Java 1996 August/Java - Summer 1996.iso/rockridge/tools/packages/classes/ImageMap.java

Java Source | 1995-11-13 | 20.1 KB | 740 lines

import browser.Applet;
import awt.DIBitmap;
import awt.Image;
import awt.Graphics;
import java.util.StringTokenizer;
import java.util.Vector;
import java.util.Hashtable;
import net.www.html.URL;

/**
 * An extensible ImageMap applet class.
 * The active areas on the image are controlled by ImageArea classes
 * that can be dynamically extended over the web.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class ImageMap extends Applet {
    /**
     * The unhighlighted image being mapped.
     */
    Image baseImage;

    /**
     * The primary highlighted image for providing user feedback.
     */
    Image hlImage;

    /**
     * The list of image area handling objects;
     */
    ImageMapArea areas[];

    /**
     * The primary highlight mode to be used.
     */
    static final int BRIGHTER = 0;
    static final int DARKER = 1;

    int hlmode = BRIGHTER;

    /**
     * The percentage of highlight to apply for the primary highlight mode.
     */
    int hlpercent = 50;

    /**
     * A Hashtable of various highlighted images for ImageAreas
     * that want a custom highlight.
     */
    Hashtable hlImages = new Hashtable();

    /**
     * Get the primary highlighted version of the baseImage.
     */
    Image getHighlight() {
    return (hlImage == null) ? makeHighlight() : hlImage;
    }

    /**
     * Get a version of the baseImage with a specific highlight.
     * Create a new highlight image if necessary.
     */
    synchronized Image getHighlight(int mode, int percent) {
    Image img = (Image) hlImages.get("HL"+mode+","+percent);
    if (img == null) {
        img = makeHighlight(mode, percent);
    }
    return img;
    }

    /**
     * Make the primary highlighted version of the baseImage.
     */
    Image makeHighlight() {
    return makeHighlight(hlmode, hlpercent);
    }

    /**
     * Create a highlighted image from a highlight mode and a percentage.
     */
    synchronized Image makeHighlight(int mode, int percent) {
    DIBitmap sourceBitmap = baseImage.getDIBitmap();

    byte newred[] = new byte[sourceBitmap.num_colors];
    byte newgreen[] = new byte[sourceBitmap.num_colors];
    byte newblue[] = new byte[sourceBitmap.num_colors];
    for (int i = 0; i < sourceBitmap.num_colors; i++) {
        if (i == sourceBitmap.trans_index) {
        newred[i] = sourceBitmap.red[i];
        newgreen[i] = sourceBitmap.green[i];
        newblue[i] = sourceBitmap.blue[i];
        } else {
        int oldred = (sourceBitmap.red[i] & 0xff);
        int oldgreen = (sourceBitmap.green[i] & 0xff);
        int oldblue = (sourceBitmap.blue[i] & 0xff);
        switch (mode) {
        case DARKER:
            newred[i] = (byte) (oldred * (100 - percent) / 100);
            newgreen[i] = (byte) (oldgreen * (100 - percent) / 100);
            newblue[i] = (byte) (oldblue * (100 - percent) / 100);
            break;
        case BRIGHTER:
            newred[i] = (byte) (255 - ((255 - oldred)
                           * (100 - percent) / 100));
            newgreen[i] = (byte) (255 - ((255 - oldgreen)
                         * (100 - percent) / 100));
            newblue[i] = (byte) (255 - ((255 - oldblue)
                        * (100 - percent) / 100));
            break;
        }
        }
    }
    DIBitmap newBitmap = new DIBitmap(sourceBitmap.width,
                      sourceBitmap.height,
                      sourceBitmap.num_colors,
                      newred, newgreen, newblue,
                      sourceBitmap.raster);
    newBitmap.trans_index = sourceBitmap.trans_index;
    Image newImage = item.parent.createImage(newBitmap);
    if (mode == hlmode && percent == hlpercent) {
        hlImage = newImage;
    }
    hlImages.put("HL"+mode+","+percent, newImage);
    return newImage;
    }

    /**
     * Parse a string representing the desired highlight to be applied.
     */
    void parseHighlight(String s) {
    if (s == null) {
        return;
    }
    if (s.startsWith("brighter")) {
        hlmode = BRIGHTER;
        if (s.length() > "brighter".length()) {
        hlpercent = Integer.parseInt(s.substring("brighter".length()));
        }
    } else if (s.startsWith("darker")) {
        hlmode = DARKER;
        if (s.length() > "darker".length()) {
        hlpercent = Integer.parseInt(s.substring("darker".length()));
        }
    }
    }

    /**
     * Initialize the applet. Get attributes.
     *
     * Initialize the ImageAreas.
     * Each ImageArea is a subclass of the class ImageArea, and is
     * specified with an attribute of the form:
     *         areaN=ImageAreaClassName,arguments...
     * The ImageAreaClassName is parsed off and a new instance of that
     * class is created.  The initializer for that class is passed a
     * reference to the applet and the remainder of the attribute
     * string, from which the class should retrieve any information it
     * needs about the area it controls and the actions it needs to
     * take within that area.
     */
    public void init() {
    String s;

    parseHighlight(getAttribute("highlight"));
    baseImage = getImage(getAttribute("img"));
    makeHighlight();
    Vector areaVec = new Vector();
    int num = 1;
    while (true) {
        ImageMapArea newArea;
        s = getAttribute("area"+num);
        if (s == null) {
        // Try rect for backwards compatibility.
        s = getAttribute("rect"+num);
        if (s == null) {
            break;
        }
        String url = getAttribute("href"+num);
        if (url != null)
            s += "," + url;
        newArea = new HrefArea();
        } else {
        int classend = s.indexOf(",");
        newArea = (ImageMapArea) new (s.substring(0, classend));
        s = s.substring(classend+1);
        }
        newArea.init(this, s);
        areaVec.addElement(newArea);
        num++;
    }
    areas = new ImageMapArea[areaVec.size()];
    areaVec.copyInto(areas);
    resize(baseImage.width, baseImage.height);
    }

    /**
     * Paint the image and all active highlights.
     */
    public void paint(Graphics g) {
    g.drawImage(baseImage, 0, 0);
    for (int i = areas.length; --i >= 0; ) {
        if (areas[i].active) {
        areas[i].setState(g, true);
        }
    }
    }

    /**
     * Update the active highlights on the image.
     */
    public void update(Graphics g) {
    // First unhighlight all of the deactivated areas
    for (int i = areas.length; --i >= 0; ) {
        if (areas[i].active && !areas[i].entered) {
        areas[i].setState(g, false);
        }
    }
    // Then highlight all of the activated areas
    for (int i = areas.length; --i >= 0; ) {
        if (areas[i].entered) {
        areas[i].setState(g, true);
        }
    }
    }

    /**
     * Make sure that no ImageAreas are highlighted.
     */
    public void mouseExit() {
    boolean changed = false;

    for (int i = 0; i < areas.length; i++) {
        if (areas[i].active) {
        areas[i].entered = false;
        changed = true;
        }
    }
    if (changed) {
        repaint();
    }
    }

    /**
     * Find the ImageAreas that the mouse is in.
     */
    public void mouseMove(int x, int y) {
    boolean changed = false;
    boolean propagate = true;

    for (int i = 0; i < areas.length; i++) {
        if (areas[i].inside(x, y)) {
        areas[i].entered = propagate;
        if (areas[i].terminal) {
            propagate = false;
        }
        } else {
        areas[i].entered = false;
        }

        if (areas[i].active != areas[i].entered) {
        changed = true;
        }
    }

    if (changed) {
        repaint();
    }
    }

    int pressX;
    int pressY;

    /**
     * Inform all active ImageAreas of a mouse press.
     */
    public void mouseDown(int x, int y) {
    pressX = x;
    pressY = y;

    for (int i = 0; i < areas.length; i++) {
        if (areas[i].inside(x, y)) {
        areas[i].press(x, y);
        if (areas[i].terminal) {
            break;
        }
        }
    }
    }

    /**
     * Inform all active ImageAreas of a mouse release.
     * Only those areas that were inside the original mouseDown()
     * are informed of the mouseUp.
     */
    public void mouseUp(int x, int y) {
    for (int i = 0; i < areas.length; i++) {
        if (areas[i].inside(pressX, pressY)) {
        areas[i].lift(x, y);
        if (areas[i].terminal) {
            break;
        }
        }
    }
    }

    /**
     * Inform all active ImageAreas of a mouse drag.
     * Only those areas that were inside the original mouseDown()
     * are informed of the mouseDrag.
     */
    public void mouseDrag(int x, int y) {
    mouseMove(x, y);
    for (int i = 0; i < areas.length; i++) {
        if (areas[i].inside(pressX, pressY)) {
        areas[i].drag(x, y);
        if (areas[i].terminal) {
            break;
        }
        }
    }
    }
}

/**
 * The base ImageArea class.
 * This class performs the basic functions that most ImageArea
 * classes will need and delegates specific actions to the subclasses.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class ImageMapArea {
    /** The Applet parent that contains this ImageArea. */
    ImageMap parent;

    /** The X location of the area (if rectangular). */
    int X;
    /** The Y location of the area (if rectangular). */
    int Y;
    /** The width of the area (if rectangular). */
    int W;
    /** The height of the area (if rectangular). */
    int H;

    /**
     * This flag indicates whether the user was in this area during the
     * last scan of mouse locations.
     */
    boolean entered = false;
    /** This flag indicates whether the area is currently highlighted. */
    boolean active = false;

    /**
     * This flag indicates whether the area is terminal.  Terminal areas
     * prevent any areas which are under them from being activated when
     * the mouse is inside them.  Some areas may wish to change this to
     * false so that they can augment other areas that they are on top of.
     */
    boolean terminal = true;

    /**
     * Initialize this ImageArea as called from the Applet.
     * If the subclass does not override this initializer, then it
     * will perform the basic functions of setting the parent applet
     * and parsing out 4 numbers from the argument string which specify
     * a rectangular region for the ImageArea to act on.
     * The remainder of the argument string is passed to the handleArg()
     * method for more specific handling by the subclass.
     */
    public void init(ImageMap parent, String args) {
    this.parent = parent;
    StringTokenizer st = new StringTokenizer(args, ", ");
    X = Integer.parseInt(st.nextToken());
    Y = Integer.parseInt(st.nextToken());
    W = Integer.parseInt(st.nextToken());
    H = Integer.parseInt(st.nextToken());
    if (st.hasMoreTokens()) {
        // hasMoreTokens() Skips the trailing comma
        handleArg(st.nextToken(""));
    } else {
        handleArg(null);
    }
    }

    /**
     * This method handles the remainder of the argument string after
     * the standard initializer has parsed off the 4 rectangular
     * parameters.  If the subclass does not override this method,
     * the remainder will be ignored.
     */
    public void handleArg(String s) {
    }

    /**
     * This method tests to see if a point is inside this ImageArea.
     * The standard method assumes a rectangular area as parsed by
     * the standard initializer.  If a more complex area is required
     * then this method will have to be overridden by the subclass.
     */
    public boolean inside(int x, int y) {
    return (x >= X && x < (X + W) && y >= Y && y < (Y + H));
    }

    /**
     * This utility method draws a rectangular subset of a highlight
     * image.
     */
    public void drawImage(Graphics g, Image img, int x, int y, int w, int h) {
    g.clipRect(x, y, w, h);
    g.drawImage(img, 0, 0);
    g.clearClip();
    }

    /**
     * This method highlights the specified area when the user enters
     * it with his mouse.  The standard highlight method is to replace
     * the indicated rectangular area of the image with the primary
     * highlighted image.
     */
    public void highlight(Graphics g, boolean on) {
    drawImage(g, on ? parent.hlImage : parent.baseImage, X, Y, W, H);
    }

    /**
     * This method changes the active state of the ImageArea, which
     * indicates whether the user is currently "inside" this area.
     * It turns around and calls the highlight method which is likely
     * to have been overridden by subclasses seeking a custom highlight.
     */
    public void setState(Graphics g, boolean on) {
    highlight(g, on);
    active = on;
    }

    /**
     * The press method is called when the user presses the mouse
     * button inside the ImageArea.  The location is supplied, but
     * the standard implementation is to call the overloaded method
     * with no arguments.
     */
    public void press(int x, int y) {
    press();
    }

    /**
     * The overloaded press method is called when the user presses the
     * mouse button inside the ImageArea.  This method can be overridden
     * if the ImageArea does not need to know the location of the press.
     */
    public void press() {
    }

    /**
     * The lift method is called when the user releases the mouse button.
     * The location is supplied, but the standard implementation is to
     * call the overloaded method with no arguments.  Only those ImageAreas
     * that were informed of a press will be informed of the corresponding
     * release.
     */
    public void lift(int x, int y) {
    lift();
    }

    /**
     * The overloaded lift method is called when the user releases the
     * mouse button.  This method can be overridden if the ImageArea
     * does not need to know the location of the release.
     */
    public void lift() {
    }

    /**
     * The drag method is called when the user moves the mouse while
     * the button is pressed.  Only those ImageAreas that were informed
     * of a press will be informed of the corresponding mouse movements.
     */
    public void drag(int x, int y) {
    }
}

/**
 * The classic "Fetch a URL" ImageArea class.
 * This class extends the basic ImageArea Class to fetch a URL when
 * the user clicks in the area.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class HrefArea extends ImageMapArea {
    /** The URL to be fetched when the user clicks on this area. */
    URL anchor;

    /**
     * The argument string is the URL to be fetched.
     */
    public void handleArg(String arg) {
    anchor = new URL(parent.documentURL, arg);
    }

    /**
     * The status message area is updated to show the destination URL.
     * The default graphics highlight feedback is used.
     */
    public void highlight(Graphics g, boolean on) {
    super.highlight(g, on);
    parent.showStatus(on ? "Go To " + anchor.toExternalForm() : null);
    }

    /**
     * The new URL is fetched when the user releases the mouse button
     * only if they are still in the area.
     */
    public void lift(int x, int y) {
    if (inside(x, y)) {
        parent.showDocument(anchor);
    }
    // Note that we should not be active, so no repaint is necessary.
    }
}

/**
 * An audio feedback ImageArea class.
 * This class extends the basic ImageArea Class to play a sound each
 * time the user enters the area.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class SoundArea extends ImageMapArea {
    /** The URL of the sound to be played. */
    String sound;

    /**
     * The argument is the URL of the sound to be played.
     * This method also sets this type of area to be non-terminal.
     */
    public void handleArg(String arg) {
    sound = arg;
    terminal = false;
    }

    /**
     * The highlight method plays the sound in addition to the usual
     * graphical highlight feedback.
     */
    public void highlight(Graphics g, boolean on) {
    super.highlight(g, on);
    if (on) {
        parent.play(sound);
    }
    }
}

/**
 * A click feedback ImageArea class.
 * This class extends the basic ImageArea Class to show the locations
 * of clicks in the image in the status message area.  This ImageArea
 * utility class is useful when setting up ImageMaps.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class ClickArea extends ImageMapArea {
    /** The X location of the last mouse press. */
    int startx;
    /** The Y location of the last mouse press. */
    int starty;

    /**
     * The argument is ignored, but we use this method to set this type
     * of area to be non-terminal.
     */
    public void handleArg(String arg) {
    terminal = false;
    }

    /** This class overrides the highlight method to prevent highlighting. */
    public void highlight(Graphics g, boolean on) {
    }

    String ptstr(int x, int y) {
    return "("+x+", "+y+")";
    }

    /**
     * When the user presses the mouse button, start showing coordinate
     * feedback in the status message line.
     */
    public void press(int x, int y) {
    parent.showStatus("Clicked at "+ptstr(x, y));
    startx = x;
    starty = y;
    }

    /**
     * Update the coordinate feedback every time the user moves the mouse
     * while he has the button pressed.
     */
    public void drag(int x, int y) {
    parent.showStatus("Rectangle from "+ptstr(startx, starty)
              +" to "+ptstr(x, y)
              +" is "+(x-startx)+"x"+(y-starty));
    }

    /**
     * Update the coordinate feedback one last time when the user releases
     * the mouse button.
     */
    public void lift(int x, int y) {
    drag(x, y);
    }
}

/**
 * A message feedback ImageArea class.
 * This class extends the basic ImageArea Class to show the a given
 * message in the status message area when the user enters this area.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class NameArea extends ImageMapArea {
    /** The string to be shown in the status message area. */
    String name;

    /**
     * The argument is the string to be displayed in the status message
     * area.  This method also sets this type of area to be non-terminal.
     */
    public void handleArg(String arg) {
    name = arg;
    terminal = false;
    }

    /**
     * The highlight method displays the message in addition to the usual
     * graphical highlight feedback.
     */
    public void highlight(Graphics g, boolean on) {
    super.highlight(g, on);
    parent.showStatus(on ? name : null);
    }

}

/**
 * An improved "Fetch a URL" ImageArea class.
 * This class extends the basic ImageArea Class to fetch a URL when
 * the user clicks in the area.  In addition, special custom highlights
 * are used to make the area look and feel like a 3-D button.
 *
 * @author     Jim Graham
 * @version     1.1, 23 Mar 1995
 */
class HrefButtonArea extends ImageMapArea {
    /** The URL to be fetched when the user clicks on this area. */
    URL anchor;

    /** The highlight image for the bright parts of the 3-D effect. */
    Image brightImage;
    /** The highlight image for the dark parts of the 3-D effect. */
    Image darkImage;
    /** The highlight image for the depressed part of the 3-D "button". */
    Image pressImage;

    /** This flag indicates if the "button" is currently pressed. */
    boolean pressed = false;

    /** The border size for the 3-D effect. */
    int border = 5;

    /**
     * The argument string is the URL to be fetched.
     * This method also constructs the various highlight images needed
     * to achieve the 3-D effect.
     */
    public void handleArg(String arg) {
    anchor = new URL(parent.documentURL, arg);
    brightImage = parent.getHighlight(parent.BRIGHTER, parent.hlpercent);
    darkImage = parent.getHighlight(parent.DARKER, parent.hlpercent);
    pressImage = parent.getHighlight(parent.DARKER, parent.hlpercent/2);
    if (border * 2 > W || border * 2 > H) {
        border = Math.min(W, H) / 2;
    }
    }

    /**
     * A utility function to draw a 3-D button wrapped with an image.
     */
    public void drawButton(Graphics g) {
    drawImage(g, pressed ? darkImage : brightImage, X, Y, W, border);
    drawImage(g, pressed ? darkImage : brightImage, X, Y, border, H);
    int R = X + W - 1;
    int B = Y + H - 1;
    if (pressed) {
        drawImage(g, pressImage,
              X+border, Y+border, W-border*2, H-border*2);
    }
    for (int i = 0; i < border; i++) {
        drawImage(g, pressed ? brightImage : darkImage, X+i, B-i, W-i, 1);
        drawImage(g, pressed ? brightImage : darkImage, R-i, Y+i, 1, H-i);
    }
    }

    /**
     * The status message area is updated to show the destination URL.
     * The graphical highlight is achieved using the drawButton method.
     */
    public void highlight(Graphics g, boolean on) {
    if (on) {
        drawButton(g);
    } else {
        super.highlight(g, false);
    }
    parent.showStatus(on ? "Go To " + anchor.toExternalForm() : null);
    }

    /**
     * Since the highlight changes when the button is pressed, we need
     * to record the "pressed" state and induce a repaint.
     */
    public void press() {
    parent.repaint();
    pressed = true;
    }

    /**
     * The new URL is fetched when the user releases the mouse button
     * only if they are still in the area.
     */
    public void lift(int x, int y) {
    pressed = false;
    if (inside(x, y)) {
        parent.showDocument(anchor);
    }
    // Note that we should not be active, so no repaint is necessary.
    }
}