Add src/main/java/com/formdev/flatlaf/intellijthemes/ListCellTitledBorder.java

src/main/java/com/formdev/flatlaf/intellijthemes/ListCellTitledBorder.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2019 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.intellijthemes;
+
+import java.awt.*;
+import java.awt.geom.Rectangle2D;
+import javax.swing.JList;
+import javax.swing.UIManager;
+import javax.swing.border.Border;
+import com.formdev.flatlaf.ui.FlatUIUtils;
+import com.formdev.flatlaf.util.UIScale;
+
+/**
+ * @author Karl Tauber
+ */
+class ListCellTitledBorder
+	implements Border
+{
+	private final JList<?> list;
+	private final String title;
+
+	ListCellTitledBorder( JList<?> list, String title ) {
+		this.list = list;
+		this.title = title;
+	}
+
+	@Override
+	public boolean isBorderOpaque() {
+		return true;
+	}
+
+	@Override
+	public Insets getBorderInsets( Component c ) {
+		int height = c.getFontMetrics( list.getFont() ).getHeight();
+		return new Insets( height, 0, 0, 0 );
+	}
+
+	@Override
+	public void paintBorder( Component c, Graphics g, int x, int y, int width, int height ) {
+		FontMetrics fm = c.getFontMetrics( list.getFont() );
+		int titleWidth = fm.stringWidth( title );
+		int titleHeight = fm.getHeight();
+
+		// fill background
+		g.setColor( list.getBackground() );
+		g.fillRect( x, y, width, titleHeight );
+
+		int gap = UIScale.scale( 4 );
+
+		Graphics2D g2 = (Graphics2D) g.create();
+		try {
+			FlatUIUtils.setRenderingHints( g2 );
+
+			g2.setColor( UIManager.getColor( "Label.disabledForeground" ) );
+
+			// paint separator lines
+			int sepWidth = (width - titleWidth) / 2 - gap - gap;
+			if( sepWidth > 0 ) {
+				int sy = y + Math.round( titleHeight / 2f );
+				float sepHeight = UIScale.scale( (float) 1 );
+
+				g2.fill( new Rectangle2D.Float( x + gap, sy, sepWidth, sepHeight ) );
+				g2.fill( new Rectangle2D.Float( x + width - gap - sepWidth, sy, sepWidth, sepHeight ) );
+			}
+
+			// draw title
+			int xt = x + ((width - titleWidth) / 2);
+			int yt = y + fm.getAscent();
+
+			FlatUIUtils.drawString( list, g2, title, xt, yt );
+		} finally {
+			g2.dispose();
+		}
+	}
+}