Tree: better support for non-wide rounded selection

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatMenuItemRenderer.java

@@ -353,9 +353,11 @@ debug*/
 
 	/** @since 3 */
 	protected void paintSelection( Graphics g, Color selectionBackground, Insets selectionInsets, int selectionArc ) {
+		float arc = scale( selectionArc / 2f );
+
 		g.setColor( deriveBackground( selectionBackground ) );
 		FlatUIUtils.paintSelection( (Graphics2D) g, 0, 0, menuItem.getWidth(), menuItem.getHeight(),
-			scale( selectionInsets ), scale( (float) selectionArc ), 0 );
+			scale( selectionInsets ), arc, arc, arc, arc, 0 );
 	}
 
 	/** @since 3 */

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTreeUI.java

@@ -17,7 +17,6 @@
 package com.formdev.flatlaf.ui;
 
 import static com.formdev.flatlaf.FlatClientProperties.*;
-
 import java.awt.Color;
 import java.awt.Component;
 import java.awt.Graphics;
@@ -377,7 +376,7 @@ public class FlatTreeUI
 	}
 
 	/**
-	 * Same as super.paintRow(), but supports wide selection and uses
+	 * Similar to super.paintRow(), but supports wide selection and uses
 	 * inactive selection background/foreground if tree is not focused.
 	 */
 	@Override
@@ -458,7 +457,7 @@ public class FlatTreeUI
 				paintWideSelection( g, clipBounds, insets, bounds, path, row, isExpanded, hasBeenExpanded, isLeaf );
 			} else {
 				// non-wide selection
-				paintCellBackground( g, rendererComponent, bounds );
+				paintCellBackground( g, rendererComponent, bounds, row, true );
 			}
 
 			// this is actually not necessary because renderer should always set color
@@ -472,7 +471,7 @@ public class FlatTreeUI
 				if( bg != null && !bg.equals( defaultCellNonSelectionBackground ) ) {
 					Color oldColor = g.getColor();
 					g.setColor( bg );
-					paintCellBackground( g, rendererComponent, bounds );
+					paintCellBackground( g, rendererComponent, bounds, row, false );
 					g.setColor( oldColor );
 				}
 			}
@@ -527,16 +526,18 @@ public class FlatTreeUI
 	private void paintWideSelection( Graphics g, Rectangle clipBounds, Insets insets, Rectangle bounds,
 		TreePath path, int row, boolean isExpanded, boolean hasBeenExpanded, boolean isLeaf )
 	{
-		int flags = 0;
+		float arcTop, arcBottom;
+		arcTop = arcBottom = UIScale.scale( selectionArc / 2f );
+
 		if( useUnitedRoundedSelection() ) {
 			if( row > 0 && tree.isRowSelected( row - 1 ) )
-				flags |= FlatUIUtils.FLAG_TOP_NOT_ROUNDED;
+				arcTop = 0;
 			if( row < tree.getRowCount() - 1 && tree.isRowSelected( row + 1 ) )
-				flags |= FlatUIUtils.FLAG_BOTTOM_NOT_ROUNDED;
+				arcBottom = 0;
 		}
 
 		FlatUIUtils.paintSelection( (Graphics2D) g, 0, bounds.y, tree.getWidth(), bounds.height,
-			UIScale.scale( selectionInsets ), UIScale.scale( (float) selectionArc ), flags );
+			UIScale.scale( selectionInsets ), arcTop, arcTop, arcBottom, arcBottom, 0 );
 
 		// paint expand/collapse icon
 		// (was already painted before, but painted over with wide selection)
@@ -546,12 +547,9 @@ public class FlatTreeUI
 		}
 	}
 
-	private boolean useUnitedRoundedSelection() {
+	private void paintCellBackground( Graphics g, Component rendererComponent, Rectangle bounds,
-		return selectionArc > 0 &&
+		int row, boolean paintSelection )
-			(selectionInsets == null || (selectionInsets.top == 0 && selectionInsets.bottom == 0));
+	{
-	}
-
-	private void paintCellBackground( Graphics g, Component rendererComponent, Rectangle bounds ) {
 		int xOffset = 0;
 		int imageOffset = 0;
 
@@ -564,8 +562,32 @@ public class FlatTreeUI
 			xOffset = label.getComponentOrientation().isLeftToRight() ? imageOffset : 0;
 		}
 
+		if( paintSelection ) {
+			float arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight;
+			arcTopLeft = arcTopRight = arcBottomLeft = arcBottomRight = UIScale.scale( selectionArc / 2f );
+
+			if( useUnitedRoundedSelection() ) {
+				if( row > 0 && tree.isRowSelected( row - 1 ) ) {
+					Rectangle r = getPathBounds( tree, tree.getPathForRow( row - 1 ) );
+					arcTopLeft = Math.min( arcTopLeft, r.x - bounds.x );
+					arcTopRight = Math.min( arcTopRight, (bounds.x + bounds.width) - (r.x + r.width) );
+				}
+				if( row < tree.getRowCount() - 1 && tree.isRowSelected( row + 1 ) ) {
+					Rectangle r = getPathBounds( tree, tree.getPathForRow( row + 1 ) );
+					arcBottomLeft = Math.min( arcBottomLeft, r.x - bounds.x );
+					arcBottomRight = Math.min( arcBottomRight, (bounds.x + bounds.width) - (r.x + r.width) );
+				}
+			}
+
 			FlatUIUtils.paintSelection( (Graphics2D) g, bounds.x + xOffset, bounds.y, bounds.width - imageOffset, bounds.height,
-			UIScale.scale( selectionInsets ), UIScale.scale( (float) selectionArc ), 0 );
+				UIScale.scale( selectionInsets ), arcTopLeft, arcTopRight, arcBottomLeft, arcBottomRight, 0 );
+		} else
+			g.fillRect( bounds.x + xOffset, bounds.y, bounds.width - imageOffset, bounds.height );
+	}
+
+	private boolean useUnitedRoundedSelection() {
+		return selectionArc > 0 &&
+			(selectionInsets == null || (selectionInsets.top == 0 && selectionInsets.bottom == 0));
 	}
 
 	/**

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java

@@ -624,26 +624,17 @@ public class FlatUIUtils
 		}
 	}
 
-	// flags for paintSelection()
-	public static final int
-		FLAG_TOP_LEFT_NOT_ROUNDED = (1 << 0),
-		FLAG_TOP_RIGHT_NOT_ROUNDED = (1 << 1),
-		FLAG_BOTTOM_LEFT_NOT_ROUNDED = (1 << 2),
-		FLAG_BOTTOM_RIGHT_NOT_ROUNDED = (1 << 3),
-		FLAG_TOP_NOT_ROUNDED = FLAG_TOP_LEFT_NOT_ROUNDED | FLAG_TOP_RIGHT_NOT_ROUNDED,
-		FLAG_BOTTOM_NOT_ROUNDED = FLAG_BOTTOM_LEFT_NOT_ROUNDED | FLAG_BOTTOM_RIGHT_NOT_ROUNDED;
-
 	/**
 	 * Paints a selection.
 	 * <p>
 	 * The bounds of the painted selection (rounded) rectangle are
 	 * {@code x + insets.left, y + insets.top, width - insets.left - insets.right, height - insets.top - insets.bottom}.
-	 * The given arc diameter refers to the painted rectangle (and not to {@code x,y,width,height}).
+	 * The given arc radius refers to the painted rectangle (and not to {@code x,y,width,height}).
 	 *
 	 * @since 3
 	 */
-	public static void paintSelection( Graphics2D g, int x, int y, int width, int height,
+	public static void paintSelection( Graphics2D g, int x, int y, int width, int height, Insets insets,
-		Insets insets, float arc, int flags )
+		float arcTopLeft, float arcTopRight, float arcBottomLeft, float arcBottomRight, int flags )
 	{
 		if( insets != null ) {
 			x += insets.left;
@@ -652,15 +643,7 @@ public class FlatUIUtils
 			height -= insets.top + insets.bottom;
 		}
 
-		if( arc > 0 ) {
+		if( arcTopLeft > 0 || arcTopRight > 0 || arcBottomLeft > 0 || arcBottomRight > 0 ) {
-			// because createRoundRectanglePath() expects a radius
-			float arcRadius = arc / 2;
-
-			float arcTopLeft = ((flags & FLAG_TOP_LEFT_NOT_ROUNDED) != 0) ? 0 : arcRadius;
-			float arcTopRight = ((flags & FLAG_TOP_RIGHT_NOT_ROUNDED) != 0) ? 0 : arcRadius;
-			float arcBottomLeft = ((flags & FLAG_BOTTOM_LEFT_NOT_ROUNDED) != 0) ? 0 : arcRadius;
-			float arcBottomRight = ((flags & FLAG_BOTTOM_RIGHT_NOT_ROUNDED) != 0) ? 0 : arcRadius;
-
 			double systemScaleFactor = UIScale.getSystemScaleFactor( g );
 			if( systemScaleFactor != 1 && systemScaleFactor != 2 ) {
 				// paint at scale 1x to avoid clipping on right and bottom edges at 125%, 150% or 175%
@@ -765,7 +748,7 @@ public class FlatUIUtils
 	}
 
 	/**
-	 * Creates a not-filled rounded rectangle shape and allows specifying the line width and the radius or each corner.
+	 * Creates a not-filled rounded rectangle shape and allows specifying the line width and the radius of each corner.
 	 */
 	public static Path2D createRoundRectangle( float x, float y, float width, float height,
 		float lineWidth, float arcTopLeft, float arcTopRight, float arcBottomLeft, float arcBottomRight )