} that displays a {@link Displayable
* Displayable} object. The displayable panel can then be made part
* of a Swing GUI.
*
* The displayable object is specified when the displayable panel is
* constructed. A different displayable object can be specified later using the
* display() method. The displayable panel's preferred size and the
* displayable panel's bounds are set to the size of the displayable object when
* the displayable panel is constructed and when the display() method
* is called. If the same displayable panel will be displaying different
* displayable objects, consider embedding the displayable panel in a
* JScrollPane so the whole displayable object can be scrolled into view if the
* displayable object becomes larger.
*
* The displayable panel supports zooming (scaling) the displayable object. The
* zoom factor is set when the displayable panel is constructed and when the
* zoom() method is called. The displayable panel's preferred size and
* bounds are actually those of the displayable object multiplied by the zoom
* factor.
*
* If the autofitting flag is true (see setAutofitting()), the
* displayable panel will display a scaled version of the displayable object,
* such that the displayable object is completely visible within the displayable
* panel's current size.
*
* @author Alan Kaminsky
* @version 10-Jul-2006
*/
public class DisplayablePanel
extends JPanel
{
// Hidden data members.
private Displayable myDisplayable;
private double myZoom = 1.0;
private Dimension mySize;
private boolean iamAutofitting;
// Exported constructors.
/**
* Construct a new displayable panel. The displayable panel's preferred size
* and bounds are set to the size of theDisplayable.
*
* @param theDisplayable Displayable object.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDisplayable is null.
*/
public DisplayablePanel
(Displayable theDisplayable)
{
super();
display (theDisplayable);
}
/**
* Construct a new displayable panel with the given zoom factor. The
* displayable panel's preferred size and bounds are set to the size of
* theDisplayable multiplied by theZoom.
*
* @param theDisplayable Displayable object.
* @param theZoom Zoom factor.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDisplayable is null.
* @exception IllegalArgumentException
* (unchecked exception) Thrown if theZoom <= 0.
*/
public DisplayablePanel
(Displayable theDisplayable,
double theZoom)
{
super();
zoom (theZoom);
display (theDisplayable);
}
// Exported operations.
/**
* Obtain this displayable panel's displayable object.
*
* @return Displayable object this displayable panel is displaying.
*/
public Displayable display()
{
return myDisplayable;
}
/**
* Tell this displayable panel to display the given displayable object.
*
* @param theDisplayable Displayable object.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDisplayable is null.
*/
public void display
(Displayable theDisplayable)
{
if (theDisplayable == null)
{
throw new NullPointerException();
}
myDisplayable = theDisplayable;
if (! iamAutofitting)
{
Rectangle2D box = theDisplayable.getBoundingBox();
double w = box.getWidth() * myZoom;
double h = box.getHeight() * myZoom;
Dimension size = new Dimension();
size.setSize (w, h);
setPreferredSize (size);
Rectangle bounds = getBounds();
setBounds (bounds.x, bounds.y, (int) w, (int) h);
}
repaint();
}
/**
* Obtain this displayable panel's zoom factor.
*
* @return Zoom factor.
*/
public double zoom()
{
return myZoom;
}
/**
* Specify this displayable panel's zoom factor.
*
* @param theZoom Zoom factor.
*
* @exception IllegalArgumentException
* (unchecked exception) Thrown if theZoom <= 0.
*/
public void zoom
(double theZoom)
{
if (theZoom <= 0.0) throw new IllegalArgumentException();
myZoom = theZoom;
if (myDisplayable != null) display (myDisplayable);
}
/**
* Determine whether this displayable panel is autofitting.
*
* @return True if this displayable panel is autofitting, false otherwise.
*/
public boolean isAutofitting()
{
return iamAutofitting;
}
/**
* Set this displayable panel's autofitting flag to the given value. If the
* autofitting flag is true, the displayable panel will display a scaled
* version of the displayable object, such that the displayable object is
* completely visible within the displayable panel's current size.
*
* @param autofit True to autofit, false otherwise.
*/
public void setAutofitting
(boolean autofit)
{
iamAutofitting = autofit;
repaint();
}
/**
* Paint this displayable panel into the given graphics context.
*
* @param g Graphics context.
*/
protected void paintComponent
(Graphics g)
{
super.paintComponent (g);
Graphics2D g2d = (Graphics2D) g;
// Save graphics context.
Paint oldPaint = g2d.getPaint();
RenderingHints oldHints = g2d.getRenderingHints();
AffineTransform oldTransform = g2d.getTransform();
// Turn on antialiasing.
g2d.setRenderingHint
(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setRenderingHint
(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
// Paint one way if autofitting is turned on.
if (iamAutofitting)
{
// Paint background.
Rectangle panelsize = getBounds (null);
g2d.setPaint (myDisplayable.getBackgroundPaint());
g2d.fill (panelsize);
// Determine X and Y scale factors.
double pw = panelsize.getWidth();
double ph = panelsize.getHeight();
Rectangle2D objectsize = myDisplayable.getBoundingBox();
double ow = objectsize.getWidth();
double oh = objectsize.getHeight();
double scalex = pw / ow;
double scaley = ph / oh;
// Set transform if X scale factor is smaller.
if (scalex < scaley)
{
g2d.translate (0.0, (ph - oh * scalex) * 0.5);
g2d.scale (scalex, scalex);
}
// Set transform if Y scale factor is smaller.
else
{
g2d.translate ((pw - ow * scaley) * 0.5, 0.0);
g2d.scale (scaley, scaley);
}
// Draw displayable object.
myDisplayable.draw (g2d);
}
// Paint another way if autofitting is turned off.
else
{
// Set zoom factor.
g2d.scale (myZoom, myZoom);
// Paint background.
g2d.setPaint (myDisplayable.getBackgroundPaint());
g2d.fill (myDisplayable.getBoundingBox());
// Draw displayable object.
myDisplayable.draw (g2d);
}
// Restore graphics context.
g2d.setPaint (oldPaint);
g2d.setRenderingHints (oldHints);
g2d.setTransform (oldTransform);
}
}