window.pdfembGrabToPan = (function GrabToPanClosure() {
/**
* Construct a GrabToPan instance for a given HTML element.
* @param options.element {Element}
* @param options.ignoreTarget {function} optional. See `ignoreTarget(node)`
* @param options.onActiveChanged {function(boolean)} optional. Called
* when grab-to-pan is (de)activated. The first argument is a boolean that
* shows whether grab-to-pan is activated.
*/
function GrabToPan(options) {
this.element = options.element;
this.document = options.element.ownerDocument;
if (typeof options.ignoreTarget === 'function') {
this.ignoreTarget = options.ignoreTarget;
}
this.onActiveChanged = options.onActiveChanged;
// Bind the contexts to ensure that `this` always points to
// the GrabToPan instance.
this.activate = this.activate.bind(this);
this.deactivate = this.deactivate.bind(this);
this.toggle = this.toggle.bind(this);
this._onmousedown = this._onmousedown.bind(this);
this._onmousemove = this._onmousemove.bind(this);
this._onmousewheel = this._onmousewheel.bind(this);
this._endPan = this._endPan.bind(this);
// This overlay will be inserted in the document when the mouse moves during
// a grab operation, to ensure that the cursor has the desired appearance.
var overlay = this.overlay = document.createElement('div');
overlay.className = 'grab-to-pan-grabbing';
}
GrabToPan.prototype = {
/**
* Class name of element which can be grabbed
*/
CSS_CLASS_GRAB: 'grab-to-pan-grab',
/**
* Bind a mousedown event to the element to enable grab-detection.
*/
activate: function GrabToPan_activate() {
if (!this.active) {
this.active = true;
this.element.addEventListener('mousedown', this._onmousedown, true);
this.element.addEventListener('mousewheel', this._onmousewheel);
this.element.addEventListener('wheel', this._onmousewheel);
this.element.addEventListener('DOMMouseScroll', this._onmousewheel);
this.element.classList.add(this.CSS_CLASS_GRAB);
if (this.onActiveChanged) {
this.onActiveChanged(true);
}
}
},
/**
* Removes all events. Any pending pan session is immediately stopped.
*/
deactivate: function GrabToPan_deactivate() {
if (this.active) {
this.active = false;
this.element.removeEventListener('mousedown', this._onmousedown, true);
this._endPan();
this.element.classList.remove(this.CSS_CLASS_GRAB);
if (this.onActiveChanged) {
this.onActiveChanged(false);
}
}
},
toggle: function GrabToPan_toggle() {
if (this.active) {
this.deactivate();
} else {
this.activate();
}
},
/**
* Whether to not pan if the target element is clicked.
* Override this method to change the default behaviour.
*
* @param node {Element} The target of the event
* @return {boolean} Whether to not react to the click event.
*/
ignoreTarget: function GrabToPan_ignoreTarget(node) {
// Use matchesSelector to check whether the clicked element
// is (a child of) an input element / link
return node[matchesSelector](
'a[href], a[href] *, input, textarea, button, button *, select, option'
);
},
/**
* @private
*/
_onmousedown: function GrabToPan__onmousedown(event) {
if (event.button !== 0 || this.ignoreTarget(event.target)) {
return;
}
if (event.originalTarget) {
try {
/* jshint expr:true */
var ottn = event.originalTarget.tagName;
} catch (e) {
// Mozilla-specific: element is a scrollbar (XUL element)
return;
}
}
this.scrollLeftStart = this.element.scrollLeft;
this.scrollTopStart = this.element.scrollTop;
this.clientXStart = event.clientX;
this.clientYStart = event.clientY;
this.document.addEventListener('mousemove', this._onmousemove, true);
this.document.addEventListener('mouseup', this._endPan, true);
// When a scroll event occurs before a mousemove, assume that the user
// dragged a scrollbar (necessary for Opera Presto, Safari and IE)
// (not needed for Chrome/Firefox)
this.element.addEventListener('scroll', this._endPan, true);
event.preventDefault();
event.stopPropagation();
this.document.documentElement.classList.add(this.CSS_CLASS_GRABBING);
var focusedElement = document.activeElement;
if (focusedElement && !focusedElement.contains(event.target)) {
focusedElement.blur();
}
},
/**
* @private
*/
_onmousemove: function GrabToPan__onmousemove(event) {
this.element.removeEventListener('scroll', this._endPan, true);
if (isLeftMouseReleased(event)) {
this._endPan();
return;
}
var xDiff = event.clientX - this.clientXStart;
var yDiff = event.clientY - this.clientYStart;
this.element.scrollTop = this.scrollTopStart - yDiff;
this.element.scrollLeft = this.scrollLeftStart - xDiff;
if (!this.overlay.parentNode) {
document.body.appendChild(this.overlay);
}
},
/**
* @private
*/
_onmousewheel: function GrabToPan__onmousewheel(event) {
this.element.removeEventListener('scroll', this._endPan, true);
var MOUSE_WHEEL_DELTA_FACTOR = 0.5;
if (event.deltaMode) {
// if 0, means measured in pixels
if (event.deltaMode == 1) { //Measured in lines
MOUSE_WHEEL_DELTA_FACTOR = 10;
}
if (event.deltaMode == 2) { // Measured in pages
MOUSE_WHEEL_DELTA_FACTOR = 1000;
}
}
var ticks = event.deltaY ? -event.deltaY // 'wheel'
: ( event.wheelDelta ? event.wheelDelta // 'mousewheel'
: -event.detail // 'DOMMouseScroll'
);
this.scrollLeftStart = this.element.scrollLeft;
this.scrollTopStart = this.element.scrollTop;
var yDiff = ticks * MOUSE_WHEEL_DELTA_FACTOR;
this.element.scrollTop = this.scrollTopStart - yDiff;
if (!this.overlay.parentNode) {
document.body.appendChild(this.overlay);
}
if (this.element.scrollTop != this.scrollTopStart || yDiff == 0) {
event.preventDefault();
return false;
}
},
/**
* @private
*/
_endPan: function GrabToPan__endPan() {
this.element.removeEventListener('scroll', this._endPan, true);
this.document.removeEventListener('mousemove', this._onmousemove, true);
this.document.removeEventListener('mouseup', this._endPan, true);
if (this.overlay.parentNode) {
this.overlay.parentNode.removeChild(this.overlay);
}
}
};
// Get the correct (vendor-prefixed) name of the matches method.
var matchesSelector;
['webkitM', 'mozM', 'msM', 'oM', 'm'].some(function(prefix) {
var name = prefix + 'atches';
if (name in document.documentElement) {
matchesSelector = name;
}
name += 'Selector';
if (name in document.documentElement) {
matchesSelector = name;
}
return matchesSelector; // If found, then truthy, and [].some() ends.
});
// Browser sniffing because it's impossible to feature-detect
// whether event.which for onmousemove is reliable
var isNotIEorIsIE10plus = !document.documentMode || document.documentMode > 9;
var chrome = window.chrome;
var isChrome15OrOpera15plus = chrome && (chrome.webstore || chrome.app);
// ^ Chrome 15+ ^ Opera 15+
var isSafari6plus = /Apple/.test(navigator.vendor) &&
/Version\/([6-9]\d*|[1-5]\d+)/.test(navigator.userAgent);
/**
* Whether the left mouse is not pressed.
* @param event {MouseEvent}
* @return {boolean} True if the left mouse button is not pressed.
* False if unsure or if the left mouse button is pressed.
*/
function isLeftMouseReleased(event) {
if ('buttons' in event && isNotIEorIsIE10plus) {
// http://www.w3.org/TR/DOM-Level-3-Events/#events-MouseEvent-buttons
// Firefox 15+
// Internet Explorer 10+
return !(event.buttons | 1);
}
if (isChrome15OrOpera15plus || isSafari6plus) {
// Chrome 14+
// Opera 15+
// Safari 6.0+
return event.which === 0;
}
}
return GrabToPan;
})();