standarddrawingview.java

来自「开源（Open Source）项目JHotDraw的文档和源程序」· Java 代码 · 共 690 行 · 第 1/2 页

        Enumeration k = selectionHandles();
        while (k.hasMoreElements()) {
            handle = (Handle) k.nextElement();
            if (handle.containsPoint(x, y))
                return handle;
        }
        return null;
    }

    /**
     * Informs that the current selection changed.
     * By default this event is forwarded to the
     * drawing editor.
     */
    protected void selectionChanged() {
        fEditor.selectionChanged(this);
    }

    /**
     * Gets the position of the last click inside the view.
     */
    public Point lastClick() {
        return fLastClick;
    }

    /**
     * Sets the grid spacing that is used to constrain points.
     */
    public void setConstrainer(PointConstrainer c) {
        fConstrainer = c;
    }

    /**
     * Gets the current constrainer.
     */
    public PointConstrainer getConstrainer() {
        return fConstrainer;
    }

    /**
     * Constrains a point to the current grid.
     */
    protected Point constrainPoint(Point p) {
        // constrin to view size
        Dimension size = getSize();
        //p.x = Math.min(size.width, Math.max(1, p.x));
        //p.y = Math.min(size.height, Math.max(1, p.y));
        p.x = Geom.range(1, size.width, p.x);
        p.y = Geom.range(1, size.height, p.y);

        if (fConstrainer != null )
            return fConstrainer.constrainPoint(p);
        return p;
	}

    /**
     * Handles mouse down events. The event is delegated to the
     * currently active tool.
     * @return whether the event was handled.
     */
    public void mousePressed(MouseEvent e) {
        requestFocus(); // JDK1.1
        Point p = constrainPoint(new Point(e.getX(), e.getY()));
        fLastClick = new Point(e.getX(), e.getY());
        tool().mouseDown(e, p.x, p.y);
        checkDamage();
    }

    /**
     * Handles mouse drag events. The event is delegated to the
     * currently active tool.
     * @return whether the event was handled.
     */
    public void mouseDragged(MouseEvent e) {
        Point p = constrainPoint(new Point(e.getX(), e.getY()));
        tool().mouseDrag(e, p.x, p.y);
        checkDamage();
    }

    /**
     * Handles mouse move events. The event is delegated to the
     * currently active tool.
     * @return whether the event was handled.
     */
    public void mouseMoved(MouseEvent e) {
        tool().mouseMove(e, e.getX(), e.getY());
    }

    /**
     * Handles mouse up events. The event is delegated to the
     * currently active tool.
     * @return whether the event was handled.
     */
    public void mouseReleased(MouseEvent e) {
        Point p = constrainPoint(new Point(e.getX(), e.getY()));
        tool().mouseUp(e, p.x, p.y);
        checkDamage();
    }

    /**
     * Handles key down events. Cursor keys are handled
     * by the view the other key events are delegated to the
     * currently active tool.
     * @return whether the event was handled.
     */
    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if ((code == KeyEvent.VK_BACK_SPACE) || (code == KeyEvent.VK_DELETE)) {
            Command cmd = new DeleteCommand("Delete", this);
            cmd.execute();
        } else if (code == KeyEvent.VK_DOWN || code == KeyEvent.VK_UP ||
            code == KeyEvent.VK_RIGHT || code == KeyEvent.VK_LEFT) {
            handleCursorKey(code);
        } else {
            tool().keyDown(e, code);
        }
        checkDamage();
    }

    /**
     * Handles cursor keys by moving all the selected figures
     * one grid point in the cursor direction.
     */
    protected void handleCursorKey(int key) {
        int dx = 0, dy = 0;
        int stepX = 1, stepY = 1;
        // should consider Null Object.
        if (fConstrainer != null) {
            stepX = fConstrainer.getStepX();
            stepY = fConstrainer.getStepY();
        }

        switch (key) {
        case KeyEvent.VK_DOWN:
            dy = stepY;
            break;
        case KeyEvent.VK_UP:
            dy = -stepY;
            break;
        case KeyEvent.VK_RIGHT:
            dx = stepX;
            break;
        case KeyEvent.VK_LEFT:
            dx = -stepX;
            break;
        }
        moveSelection(dx, dy);
    }


    private void moveSelection(int dx, int dy) {
        FigureEnumeration figures = selectionElements();
        while (figures.hasMoreElements())
            figures.nextFigure().moveBy(dx, dy);
        checkDamage();
    }

    /**
     * Refreshes the drawing if there is some accumulated damage
     */
    public synchronized void checkDamage() {
        Enumeration each = drawing().drawingChangeListeners();
        while (each.hasMoreElements()) {
            Object l = each.nextElement();
            if (l instanceof DrawingView) {
                ((DrawingView)l).repairDamage();
            }
        }
    }

    public void repairDamage() {
        if (fDamage != null) {
            repaint(fDamage.x, fDamage.y, fDamage.width, fDamage.height);
            fDamage = null;
        }
    }

    public void drawingInvalidated(DrawingChangeEvent e) {
        Rectangle r = e.getInvalidatedRectangle();
        if (fDamage == null)
            fDamage = r;
        else
            fDamage.add(r);
    }

    public void drawingRequestUpdate(DrawingChangeEvent e) {
        repairDamage();
    }

    /**
     * Updates the drawing view.
     */
    public void update(Graphics g) {
        paint(g);
    }

    /**
     * Paints the drawing view. The actual drawing is delegated to
     * the current update strategy.
     * @see Painter
     */
    public void paint(Graphics g) {
        fUpdateStrategy.draw(g, this);
    }

    /**
     * Draws the contents of the drawing view.
     * The view has three layers: background, drawing, handles.
     * The layers are drawn in back to front order.
     */
    public void drawAll(Graphics g) {
        boolean isPrinting = g instanceof PrintGraphics;
        drawBackground(g);
        if (fBackgrounds != null && !isPrinting)
            drawPainters(g, fBackgrounds);
        drawDrawing(g);
        if (fForegrounds != null && !isPrinting)
            drawPainters(g, fForegrounds);
        if (!isPrinting)
            drawHandles(g);
    }

    /**
     * Draws the currently active handles.
     */
    public void drawHandles(Graphics g) {
        Enumeration k = selectionHandles();
        while (k.hasMoreElements())
            ((Handle) k.nextElement()).draw(g);
    }

    /**
     * Draws the drawing.
     */
    public void drawDrawing(Graphics g) {
        fDrawing.draw(g);
    }

    /**
     * Draws the background. If a background pattern is set it
     * is used to fill the background. Otherwise the background
     * is filled in the background color.
     */
    public void drawBackground(Graphics g) {
        g.setColor(getBackground());
        g.fillRect(0, 0, getBounds().width, getBounds().height);
    }

    private void drawPainters(Graphics g, Vector v) {
        for (int i = 0; i < v.size(); i++)
            ((Painter)v.elementAt(i)).draw(g, this);
    }

    /**
     * Adds a background.
     */
    public void addBackground(Painter painter)  {
        if (fBackgrounds == null)
            fBackgrounds = new Vector(3);
        fBackgrounds.addElement(painter);
        repaint();
    }

    /**
     * Removes a background.
     */
    public void removeBackground(Painter painter)  {
        if (fBackgrounds != null)
            fBackgrounds.removeElement(painter);
        repaint();
    }

    /**
     * Removes a foreground.
     */
    public void removeForeground(Painter painter)  {
        if (fForegrounds != null)
            fForegrounds.removeElement(painter);
        repaint();
    }

    /**
     * Adds a foreground.
     */
    public void addForeground(Painter painter)  {
        if (fForegrounds == null)
            fForegrounds = new Vector(3);
        fForegrounds.addElement(painter);
        repaint();
    }

    /**
     * Freezes the view by acquiring the drawing lock.
     * @see Drawing#lock
     */
    public void freezeView() {
        drawing().lock();
    }

    /**
     * Unfreezes the view by releasing the drawing lock.
     * @see Drawing#unlock
     */
    public void unfreezeView() {
        drawing().unlock();
    }

    private void readObject(ObjectInputStream s)
        throws ClassNotFoundException, IOException {

        s.defaultReadObject();

        fSelection = new Vector(); // could use lazy initialization instead
        if (fDrawing != null)
            fDrawing.addDrawingChangeListener(this);
    }

    private void checkMinimumSize() {
        FigureEnumeration k = drawing().figures();
        Dimension d = new Dimension(0, 0);
        while (k.hasMoreElements()) {
            Rectangle r = k.nextFigure().displayBox();
            d.width = Math.max(d.width, r.x+r.width);
            d.height = Math.max(d.height, r.y+r.height);
        }
        if (fViewSize.height < d.height || fViewSize.width < d.width) {
            fViewSize.height = d.height+10;
            fViewSize.width = d.width+10;
            setSize(fViewSize);
        }
    }

    public boolean isFocusTraversable() {
        return true;
    }

    // listener methods we are not interested in
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}
    public void mouseClicked(MouseEvent e) {}
    public void keyTyped(KeyEvent e) {}
    public void keyReleased(KeyEvent e) {}
}