/**
* A sort of "transparent background" JFrame that:
* <p>
* - supports a "fake" transparent title bar<br>
* - give limited support for transparency to menu bar and buttons<br>
* - supports a "fake" transparent content pane (JTransparentComponent).<br>
* - can contain only lightweight components (no heavyweight).
* <p>
* It make this setting as non-opaque all added components to it's special content
* pane (a JTransparentComponent).
* <p>
* The frame itself is an undecorated JFrame: this turn of the visible title bar and
* the insets border commonly used to resize a frame. To overcome this limitation a
* FakeTitleArea container is added on the "north" portion of the JTransparentComponent
* installed as the content pane (it provide common functionality for the title bar and
* manages another small area below the title bar used for supporting a JMenuBar).
* A FakeClientArea is added to the "central" portion of the content pane, and all calls
* for adding components to the frame content pane are redirected to target it as the
* container.<br>
*
* @author francesco
*/
package transparentbackground;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowEvent;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.Border;
/**
* A sort of "transparent background" JFrame that:
* <p>
* - supports a "fake" transparent title bar<br>
* - give limited support for transparency to menu bar and buttons<br>
* - supports a "fake" transparent content pane (JTransparentComponent).<br>
* - can contain only lightweight components (no heavyweight).
* <p>
* It make this setting as non-opaque all added components to it's special content
* pane (a JTransparentComponent).
* <p>
* The frame itself is an undecorated JFrame: this turn of the visible title bar and
* the insets border commonly used to resize a frame. To overcome this limitation a
* FakeTitleArea container is added on the "north" portion of the JTransparentComponent
* installed as the content pane (it provide common functionality for the title bar and
* manages another small area below the title bar used for supporting a JMenuBar).
* A FakeClientArea is added to the "central" portion of the content pane, and all calls
* for adding components to the frame content pane are redirected to target it as the
* container.<br>
*
* @author francesco
*/
public class JGhostFrame extends JFrame
{
// TASK: Usage Examples
// 1- usage of JGhostFrame as "decorated" frame (DONE)
// 2- usage of JGhostFrame as "undecorated", with image that support alpha channels
// 3- try fancy use of JTransparentComponent as one the subcomponents used in an ordinary JFrame.
/**
* Set the global background transparency value for all frames created.
* @param transparency must be in the range 0-255 inclusive.
*/
public static void setTransparency(int transparency) {
if (transparency >= 0 && transparency <= 255)
JTransparentComponent.backgroundTransparency = transparency;
}
private static final Border STD_BORDER =
BorderFactory.createLineBorder(Color.black, 1);
private final JTransparentComponent BACKGROUND;
private final FakeTitleArea TITLE_AREA;
private final FakeClientArea CLIENT_AREA;
private final OpacityManager OPACITY_MANAGER;
// Overrided properties
boolean undecorated;
public JGhostFrame() {
super();
super.setUndecorated(true);
// Change our content pane to JTransparentComponent
BACKGROUND = new JTransparentComponent(this);
BACKGROUND.setBorder(STD_BORDER);
this.setContentPane(BACKGROUND);
// Build fake title bar
TITLE_AREA = new FakeTitleArea(this);
BACKGROUND.add("North", TITLE_AREA);
// Build fake client area
CLIENT_AREA = new FakeClientArea(this);
BACKGROUND.add("Center", CLIENT_AREA);
// initialize the Opacity Manager
OPACITY_MANAGER =
new OpacityManager(JTransparentComponent.backgroundTransparency);
}
/**
* Wrapped: the menubar is managed by the FakeTitleArea instead of
* the standard JFrame's RootPane.
*/
@Override
public void setJMenuBar(JMenuBar menubar) {
TITLE_AREA.setJMenuBar(menubar);
}
/**
* Wrapped: the menubar is managed by the FakeTitleArea instead of
* the standard JFrame's RootPane.
*/
@Override
public JMenuBar getJMenuBar() {
return TITLE_AREA.getJMenuBar();
}
/**
* Wrapped: each JComponent added must be setted non-opaque, and
* all children it contains. Only lightweight components.
*/
@Override
public Component add(Component comp) {
OPACITY_MANAGER.makeNonOpaque(comp);
CLIENT_AREA.add(comp);
return comp;
}
/**
* Wrapped: each JComponent added must be setted non-opaque, and
* all children it contains. Only lightweight components.
*/
@Override
public Component add(String name, Component comp) {
OPACITY_MANAGER.makeNonOpaque(comp);
CLIENT_AREA.add(name, comp);
return comp;
}
/**
* Wrapped: each JComponent added must be setted non-opaque, and
* all children it contains. Only lightweight components.
*/
@Override
public Component add(Component comp, int index) {
OPACITY_MANAGER.makeNonOpaque(comp);
CLIENT_AREA.add(comp, index);
return comp;
}
/**
* Wrapped: each JComponent added must be setted non-opaque, and
* all children it contains. Only lightweight components.
*/
@Override
public void add(Component comp, Object constraints) {
if (CLIENT_AREA != null) {
OPACITY_MANAGER.makeNonOpaque(comp);
CLIENT_AREA.add(comp, constraints);
}
else
super.add(comp, constraints);
}
/**
* Wrapped: each JComponent added must be setted non-opaque, and
* all children it contains. Only lightweight components.
*/
@Override
public void add(Component comp, Object constraints, int index) {
if (CLIENT_AREA != null) {
OPACITY_MANAGER.makeNonOpaque(comp);
CLIENT_AREA.add(comp, constraints, index);
}
else
super.add(comp, constraints, index);
}
/**
* Wrapped: the menubar is managed by the FakeTitleArea instead of
* the standard JFrame's RootPane.
*/
@Override
public void setUndecorated(boolean undecorate) {
if (undecorate) {
BACKGROUND.remove(TITLE_AREA);
this.validate();
}
else if (isUndecorated()) {
BACKGROUND.add("North", TITLE_AREA);
this.validate();
}
this.undecorated = undecorate;
}
/**
* Wrapped: the menubar is managed by the FakeTitleArea instead of
* the standard JFrame's RootPane.
*/
@Override
public boolean isUndecorated() {
return this.undecorated;
}
/**
* Wrapped: title bar is "faked", so JGhostFrame must explicitly
* manage title updates.
*/
@Override
public void setTitle(String title) {
super.setTitle(title);
TITLE_AREA.updateTitle(title);
}
class FakeTitleArea extends JPanel
{
private final JGhostFrame T_FRAME;
// North area is for title box; South area is for menubar panel.
private final Box TITLE_BOX;
private final JLabel LB_TITLE;
private JMenuBar menubar;
FakeTitleArea(JGhostFrame f) {
super();
setOpaque(false);
setLayout(new BorderLayout());
T_FRAME = f;
TITLE_BOX = Box.createHorizontalBox();
TITLE_BOX.setOpaque(false);
TITLE_BOX.setBorder(JGhostFrame.STD_BORDER);
MouseAdapter moveHandler = new MouseAdapter()
{
Point last = null;
Point offset = new Point();
@Override public void mouseDragged(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
Point p = e.getLocationOnScreen();
if (last != null) {
offset.x = p.x - last.x;
offset.y = p.y - last.y;
Point loc = T_FRAME.getLocationOnScreen();
T_FRAME.setLocation(loc.x + offset.x, loc.y + offset.y);
}
last = p;
}
}
@Override public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e))
last = null;
}
};
TITLE_BOX.addMouseMotionListener(moveHandler);
TITLE_BOX.addMouseListener(moveHandler);
JLabel resizer = new JLabel("[o]");
resizer.setToolTipText("resize");
MouseAdapter resizeHandler = new MouseAdapter()
{
Point last = null;
Point offset = new Point();
@Override public void mouseDragged(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
Point p = e.getPoint();
if (last != null && T_FRAME.isVisible()) {
offset.x = p.x - last.x;
offset.y = p.y - last.y;
Dimension size = T_FRAME.getSize();
int newX = size.width + offset.x;
int newY = size.height + offset.y;
T_FRAME.setSize(newX, newY);
}
last = p;
}
}
@Override public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e))
last = null;
}
};
resizer.addMouseMotionListener(resizeHandler);
resizer.addMouseListener(resizeHandler);
JLabel iconizer = new JLabel("[-]");
iconizer.setToolTipText("iconize");
iconizer.addMouseListener(new MouseAdapter() {
@Override public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e))
T_FRAME.setExtendedState(JFrame.ICONIFIED);
}
});
JLabel maximizer = new JLabel("[#]");
maximizer.setToolTipText("maximize");
maximizer.addMouseListener(new MouseAdapter() {
Rectangle bounds = null;
@Override public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
int state = T_FRAME.getExtendedState();
if ((state & JFrame.MAXIMIZED_BOTH) != JFrame.MAXIMIZED_BOTH) {
bounds = T_FRAME.getBounds(bounds);
T_FRAME.setExtendedState(JFrame.MAXIMIZED_BOTH);
}
else
T_FRAME.setBounds(bounds);
}
}
});
JLabel quitter = new JLabel("[x]");
quitter.setToolTipText("close");
quitter.addMouseListener(new MouseAdapter() {
@Override public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
WindowEvent close = new WindowEvent(T_FRAME, WindowEvent.WINDOW_CLOSING);
T_FRAME.dispatchEvent(close);
}
}
});
LB_TITLE = new JLabel();
LB_TITLE.setOpaque(false);
TITLE_BOX.add(Box.createHorizontalStrut(1));
TITLE_BOX.add(resizer);
TITLE_BOX.add(Box.createHorizontalGlue());
TITLE_BOX.add(LB_TITLE);
TITLE_BOX.add(Box.createHorizontalGlue());
TITLE_BOX.add(iconizer);
TITLE_BOX.add(Box.createHorizontalStrut(3));
TITLE_BOX.add(maximizer);
TITLE_BOX.add(Box.createHorizontalStrut(3));
TITLE_BOX.add(quitter);
TITLE_BOX.add(Box.createHorizontalStrut(1));
this.add(TITLE_BOX, BorderLayout.NORTH);
}
private void updateTitle(String title) {
LB_TITLE.setText(title);
}
/**
* Wrapped: any Component added must be setted non-opaque, and
* all children it contains, so only JComponent and its subclasses
* are allowed.
*/
public void setJMenuBar(JMenuBar menubar) {
if (menubar != null) {
OPACITY_MANAGER.makeNonOpaque(menubar);
menubar.setBorder(JGhostFrame.STD_BORDER);
this.menubar = menubar;
this.add(menubar, BorderLayout.SOUTH);
}
}
public JMenuBar getJMenuBar() {
return this.menubar;
}
}
class FakeClientArea extends JPanel
{
private final JGhostFrame T_FRAME;
FakeClientArea(JGhostFrame f) {
T_FRAME = f;
setOpaque(false);
setBorder(JGhostFrame.STD_BORDER);
// mimic a frame content pane
setLayout(new BorderLayout());
}
}
}
Ora JGhostFrame fa uso di OpacityManager per gestire le questioni relative alla trasparenza quando gli viene aggiunto (metodi add) un child component:
package transparentbackground;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.util.Stack;
import javax.swing.JComponent;
/**
* This class is an helper used during add() operation on a "ghost frame", for validation
* and opacity setting.
* <p>
* It performs validation on the component to be added because only Swing "lightweight"
* components have the setOpacity() method that enables translucency for their background.
*
* @author francesco
*/
public class OpacityManager
{
private static final String MSG_INVALID_COMPONENT =
"Only \"lightweight\" components could be added.";
/**
* utility stack of components that allow easy insertion (pushes)
* of all the children of a container
*/
private class ComponentStack
{
private Stack<Component> stack =
new Stack<Component>();
public void push(Component comp) {
stack.push(comp);
}
public Component pop() {
return stack.pop();
}
public Component peek() {
return stack.peek();
}
public boolean notEmpty() {
return !stack.empty();
}
public void pushChildren(Container container) {
for (Component c : container.getComponents())
stack.push(c);
}
public void clear() {
stack.clear();
}
}
private final ComponentStack STACK;
private final int OPACITY;
/**
* Construct an OpacityManager for a given transparency
* @param alpha the alpha value for transparency (0-255)
*/
public OpacityManager(int alpha) {
STACK = new ComponentStack();
OPACITY = alpha;
}
/**
* Validate and set the opacity for a given Component and all
* its children that have to be added to a "ghost frame"
* @param comp the candidate component
*/
public void makeNonOpaque(Component comp) {
STACK.clear();
STACK.push(comp);
while (STACK.notEmpty()) {
Component popped = STACK.pop();
//System.out.println(popped.getClass().getName());
if (popped instanceof JComponent) {
JComponent jComp = (JComponent) popped;
STACK.pushChildren(jComp);
// make non-opaque:
jComp.setOpaque(false);
// set background color alpha channel transparency
// to the same value used in the color painted above
// the screenshot. This is useful for make some
// components, like buttons, truly transparent
// (in some LnF, for example: MetalLookAndFeel)
changeBackgroundOpacity(jComp, OPACITY);
}
else if (popped instanceof Container) {
Container cont = (Container) popped;
STACK.pushChildren(cont);
String className = cont.getClass().getName();
if (! className.startsWith("javax.swing."))
throw new IllegalArgumentException(MSG_INVALID_COMPONENT);
}
else
throw new IllegalArgumentException(MSG_INVALID_COMPONENT);
}
}
private void changeBackgroundOpacity(Component comp, int alpha) {
Color col = comp.getBackground();
if (col != null)
comp.setBackground(
new Color(col.getRed(), col.getGreen(), col.getBlue(), alpha));
}
}