five-bells-visualization
Version:
Tool to visualize Five Bells payments
258 lines (215 loc) • 7.77 kB
HTML
<!--
Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->
<!--
`core-image` is an element for displaying an image that provides useful sizing and
preloading options not found on the standard `<img>` tag.
The `sizing` option allows the image to be either cropped (`cover`) or
letterboxed (`contain`) to fill a fixed user-size placed on the element.
The `preload` option prevents the browser from rendering the image until the
image is fully loaded. In the interim, either the element's CSS `background-color`
can be be used as the placeholder, or the `placeholder` property can be
set to a URL (preferably a data-URI, for instant rendering) for an
placeholder image.
The `fade` option (only valid when `preload` is set) will cause the placeholder
image/color to be faded out once the image is rendered.
Examples:
Basically identical to <img src="..."> tag:
<core-image src="http://lorempixel.com/400/400"></core-image>
Will letterbox the image to fit:
<core-image style="width:400px; height:400px;" sizing="contain"
src="http://lorempixel.com/600/400"></core-image>
Will crop the image to fit:
<core-image style="width:400px; height:400px;" sizing="cover"
src="http://lorempixel.com/600/400"></core-image>
Will show light-gray background until the image loads:
<core-image style="width:400px; height:400px; background-color: lightgray;"
sizing="cover" preload src="http://lorempixel.com/600/400"></core-image>
Will show a base-64 encoded placeholder image until the image loads:
<core-image style="width:400px; height:400px;" placeholder="data:image/gif;base64,..."
sizing="cover" preload src="http://lorempixel.com/600/400"></core-image>
Will fade the light-gray background out once the image is loaded:
<core-image style="width:400px; height:400px; background-color: lightgray;"
sizing="cover" preload fade src="http://lorempixel.com/600/400"></core-image>
@group Polymer Core Elements
@element core-image
@homepage github.io
-->
<link rel="import" href="../polymer/polymer.html">
<polymer-element name="core-image">
<template>
<link rel="stylesheet" href="core-image.css">
<template if="{{!sizing}}">
<img id="img" role="none">
</template>
<template if="{{preload && fade}}">
<div id="placeholder" fit></div>
</template>
<content></content>
</template>
<script>
Polymer({
publish: {
/**
* The URL of an image.
*
* @attribute src
* @type string
* @default null
*/
src: null,
/**
* When false, the image is prevented from loading and any placeholder is
* shown. This may be useful when a binding to the src property is known to
* be invalid, to prevent 404 requests.
*
* @attribute load
* @type boolean
* @default true
*/
load: true,
/**
* Sets a sizing option for the image. Valid values are `contain` (full
* aspect ratio of the image is contained within the element and
* letterboxed) or `cover` (image is cropped in order to fully cover the
* bounds of the element), or `null` (default: image takes natural size).
*
* @attribute sizing
* @type string
* @default null
*/
sizing: null,
/**
* When a sizing option is uzed (`cover` or `contain`), this determines
* how the image is aligned within the element bounds.
*
* @attribute position
* @type string
* @default 'center'
*/
position: 'center',
/**
* When `true`, any change to the `src` property will cause the `placeholder`
* image (or background color, if no `placeholder` is specified) to be shown
* until the image has loaded.
*
* @attribute preload
* @type boolean
* @default false
*/
preload: false,
/**
* This image will be used as a background/placeholder until the src image has
* loaded. Use of a data-URI for placeholder is encouraged for instant rendering.
*
* @attribute placeholder
* @type string
* @default null
*/
placeholder: null,
/**
* ARIA role for this element. It defaults to `img` since this element is
* intended to be behave like an `<img>`.
*
* @attribute role
* @type string
* @default "img"
*/
role: {
reflect: true,
value: 'img'
},
/**
* When `preload` is true, setting `fade` to true will cause the image to
* fade into place.
*
* @attribute fade
* @type boolean
* @default false
*/
fade: false,
/**
* Read-only value that tracks the loading state of the image when the `preload`
* option is used.
*
* @attribute loading
* @type boolean
* @default false
*/
loading: false,
/**
* Can be used to set the width of image (e.g. via binding); size may also be
* set via CSS.
*
* @attribute width
* @type number
* @default null
*/
width: null,
/**
* Can be used to set the height of image (e.g. via binding); size may also be
* set via CSS.
*
* @attribute height
* @type number
* @default null
*/
height: null
},
observe: {
'preload color sizing position src fade': 'update'
},
widthChanged: function() {
this.style.width = isNaN(this.width) ? this.width : this.width + 'px';
},
heightChanged: function() {
this.style.height = isNaN(this.height) ? this.height : this.height + 'px';
},
update: function() {
this.style.backgroundSize = this.sizing;
this.style.backgroundPosition = this.sizing ? this.position : null;
this.style.backgroundRepeat = this.sizing ? 'no-repeat' : null;
if (this.preload) {
if (this.fade) {
if (!this._placeholderEl) {
this._placeholderEl = this.shadowRoot.querySelector('#placeholder');
}
this._placeholderEl.style.backgroundSize = this.sizing;
this._placeholderEl.style.backgroundPosition = this.sizing ? this.position : null;
this._placeholderEl.style.backgroundRepeat = this.sizing ? 'no-repeat' : null;
this._placeholderEl.classList.remove('fadein');
this._placeholderEl.style.backgroundImage = (this.load && this.placeholder) ? 'url(' + this.placeholder + ')': null;
} else {
this._setSrc(this.placeholder);
}
if (this.load && this.src) {
var img = new Image();
img.src = this.src;
this.loading = true;
img.onload = function() {
this._setSrc(this.src);
this.loading = false;
if (this.fade) {
this._placeholderEl.classList.add('fadein');
}
}.bind(this);
}
} else {
this._setSrc(this.src);
}
},
_setSrc: function(src) {
if (this.sizing) {
this.style.backgroundImage = src ? 'url(' + src + ')': '';
} else {
this.$.img.src = src || '';
}
}
});
</script>
</polymer-element>