How to scale selections?

[Michael Thaler]

Hello,

I just tried what happens when I scale an image with a selection with my 
scaling code. What happens is, that the selection is just untouched (however 
it is extended to the new image size). If the selection is really only a 
layer, it should be straight-forward to scale it, too. How can I do this?

The relevant code that iterates over all layers is in kis_image.cc:

void KisImage::scale(double sx, double sy, KisProgressDisplayInterface 
*m_progress, enumFilterType ftype)
{
 	kdDebug(DBG_AREA_CORE) << "KisImage::scale. SX: "
 		  << sx
 		  << ", SY:"
 		  << sy
 		  << "\n";

	if (m_layers.empty()) return; // Nothing to scale

	// New image size. XXX: Pass along to discourage rounding errors?
	Q_INT32 w, h;
	w = (Q_INT32)(( width() * sx) + 0.5);
	h = (Q_INT32)(( height() * sy) + 0.5);

	if (w != width() || h != height()) {

		undoAdapter() -> beginMacro("Scale image");

		vKisLayerSP_it it;
		for ( it = m_layers.begin(); it != m_layers.end(); ++it ) {
			KisLayerSP layer = (*it);
			KisTransaction *cmd = 0;

			if (undoAdapter() -> undo()) {
				cmd = new KisTransaction("", layer.data());
				Q_CHECK_PTR(cmd);
			}

			layer -> scale(sx, sy, m_progress, ftype);

			if (undoAdapter() -> undo()) {
				undoAdapter() -> addCommand(cmd);
			}
		}

		undoAdapter() -> addCommand(new KisResizeImageCmd(m_adapter, this, w, h, 
width(), height()));

		m_width = w;
		m_height = h;

		m_projection = new KisLayer(this, "projection", OPACITY_OPAQUE);
		Q_CHECK_PTR(m_projection);

		m_bkg = new KisBackground(this, w, h);
		Q_CHECK_PTR(m_bkg);

		undoAdapter() -> endMacro();

		emit sizeChanged(KisImageSP(this), w, h);
	}
}


How can I add the selection layer here?

Greetings,
Michael