Merge "jquery.textSelection: Rewrite 'scrollToCaretPosition'"

diff --git a/resources/src/jquery/jquery.textSelection.js b/resources/src/jquery/jquery.textSelection.js
index 3891d6d..993a119 100644 (file)
--- a/resources/src/jquery/jquery.textSelection.js
+++ b/resources/src/jquery/jquery.textSelection.js
@@ -293,66 +293,39 @@
                         * @chainable
                         */
                        scrollToCaretPosition: function ( options ) {
-                               function getLineLength( e ) {
-                                       return Math.floor( e.scrollWidth / ( $.client.profile().platform === 'linux' ? 7 : 8 ) );
-                               }
-                               function getCaretScrollPosition( e ) {
-                                       // FIXME: This functions sucks and is off by a few lines most
-                                       // of the time. It should be replaced by something decent.
-                                       var i, j,
-                                               nextSpace,
-                                               text = e.value.replace( /\r/g, '' ),
-                                               caret = $( e ).textSelection( 'getCaretPosition' ),
-                                               lineLength = getLineLength( e ),
-                                               row = 0,
-                                               charInLine = 0,
-                                               lastSpaceInLine = 0;
-
-                                       for ( i = 0; i < caret; i++ ) {
-                                               charInLine++;
-                                               if ( text.charAt( i ) === ' ' ) {
-                                                       lastSpaceInLine = charInLine;
-                                               } else if ( text.charAt( i ) === '\n' ) {
-                                                       lastSpaceInLine = 0;
-                                                       charInLine = 0;
-                                                       row++;
-                                               }
-                                               if ( charInLine > lineLength ) {
-                                                       if ( lastSpaceInLine > 0 ) {
-                                                               charInLine = charInLine - lastSpaceInLine;
-                                                               lastSpaceInLine = 0;
-                                                               row++;
-                                                       }
-                                               }
-                                       }
-                                       nextSpace = 0;
-                                       for ( j = caret; j < caret + lineLength; j++ ) {
-                                               if (
-                                                       text.charAt( j ) === ' ' ||
-                                                       text.charAt( j ) === '\n' ||
-                                                       caret === text.length
-                                               ) {
-                                                       nextSpace = j;
-                                                       break;
-                                               }
-                                       }
-                                       if ( nextSpace > lineLength && caret <= lineLength ) {
-                                               charInLine = caret - lastSpaceInLine;
-                                               row++;
-                                       }
-                                       return ( $.client.profile().platform === 'mac' ? 13 : ( $.client.profile().platform === 'linux' ? 15 : 16 ) ) * row;
-                               }
                                return this.each( function () {
-                                       var scroll;
+                                       var
+                                               clientHeight = this.clientHeight,
+                                               origValue = this.value,
+                                               origSelectionStart = this.selectionStart,
+                                               origSelectionEnd = this.selectionEnd,
+                                               origScrollTop = this.scrollTop,
+                                               calcScrollTop;
+
                                        // Do nothing if hidden
                                        if ( !$( this ).is( ':hidden' ) ) {
-                                               if ( this.selectionStart || this.selectionStart === 0 ) {
-                                                       scroll = getCaretScrollPosition( this );
-                                                       if ( options.force || scroll < $( this ).scrollTop() ||
-                                                                       scroll > $( this ).scrollTop() + $( this ).height() ) {
-                                                               $( this ).scrollTop( scroll );
+                                               // Delete all text after the selection and scroll the textarea to the end.
+                                               // This ensures the selection is visible (aligned to the bottom of the textarea).
+                                               // Then restore the text we deleted without changing scroll position.
+                                               this.value = this.value.slice( 0, this.selectionEnd );
+                                               this.scrollTop = this.scrollHeight;
+                                               // Chrome likes to adjust scroll position when changing value, so save and re-set later.
+                                               // Note that this is not equal to scrollHeight, it's scrollHeight minus clientHeight.
+                                               calcScrollTop = this.scrollTop;
+                                               this.value = origValue;
+                                               this.selectionStart = origSelectionStart;
+                                               this.selectionEnd = origSelectionEnd;
+
+                                               if ( !options.force ) {
+                                                       // Check if all the scrolling was unnecessary and if so, restore previous position.
+                                                       // If the current position is no more than a screenful above the original,
+                                                       // the selection was previously visible on the screen.
+                                                       if ( calcScrollTop < origScrollTop && origScrollTop - calcScrollTop < clientHeight ) {
+                                                               calcScrollTop = origScrollTop;
                                                        }
                                                }
+
+                                               this.scrollTop = calcScrollTop;
                                        }
                                        $( this ).trigger( 'scrollToPosition' );
                                } );