* @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' );
} );