Package panamagl.canvas

Class PixelScaleSupportAWT

java.lang.Object

panamagl.canvas.PixelScaleSupportAWT

public class PixelScaleSupportAWT
extends Object

Shared HiDPI plumbing for AWT and Swing canvases.

Reads the current pixel scale via GraphicsConfiguration.getDefaultTransform() (Java 9+) and notifies registered PixelScaleListeners when it changes. Three signals trigger a re-check:

• "graphicsConfiguration" property change — fired when the component is moved between monitors of different DPI;
• HierarchyEvent.DISPLAYABILITY_CHANGED — captures the initial value once the component is attached to a peer;
• polling on a background thread (default 200 ms) — fallback for cases where neither of the above fires (some JVMs, mixed-DPI setups).

Listeners always run on the EDT.

Field Summary

Fields

Modifier and Type	Field	Description
static final long	DEFAULT_POLL_INTERVAL_MS	Default polling interval in milliseconds.

Constructor Summary

Constructors

Constructor	Description
PixelScaleSupportAWT(Component component)
PixelScaleSupportAWT(Component component, boolean pollingEnabled, long pollIntervalMs)

Method Summary

Modifier and Type	Method	Description
void	addListener(panamagl.canvas.PixelScaleListener l)
panamagl.canvas.PixelScale	current()	Last value reported to listeners.
long	getPollIntervalMs()
boolean	isPollingEnabled()
panamagl.canvas.PixelScale	read()	Read the current pixel scale from the component's GraphicsConfiguration.
void	removeListener(panamagl.canvas.PixelScaleListener l)
void	setPollingEnabled(boolean pollingEnabled)	Enable or disable the polling fallback at runtime.
void	setPollIntervalMs(long pollIntervalMs)
void	start()	Install all listeners and start the polling thread (if enabled).
void	stop()	Remove listeners and stop polling.

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_POLL_INTERVAL_MS

public static final long DEFAULT_POLL_INTERVAL_MS

Default polling interval in milliseconds. Polling is enabled by default to cover platforms or JVMs where AWT does not publish graphicsConfiguration property change events consistently.

See Also:

• Constant Field Values

Constructor Details

PixelScaleSupportAWT

public PixelScaleSupportAWT(Component component)

PixelScaleSupportAWT

public PixelScaleSupportAWT(Component component,
 boolean pollingEnabled,
 long pollIntervalMs)

Method Details

read

public panamagl.canvas.PixelScale read()

Read the current pixel scale from the component's GraphicsConfiguration. Returns the last known value if the component is not yet displayable.

current

public panamagl.canvas.PixelScale current()

Last value reported to listeners. Updated only on the EDT.

start

public void start()

Install all listeners and start the polling thread (if enabled). Idempotent — calling twice has no effect.

stop

public void stop()

Remove listeners and stop polling. Idempotent.

addListener

public void addListener(panamagl.canvas.PixelScaleListener l)

removeListener

public void removeListener(panamagl.canvas.PixelScaleListener l)

isPollingEnabled

public boolean isPollingEnabled()

setPollingEnabled

public void setPollingEnabled(boolean pollingEnabled)

Enable or disable the polling fallback at runtime. Takes effect on the next start() call — call stop() then start() to restart the poller.

getPollIntervalMs

public long getPollIntervalMs()

setPollIntervalMs

public void setPollIntervalMs(long pollIntervalMs)