/**
* Text selection related functions.
*/
/**
* selection prototype
*
* Object that capsulates the selection in a textarea. Returned by DWgetSelection.
*
* @author Andreas Gohr <andi@splitbrain.org>
*/
function selection_class(){
this.start = 0;
this.end = 0;
this.obj = null;
this.rangeCopy = null;
this.scroll = 0;
this.fix = 0;
this.getLength = function(){
return this.end - this.start;
};
this.getText = function(){
return (!this.obj) ? '' : this.obj.value.substring(this.start,this.end);
};
}
/**
* Get current selection/cursor position in a given textArea
*
* @link http://groups.drupal.org/node/1210
* @author Andreas Gohr <andi@splitbrain.org>
* @link http://linebyline.blogspot.com/2006/11/textarea-cursor-position-in-internet.html
* @returns object - a selection object
*/
function DWgetSelection(textArea) {
var sel = new selection_class();
sel.obj = textArea;
sel.start = textArea.value.length;
sel.end = textArea.value.length;
textArea.focus();
if(document.getSelection) { // Mozilla et al.
sel.start = textArea.selectionStart;
sel.end = textArea.selectionEnd;
sel.scroll = textArea.scrollTop;
} else if(document.selection) { // MSIE
/*
* This huge lump of code is neccessary to work around two MSIE bugs:
*
* 1. Selections trim newlines at the end of the code
* 2. Selections count newlines as two characters
*/
// The current selection
sel.rangeCopy = document.selection.createRange().duplicate();
if (textArea.tagName === 'INPUT') {
var before_range = textArea.createTextRange();
before_range.expand('textedit'); // Selects all the text
} else {
var before_range = document.body.createTextRange();
before_range.moveToElementText(textArea); // Selects all the text
}
before_range.setEndPoint("EndToStart", sel.rangeCopy); // Moves the end where we need it
var before_finished = false, selection_finished = false;
var before_text, selection_text;
// Load the text values we need to compare
before_text = before_range.text;
selection_text = sel.rangeCopy.text;
sel.start = before_text.length;
sel.end = sel.start + selection_text.length;
// Check each range for trimmed newlines by shrinking the range by 1 character and seeing
// if the text property has changed. If it has not changed then we know that IE has trimmed
// a \r\n from the end.
do {
if (!before_finished) {
if (before_range.compareEndPoints("StartToEnd", before_range) == 0) {
before_finished = true;
} else {
before_range.moveEnd("character", -1);
if (before_range.text == before_text) {
sel.start += 2;
sel.end += 2;
} else {
before_finished = true;
}
}
}
if (!selection_finished) {
if (sel.rangeCopy.compareEndPoints("StartToEnd", sel.rangeCopy) == 0) {
selection_finished = true;
} else {
sel.rangeCopy.moveEnd("character", -1);
if (sel.rangeCopy.text == selection_text) {
sel.end += 2;
} else {
selection_finished = true;
}
}
}
} while ((!before_finished || !selection_finished));
// count number of newlines in str to work around stupid IE selection bug
var countNL = function(str) {
var m = str.split("\r\n");
if (!m || !m.length) return 0;
return m.length-1;
};
sel.fix = countNL(sel.obj.value.substring(0,sel.start));
}
return sel;
}
/**
* Set the selection
*
* You need to get a selection object via DWgetSelection() first, then modify the
* start and end properties and pass it back to this function.
*
* @link http://groups.drupal.org/node/1210
* @author Andreas Gohr <andi@splitbrain.org>
* @param {selection_class} selection a selection object as returned by DWgetSelection()
*/
function DWsetSelection(selection){
if(document.getSelection){ // FF
// what a pleasure in FF ;)
selection.obj.setSelectionRange(selection.start,selection.end);
if(selection.scroll) selection.obj.scrollTop = selection.scroll;
} else if(document.selection) { // IE
selection.rangeCopy.collapse(true);
selection.rangeCopy.moveStart('character',selection.start - selection.fix);
selection.rangeCopy.moveEnd('character',selection.end - selection.start);
selection.rangeCopy.select();
}
}
/**
* Inserts the given text at the current cursor position or replaces the current
* selection
*
* @author Andreas Gohr <andi@splitbrain.org>
* @param {string} text the new text to be pasted
* @param {selection_class} selection selection object returned by DWgetSelection
* @param {int} opts.startofs number of charcters at the start to skip from new selection
* @param {int} opts.endofs number of characters at the end to skip from new selection
* @param {boolean} opts.nosel set true if new text should not be selected
*/
function pasteText(selection,text,opts){
if(!opts) opts = {};
// replace the content
selection.obj.value =
selection.obj.value.substring(0, selection.start) + text +
selection.obj.value.substring(selection.end, selection.obj.value.length);
// set new selection
if (is_opera) {
// Opera replaces \n by \r\n when inserting text.
selection.end = selection.start + text.replace(/\r?\n/g, '\r\n').length;
} else {
selection.end = selection.start + text.length;
}
// modify the new selection if wanted
if(opts.startofs) selection.start += opts.startofs;
if(opts.endofs) selection.end -= opts.endofs;
// no selection wanted? set cursor to end position
if(opts.nosel) selection.start = selection.end;
DWsetSelection(selection);
}
/**
* Format selection
*
* Apply tagOpen/tagClose to selection in textarea, use sampleText instead
* of selection if there is none.
*
* @author Andreas Gohr <andi@splitbrain.org>
*/
function insertTags(textAreaID, tagOpen, tagClose, sampleText){
var txtarea = jQuery('#' + textAreaID)[0];
var selection = DWgetSelection(txtarea);
var text = selection.getText();
var opts;
// don't include trailing space in selection
if(text.charAt(text.length - 1) == ' '){
selection.end--;
text = selection.getText();
}
if(!text){
// nothing selected, use the sample text and select it
text = sampleText;
opts = {
startofs: tagOpen.length,
endofs: tagClose.length
};
}else{
// place cursor at the end
opts = {
nosel: true
};
}
// surround with tags
text = tagOpen + text + tagClose;
// do it
pasteText(selection,text,opts);
}
/**
* Wraps around pasteText() for backward compatibility
*
* @author Andreas Gohr <andi@splitbrain.org>
*/
function insertAtCarret(textAreaID, text){
var txtarea = jQuery('#' + textAreaID)[0];
var selection = DWgetSelection(txtarea);
pasteText(selection,text,{nosel: true});
}