// TODO: make this a method of SikuliDocument, no need to pass document as argument
private void changeIndentation(DefaultStyledDocument doc, int linenum, int columns)
throws BadLocationException {
PreferencesUser pref = PreferencesUser.getInstance();
boolean expandTab = pref.getExpandTab();
int tabWidth = pref.getTabWidth();
if (linenum < 0) {
throw new BadLocationException("Negative line", -1);
}
Element map = doc.getDefaultRootElement();
if (linenum >= map.getElementCount()) {
throw new BadLocationException("No such line", doc.getLength() + 1);
}
if (columns == 0) {
return;
}
Element lineElem = map.getElement(linenum);
int lineStart = lineElem.getStartOffset();
int lineLength = lineElem.getEndOffset() - lineStart;
String line = doc.getText(lineStart, lineLength);
// determine current indentation and number of whitespace characters
int wsChars;
int indentation = 0;
for (wsChars = 0; wsChars < line.length(); wsChars++) {
char c = line.charAt(wsChars);
if (c == ' ') {
indentation++;
} else if (c == '\t') {
indentation += tabWidth;
} else {
break;
}
}
int newIndentation = indentation + columns;
if (newIndentation <= 0) {
doc.remove(lineStart, wsChars);
return;
}
// build whitespace string for new indentation
StringBuilder newWs = new StringBuilder(newIndentation / tabWidth + tabWidth - 1);
int ind = 0;
if (!expandTab) {
for (; ind + tabWidth <= newIndentation; ind += tabWidth) {
newWs.append('\t');
}
}
for (; ind < newIndentation; ind++) {
newWs.append(' ');
}
doc.replace(lineStart, wsChars, newWs.toString(), null);
}
