[Gzz] PEG ``vob_bgvob--humppake``: Background Vob interface

[Asko Soukka]

=====================================================
PEG ``vob_bgvob--humppake``: Background Vob interface
=====================================================

:Authors:   Asko Soukka
:Stakeholders: Benja Fallenstein, Tuomas Lukka 
:Date-created: 2003-03-05
:Last-Modified: $Date: 2003/03/05 16:12:13 $
:Revision: $Revision: 1.1 $
:Status:   Current
:Scope:    Trivial
:Type:     Feature

This PEG proposes of creating **Background Vob interface**, which at
first includes the border flag and color handling originally made for
``RectBgVob``. The new interface allows the easy use of different
(*Background*) Vobs in a single View.

Issues
------

- How interface should be named?

  RESOLVED: Interface ``BgVob``

- Where it will be located?

  RESOLVED: Currently at ``gzz.vob.BgVob``, probably in the
  future at ``org.libvob.vob.BgVob``.

- What should interface ``BgVob`` contain?

  RESOLVED: At first it should containt the handling of background 
  color and *solid colors* from ``RectBgVob``. Those are currently
  also copied to ``ColoredSectorVob``.

- How should *solids* be renamed?

  RESOLVED: *cellColors* has been proposed, but now we are
  moving away from *cells* to *nodes*. Therefore *solids* could
  be called simply *colors*. Already the method adding them
  have been called *addColor*.

- Should we use an *array* or *Vector* to store *colors*?

  RESOLVED: We should use ``java.util.Vector`` if it's performance
  is not a problem. Currently ``RectBgVob`` uses array and resizing
  it needs additional work. Also those AWT tools, which have used Vobs'
  ``java.awt.Color`` arrays are already moved to ``basalt``. Though, the
  content of vector could still be passed on in an array.
  
Changes
-------

Interface BgVob with following attributes and methods will
be created::

    /** Flag for drawing border. */
    public boolean drawBorder = true;

    /** Vector to store Colors. */
    protected Vector colors = new Vector(5, 5);
        
    /** Background color of the Vob */
    protected Color bg = Color.white;

    /** Set the background color of the Vob */
    public void setBg(Color c){ if( c != null ) bg = c; }

    /** @return the background color of the Vob */
    public Color getBg() { return bg; }

    /** Adds one more color to be drawn inside the Vob. */
    public void addColor(Color c) {
        if (Color != null) colors.addElement(c);
    }

    /** The currently put node colors.
     * @return an array of Colors or null if no colors is set. 
     */
    public Color[] getColors() {
        if (colors.size() == 0) return null;
        Color[] c = new Color[colors.size()];
        for (i=0; i<colors.size(); i++)
            c[i] = (Color)colors.elementAt(i);
        return c; 
    }

Current vobs should be changed to implement this interface
(``RectBgVob`` and ``ColoredSectorVob``). Also many other Vobs should
be changed to use a new Color Vector instead of old *nsolids* color
counter and *solids* Color array. No ``CellViews`` or ``NodeViews``
should be broken after this change, since RectBgVob's addColor
interface remains same. Although, at least Loom's ``NodeViews`` should
be build using ``BgVob`` instead of ``RectBgVob`` or any other particular
Vob.

-- 
Asko Soukka <address@hidden>
<http://www.iki.fi/asko.soukka/>