https://www.drgeek.fr/wp-content/plugins/global-gallery/js/lightbo…/lib/FlameViewportScale.js?ver=5.4

1/*
2FlameViewportScale. 0.12. Facilitates a simple viewport scale query.
3Optic Swerve, opticswerve.com
4Documented at http://menacingcloud.com/?c=viewportScale
5*/
6
7/*--------------------------|
8| FlameViewportScale		|
9|--------------------------*/
10function FlameViewportScale() {
11	this.delay = 600; // Delay after calling update to account for viewport bounce
12	this.orientation;
13	this.screenWidth; // Screen width corrected for orientation
14	this.timeout;
15	this.viewportScale;
16
17	// Get current scale
18	//-------------------
19	this.getScale = function() {
20		this.viewportScale = undefined;
21
22		// Get viewport width
23		var viewportWidth = document.documentElement.clientWidth;
24
25		// Abort. Screen width is greater than the viewport width (not fullscreen).
26		if(screen.width > viewportWidth) {
27			console.log('Aborted viewport scale measurement. Screen width > viewport width');
28			return;
29
30		}
31
32		// Get the orientation corrected screen width
33		this.updateOrientation();
34		this.screenWidth = screen.width;
35
36		if(this.orientation === 'portrait') {
37			// Take smaller of the two dimensions
38			if(screen.width > screen.height) this.screenWidth = screen.height;
39
40		}
41		else {
42			// Take larger of the two dimensions
43			if(screen.width < screen.height) this.screenWidth = screen.height;
44
45		}
46
47		// Calculate viewport scale
48		this.viewportScale = this.screenWidth / window.innerWidth;
49		return this.viewportScale;
50
51	};
52
53	// Update viewport orientation
54	//-----------------------------
55	this.updateOrientation = function() {
56		this.orientation = window.orientation;
57
58		if(this.orientation === undefined) {
59			// No JavaScript orientation support. Work it out.
60			if(document.documentElement.clientWidth > document.documentElement.clientHeight) this.orientation = 'landscape';
61			else this.orientation = 'portrait';
62
63		}
64		else if(this.orientation === 0 || this.orientation === 180) this.orientation = 'portrait';
65		else this.orientation = 'landscape'; // Assumed default, most laptop and PC screens.
66
67	};
68
69	// Update
70	//--------	
71	this.update = function(callback) {
72		// Clear timeout if already set
73		if(this.timeout !== undefined) {
74			clearTimeout(this.timeout);
75			this.timeout = undefined;
76
77		}
78
79		if(this.delay > 0) {
80			// Delay compensates for viewport bounce
81			var viewScale = this;
82
83			this.timeout = setTimeout(function() {
84				viewScale.getScale();
85				if(callback !== undefined) callback();
86
87			}, this.delay);
88
89		}
90		else {
91			// Immediate scale update
92			this.getScale();
93			if(callback !== undefined) callback();
94
95		}
96
97	};
98
99	return true;
100
101}