Bug 127861 [DataBinding] Mark API provisional
examples/org.eclipse.jface.examples.databinding/src/org/eclipse/jface/layout/LayoutConstants.java
private static Point dialogMargins = null;
	private static Point dialogSpacing = null;
	private static Point minButtonSize = null;
	
	private static void initializeConstants() {
		if (dialogMargins != null) {
			return;
		}
		
		GC gc = new GC(Display.getCurrent());
		gc.setFont(JFaceResources.getDialogFont());
		FontMetrics fontMetrics = gc.getFontMetrics();
		dialogMargins = new Point(Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.HORIZONTAL_MARGIN),
				Dialog.convertVerticalDLUsToPixels(fontMetrics, IDialogConstants.VERTICAL_MARGIN));
		dialogSpacing = new Point(Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.HORIZONTAL_SPACING),
				Dialog.convertVerticalDLUsToPixels(fontMetrics, IDialogConstants.VERTICAL_SPACING));
		minButtonSize  = new Point(Dialog.convertHorizontalDLUsToPixels(fontMetrics, IDialogConstants.BUTTON_WIDTH), 0);
		
		gc.dispose();
	}