source: other-projects/rsyntax-textarea/src/java/org/fife/ui/rtextarea/VolatileImageBackgroundPainterStrategy.java@ 25584

/*
 * 01/22/2005
 *
 * VolatileImageBackgroundPainterStrategy.java - Renders an RTextAreaBase's
 * background as an image using VolatileImages.
 * 
 * This library is distributed under a modified BSD license.  See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.rtextarea;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.VolatileImage;


/**
 * A strategy for painting the background of an <code>RTextAreaBase</code>
 * as an image.  The image is always stretched to completely fill the
 * <code>RTextAreaBase</code>.<p>
 *
 * A <code>java.awt.image.VolatileImage</code> is used for rendering;
 * theoretically, this should be the best image format for performance.<p>
 *
 * You can set the scaling hint used when stretching/skewing the image
 * to fit in the <code>RTextAreaBase</code>'s background via the
 * <code>setScalingHint</code> method, but keep in mind the more
 * accurate the scaling hint, the less responsive your application will
 * be when stretching the window (as that's the only time the image's
 * size is recalculated).
 *
 * @author Robert Futrell
 * @version 0.1
 * @see org.fife.ui.rtextarea.ImageBackgroundPainterStrategy
 * @see org.fife.ui.rtextarea.BufferedImageBackgroundPainterStrategy
 */
public class VolatileImageBackgroundPainterStrategy
                    extends ImageBackgroundPainterStrategy {

    private VolatileImage bgImage;


    /**
     * Constructor.
     *
     * @param ta The text area whose background we'll be painting.
     */
    public VolatileImageBackgroundPainterStrategy(RTextAreaBase ta) {
        super(ta);
    }


    /**
     * Paints the image at the specified location.  This method assumes
     * scaling has already been done, and simply paints the background
     * image "as-is."
     *
     * @param g The graphics context.
     * @param x The x-coordinate at which to paint.
     * @param y The y-coordinate at which to paint.
     */
    protected void paintImage(Graphics g, int x, int y) {
        if (bgImage != null) {
            do {
                int rc = bgImage.validate(null);//getGraphicsConfiguration());
                if (rc==VolatileImage.IMAGE_RESTORED) {
                    // FIXME:  If the image needs to be restored are its width
                    // and height still valid??  If not, we'll need to cache
                    // these values...
                    renderImage(bgImage.getWidth(), bgImage.getHeight(),
                        getScalingHint());
                }
                g.drawImage(bgImage, x,y, null);
            } while (bgImage.contentsLost());
        }
    }


    /**
     * Renders the image at the proper size into <code>bgImage</code>.
     * This method assumes that <code>bgImage</code> is not
     * <code>null</code>.
     *
     * @param width The width of the volatile image to render into.
     * @param height The height of the volatile image to render into.
     * @param hint The scaling hint to use.
     */
    protected void renderImage(int width, int height, int hint) {
        Image master = getMasterImage();
        if (master!=null) {
            do {
                Image i = master.getScaledInstance(width,height, hint);
                tracker.addImage(i, 1);
                try {
                    tracker.waitForID(1);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                    bgImage = null;
                    return;
                } finally {
                    tracker.removeImage(i, 1);
                }
                bgImage.getGraphics().drawImage(i, 0,0, null);
                tracker.addImage(bgImage, 0);
                try {
                    tracker.waitForID(0);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                    bgImage = null;
                    return;
                } finally {
                    tracker.removeImage(bgImage, 0);
                }
            } while (bgImage.contentsLost());
        } // End of if (master!=null).
        else {
            bgImage = null;
        }
    }


    /**
     * Rescales the displayed image to be the specified size.
     *
     * @param width The new width of the image.
     * @param height The new height of the image.
     * @param hint The scaling hint to use.
     */
    protected void rescaleImage(int width, int height, int hint) {
        bgImage = getRTextAreaBase().createVolatileImage(width, height);
        if (bgImage!=null)
            renderImage(width, height, hint);
    }


}