holder.js 14 KB

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  1. /*
  2. Holder - 2.2 - client side image placeholders
  3. (c) 2012-2013 Ivan Malopinsky / http://imsky.co
  4. Provided under the MIT License.
  5. Commercial use requires attribution.
  6. */
  7. var Holder = Holder || {};
  8. (function (app, win) {
  9. var preempted = false,
  10. fallback = false,
  11. canvas = document.createElement('canvas');
  12. var dpr = 1, bsr = 1;
  13. var resizable_images = [];
  14. if (!canvas.getContext) {
  15. fallback = true;
  16. } else {
  17. if (canvas.toDataURL("image/png")
  18. .indexOf("data:image/png") < 0) {
  19. //Android doesn't support data URI
  20. fallback = true;
  21. } else {
  22. var ctx = canvas.getContext("2d");
  23. }
  24. }
  25. if(!fallback){
  26. dpr = window.devicePixelRatio || 1,
  27. bsr = ctx.webkitBackingStorePixelRatio || ctx.mozBackingStorePixelRatio || ctx.msBackingStorePixelRatio || ctx.oBackingStorePixelRatio || ctx.backingStorePixelRatio || 1;
  28. }
  29. var ratio = dpr / bsr;
  30. var settings = {
  31. domain: "holder.js",
  32. images: "img",
  33. bgnodes: ".holderjs",
  34. themes: {
  35. "gray": {
  36. background: "#eee",
  37. foreground: "#aaa",
  38. size: 12
  39. },
  40. "social": {
  41. background: "#3a5a97",
  42. foreground: "#fff",
  43. size: 12
  44. },
  45. "industrial": {
  46. background: "#434A52",
  47. foreground: "#C2F200",
  48. size: 12
  49. },
  50. "sky": {
  51. background: "#0D8FDB",
  52. foreground: "#fff",
  53. size: 12
  54. },
  55. "vine": {
  56. background: "#39DBAC",
  57. foreground: "#1E292C",
  58. size: 12
  59. },
  60. "lava": {
  61. background: "#F8591A",
  62. foreground: "#1C2846",
  63. size: 12
  64. }
  65. },
  66. stylesheet: ""
  67. };
  68. app.flags = {
  69. dimensions: {
  70. regex: /^(\d+)x(\d+)$/,
  71. output: function (val) {
  72. var exec = this.regex.exec(val);
  73. return {
  74. width: +exec[1],
  75. height: +exec[2]
  76. }
  77. }
  78. },
  79. fluid: {
  80. regex: /^([0-9%]+)x([0-9%]+)$/,
  81. output: function (val) {
  82. var exec = this.regex.exec(val);
  83. return {
  84. width: exec[1],
  85. height: exec[2]
  86. }
  87. }
  88. },
  89. colors: {
  90. regex: /#([0-9a-f]{3,})\:#([0-9a-f]{3,})/i,
  91. output: function (val) {
  92. var exec = this.regex.exec(val);
  93. return {
  94. size: settings.themes.gray.size,
  95. foreground: "#" + exec[2],
  96. background: "#" + exec[1]
  97. }
  98. }
  99. },
  100. text: {
  101. regex: /text\:(.*)/,
  102. output: function (val) {
  103. return this.regex.exec(val)[1];
  104. }
  105. },
  106. font: {
  107. regex: /font\:(.*)/,
  108. output: function (val) {
  109. return this.regex.exec(val)[1];
  110. }
  111. },
  112. auto: {
  113. regex: /^auto$/
  114. },
  115. textmode: {
  116. regex: /textmode\:(.*)/,
  117. output: function(val){
  118. return this.regex.exec(val)[1];
  119. }
  120. }
  121. }
  122. //getElementsByClassName polyfill
  123. document.getElementsByClassName||(document.getElementsByClassName=function(e){var t=document,n,r,i,s=[];if(t.querySelectorAll)return t.querySelectorAll("."+e);if(t.evaluate){r=".//*[contains(concat(' ', @class, ' '), ' "+e+" ')]",n=t.evaluate(r,t,null,0,null);while(i=n.iterateNext())s.push(i)}else{n=t.getElementsByTagName("*"),r=new RegExp("(^|\\s)"+e+"(\\s|$)");for(i=0;i<n.length;i++)r.test(n[i].className)&&s.push(n[i])}return s})
  124. //getComputedStyle polyfill
  125. window.getComputedStyle||(window.getComputedStyle=function(e){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})
  126. //http://javascript.nwbox.com/ContentLoaded by Diego Perini with modifications
  127. 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)}}
  128. //https://gist.github.com/991057 by Jed Schmidt with modifications
  129. function selector(a){
  130. a=a.match(/^(\W)?(.*)/);var b=document["getElement"+(a[1]?a[1]=="#"?"ById":"sByClassName":"sByTagName")](a[2]);
  131. var ret=[]; b!==null&&(b.length?ret=b:b.length===0?ret=b:ret=[b]); return ret;
  132. }
  133. //shallow object property extend
  134. function extend(a,b){
  135. var c={};
  136. for(var i in a){
  137. if(a.hasOwnProperty(i)){
  138. c[i]=a[i];
  139. }
  140. }
  141. for(var i in b){
  142. if(b.hasOwnProperty(i)){
  143. c[i]=b[i];
  144. }
  145. }
  146. return c
  147. }
  148. //hasOwnProperty polyfill
  149. if (!Object.prototype.hasOwnProperty)
  150. /*jshint -W001, -W103 */
  151. Object.prototype.hasOwnProperty = function(prop) {
  152. var proto = this.__proto__ || this.constructor.prototype;
  153. return (prop in this) && (!(prop in proto) || proto[prop] !== this[prop]);
  154. }
  155. /*jshint +W001, +W103 */
  156. function text_size(width, height, template) {
  157. height = parseInt(height, 10);
  158. width = parseInt(width, 10);
  159. var bigSide = Math.max(height, width)
  160. var smallSide = Math.min(height, width)
  161. var scale = 1 / 12;
  162. var newHeight = Math.min(smallSide * 0.75, 0.75 * bigSide * scale);
  163. return {
  164. height: Math.round(Math.max(template.size, newHeight))
  165. }
  166. }
  167. function draw(args) {
  168. var ctx = args.ctx;
  169. var dimensions = args.dimensions;
  170. var template = args.template;
  171. var ratio = args.ratio;
  172. var holder = args.holder;
  173. var literal = holder.textmode == "literal";
  174. var exact = holder.textmode == "exact";
  175. var ts = text_size(dimensions.width, dimensions.height, template);
  176. var text_height = ts.height;
  177. var width = dimensions.width * ratio,
  178. height = dimensions.height * ratio;
  179. var font = template.font ? template.font : "sans-serif";
  180. canvas.width = width;
  181. canvas.height = height;
  182. ctx.textAlign = "center";
  183. ctx.textBaseline = "middle";
  184. ctx.fillStyle = template.background;
  185. ctx.fillRect(0, 0, width, height);
  186. ctx.fillStyle = template.foreground;
  187. ctx.font = "bold " + text_height + "px " + font;
  188. var text = template.text ? template.text : (Math.floor(dimensions.width) + "x" + Math.floor(dimensions.height));
  189. if (literal) {
  190. var dimensions = holder.dimensions;
  191. text = dimensions.width + "x" + dimensions.height;
  192. }
  193. else if(exact && holder.exact_dimensions){
  194. var dimensions = holder.exact_dimensions;
  195. text = (Math.floor(dimensions.width) + "x" + Math.floor(dimensions.height));
  196. }
  197. var text_width = ctx.measureText(text).width;
  198. if (text_width / width >= 0.75) {
  199. text_height = Math.floor(text_height * 0.75 * (width / text_width));
  200. }
  201. //Resetting font size if necessary
  202. ctx.font = "bold " + (text_height * ratio) + "px " + font;
  203. ctx.fillText(text, (width / 2), (height / 2), width);
  204. return canvas.toDataURL("image/png");
  205. }
  206. function render(mode, el, holder, src) {
  207. var dimensions = holder.dimensions,
  208. theme = holder.theme,
  209. text = holder.text ? decodeURIComponent(holder.text) : holder.text;
  210. var dimensions_caption = dimensions.width + "x" + dimensions.height;
  211. theme = (text ? extend(theme, {
  212. text: text
  213. }) : theme);
  214. theme = (holder.font ? extend(theme, {
  215. font: holder.font
  216. }) : theme);
  217. el.setAttribute("data-src", src);
  218. holder.theme = theme;
  219. el.holder_data = holder;
  220. if (mode == "image") {
  221. el.setAttribute("alt", text ? text : theme.text ? theme.text + " [" + dimensions_caption + "]" : dimensions_caption);
  222. if (fallback || !holder.auto) {
  223. el.style.width = dimensions.width + "px";
  224. el.style.height = dimensions.height + "px";
  225. }
  226. if (fallback) {
  227. el.style.backgroundColor = theme.background;
  228. } else {
  229. el.setAttribute("src", draw({ctx: ctx, dimensions: dimensions, template: theme, ratio:ratio, holder: holder}));
  230. if(holder.textmode && holder.textmode == "exact"){
  231. resizable_images.push(el);
  232. resizable_update(el);
  233. }
  234. }
  235. } else if (mode == "background") {
  236. if (!fallback) {
  237. el.style.backgroundImage = "url(" + draw({ctx:ctx, dimensions: dimensions, template: theme, ratio: ratio, holder: holder}) + ")";
  238. el.style.backgroundSize = dimensions.width + "px " + dimensions.height + "px";
  239. }
  240. } else if (mode == "fluid") {
  241. el.setAttribute("alt", text ? text : theme.text ? theme.text + " [" + dimensions_caption + "]" : dimensions_caption);
  242. if (dimensions.height.slice(-1) == "%") {
  243. el.style.height = dimensions.height
  244. } else {
  245. el.style.height = dimensions.height + "px"
  246. }
  247. if (dimensions.width.slice(-1) == "%") {
  248. el.style.width = dimensions.width
  249. } else {
  250. el.style.width = dimensions.width + "px"
  251. }
  252. if (el.style.display == "inline" || el.style.display === "" || el.style.display == "none") {
  253. el.style.display = "block";
  254. }
  255. if (fallback) {
  256. el.style.backgroundColor = theme.background;
  257. } else {
  258. resizable_images.push(el);
  259. resizable_update(el);
  260. }
  261. }
  262. }
  263. function dimension_check(el, callback) {
  264. var dimensions = {
  265. height: el.clientHeight,
  266. width: el.clientWidth
  267. };
  268. if (!dimensions.height && !dimensions.width) {
  269. if (el.hasAttribute("data-holder-invisible")) {
  270. throw new Error("Holder: placeholder is not visible");
  271. } else {
  272. el.setAttribute("data-holder-invisible", true)
  273. setTimeout(function () {
  274. callback.call(this, el)
  275. }, 1)
  276. return null;
  277. }
  278. } else {
  279. el.removeAttribute("data-holder-invisible")
  280. }
  281. return dimensions;
  282. }
  283. function resizable_update(element) {
  284. var images;
  285. if (element.nodeType == null) {
  286. images = resizable_images;
  287. } else {
  288. images = [element]
  289. }
  290. for (var i in images) {
  291. if (!images.hasOwnProperty(i)) {
  292. continue;
  293. }
  294. var el = images[i]
  295. if (el.holder_data) {
  296. var holder = el.holder_data;
  297. var dimensions = dimension_check(el, resizable_update)
  298. if(dimensions){
  299. if(holder.fluid){
  300. el.setAttribute("src", draw({
  301. ctx: ctx,
  302. dimensions: dimensions,
  303. template: holder.theme,
  304. ratio: ratio,
  305. holder: holder
  306. }))
  307. }
  308. if(holder.textmode && holder.textmode == "exact"){
  309. holder.exact_dimensions = dimensions;
  310. el.setAttribute("src", draw({
  311. ctx: ctx,
  312. dimensions: holder.dimensions,
  313. template: holder.theme,
  314. ratio: ratio,
  315. holder: holder
  316. }))
  317. }
  318. }
  319. }
  320. }
  321. }
  322. function parse_flags(flags, options) {
  323. var ret = {
  324. theme: extend(settings.themes.gray, {})
  325. };
  326. var render = false;
  327. for (sl = flags.length, j = 0; j < sl; j++) {
  328. var flag = flags[j];
  329. if (app.flags.dimensions.match(flag)) {
  330. render = true;
  331. ret.dimensions = app.flags.dimensions.output(flag);
  332. } else if (app.flags.fluid.match(flag)) {
  333. render = true;
  334. ret.dimensions = app.flags.fluid.output(flag);
  335. ret.fluid = true;
  336. } else if (app.flags.textmode.match(flag)) {
  337. ret.textmode = app.flags.textmode.output(flag)
  338. } else if (app.flags.colors.match(flag)) {
  339. ret.theme = app.flags.colors.output(flag);
  340. } else if (options.themes[flag]) {
  341. //If a theme is specified, it will override custom colors
  342. if(options.themes.hasOwnProperty(flag)){
  343. ret.theme = extend(options.themes[flag], {});
  344. }
  345. } else if (app.flags.font.match(flag)) {
  346. ret.font = app.flags.font.output(flag);
  347. } else if (app.flags.auto.match(flag)) {
  348. ret.auto = true;
  349. } else if (app.flags.text.match(flag)) {
  350. ret.text = app.flags.text.output(flag);
  351. }
  352. }
  353. return render ? ret : false;
  354. }
  355. for (var flag in app.flags) {
  356. if (!app.flags.hasOwnProperty(flag)) continue;
  357. app.flags[flag].match = function (val) {
  358. return val.match(this.regex)
  359. }
  360. }
  361. app.add_theme = function (name, theme) {
  362. name != null && theme != null && (settings.themes[name] = theme);
  363. return app;
  364. };
  365. app.add_image = function (src, el) {
  366. var node = selector(el);
  367. if (node.length) {
  368. for (var i = 0, l = node.length; i < l; i++) {
  369. var img = document.createElement("img")
  370. img.setAttribute("data-src", src);
  371. node[i].appendChild(img);
  372. }
  373. }
  374. return app;
  375. };
  376. app.run = function (o) {
  377. preempted = true;
  378. var options = extend(settings, o),
  379. images = [],
  380. imageNodes = [],
  381. bgnodes = [];
  382. if (typeof (options.images) == "string") {
  383. imageNodes = selector(options.images);
  384. } else if (window.NodeList && options.images instanceof window.NodeList) {
  385. imageNodes = options.images;
  386. } else if (window.Node && options.images instanceof window.Node) {
  387. imageNodes = [options.images];
  388. }
  389. if (typeof (options.bgnodes) == "string") {
  390. bgnodes = selector(options.bgnodes);
  391. } else if (window.NodeList && options.elements instanceof window.NodeList) {
  392. bgnodes = options.bgnodes;
  393. } else if (window.Node && options.bgnodes instanceof window.Node) {
  394. bgnodes = [options.bgnodes];
  395. }
  396. for (i = 0, l = imageNodes.length; i < l; i++) images.push(imageNodes[i]);
  397. var holdercss = document.getElementById("holderjs-style");
  398. if (!holdercss) {
  399. holdercss = document.createElement("style");
  400. holdercss.setAttribute("id", "holderjs-style");
  401. holdercss.type = "text/css";
  402. document.getElementsByTagName("head")[0].appendChild(holdercss);
  403. }
  404. if (!options.nocss) {
  405. if (holdercss.styleSheet) {
  406. holdercss.styleSheet.cssText += options.stylesheet;
  407. } else {
  408. holdercss.appendChild(document.createTextNode(options.stylesheet));
  409. }
  410. }
  411. var cssregex = new RegExp(options.domain + "\/(.*?)\"?\\)");
  412. for (var l = bgnodes.length, i = 0; i < l; i++) {
  413. var src = window.getComputedStyle(bgnodes[i], null)
  414. .getPropertyValue("background-image");
  415. var flags = src.match(cssregex);
  416. var bgsrc = bgnodes[i].getAttribute("data-background-src");
  417. if (flags) {
  418. var holder = parse_flags(flags[1].split("/"), options);
  419. if (holder) {
  420. render("background", bgnodes[i], holder, src);
  421. }
  422. } else if (bgsrc != null) {
  423. var holder = parse_flags(bgsrc.substr(bgsrc.lastIndexOf(options.domain) + options.domain.length + 1)
  424. .split("/"), options);
  425. if (holder) {
  426. render("background", bgnodes[i], holder, src);
  427. }
  428. }
  429. }
  430. for (l = images.length, i = 0; i < l; i++) {
  431. var attr_data_src, attr_src;
  432. attr_src = attr_data_src = src = null;
  433. try {
  434. attr_src = images[i].getAttribute("src");
  435. attr_datasrc = images[i].getAttribute("data-src");
  436. } catch (e) {}
  437. if (attr_datasrc == null && !! attr_src && attr_src.indexOf(options.domain) >= 0) {
  438. src = attr_src;
  439. } else if ( !! attr_datasrc && attr_datasrc.indexOf(options.domain) >= 0) {
  440. src = attr_datasrc;
  441. }
  442. if (src) {
  443. var holder = parse_flags(src.substr(src.lastIndexOf(options.domain) + options.domain.length + 1)
  444. .split("/"), options);
  445. if (holder) {
  446. if (holder.fluid) {
  447. render("fluid", images[i], holder, src)
  448. } else {
  449. render("image", images[i], holder, src);
  450. }
  451. }
  452. }
  453. }
  454. return app;
  455. };
  456. contentLoaded(win, function () {
  457. if (window.addEventListener) {
  458. window.addEventListener("resize", resizable_update, false);
  459. window.addEventListener("orientationchange", resizable_update, false);
  460. } else {
  461. window.attachEvent("onresize", resizable_update)
  462. }
  463. preempted || app.run();
  464. });
  465. if (typeof define === "function" && define.amd) {
  466. define([], function () {
  467. return app;
  468. });
  469. }
  470. })(Holder, window);