Hide find/replace overlay when target editor is too small #1989

The find/replace overlay is still visible when it does not vertically
fit into the target editor.
With this change, the overlay is hidden as long the target editor has
insufficient height. It also streamlines the whole calculation of the
overlay positioning to be properly reusable when determining its
visibility.

Fixes #1989

Author: HeikoKlare

bundles/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/findandreplace/overlay/FindReplaceOverlay.java

@@ -751,7 +751,7 @@ private void enableReplaceTools(boolean enable) {
 		replaceTools.setVisible(enable);
 	}
 
-	private int getIdealDialogWidth(Rectangle targetBounds) {
+	private int getIdealOverlayWidth(Rectangle targetBounds) {
 		int idealOverlayWidth = calculateOverlayWidthWithToolbars(IDEAL_WIDTH_TEXT);
 		int minimumOverlayWidth = Math.min(calculateOverlayWidthWithoutToolbars(MINIMAL_WIDTH_TEXT),
 				(int) (targetBounds.width * WORST_CASE_RATIO_EDITOR_TO_OVERLAY));
@@ -799,20 +799,6 @@ private int getTextWidthInSearchBar(String input) {
 		return textWidth;
 	}
 
-	private Point getNewPosition(Widget targetTextWidget, Point targetOrigin, Rectangle targetBounds,
-			Point expectedSize) {
-		Point verticalScrollBarSize = ((Scrollable) targetTextWidget).getVerticalBar().getSize();
-		Point horizontalScrollBarSize = ((Scrollable) targetTextWidget).getHorizontalBar().getSize();
-
-		int newX = targetOrigin.x + targetBounds.width - expectedSize.x - verticalScrollBarSize.x
-				- ((StyledText) targetTextWidget).getRightMargin();
-		int newY = targetOrigin.y;
-		if (!positionAtTop) {
-			newY += targetBounds.height - expectedSize.y - horizontalScrollBarSize.y;
-		}
-		return new Point(newX, newY);
-	}
-
 	/**
 	 * When making the text-bar 100% small and then regrowing it, we want the text
 	 * to start at the first character again.
@@ -828,30 +814,66 @@ private void repositionTextSelection() {
 
 	private void positionToPart() {
 		getShell().requestLayout();
-		if (!(targetPart instanceof StatusTextEditor)) {
+		if (!(targetPart instanceof StatusTextEditor textEditor)) {
 			return;
 		}
 
-		StatusTextEditor textEditor = (StatusTextEditor) targetPart;
 		Control targetWidget = textEditor.getAdapter(ITextViewer.class).getTextWidget();
 		if (!okayToUse(targetWidget)) {
 			this.close();
 			return;
 		}
 
-		Point targetOrigin = targetWidget.toDisplay(0, 0);
-		Rectangle targetBounds = targetWidget.getBounds();
+		Rectangle targetControlBounds = calculateAbsoluteControlBounds(targetWidget);
+		Rectangle overlayBounds = calculateDesiredOverlayBounds(targetControlBounds);
+		updatePosition(overlayBounds);
+		configureDisplayedWidgetsForWidth(overlayBounds.width);
+		updateVisibility(targetControlBounds, overlayBounds);
 
-		int newWidth = getIdealDialogWidth(targetBounds);
-		int newHeight = container.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
+		repositionTextSelection();
+	}
+
+	private Rectangle calculateAbsoluteControlBounds(Control control) {
+		Rectangle localControlBounds = control.getBounds();
+		int width = localControlBounds.width;
+		int height = localControlBounds.height;
+		if (control instanceof Scrollable scrollable) {
+			width -= scrollable.getVerticalBar().getSize().x;
+			height -= scrollable.getHorizontalBar().getSize().y;
+		}
+		if (control instanceof StyledText styledText) {
+			width -= styledText.getRightMargin();
+		}
+		Point absoluteControlPosition = control.toDisplay(0, 0);
+		return new Rectangle(absoluteControlPosition.x, absoluteControlPosition.y, width, height);
+	}
 
-		Point newPosition = getNewPosition(targetWidget, targetOrigin, targetBounds, new Point(newWidth, newHeight));
+	private Rectangle calculateDesiredOverlayBounds(Rectangle targetControlBounds) {
+		int width = getIdealOverlayWidth(targetControlBounds);
+		int height = container.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
 
-		getShell().setSize(new Point(newWidth, newHeight));
-		getShell().setLocation(newPosition);
+		int x = targetControlBounds.x + targetControlBounds.width - width;
+		int y = targetControlBounds.y;
+		if (!positionAtTop) {
+			y += targetControlBounds.height - height;
+		}
+
+		return new Rectangle(x, y, width, height);
+	}
+
+	private void updatePosition(Rectangle overlayBounds) {
+		getShell().setSize(new Point(overlayBounds.width, overlayBounds.height));
+		getShell().setLocation(new Point(overlayBounds.x, overlayBounds.y));
 		getShell().layout(true);
-		configureDisplayedWidgetsForWidth(newWidth);
-		repositionTextSelection();
+	}
+
+	private void updateVisibility(Rectangle targetControlBounds, Rectangle overlayBounds) {
+		if (positionAtTop) {
+			getShell().setVisible(
+					overlayBounds.y + overlayBounds.height <= targetControlBounds.y + targetControlBounds.height);
+		} else {
+			getShell().setVisible(overlayBounds.y >= targetControlBounds.y);
+		}
 	}
 
 	private String getFindString() {