Fix #458: Add 'chevron' fold icon style, toggleable via FoldIconStyle

RSyntaxTextArea/src/main/java/org/fife/ui/rtextarea/ChevronFoldIcon.java

@@ -0,0 +1,65 @@
+/*
+ * This library is distributed under a modified BSD license.  See the included
+ * LICENSE file for details.
+ */
+package org.fife.ui.rtextarea;
+
+import java.awt.*;
+import java.awt.geom.Path2D;
+
+
+/**
+ * A fold icon represented by a chevron.
+ */
+class ChevronFoldIcon extends FoldIndicatorIcon {
+
+	ChevronFoldIcon(boolean collapsed) {
+		super(collapsed);
+	}
+
+	/**
+	 * Creates a closed path for the given points.
+	 */
+	private Path2D createPath(double... points) {
+		Path2D path = new Path2D.Float();
+		path.moveTo(points[0], points[1]);
+		for (int i = 2; i < points.length; i += 2) {
+			path.lineTo(points[i], points[i + 1]);
+		}
+		path.closePath();
+		return path;
+	}
+
+	@Override
+	public int getIconHeight() {
+		return 11;
+	}
+
+	@Override
+	public int getIconWidth() {
+		return 11;
+	}
+
+	@Override
+	public void paintIcon(Component c, Graphics g, int x, int y) {
+
+		int width = getIconWidth();
+		int height = getIconHeight();
+		Graphics2D g2d = (Graphics2D)g.create();
+
+		try {
+
+			g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
+				RenderingHints.VALUE_ANTIALIAS_ON);
+			g2d.setColor(c.getForeground());
+			g2d.translate(x, y);
+			if (!isCollapsed()) {
+				g2d.rotate(Math.toRadians(90), width / 2f, height / 2f);
+			}
+			g2d.fill(createPath(3, 1, 3, 2.5, 6, 5.5, 3, 8.5, 3, 10, 4.5, 10, 9, 5.5, 4.5, 1));
+		} finally {
+			g2d.dispose();
+		}
+	}
+
+}