resources/mediawiki.special/mediawiki.special.upload.js

   1 /*
   2  * JavaScript for Special:Upload
   3  * Note that additional code still lives in skins/common/upload.js
   4  */
   5
   6 $(function() {
   7         /**
   8          * Is the FileAPI available with sufficient functionality?
   9          */
  10         function hasFileAPI() {
  11                 return (typeof window.FileReader != "undefined");
  12         }
  13
  14         /**
  15          * Check if this is a recognizable image type...
  16          * Also excludes files over 10M to avoid going insane on memory usage.
  17          *
  18          * @todo is there a way we can ask the browser what's supported in <img>s?
  19          *
  20          * @param {File} file
  21          * @return boolean
  22          */
  23         function fileIsPreviewable(file) {
  24                 var known = ['image/png', 'image/gif', 'image/jpeg', 'image/svg+xml'];
  25                 var tooHuge = 10 * 1024 * 1024;
  26                 return ($.inArray(file.type, known) != -1) && (file.size > 0) && (file.size < tooHuge);
  27         }
  28
  29         /**
  30          * Show a thumbnail preview of PNG, JPEG, GIF, and SVG files prior to upload
  31          * in browsers supporting HTML5 FileAPI.
  32          *
  33          * As of this writing, known good:
  34          * - Firefox 3.6+
  35          * - Chrome 7.something
  36          *
  37          * @todo check file size limits and warn of likely failures
  38          *
  39          * @param {File} file
  40          */
  41         function showPreview(file) {
  42                 var previewSize = 180;
  43
  44                 var thumb = $("<div id='mw-upload-thumbnail' class='thumb tright'>" +
  45                                             "<div class='thumbinner'>" +
  46                                               "<canvas width=" + previewSize + " height=" + previewSize + " ></canvas>" +
  47                                               "<div class='thumbcaption'><div class='filename'></div><div class='fileinfo'></div></div>" +
  48                                             "</div>" +
  49                                           "</div>");
  50                 thumb.find('.filename').text(file.name).end()
  51                      .find('.fileinfo').text(prettySize(file.size)).end();
  52
  53                 var ctx = thumb.find('canvas')[0].getContext('2d');
  54                 var spinner = new Image();
  55                 spinner.onload = function () {
  56                         ctx.drawImage( spinner, (previewSize - spinner.width) / 2,
  57                                         (previewSize - spinner.height) / 2 );
  58                 };
  59                 spinner.src = wgScriptPath + '/skins/common/images/spinner.gif';
  60                 $('#mw-htmlform-source').parent().prepend(thumb);
  61
  62                 fetchPreview(file, function(dataURL) {
  63                         var img = new Image();
  64                         var rotation = 0;
  65                         img.onload = function() {
  66                                 // Fit the image within the previewSizexpreviewSize box
  67                                 if ( img.width > img.height ) {
  68                                         width = previewSize;
  69                                         height = img.height / img.width * previewSize;
  70                                 } else {
  71                                         height = previewSize;
  72                                         width = img.width / img.height * previewSize;
  73                                 }
  74                                 // Determine the offset required to center the image
  75                                 dx = (180 - width) / 2;
  76                                 dy = (180 - height) / 2;
  77                                 switch (rotation) {
  78                                         // If a rotation is applied, the direction of the axis
  79                                         // changes as well. You can derive the values below by
  80                                         // drawing on paper an axis system, rotate it and see
  81                                         // where the positive axis direction is
  82                                         case 0:
  83                                                 x = dx;
  84                                                 y = dy;
  85                                                 break;
  86                                         case 90:
  87                                                 x = dx;
  88                                                 y = dy - previewSize;
  89                                                 break;
  90                                         case 180:
  91                                                 x = dx - previewSize;
  92                                                 y = dy - previewSize;
  93                                                 break;
  94                                         case 270:
  95                                                 x = dx - previewSize;
  96                                                 y = dy;
  97                                                 break;
  98                                 }
  99
 100                                 ctx.clearRect( 0, 0, 180, 180 );
 101                                 ctx.rotate( rotation / 180 * Math.PI );
 102                                 ctx.drawImage( img, x, y, width, height );
 103
 104                                 // Image size
 105                                 var info = mediaWiki.msg('widthheight', img.width, img.height) +
 106                                         ', ' + prettySize(file.size);
 107                                 $('#mw-upload-thumbnail .fileinfo').text(info);
 108                         }
 109                         img.src = dataURL;
 110                 });
 111         }
 112
 113         /**
 114          * Start loading a file into memory; when complete, pass it as a
 115          * data URL to the callback function.
 116          *
 117          * @param {File} file
 118          * @param {function} callback
 119          */
 120         function fetchPreview(file, callback) {
 121                 var reader = new FileReader();
 122                 reader.onload = function() {
 123                         callback(reader.result);
 124                 };
 125                 reader.readAsDataURL(file);
 126         }
 127
 128         /**
 129          * Format a file size attractively.
 130          * @todo match numeric formatting
 131          *
 132          * @param {number} s
 133          * @return string
 134          */
 135         function prettySize(s) {
 136                 var sizes = ['size-bytes', 'size-kilobytes', 'size-megabytes', 'size-gigabytes'];
 137                 while (s >= 1024 && sizes.length > 1) {
 138                         s /= 1024;
 139                         sizes = sizes.slice(1);
 140                 }
 141                 return mediaWiki.msg(sizes[0], Math.round(s))
 142         }
 143
 144         /**
 145          * Clear the file upload preview area.
 146          */
 147         function clearPreview() {
 148                 $('#mw-upload-thumbnail').remove();
 149         }
 150
 151
 152         if (hasFileAPI()) {
 153                 // Update thumbnail when the file selection control is updated.
 154                 $('#wpUploadFile').change(function() {
 155                         clearPreview();
 156                         if (this.files && this.files.length) {
 157                                 // Note: would need to be updated to handle multiple files.
 158                                 var file = this.files[0];
 159                                 if (fileIsPreviewable(file)) {
 160                                         showPreview(file);
 161                                 }
 162                         }
 163                 });
 164         }
 165 });