Current File : /var/www/html/news/public/bower_components/chart.js/src/platforms/platform.dom.js
'use strict';
// Chart.Platform implementation for targeting a web browser
module.exports = function(Chart) {
var helpers = Chart.helpers;
// DOM event types -> Chart.js event types.
// Note: only events with different types are mapped.
// https://developer.mozilla.org/en-US/docs/Web/Events
var eventTypeMap = {
// Touch events
touchstart: 'mousedown',
touchmove: 'mousemove',
touchend: 'mouseup',
// Pointer events
pointerenter: 'mouseenter',
pointerdown: 'mousedown',
pointermove: 'mousemove',
pointerup: 'mouseup',
pointerleave: 'mouseout',
pointerout: 'mouseout'
};
/**
* The "used" size is the final value of a dimension property after all calculations have
* been performed. This method uses the computed style of `element` but returns undefined
* if the computed style is not expressed in pixels. That can happen in some cases where
* `element` has a size relative to its parent and this last one is not yet displayed,
* for example because of `display: none` on a parent node.
* @see https://developer.mozilla.org/en-US/docs/Web/CSS/used_value
* @returns {Number} Size in pixels or undefined if unknown.
*/
function readUsedSize(element, property) {
var value = helpers.getStyle(element, property);
var matches = value && value.match(/^(\d+)(\.\d+)?px$/);
return matches? Number(matches[1]) : undefined;
}
/**
* Initializes the canvas style and render size without modifying the canvas display size,
* since responsiveness is handled by the controller.resize() method. The config is used
* to determine the aspect ratio to apply in case no explicit height has been specified.
*/
function initCanvas(canvas, config) {
var style = canvas.style;
// NOTE(SB) canvas.getAttribute('width') !== canvas.width: in the first case it
// returns null or '' if no explicit value has been set to the canvas attribute.
var renderHeight = canvas.getAttribute('height');
var renderWidth = canvas.getAttribute('width');
// Chart.js modifies some canvas values that we want to restore on destroy
canvas._chartjs = {
initial: {
height: renderHeight,
width: renderWidth,
style: {
display: style.display,
height: style.height,
width: style.width
}
}
};
// Force canvas to display as block to avoid extra space caused by inline
// elements, which would interfere with the responsive resize process.
// https://github.com/chartjs/Chart.js/issues/2538
style.display = style.display || 'block';
if (renderWidth === null || renderWidth === '') {
var displayWidth = readUsedSize(canvas, 'width');
if (displayWidth !== undefined) {
canvas.width = displayWidth;
}
}
if (renderHeight === null || renderHeight === '') {
if (canvas.style.height === '') {
// If no explicit render height and style height, let's apply the aspect ratio,
// which one can be specified by the user but also by charts as default option
// (i.e. options.aspectRatio). If not specified, use canvas aspect ratio of 2.
canvas.height = canvas.width / (config.options.aspectRatio || 2);
} else {
var displayHeight = readUsedSize(canvas, 'height');
if (displayWidth !== undefined) {
canvas.height = displayHeight;
}
}
}
return canvas;
}
function createEvent(type, chart, x, y, nativeEvent) {
return {
type: type,
chart: chart,
native: nativeEvent || null,
x: x !== undefined? x : null,
y: y !== undefined? y : null,
};
}
function fromNativeEvent(event, chart) {
var type = eventTypeMap[event.type] || event.type;
var pos = helpers.getRelativePosition(event, chart);
return createEvent(type, chart, pos.x, pos.y, event);
}
function createResizer(handler) {
var iframe = document.createElement('iframe');
iframe.className = 'chartjs-hidden-iframe';
iframe.style.cssText =
'display:block;'+
'overflow:hidden;'+
'border:0;'+
'margin:0;'+
'top:0;'+
'left:0;'+
'bottom:0;'+
'right:0;'+
'height:100%;'+
'width:100%;'+
'position:absolute;'+
'pointer-events:none;'+
'z-index:-1;';
// Prevent the iframe to gain focus on tab.
// https://github.com/chartjs/Chart.js/issues/3090
iframe.tabIndex = -1;
// If the iframe is re-attached to the DOM, the resize listener is removed because the
// content is reloaded, so make sure to install the handler after the iframe is loaded.
// https://github.com/chartjs/Chart.js/issues/3521
helpers.addEvent(iframe, 'load', function() {
helpers.addEvent(iframe.contentWindow || iframe, 'resize', handler);
// The iframe size might have changed while loading, which can also
// happen if the size has been changed while detached from the DOM.
handler();
});
return iframe;
}
function addResizeListener(node, listener, chart) {
var stub = node._chartjs = {
ticking: false
};
// Throttle the callback notification until the next animation frame.
var notify = function() {
if (!stub.ticking) {
stub.ticking = true;
helpers.requestAnimFrame.call(window, function() {
if (stub.resizer) {
stub.ticking = false;
return listener(createEvent('resize', chart));
}
});
}
};
// Let's keep track of this added iframe and thus avoid DOM query when removing it.
stub.resizer = createResizer(notify);
node.insertBefore(stub.resizer, node.firstChild);
}
function removeResizeListener(node) {
if (!node || !node._chartjs) {
return;
}
var resizer = node._chartjs.resizer;
if (resizer) {
resizer.parentNode.removeChild(resizer);
node._chartjs.resizer = null;
}
delete node._chartjs;
}
return {
acquireContext: function(item, config) {
if (typeof item === 'string') {
item = document.getElementById(item);
} else if (item.length) {
// Support for array based queries (such as jQuery)
item = item[0];
}
if (item && item.canvas) {
// Support for any object associated to a canvas (including a context2d)
item = item.canvas;
}
// To prevent canvas fingerprinting, some add-ons undefine the getContext
// method, for example: https://github.com/kkapsner/CanvasBlocker
// https://github.com/chartjs/Chart.js/issues/2807
var context = item && item.getContext && item.getContext('2d');
// `instanceof HTMLCanvasElement/CanvasRenderingContext2D` fails when the item is
// inside an iframe or when running in a protected environment. We could guess the
// types from their toString() value but let's keep things flexible and assume it's
// a sufficient condition if the item has a context2D which has item as `canvas`.
// https://github.com/chartjs/Chart.js/issues/3887
// https://github.com/chartjs/Chart.js/issues/4102
// https://github.com/chartjs/Chart.js/issues/4152
if (context && context.canvas === item) {
initCanvas(item, config);
return context;
}
return null;
},
releaseContext: function(context) {
var canvas = context.canvas;
if (!canvas._chartjs) {
return;
}
var initial = canvas._chartjs.initial;
['height', 'width'].forEach(function(prop) {
var value = initial[prop];
if (value === undefined || value === null) {
canvas.removeAttribute(prop);
} else {
canvas.setAttribute(prop, value);
}
});
helpers.each(initial.style || {}, function(value, key) {
canvas.style[key] = value;
});
// The canvas render size might have been changed (and thus the state stack discarded),
// we can't use save() and restore() to restore the initial state. So make sure that at
// least the canvas context is reset to the default state by setting the canvas width.
// https://www.w3.org/TR/2011/WD-html5-20110525/the-canvas-element.html
canvas.width = canvas.width;
delete canvas._chartjs;
},
addEventListener: function(chart, type, listener) {
var canvas = chart.canvas;
if (type === 'resize') {
// Note: the resize event is not supported on all browsers.
addResizeListener(canvas.parentNode, listener, chart);
return;
}
var stub = listener._chartjs || (listener._chartjs = {});
var proxies = stub.proxies || (stub.proxies = {});
var proxy = proxies[chart.id + '_' + type] = function(event) {
listener(fromNativeEvent(event, chart));
};
helpers.addEvent(canvas, type, proxy);
},
removeEventListener: function(chart, type, listener) {
var canvas = chart.canvas;
if (type === 'resize') {
// Note: the resize event is not supported on all browsers.
removeResizeListener(canvas.parentNode, listener);
return;
}
var stub = listener._chartjs || {};
var proxies = stub.proxies || {};
var proxy = proxies[chart.id + '_' + type];
if (!proxy) {
return;
}
helpers.removeEvent(canvas, type, proxy);
}
};
};
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