Description Sandip Chitale 2009-03-29 14:50:27 EDT

In a text widget such as StyledText the selection can be a forward or backward selection. What I mean by that is that the caret may be positioned at the beginning or at the end of the selection range. However sometimes one needs to move the caret to the other end of the selection to further extend it at that end. To do this one needs to be able to move the caret to the other end of the selection. This is similar to Eclipse's exchange-dot-and-mark command.

I know there is Set, Swap and Clear Mark commands but they do not seem to relate to selection.

Here is how the code may look like:

/**
* Reverses the direction of selection by moving the caret to the other
* end of the selection.
*/
void doReverseSelectionDirection() {
    // check if selection has reversed direction
    if (caretOffset == selection.x) {
        // Change the direction to forward
	setSelection(selection.x, selection.y);
    } else {
        // Change the direction to backward
        setSelection(selection.y, selection.x);
    }
}

Suggested action constant in org.eclipse.swt.custom.ST :

public static final int SELECT_REVERSE_DIRECTION = /* something platform specific that makes sense. CTRL+X CTRL+X in Emacs profile of Eclipse. */;