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 jQuery( 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                         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                         thumb = $( '<div id="mw-upload-thumbnail" class="thumb tright">' +
  44                                                 '<div class="thumbinner">' +
  45                                                         '<canvas width="' + previewSize + '" height="' + previewSize + '" ></canvas>' +
  46                                                         '<div class="thumbcaption"><div class="filename"></div><div class="fileinfo"></div></div>' +
  47                                                 '</div>' +
  48                                         '</div>' );
  49                 thumb.find( '.filename' ).text( file.name ).end()
  50                         .find( '.fileinfo' ).text( prettySize( file.size ) ).end();
  51
  52                 var     ctx = thumb.find( 'canvas' )[0].getContext( '2d' ),
  53                         spinner = new Image();
  54                 spinner.onload = function() {
  55                         ctx.drawImage( spinner, (previewSize - spinner.width) / 2,
  56                                         (previewSize - spinner.height) / 2 );
  57                 };
  58                 spinner.src = mw.config.get( 'wgScriptPath' ) + '/skins/common/images/spinner.gif';
  59                 $( '#mw-htmlform-source' ).parent().prepend( thumb );
  60
  61                 fetchPreview( file, function( dataURL ) {
  62                         var     img = new Image(),
  63                                 rotation = 0;
  64                         img.onload = function() {
  65                                 // Fit the image within the previewSizexpreviewSize box
  66                                 if ( img.width > img.height ) {
  67                                         width = previewSize;
  68                                         height = img.height / img.width * previewSize;
  69                                 } else {
  70                                         height = previewSize;
  71                                         width = img.width / img.height * previewSize;
  72                                 }
  73                                 // Determine the offset required to center the image
  74                                 dx = (180 - width) / 2;
  75                                 dy = (180 - height) / 2;
  76                                 switch ( rotation ) {
  77                                         // If a rotation is applied, the direction of the axis
  78                                         // changes as well. You can derive the values below by
  79                                         // drawing on paper an axis system, rotate it and see
  80                                         // where the positive axis direction is
  81                                         case 0:
  82                                                 x = dx;
  83                                                 y = dy;
  84                                                 break;
  85                                         case 90:
  86                                                 x = dx;
  87                                                 y = dy - previewSize;
  88                                                 break;
  89                                         case 180:
  90                                                 x = dx - previewSize;
  91                                                 y = dy - previewSize;
  92                                                 break;
  93                                         case 270:
  94                                                 x = dx - previewSize;
  95                                                 y = dy;
  96                                                 break;
  97                                 }
  98
  99                                 ctx.clearRect( 0, 0, 180, 180 );
 100                                 ctx.rotate( rotation / 180 * Math.PI );
 101                                 ctx.drawImage( img, x, y, width, height );
 102
 103                                 // Image size
 104                                 var info = mw.msg( 'widthheight', img.width, img.height ) +
 105                                         ', ' + prettySize( file.size );
 106                                 $( '#mw-upload-thumbnail .fileinfo' ).text( info );
 107                         };
 108                         img.src = dataURL;
 109                 } );
 110         }
 111
 112         /**
 113          * Start loading a file into memory; when complete, pass it as a
 114          * data URL to the callback function.
 115          *
 116          * @param {File} file
 117          * @param {function} callback
 118          */
 119         function fetchPreview( file, callback ) {
 120                 var reader = new FileReader();
 121                 reader.onload = function() {
 122                         callback( reader.result );
 123                 };
 124                 reader.readAsDataURL( file );
 125         }
 126
 127         /**
 128          * Format a file size attractively.
 129          * @todo match numeric formatting
 130          *
 131          * @param {number} s
 132          * @return string
 133          */
 134         function prettySize( s ) {
 135                 var sizes = ['size-bytes', 'size-kilobytes', 'size-megabytes', 'size-gigabytes'];
 136                 while ( s >= 1024 && sizes.length > 1 ) {
 137                         s /= 1024;
 138                         sizes = sizes.slice( 1 );
 139                 }
 140                 return mw.msg( sizes[0], Math.round( s ) );
 141         }
 142
 143         /**
 144          * Clear the file upload preview area.
 145          */
 146         function clearPreview() {
 147                 $( '#mw-upload-thumbnail' ).remove();
 148         }
 149
 150
 151         if ( hasFileAPI() ) {
 152                 // Update thumbnail when the file selection control is updated.
 153                 $( '#wpUploadFile' ).change( function() {
 154                         clearPreview();
 155                         if ( this.files && this.files.length ) {
 156                                 // Note: would need to be updated to handle multiple files.
 157                                 var file = this.files[0];
 158                                 if ( fileIsPreviewable( file ) ) {
 159                                         showPreview( file );
 160                                 }
 161                         }
 162                 } );
 163         }
 164 } );