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mirror of https://github.com/twbs/bootstrap.git synced 2024-11-30 12:24:19 +01:00
Bootstrap/docs/assets/js/holder/holder.js
2012-11-29 20:59:14 -08:00

231 lines
7.1 KiB
JavaScript
Executable File

/*
Holder - 1.4 - client side image placeholders
(c) 2012 Ivan Malopinsky / http://imsky.co
Provided under the Apache 2.0 License: http://www.apache.org/licenses/LICENSE-2.0
Commercial use requires attribution.
*/
var Holder = Holder || {};
(function (app, win) {
var preempted = false,
fallback = false,
canvas = document.createElement('canvas');
//getElementsByClassName polyfill
document.getElementsByClassName||(document.getElementsByClassName=function(e){var t=document,n,r,i,s=[];if(t.querySelectorAll)return t.querySelectorAll("."+e);if(t.evaluate){r=".//*[contains(concat(' ', @class, ' '), ' "+e+" ')]",n=t.evaluate(r,t,null,0,null);while(i=n.iterateNext())s.push(i)}else{n=t.getElementsByTagName("*"),r=new RegExp("(^|\\s)"+e+"(\\s|$)");for(i=0;i<n.length;i++)r.test(n[i].className)&&s.push(n[i])}return s})
//getComputedStyle polyfill
window.getComputedStyle||(window.getComputedStyle=function(e,t){return this.el=e,this.getPropertyValue=function(t){var n=/(\-([a-z]){1})/g;return t=="float"&&(t="styleFloat"),n.test(t)&&(t=t.replace(n,function(){return arguments[2].toUpperCase()})),e.currentStyle[t]?e.currentStyle[t]:null},this})
//http://javascript.nwbox.com/ContentLoaded by Diego Perini with modifications
function contentLoaded(n,t){var l="complete",s="readystatechange",u=!1,h=u,c=!0,i=n.document,a=i.documentElement,e=i.addEventListener?"addEventListener":"attachEvent",v=i.addEventListener?"removeEventListener":"detachEvent",f=i.addEventListener?"":"on",r=function(e){(e.type!=s||i.readyState==l)&&((e.type=="load"?n:i)[v](f+e.type,r,u),!h&&(h=!0)&&t.call(n,null))},o=function(){try{a.doScroll("left")}catch(n){setTimeout(o,50);return}r("poll")};if(i.readyState==l)t.call(n,"lazy");else{if(i.createEventObject&&a.doScroll){try{c=!n.frameElement}catch(y){}c&&o()}i[e](f+"DOMContentLoaded",r,u),i[e](f+s,r,u),n[e](f+"load",r,u)}};
//https://gist.github.com/991057 by Jed Schmidt with modifications
function selector(a){
a=a.match(/^(\W)?(.*)/);var b=document["getElement"+(a[1]?a[1]=="#"?"ById":"sByClassName":"sByTagName")](a[2]);
var ret=[]; b!=null&&(b.length?ret=b:b.length==0?ret=b:ret=[b]); return ret;
}
//shallow object property extend
function extend(a,b){var c={};for(var d in a)c[d]=a[d];for(var e in b)c[e]=b[e];return c}
function draw(ctx, dimensions, template) {
var dimension_arr = [dimensions.height, dimensions.width].sort();
var maxFactor = Math.round(dimension_arr[1] / 16),
minFactor = Math.round(dimension_arr[0] / 16);
var text_height = Math.max(template.size, maxFactor);
canvas.width = dimensions.width;
canvas.height = dimensions.height;
ctx.textAlign = "center";
ctx.textBaseline = "middle";
ctx.fillStyle = template.background;
ctx.fillRect(0, 0, dimensions.width, dimensions.height);
ctx.fillStyle = template.foreground;
ctx.font = "bold " + text_height + "px sans-serif";
var text = template.text ? template.text : (dimensions.width + "x" + dimensions.height);
if (Math.round(ctx.measureText(text).width) / dimensions.width > 1) {
text_height = Math.max(minFactor, template.size);
}
ctx.font = "bold " + text_height + "px sans-serif";
ctx.fillText(text, (dimensions.width / 2), (dimensions.height / 2), dimensions.width);
return canvas.toDataURL("image/png");
}
if (!canvas.getContext) {
fallback = true;
} else {
if (canvas.toDataURL("image/png").indexOf("data:image/png") < 0) {
//Android doesn't support data URI
fallback = true;
} else {
var ctx = canvas.getContext("2d");
}
}
function render(mode, el, holder, src){
var dimensions = holder.dimensions, theme = holder.theme, text = holder.text;
var dimensions_caption = dimensions.width + "x" + dimensions.height;
theme = (text ? extend(theme, { text: text }) : theme);
if(mode == "image"){
el.setAttribute("data-src", src);
el.setAttribute("alt", text ? text : theme.text ? theme.text + " [" + dimensions_caption + "]" : dimensions_caption);
el.style.width = dimensions.width + "px";
el.style.height = dimensions.height + "px";
el.style.backgroundColor = theme.background;
if(!fallback){
el.setAttribute("src", draw(ctx, dimensions, theme));
}
}
else {
if(!fallback){
el.style.backgroundImage = "url("+draw(ctx, dimensions, theme)+")";
}
}
};
function parse_flags(flags, options){
var ret = {
theme: settings.themes.gray
}, render = false;
for (sl = flags.length, j = 0; j < sl; j++) {
if (app.flags.dimensions.match(flags[j])) {
render = true;
ret.dimensions = app.flags.dimensions.output(flags[j]);
} else if (app.flags.colors.match(flags[j])) {
ret.theme = app.flags.colors.output(flags[j]);
} else if (options.themes[flags[j]]) {
//If a theme is specified, it will override custom colors
ret.theme = options.themes[flags[j]];
} else if (app.flags.text.match(flags[j])) {
ret.text = app.flags.text.output(flags[j]);
}
}
return render ? ret : false;
};
var settings = {
domain: "holder.js",
images: "img",
elements: ".holderjs",
themes: {
"gray": {
background: "#eee",
foreground: "#aaa",
size: 12
},
"social": {
background: "#3a5a97",
foreground: "#fff",
size: 12
},
"industrial": {
background: "#434A52",
foreground: "#C2F200",
size: 12
}
}
};
app.flags = {
dimensions: {
regex: /([0-9]+)x([0-9]+)/,
output: function(val){
var exec = this.regex.exec(val);
return {
width: +exec[1],
height: +exec[2]
}
}
},
colors: {
regex: /#([0-9a-f]{3,})\:#([0-9a-f]{3,})/i,
output: function(val){
var exec = this.regex.exec(val);
return {
size: settings.themes.gray.size,
foreground: "#" + exec[2],
background: "#" + exec[1]
}
}
},
text: {
regex: /text\:(.*)/,
output: function(val){
return this.regex.exec(val)[1];
}
}
}
for(var flag in app.flags){
app.flags[flag].match = function (val){
return val.match(this.regex)
}
}
app.add_theme = function (name, theme) {
name != null && theme != null && (settings.themes[name] = theme);
return app;
};
app.add_image = function (src, el) {
var node = selector(el);
if (node.length) {
for (var i = 0, l = node.length; i < l; i++) {
var img = document.createElement("img")
img.setAttribute("data-src", src);
node[i].appendChild(img);
}
}
return app;
};
app.run = function (o) {
var options = extend(settings, o),
images = selector(options.images),
elements = selector(options.elements),
preempted = true;
var cssregex = new RegExp(options.domain+"\/(.*?)\"?\\)");
for(var l = elements.length, i = 0; i < l; i++){
var src = window.getComputedStyle(elements[i],null).getPropertyValue("background-image");
var flags = src.match(cssregex);
if(flags){
var holder = parse_flags(flags[1].split("/"), options);
if(holder){
render("background", elements[i], holder, src);
}
}
}
for (var l = images.length, i = 0; i < l; i++) {
var src = images[i].getAttribute("data-src") || images[i].getAttribute("src");
if (src.indexOf(options.domain)>=0) {
var holder = parse_flags(src.substr(src.lastIndexOf(options.domain) + options.domain.length + 1).split("/"), options);
if (holder) {
render("image", images[i], holder, src);
}
}
}
return app;
};
contentLoaded(win, function () {
preempted || app.run()
});
})(Holder, window);