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 = mw.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 mw.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 } );