal. If presentation mode is off, it turns it on and set the cursor to the configuration item presentingCursor.