ByteEdit/src/org/fife/ui/autocomplete/OutlineHighlightPainter.java

/*
 * 04/26/2009
 * OutlineHighlightPainter.java - Highlight painter that draws an outline
 * around its text.
 * This library is distributed under a modified BSD license. See the included
 * AutoComplete.License.txt file for details.
 */
package org.fife.ui.autocomplete;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.Shape;

import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultHighlighter;
import javax.swing.text.JTextComponent;
import javax.swing.text.Position;
import javax.swing.text.View;

/**
 * Highlight painter that draws an outline around the text. This is used to draw
 * bounds around function/method parameters.
 *
 * @author Robert Futrell
 * @version 1.0
 */
/*
 * NOTE: Whenever you see text like "Workaround for Java Highlight issues", this
 * is because highlighted text in a JTextComponent gets "pushed" forward when
 * the caret is at the Highlight's start, when we need it to instead get
 * prepended to. For this reason, the auto-complete package adds its Highlights
 * 1 char too long (1 char earlier than where it should really start), but only
 * paint the Highlight from the 2nd char on.
 */
class OutlineHighlightPainter extends DefaultHighlighter.DefaultHighlightPainter {

	/**
	 * DefaultHighlightPainter doesn't allow changing color, so we must cache ours
	 * here.
	 */
	private Color color;

	/**
	 * Constructor.
	 *
	 * @param color The color to draw the bounding boxes with. This cannot be
	 *              <code>null</code>.
	 */
	public OutlineHighlightPainter(Color color) {
		super(color);
		setColor(color);
	}

	/**
	 * Returns the color to paint bounding boxes with.
	 *
	 * @return The color.
	 * @see #setColor(Color)
	 */
	@Override
	public Color getColor() {
		return color;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public Shape paintLayer(Graphics g, int p0, int p1, Shape viewBounds, JTextComponent c, View view) {
		g.setColor(getColor());
		p0++; // Workaround for Java Highlight issues.
		// This special case isn't needed for most standard Swing Views (which
		// always return a width of 1 for modelToView() calls), but it is
		// needed for RSTA views, which actually return the width of chars for
		// modelToView calls. But this should be faster anyway, as we
		// short-circuit and do only one modelToView() for one offset.
		if (p0 == p1) {
			try {
				Shape s = view.modelToView(p0, viewBounds, Position.Bias.Forward);
				Rectangle r = s.getBounds();
				g.drawLine(r.x, r.y, r.x, r.y + r.height);
				return r;
			} catch (BadLocationException ble) {
				ble.printStackTrace(); // Never happens
				return null;
			}
		}
		if (p0 == view.getStartOffset() && p1 == view.getEndOffset()) {
			// Contained in view, can just use bounds.
			Rectangle alloc;
			if (viewBounds instanceof Rectangle) {
				alloc = (Rectangle) viewBounds;
			} else {
				alloc = viewBounds.getBounds();
			}
			g.drawRect(alloc.x, alloc.y, alloc.width - 1, alloc.height - 1);
			return alloc;
		}
		// Should only render part of View.
		try {
			// --- determine locations ---
			Shape shape = view.modelToView(p0, Position.Bias.Forward, p1, Position.Bias.Backward, viewBounds);
			Rectangle r = (shape instanceof Rectangle) ? (Rectangle) shape : shape.getBounds();
			g.drawRect(r.x, r.y, r.width - 1, r.height - 1);
			return r;
		} catch (BadLocationException e) { // Never happens
			e.printStackTrace();
			return null;
		}
	}

	/**
	 * Sets the color to paint the bounding boxes with.
	 *
	 * @param color The new color. This cannot be <code>null</code>.
	 * @see #getColor()
	 */
	public void setColor(Color color) {
		if (color == null) {
			throw new IllegalArgumentException("color cannot be null");
		}
		this.color = color;
	}
}