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[Win32] Move DPI change handling from Control to Shell #2639

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Merged
merged 1 commit into from
Oct 21, 2025
Merged

[Win32] Move DPI change handling from Control to Shell #2639

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56 changes: 4 additions & 52 deletions bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Control.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.gdip.*;
import org.eclipse.swt.internal.ole.win32.*;
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.ole.win32.*;

Expand Down Expand Up @@ -80,9 +79,6 @@ public abstract class Control extends Widget implements Drawable {
int drawCount, foreground, background, backgroundAlpha = 255;
boolean autoScaleDisabled = false;

/** Cache for currently processed DPI change event to be able to cancel it if a new one is triggered */
Event currentDpiChangeEvent;

private static final String DATA_SHELL_ZOOM = "SHELL_ZOOM";

private static final String DATA_AUTOSCALE_DISABLED = "AUTOSCALE_DISABLED";
Expand Down Expand Up @@ -5014,20 +5010,6 @@ LRESULT WM_DESTROY (long wParam, long lParam) {
return null;
}

private void handleMonitorSpecificDpiChange(int newNativeZoom, Rectangle newBoundsInPixels) {
DPIUtil.setDeviceZoom (newNativeZoom);
// Do not process DPI change for child shells asynchronous to avoid relayouting when
// repositioning the child shell to a different monitor upon opening
boolean processDpiChangeAsynchronous = getShell().getParent() == null;
Event zoomChangedEvent = createZoomChangedEvent(newNativeZoom, processDpiChangeAsynchronous);
if (currentDpiChangeEvent != null) {
currentDpiChangeEvent.doit = false;
}
currentDpiChangeEvent = zoomChangedEvent;
notifyListeners(SWT.ZoomChanged, zoomChangedEvent);
this.setBoundsInPixels(newBoundsInPixels.x, newBoundsInPixels.y, newBoundsInPixels.width, newBoundsInPixels.height);
}

Event createZoomChangedEvent(int zoom, boolean asyncExec) {
Event event = new Event();
event.type = SWT.ZoomChanged;
Expand All @@ -5040,38 +5022,12 @@ Event createZoomChangedEvent(int zoom, boolean asyncExec) {
return event;
}

LRESULT WM_DPICHANGED (long wParam, long lParam) {
// Map DPI to Zoom and compare
int newNativeZoom = DPIUtil.mapDPIToZoom (OS.HIWORD (wParam));
if (getDisplay().isRescalingAtRuntime()) {
Device.win32_destroyUnusedHandles(getDisplay());
RECT rect = new RECT ();
COM.MoveMemory(rect, lParam, RECT.sizeof);
handleMonitorSpecificDpiChange(newNativeZoom, new Rectangle(rect.left, rect.top, rect.right - rect.left, rect.bottom-rect.top));
return LRESULT.ZERO;
} else {
int newZoom = DPIUtil.getZoomForAutoscaleProperty (newNativeZoom);
int oldZoom = DPIUtil.getZoomForAutoscaleProperty (nativeZoom);
if (newZoom != oldZoom) {
// Throw the DPI change event if zoom value changes
Event event = new Event();
event.type = SWT.ZoomChanged;
event.widget = this;
event.detail = DPIUtil.getZoomForAutoscaleProperty(newNativeZoom);
event.doit = true;
notifyListeners(SWT.ZoomChanged, event);
return LRESULT.ZERO;
}
}
return LRESULT.ONE;
LRESULT WM_DPICHANGED(long wParam, long lParam) {
return null;
}

LRESULT WM_DISPLAYCHANGE (long wParam, long lParam) {
if (getDisplay().isRescalingAtRuntime()) {
Device.win32_destroyUnusedHandles(getDisplay());
return LRESULT.ZERO;
}
return LRESULT.ONE;
LRESULT WM_DISPLAYCHANGE(long wParam, long lParam) {
return null;
}

LRESULT WM_DRAWITEM (long wParam, long lParam) {
Expand Down Expand Up @@ -5980,7 +5936,6 @@ private boolean decrement() {
}

void sendZoomChangedEvent(Event event, Shell shell) {
this.currentDpiChangeEvent = event;
if (event.data instanceof DPIChangeExecution dpiExecData) {
dpiExecData.increment();
dpiExecData.process(this, () -> {
Expand All @@ -5993,9 +5948,6 @@ void sendZoomChangedEvent(Event event, Shell shell) {
return;
}
if (dpiExecData.decrement()) {
if (event == currentDpiChangeEvent) {
currentDpiChangeEvent = null;
}
if (event.doit) {
shell.WM_SIZE(0, 0);
}
Expand Down
56 changes: 56 additions & 0 deletions bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Shell.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.ole.win32.*;
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.internal.win32.version.*;

Expand Down Expand Up @@ -150,6 +151,10 @@ public class Shell extends Decorations {
DialogProc = lpWndClass.lpfnWndProc;
}

/** Cache for currently processed DPI change event to be able to cancel it if a new one is triggered */
Event lastDpiChangeEvent;


/**
* Constructs a new instance of this class. This is equivalent
* to calling <code>Shell((Display) null)</code>.
Expand Down Expand Up @@ -2430,6 +2435,57 @@ LRESULT WM_DESTROY (long wParam, long lParam) {
return result;
}

@Override
LRESULT WM_DISPLAYCHANGE (long wParam, long lParam) {
if (getDisplay().isRescalingAtRuntime()) {
Device.win32_destroyUnusedHandles(getDisplay());
return LRESULT.ZERO;
}
return LRESULT.ONE;
}

@Override
LRESULT WM_DPICHANGED (long wParam, long lParam) {
// Map DPI to Zoom and compare
int newNativeZoom = DPIUtil.mapDPIToZoom (OS.HIWORD (wParam));
if (getDisplay().isRescalingAtRuntime()) {
Device.win32_destroyUnusedHandles(getDisplay());
RECT rect = new RECT ();
COM.MoveMemory(rect, lParam, RECT.sizeof);
Rectangle newBoundsInPixels = new Rectangle(rect.left, rect.top, rect.right - rect.left, rect.bottom-rect.top);
handleMonitorSpecificDpiChange(newNativeZoom, newBoundsInPixels);
return LRESULT.ZERO;
} else {
int newZoom = DPIUtil.getZoomForAutoscaleProperty (newNativeZoom);
int oldZoom = DPIUtil.getZoomForAutoscaleProperty (nativeZoom);
if (newZoom != oldZoom) {
// Throw the DPI change event if zoom value changes
Event event = new Event();
event.type = SWT.ZoomChanged;
event.widget = this;
event.detail = DPIUtil.getZoomForAutoscaleProperty(newNativeZoom);
event.doit = true;
notifyListeners(SWT.ZoomChanged, event);
return LRESULT.ZERO;
}
}
return LRESULT.ONE;
}

private void handleMonitorSpecificDpiChange(int newNativeZoom, Rectangle newBoundsInPixels) {
DPIUtil.setDeviceZoom (newNativeZoom);
// Do not process DPI change for child shells asynchronous to avoid relayouting when
// repositioning the child shell to a different monitor upon opening
boolean processDpiChangeAsynchronous = getParent() == null;
Event zoomChangedEvent = createZoomChangedEvent(newNativeZoom, processDpiChangeAsynchronous);
if (lastDpiChangeEvent != null) {
lastDpiChangeEvent.doit = false;
}
lastDpiChangeEvent = zoomChangedEvent;
notifyListeners(SWT.ZoomChanged, zoomChangedEvent);
this.setBoundsInPixels(newBoundsInPixels.x, newBoundsInPixels.y, newBoundsInPixels.width, newBoundsInPixels.height);
}

@Override
LRESULT WM_ENTERIDLE (long wParam, long lParam) {
LRESULT result = super.WM_ENTERIDLE (wParam, lParam);
Expand Down
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