Package org.emrick.project

Class PanningMouseAdapter

java.lang.Object

java.awt.event.MouseAdapter

org.emrick.project.PanningMouseAdapter

All Implemented Interfaces:

MouseListener, MouseMotionListener, MouseWheelListener, EventListener

class PanningMouseAdapter
extends MouseAdapter

Scroll-click drag panning adapter implementation Provides smooth, precise panning of Swing components using the scroll-click (middle mouse button) This implementation directly manipulates the viewport position to ensure content moves exactly with the mouse cursor, providing the most natural panning experience

Field Summary

Fields

Modifier and Type	Field	Description
private Runnable	afterPanAction
private final JComponent	component
private Point	holdPoint
private final JScrollPane	scrollPane

Constructor Summary

Constructors

Constructor	Description
PanningMouseAdapter(JComponent component, JScrollPane scrollPane)	Creates a new panning adapter for the specified component and scroll pane
PanningMouseAdapter(JComponent component, JScrollPane scrollPane, Runnable afterPanAction)	Creates a new panning adapter with a callback that runs after each pan movement

Method Summary

Modifier and Type	Method	Description
private void	initializeListeners()	Safely initialize the mouse listeners to avoid "leaking this" warning
void	mouseDragged(MouseEvent e)
void	mousePressed(MouseEvent e)
void	mouseReleased(MouseEvent e)
static MouseAdapter	passMiddleMouseEvents(JComponent component, JComponent target)	Makes a component transparent to middle mouse events and passes them through to a target component.

Methods inherited from class java.awt.event.MouseAdapter

mouseClicked, mouseEntered, mouseExited, mouseMoved, mouseWheelMoved

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

component

private final JComponent component

scrollPane

private final JScrollPane scrollPane

holdPoint

private Point holdPoint

afterPanAction

private Runnable afterPanAction

Constructor Details

PanningMouseAdapter

public PanningMouseAdapter(JComponent component,
 JScrollPane scrollPane)

Creates a new panning adapter for the specified component and scroll pane

Parameters:

component - The component to enable panning for

scrollPane - The scroll pane containing the component

PanningMouseAdapter

public PanningMouseAdapter(JComponent component,
 JScrollPane scrollPane,
 Runnable afterPanAction)

Creates a new panning adapter with a callback that runs after each pan movement

Parameters:

component - The component to enable panning for

scrollPane - The scroll pane containing the component

afterPanAction - Action to run after each pan movement (e.g., repainting other components)

Method Details

initializeListeners

private void initializeListeners()

Safely initialize the mouse listeners to avoid "leaking this" warning

mousePressed

public void mousePressed(MouseEvent e)

Specified by:

mousePressed in interface MouseListener

Overrides:

mousePressed in class MouseAdapter

mouseReleased

public void mouseReleased(MouseEvent e)

Specified by:

mouseReleased in interface MouseListener

Overrides:

mouseReleased in class MouseAdapter

mouseDragged

public void mouseDragged(MouseEvent e)

Specified by:

mouseDragged in interface MouseMotionListener

Overrides:

mouseDragged in class MouseAdapter

passMiddleMouseEvents

public static MouseAdapter passMiddleMouseEvents(JComponent component,
 JComponent target)

Makes a component transparent to middle mouse events and passes them through to a target component. This allows clicking through widgets like buttons and labels to enable panning on the underlying component.

Parameters:

component - The component to make transparent to middle mouse events

target - The target component to which events should be forwarded

Returns:

The MouseAdapter that was added to the component for event forwarding