https://www.bostonfed.org/Scripts/vendor/focuspoint/focuspoint-v2.js

1/**
2 * jQuery FocusPoint; version: 1.1.1
3 * Author: http://jonathonmenz.com
4 * Source: https://github.com/jonom/jquery-focuspoint
5 * Copyright (c) 2014 J. Menz; MIT License
6 * @preserve
7 * modified by: [email protected]
8 */
9;
10(function ($) {
11
12    var defaults = {
13        reCalcOnWindowResize: true,
14        throttleDuration: 0 //ms - set to 0 to disable throttling
15    };
16
17    //Create a throttled version of a function
18    var throttle = function (fn, ms) {
19        var isRunning = false;
20        return function () {
21            var args = Array.prototype.slice.call(arguments, 0);
22            if (isRunning) return false;
23            isRunning = true;
24            setTimeout(function () {
25                isRunning = false;
26                fn.apply(null, args);
27            }, ms);
28        };
29    };
30
31    //Calculate the new left/top values of an image
32    var calcShift = function (conToImageRatio, containerSize, imageSize, focusSize, toMinus) {
33        var containerCenter = Math.floor(containerSize / 2); //Container center in px
34        var focusFactor = (focusSize + 1) / 2; //Focus point of resize image in px
35        var scaledImage = Math.floor(imageSize / conToImageRatio); //Can't use width() as images may be display:none
36        var focus = Math.floor(focusFactor * scaledImage);
37        if (toMinus) focus = scaledImage - focus;
38        var focusOffset = focus - containerCenter; //Calculate difference between focus point and center
39        var remainder = scaledImage - focus; //Reduce offset if necessary so image remains filled
40        var containerRemainder = containerSize - containerCenter;
41        if (remainder < containerRemainder) focusOffset -= containerRemainder - remainder;
42        if (focusOffset < 0) focusOffset = 0;
43
44        return (focusOffset * -100 / containerSize) + '%';
45    };
46
47    //Re-adjust the focus
48    var adjustFocus = function ($el) {
49
50        var $img = $el.find('img');
51
52        var imageW = $img[0].naturalWidth;
53        var imageH = $img[0].naturalHeight;
54
55        //console.log('adjusting focus for img ' + $img.attr('srcset') + ' with size ' + imageW + ' X ' + imageH);
56
57        var containerW = $el.width();
58        var containerH = $el.outerHeight();
59        
60        var focusX = parseFloat($el.data('focusX'));
61        var focusY = parseFloat($el.data('focusY'));
62
63        var $image = $el.find('img').first();
64
65        //Amount position will be shifted
66        var hShift = 0;
67        var vShift = 0;
68
69        if (!(containerW > 0 && containerH > 0 && imageW > 0 && imageH > 0)) {
70            return false; //Need dimensions to proceed
71        }
72
73        //Which is over by more?
74        var wR = imageW / containerW;
75        var hR = imageH / containerH;
76
77        //Reset max-width and -height
78        $image.css({
79            'max-width': '',
80            'max-height': ''
81        });
82
83        //Minimize image while still filling space
84        if (imageW > containerW && imageH > containerH) {
85            $image.css((wR > hR) ? 'max-height' : 'max-width', '100%');
86        }
87
88        if (wR > hR) {
89            hShift = calcShift(hR, containerW, imageW, focusX);
90        } else if (wR < hR) {
91            vShift = calcShift(wR, containerH, imageH, focusY, true);
92        }
93
94        $image.css({
95            top: vShift,
96            left: hShift
97        });
98
99    };
100
101    var $window = $(window);
102
103    var focusPoint = function ($el, settings) {
104
105        var $img = $el.find('img');
106
107        var thrAdjustFocus =
108
109            settings.throttleDuration ?
110
111            throttle(function () {
112
113                Utilities.waitForImageToLoad($img[0], false, function (didExpire) {
114                    adjustFocus($el);
115                });
116
117            }, settings.throttleDuration)
118
119            : function () {
120                Utilities.waitForImageToLoad($img[0], false, function (didExpire) {
121                    adjustFocus($el);
122                });
123
124            };//Only throttle when desired
125        var isListening = false;
126
127        //Focus image in container
128
129        Utilities.waitForImageToLoad($img[0], false, function (didExpire) {
130            adjustFocus($el);
131        });
132
133        //Expose a public API
134        return {
135
136            adjustFocus: function () {
137
138                Utilities.waitForImageToLoad($img[0], false, function (didExpire) {
139                    adjustFocus($el);
140                });
141
142            },
143
144            windowOn: function () {
145                if (isListening) return;
146                //Recalculate each time the window is resized
147                $window.on('resize', thrAdjustFocus);
148                return isListening = true;
149            },
150
151            windowOff: function () {
152                if (!isListening) return;
153                //Stop listening to the resize event
154                $window.off('resize', thrAdjustFocus);
155                isListening = false;
156                return true;
157            },
158
159            imgLoadOn: function() {
160                $img.on('load', function () {
161                    thrAdjustFocus();
162                });
163            },
164
165            imgLoadOff: function() {
166                $img.off('load', thrAdjustFocus);
167            },
168
169            customTrigger: function(trigger) {
170                trigger(thrAdjustFocus);
171            }
172        };
173    };
174
175    $.fn.focusPoint = function (optionsOrMethod) {
176        //Shortcut to functions - if string passed assume method n

176ame and execute
177        if (typeof optionsOrMethod === 'string') {
178            return this.each(function () {
179                var $el = $(this);
180                $el.data('focusPoint')[optionsOrMethod]();
181            });
182        }
183        //Otherwise assume options being passed and setup
184        var settings = $.extend({}, defaults, optionsOrMethod);
185        
186        return this.each(function () {
187            var $el = $(this);
188
189            var fp = focusPoint($el, settings);
190
191            //Stop the resize event of any previous attached
192            //focusPoint instances
193            if ($el.data('focusPoint')) {
194                $el.data('focusPoint').windowOff();
195                $el.data('focusPoint').imgLoadOff();
196            }
197
198            $el.data('focusPoint', fp);
199
200            if (settings.reCalcOnWindowResize)
201                fp.windowOn();
202
203            fp.imgLoadOn();
204
205            if (settings.customReCalcTrigger)
206                fp.customTrigger(settings.customReCalcTrigger);
207
208        });
209
210    };
211
212    $.fn.adjustFocus = function () {
213        //Deprecated v1.2
214        return this.each(function () {
215            adjustFocus($(this));
216        });
217    };
218
219})(jQuery);