Bug 161902 [JFace] Enhancements to GridLayoutFactory.margins
This enhancement requests the following: 1. Rename the new GridLayoutFactory.margins(int,int,int,int) to GridLayoutFactory.extendedMargins(int,int,int,int) 2. Add a GridLayoutFactory.extendedMargins(Rectangle) method that accepts a difference rectangle. 3. Add static methods to Geometry in order to easily construct difference rectangles. Why? 1. We should not use overloaded methods in GridLayoutFactory unless they really do set the same thing. Since the four-argument margins(...) method and the two-argument margins(...) method set independent values, we should give them different names or clients will expect a call to margins(int, int, int, int) to overwrite a previous call to margins(int, int). 2. All methods on GridLayoutFactory and GridDataFactory should have vector initializers, so that clients can store and reuse standard margin settings in a single variable. 3. Vector initializers are only a convenience if there is a convenient way to construct the vector.
bundles/org.eclipse.jface/src/org/eclipse/jface/layout/GridLayoutFactory.java
}
    /**
     * Creates a new GridLayout, and initializes it with values from the factory.
     * 
     * @return a new initialized GridLayout.
     * @see #applyTo
     */
    public GridLayout create() {
        return copyLayout(l);
    }
    /**
     * Creates a new GridLayout and attaches it to the given composite.
     * Does not create the GridData of any of the controls in the composite.
     * 
     * @param c composite whose layout will be set
     * @see #generateLayout
     * @see #create
     * @see GridLayoutFactory
     */
    public void applyTo(Composite c) {
        c.setLayout(copyLayout(l));
    }
    /**
     * Copies the given GridLayout instance
     * 
     * @param l layout to copy
     * @return a new GridLayout
     */
    public static GridLayout copyLayout(GridLayout l) {
        GridLayout result = new GridLayout(l.numColumns, l.makeColumnsEqualWidth);