PaintableObject.java

/*******************************************************************************
 * Copyright (c) Gil Barash - chookapp@yahoo.com
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Gil Barash - initial API and implementation
 *******************************************************************************/
package com.chookapp.org.bracketeer.core;

import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Position;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;


public abstract class PaintableObject
{
    protected Position _position;
    protected RGB _foreground;
    protected RGB _background;
    
    public PaintableObject(Position position, RGB foreground, RGB background)
    {
        _position = position;
        _foreground = foreground;
        _background = background;
    }

    public Position getPosition()
    {
        return _position;
    }

    public RGB getForeground()
    {
        return _foreground;
    }

    public RGB getBackground()
    {
        return _background;
    }
    
    @Override
    public boolean equals(Object obj)
    {
        if( !(obj instanceof PaintableObject))
            return false;
        
        PaintableObject other = (PaintableObject) obj;
        
        boolean eq = true;
        eq &= _position.equals(other._position);
        eq &= equalNulls(_foreground, other._foreground);
        eq &= equalNulls(_background, other._background);
        
        return  eq;
    }

    private boolean equalNulls(Object obj1, Object obj2)
    {
        if( (obj1 == null) ^ (obj2 == null) )
            return false;
        if( obj1 != null )
            return obj1.equals(obj2);
        return true;
    }

    public void paint(GC gc, StyledText st, IDocument doc, IRegion widgetRange, Rectangle rect)
    {
        if(_position.isDeleted || _position.length == 0)
            return;
        
        if( widgetRange == null )
            return;
   
        Color bg = null, fg = null;
        Color oldBackground = null, oldForeground = null;
        
        if( _background != null )
        {
            bg = new Color(Display.getDefault(), _background);
            oldBackground = gc.getBackground();
            gc.setBackground(bg);
        }
        
        if( _foreground != null )
        {
            fg = new Color(Display.getDefault(), _foreground);
            oldForeground = gc.getForeground();
            gc.setForeground(fg);
        }
        
        innerPaint(gc, st, doc, widgetRange, rect);
        
        if( _background != null )
        {
            gc.setBackground(oldBackground);
            bg.dispose();
        }
        if( _foreground != null )
        {
            gc.setForeground(oldForeground);                
            fg.dispose();
        }
        
    }

    protected abstract void innerPaint(GC gc, StyledText st, IDocument doc,
                                       IRegion widgetRange, Rectangle rect);    
   
}