ImageContext.java

/*
 * @(#)ImageContext.java
 *
 * $Date: 2014-05-04 18:08:30 +0200 (V, 04 máj. 2014) $
 *
 * Copyright (c) 2014 by Jeremy Wood.
 * All rights reserved.
 *
 * The copyright of this software is owned by Jeremy Wood. 
 * You may not use, copy or modify this software, except in  
 * accordance with the license agreement you entered into with  
 * Jeremy Wood. For details see accompanying license terms.
 * 
 * This software is probably, but not necessarily, discussed here:
 * https://javagraphics.java.net/
 * 
 * That site should also contain the most recent official version
 * of this software.  (See the SVN repository for more details.)
 */
package com.bric.image;

import java.awt.RenderingHints;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.util.HashMap;

/** This context paints a BufferedImage using 4 corner points.
 * <p>As of this writing: this is only expected to support RGB or ARGB images.
 * <p>(The standard <code>java.awt.Graphics2D</code> supports
 * <code>AffineTransforms</code>, which effectively use 3 corner points.
 * Using a 4th point is mathematically harder to do, but is considered
 * crucial for projecting a plane as if in a 3D view. The
 * <code>PerspectiveTransform</code> class generally handles the math
 * of the transform itself.)
 */
public abstract class ImageContext {
	
	/** Create an <code>ImageContext</code> for a <code>BufferedImage</code>.
	 * <p>This is shorthand for:
	 * <br><code>ImageContextFactory.get().create(image)</code>
	 */
	public static ImageContext create(BufferedImage image) {
		return ImageContextFactory.get().create(image);
	}
	
	/** The currently defined RenderingHints.
	 * 
	 */
	protected RenderingHints renderingHints = new RenderingHints(new HashMap<RenderingHints.Key, Object>());
	
	public abstract void drawImage(BufferedImage img,Point2D topLeft,Point2D topRight,Point2D bottomRight,Point2D bottomLeft);
	
	public abstract void dispose();
	
	/** Define a rendering hint. */
	public void setRenderingHint(RenderingHints.Key key,Object value) {
		if(value==null) renderingHints.remove(key);
		renderingHints.put(key, value);
	}
	
	/** Replace all current rendering hints with the argument. */
	public void setRenderingHints(RenderingHints hints) {
		renderingHints = new RenderingHints(new HashMap<RenderingHints.Key, Object>());
		renderingHints.putAll(hints);
	}
	
	/** Return the interpolation rendering hint to use. This will not
	 * return null. If this is undefined, then the antialiasing
	 * and rendering hints are consulted (which will return either
	 * NEAREST_NEIGHBOR or BILINEAR). If nothing is defined then this
	 * returns BILINEAR.
	 */
	protected Object getInterpolationRenderingHint() {
		Object v = renderingHints.get(RenderingHints.KEY_INTERPOLATION);
		if(v!=null) return v;
		
		v = renderingHints.get(RenderingHints.KEY_ANTIALIASING);
		if(RenderingHints.VALUE_ANTIALIAS_ON.equals(v)) {
			return RenderingHints.VALUE_INTERPOLATION_BILINEAR;
		} else if(RenderingHints.VALUE_ANTIALIAS_OFF.equals(v)) {
			return RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR;
		}
		
		v = renderingHints.get(RenderingHints.KEY_RENDERING);
		if(RenderingHints.VALUE_RENDER_QUALITY.equals(v)) {
			return RenderingHints.VALUE_INTERPOLATION_BILINEAR;
		} else if(RenderingHints.VALUE_RENDER_SPEED.equals(v)) {
			return RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR;
		}
		
		//nothing is defined:
		return RenderingHints.VALUE_INTERPOLATION_BILINEAR;
	}
}