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[Win] StyledText with paint artifacts #3338

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[Win] StyledText with paint artifacts #3338

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c94b5aa
Win32DPIUtils: fix pixelToPointWithSufficientlyLargeSize
May 28, 2026
91677aa
[Win] StyledText with paint artifacts #3298
May 28, 2026
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8 changes: 7 additions & 1 deletion bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/internal/Win32DPIUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -178,7 +178,13 @@ public static Rectangle pixelToPoint(Rectangle rect, int zoom) {
}

public static Rectangle pixelToPointWithSufficientlyLargeSize(Rectangle rect, int zoom) {
return pixelToPoint(rect, zoom, RoundingMode.UP);
if (zoom == 100 || rect == null) return rect;

Point scaledTopLeft = pixelToPoint(new Point(rect.x, rect.y), zoom, RoundingMode.DOWN);
Point scaledBottomRight = pixelToPoint(new Point(rect.x + rect.width, rect.y + rect.height), zoom, RoundingMode.UP);
Comment on lines +183 to +184
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@HeikoKlare HeikoKlare May 28, 2026

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This calculation can lead to an unintended overcalculation. In addition, it does not consider input rectangles already being at floating-point precision, for which an exact conversion was done before this change.
Can't we solve the issue at the root (inside the pixelToPoint method), which already seems to yield unexpected results when using rounding mode "up". E.g., the scaledBottomRight calculation may incorporate the rounding mode with something like Point.OfFloat.from(pixelToPoint(floatRect.getBottomRight(), zoom, sizeRounding)).
Also note that the pixelToPoint calculation does some internal rounding (calculating based on rounded values instead of the float-based values and rounding afterwards) because everything else broke one case or another.

It would also be good to isolate this change from further changes, such as consumers of this method.

return new Rectangle(scaledTopLeft.x, scaledTopLeft.y,
scaledBottomRight.x - scaledTopLeft.x,
scaledBottomRight.y - scaledTopLeft.y);
}

private static Rectangle pixelToPoint(Rectangle rect, int zoom, RoundingMode sizeRounding) {
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2 changes: 1 addition & 1 deletion bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Composite.java
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Expand Up @@ -1532,7 +1532,7 @@ LRESULT WM_PAINT (long wParam, long lParam) {

Event event = new Event ();
event.gc = gc;
event.setBounds(Win32DPIUtils.pixelToPoint(new Rectangle.OfFloat(ps.left, ps.top, width, height), getAutoscalingZoom()));
event.setBounds(Win32DPIUtils.pixelToPointWithSufficientlyLargeSize(new Rectangle.OfFloat(ps.left, ps.top, width, height), getAutoscalingZoom()));
sendEvent (SWT.Paint, event);
if (data.focusDrawn && !isDisposed ()) updateUIState ();
gc.dispose ();
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2 changes: 1 addition & 1 deletion bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Scrollable.java
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Expand Up @@ -210,7 +210,7 @@ void destroyScrollBar (int type) {
*/
public Rectangle getClientArea () {
checkWidget ();
return Win32DPIUtils.pixelToPoint(getClientAreaInPixels(), getAutoscalingZoom());
return Win32DPIUtils.pixelToPointWithSufficientlyLargeSize(getClientAreaInPixels(), getAutoscalingZoom());
}

Rectangle getClientAreaInPixels () {
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