swingx-master/swingx-demos/swingx-demos-swingxset/src/main/java/com/sun/swingset3/codeview/SnippetHighlighter.java
/*
 * Copyright 2007-2008 Sun Microsystems, Inc.  All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.sun.swingset3.codeview;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Shape;
import java.util.*;
import javax.swing.SwingUtilities;
import javax.swing.plaf.TextUI;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.Highlighter;
import javax.swing.text.JTextComponent;
import javax.swing.text.LayeredHighlighter;
import javax.swing.text.Position;
import javax.swing.text.View;

/**
 * Implements the Highlighter interfaces.  Implements a simple highlight
 * painter that renders in a solid color.
 * 
 * @see     Highlighter
 */
public class SnippetHighlighter extends LayeredHighlighter {

    /**
     * Creates a new DefaultHighlighther object.
     */
    public SnippetHighlighter() {
	drawsLayeredHighlights = true;
    }

    // ---- Highlighter methods ----------------------------------------------

    /**
     * Renders the highlights.
     *
     * @param g the graphics context
     */
    public void paint(Graphics g) {
        // PENDING(prinz) - should cull ranges not visible
        int len = highlights.size();
        for (int i = 0; i < len; i++) {
	    HighlightInfo info = highlights.elementAt(i);
	    if (!(info instanceof LayeredHighlightInfo)) {
		// Avoid allocing unless we need it.
		Rectangle a = component.getBounds();
		Insets insets = component.getInsets();
		a.x = insets.left;
		a.y = insets.top;
		a.width -= insets.left + insets.right;
		a.height -= insets.top + insets.bottom;
		for (; i < len; i++) {
		    info = highlights.elementAt(i);
		    if (!(info instanceof LayeredHighlightInfo)) {
			Highlighter.HighlightPainter p = info.getPainter();
			p.paint(g, info.getStartOffset(), info.getEndOffset(),
				a, component);
		    }
		}
	    }
	}
    }

    /**
     * Called when the UI is being installed into the
     * interface of a JTextComponent.  Installs the editor, and
     * removes any existing highlights.
     *
     * @param c the editor component
     * @see Highlighter#install
     */
    public void install(JTextComponent c) {
	component = c;
	removeAllHighlights();
    }

    /**
     * Called when the UI is being removed from the interface of
     * a JTextComponent.
     *
     * @param c the component
     * @see Highlighter#deinstall
     */
    public void deinstall(JTextComponent c) {
	component = null;
    }

    /**
     * Adds a highlight to the view.  Returns a tag that can be used 
     * to refer to the highlight.
     *
     * @param p0   the start offset of the range to highlight >= 0
     * @param p1   the end offset of the range to highlight >= p0
     * @param p    the painter to use to actually render the highlight
     * @return     an object that can be used as a tag
     *   to refer to the highlight
     * @exception BadLocationException if the specified location is invalid
     */
    public Object addHighlight(int p0, int p1, Highlighter.HighlightPainter p) throws BadLocationException {
	Document doc = component.getDocument();
	HighlightInfo i = (getDrawsLayeredHighlights() &&
			   (p instanceof LayeredHighlighter.LayerPainter)) ?
	                  new LayeredHighlightInfo() : new HighlightInfo();
	i.painter = p;
	i.p0 = doc.createPosition(p0);
	i.p1 = doc.createPosition(p1);
        // For snippets, we want to make sure selection is layered ON TOP
        // since we add transparency to the selection color;  so rather
        // than append the highlight, we insert it in the front.
	highlights.insertElementAt(i, 0);
        safeDamageRange(p0, p1);
        return i;
    }

    /**
     * Removes a highlight from the view.
     *
     * @param tag the reference to the highlight
     */
    public void removeHighlight(Object tag) {
	if (tag instanceof LayeredHighlightInfo) {
	    LayeredHighlightInfo lhi = (LayeredHighlightInfo)tag;
	    if (lhi.width > 0 && lhi.height > 0) {
		component.repaint(lhi.x, lhi.y, lhi.width, lhi.height);
	    }
	}
	else {
	    HighlightInfo info = (HighlightInfo) tag;
            safeDamageRange(info.p0, info.p1);
	}
	highlights.removeElement(tag);
    }

    /**
     * Removes all highlights.
     */
    public void removeAllHighlights() {
	TextUI mapper = component.getUI();
	if (getDrawsLayeredHighlights()) {
	    int len = highlights.size();
	    if (len != 0) {
		int minX = 0;
		int minY = 0;
		int maxX = 0;
		int maxY = 0;
		int p0 = -1;
		int p1 = -1;
		for (int i = 0; i < len; i++) {
                    HighlightInfo hi = highlights.elementAt(i);
                    if (hi instanceof LayeredHighlightInfo) {
                        LayeredHighlightInfo info = (LayeredHighlightInfo)hi;
                        minX = Math.min(minX, info.x);
                        minY = Math.min(minY, info.y);
                        maxX = Math.max(maxX, info.x + info.width);
                        maxY = Math.max(maxY, info.y + info.height);
                    }
                    else {
                        if (p0 == -1) {
                            p0 = hi.p0.getOffset();
                            p1 = hi.p1.getOffset();
                        }
                        else {
                            p0 = Math.min(p0, hi.p0.getOffset());
                            p1 = Math.max(p1, hi.p1.getOffset());
                        }
                    }
                }
		if (minX != maxX && minY != maxY) {
		    component.repaint(minX, minY, maxX - minX, maxY - minY);
		}
                if (p0 != -1) {
                    try {
                        safeDamageRange(p0, p1);
                    } catch (BadLocationException e) {}
                }
		highlights.removeAllElements();
	    }
	}
	else if (mapper != null) {
	    int len = highlights.size();
	    if (len != 0) {
		int p0 = Integer.MAX_VALUE;
		int p1 = 0;
		for (int i = 0; i < len; i++) {
		    HighlightInfo info = highlights.elementAt(i);
		    p0 = Math.min(p0, info.p0.getOffset());
		    p1 = Math.max(p1, info.p1.getOffset());
		}
                try {
                    safeDamageRange(p0, p1);
                } catch (BadLocationException e) {}

		highlights.removeAllElements();
	    }
	}
    }

    /**
     * Changes a highlight.
     *
     * @param tag the highlight tag
     * @param p0 the beginning of the range >= 0
     * @param p1 the end of the range >= p0
     * @exception BadLocationException if the specified location is invalid
     */
    public void changeHighlight(Object tag, int p0, int p1) throws BadLocationException {
	Document doc = component.getDocument();
	if (tag instanceof LayeredHighlightInfo) {
	    LayeredHighlightInfo lhi = (LayeredHighlightInfo)tag;
	    if (lhi.width > 0 && lhi.height > 0) {
		component.repaint(lhi.x, lhi.y, lhi.width, lhi.height);
	    }
	    // Mark the highlights region as invalid, it will reset itself
	    // next time asked to paint.
	    lhi.width = lhi.height = 0;
	    lhi.p0 = doc.createPosition(p0);
	    lhi.p1 = doc.createPosition(p1);
            safeDamageRange(Math.min(p0, p1), Math.max(p0, p1));
	}
	else {
	    HighlightInfo info = (HighlightInfo) tag;
	    int oldP0 = info.p0.getOffset();
	    int oldP1 = info.p1.getOffset();
	    if (p0 == oldP0) {
                safeDamageRange(Math.min(oldP1, p1),
				   Math.max(oldP1, p1));
	    } else if (p1 == oldP1) {
                safeDamageRange(Math.min(p0, oldP0),
				   Math.max(p0, oldP0));
	    } else {
                safeDamageRange(oldP0, oldP1);
                safeDamageRange(p0, p1);
	    }
	    info.p0 = doc.createPosition(p0);
	    info.p1 = doc.createPosition(p1);
	}
    }

    /**
     * Makes a copy of the highlights.  Does not actually clone each highlight,
     * but only makes references to them.
     *
     * @return the copy
     * @see Highlighter#getHighlights
     */
    public Highlighter.Highlight[] getHighlights() {
        int size = highlights.size();
        if (size == 0) {
            return noHighlights;
        }
	Highlighter.Highlight[] h = new Highlighter.Highlight[size];
	highlights.copyInto(h);
	return h;
    }

    /**
     * When leaf Views (such as LabelView) are rendering they should
     * call into this method. If a highlight is in the given region it will
     * be drawn immediately.
     *
     * @param g Graphics used to draw
     * @param p0 starting offset of view
     * @param p1 ending offset of view
     * @param viewBounds Bounds of View
     * @param editor JTextComponent
     * @param view View instance being rendered
     */
    public void paintLayeredHighlights(Graphics g, int p0, int p1,
				       Shape viewBounds,
				       JTextComponent editor, View view) {
	for (int counter = highlights.size() - 1; counter >= 0; counter--) {
	    Object tag = highlights.elementAt(counter);
	    if (tag instanceof LayeredHighlightInfo) {
		LayeredHighlightInfo lhi = (LayeredHighlightInfo)tag;
		int start = lhi.getStartOffset();
		int end = lhi.getEndOffset();
		if ((p0 < start && p1 > start) ||
		    (p0 >= start && p0 < end)) {
		    lhi.paintLayeredHighlights(g, p0, p1, viewBounds,
					       editor, view);
		}
	    }
	}
    }

    /**
     * Queues damageRange() call into event dispatch thread
     * to be sure that views are in consistent state.
     */
    private void safeDamageRange(final Position p0, final Position p1) {
        safeDamager.damageRange(p0, p1);
    }

    /**
     * Queues damageRange() call into event dispatch thread
     * to be sure that views are in consistent state.
     */
    private void safeDamageRange(int a0, int a1) throws BadLocationException {
        Document doc = component.getDocument();
        safeDamageRange(doc.createPosition(a0), doc.createPosition(a1));
    }

    /**
     * If true, highlights are drawn as the Views draw the text. That is
     * the Views will call into <code>paintLayeredHighlight</code> which
     * will result in a rectangle being drawn before the text is drawn
     * (if the offsets are in a highlighted region that is). For this to
     * work the painter supplied must be an instance of
     * LayeredHighlightPainter.
     */
    public void setDrawsLayeredHighlights(boolean newValue) {
	drawsLayeredHighlights = newValue;
    }

    public boolean getDrawsLayeredHighlights() {
	return drawsLayeredHighlights;
    }

    // ---- member variables --------------------------------------------
    
    private final static Highlighter.Highlight[] noHighlights =
            new Highlighter.Highlight[0];
    private final Vector<HighlightInfo> highlights = new Vector<HighlightInfo>();
    private JTextComponent component;
    private boolean drawsLayeredHighlights;
    private final SafeDamager safeDamager = new SafeDamager();


    /**
     * Default implementation of LayeredHighlighter.LayerPainter that can
     * be used for painting highlights.
     * <p>
     * As of 1.4 this field is final.
     */
    public static LayeredHighlighter.LayerPainter SnippetPainter = new SnippetHighlightPainter(null);


    /**
     * Simple highlight painter that fills a highlighted area with
     * a solid color.
     */
    public static class SnippetHighlightPainter extends LayeredHighlighter.LayerPainter {

        /**
         * Constructs a new highlight painter. If <code>c</code> is null,
	 * the JTextComponent will be queried for its selection color.
         *
         * @param c the color for the highlight
         */
        public SnippetHighlightPainter(Color c) {
	    color = c;
	}
	
        /**
         * Returns the color of the highlight.
         *
         * @return the color
         */
	public Color getColor() {
	    return color;
	}

	// --- HighlightPainter methods ---------------------------------------

        /**
         * Paints a highlight.
         *
         * @param g the graphics context
         * @param offs0 the starting model offset >= 0
         * @param offs1 the ending model offset >= offs1
         * @param bounds the bounding box for the highlight
         * @param c the editor
         */
        public void paint(Graphics g, int offs0, int offs1, Shape bounds, JTextComponent c) {
	    Rectangle alloc = bounds.getBounds();
	    try {
		// --- determine locations ---
		TextUI mapper = c.getUI();
		Rectangle p0 = mapper.modelToView(c, offs0);
		Rectangle p1 = mapper.modelToView(c, offs1);

		// --- render ---
		Color color = getColor();

		if (color == null) {
		    g.setColor(c.getSelectionColor());
		}
		else {
		    g.setColor(color);
		}
		if (p0.y == p1.y) {
		    // same line, render a rectangle
		    Rectangle r = p0.union(p1);
		    g.fillRect(r.x, r.y, r.width, r.height);
		} else {
		    // different lines
		    int p0ToMarginWidth = alloc.x + alloc.width - p0.x;
		    g.fillRect(p0.x, p0.y, p0ToMarginWidth, p0.height);
		    if ((p0.y + p0.height) != p1.y) {
			g.fillRect(alloc.x, p0.y + p0.height, alloc.width, 
				   p1.y - (p0.y + p0.height));
		    } 
		    g.fillRect(alloc.x, p1.y, (p1.x - alloc.x), p1.height);
		}
	    } catch (BadLocationException e) {
		// can't render
	    }
	}

	// --- LayerPainter methods ----------------------------
        /**
         * Paints a portion of a highlight.
         *
         * @param g the graphics context
         * @param offs0 the starting model offset >= 0
         * @param offs1 the ending model offset >= offs1
         * @param bounds the bounding box of the view, which is not
	 *        necessarily the region to paint.
         * @param c the editor
	 * @param view View painting for
	 * @return region drawing occured in
         */
	public Shape paintLayer(Graphics g, int offs0, int offs1,
				Shape bounds, JTextComponent c, View view) {
	    Color base = getColor();
            // use transparency so selection isn't clobbered
            Color color = base != null? 
                          new Color(base.getRed(), base.getGreen(), base.getBlue(),
                                    255) : null;

	    if (color == null) {
		g.setColor(c.getSelectionColor());
	    }
	    else {
		g.setColor(color);
	    }
	    if (offs0 == view.getStartOffset() &&
		offs1 == view.getEndOffset()) {
		// Contained in view, can just use bounds.
		Rectangle alloc;
		if (bounds instanceof Rectangle) {
		    alloc = (Rectangle)bounds;
		}
		else {
		    alloc = bounds.getBounds();
		}
                // For CodeViewer Snippet painting, this is the paint block that is called.
                // We want to paint the highlight on the full width of the text pane,
                // so we only need to do this when the region is the beginning of a new
                // line.
                //g.fillRect(alloc.x, alloc.y, alloc.width, alloc.height);
                g.fillRect(alloc.x, alloc.y, c.getWidth() - alloc.x, alloc.height);

	    }
	    else {
		// Should only render part of View.
		try {
		    // --- determine locations ---
                    Shape shape = view.modelToView(offs0, Position.Bias.Forward,
                                                   offs1,Position.Bias.Backward,
                                                   bounds);
                    Rectangle r = (shape instanceof Rectangle) ?
                                  (Rectangle)shape : shape.getBounds();

                    g.fillRect(0, r.y, c.getWidth(), r.height);
                    return r;
		} catch (BadLocationException e) {
		    // can't render
		}
	    }
	    // Only if exception
	    return null;
	}

	private Color color;

    }


    private static class HighlightInfo implements Highlighter.Highlight {

	public int getStartOffset() {
	    return p0.getOffset();
	}

	public int getEndOffset() {
	    return p1.getOffset();
	}

	public Highlighter.HighlightPainter getPainter() {
	    return painter;
	}

	Position p0;
	Position p1;
        Highlighter.HighlightPainter painter;
    }


    /**
     * LayeredHighlightPainter is used when a drawsLayeredHighlights is
     * true. It maintains a rectangle of the region to paint.
     */
    private static class LayeredHighlightInfo extends HighlightInfo {

	void union(Shape bounds) {
	    if (bounds == null)
		return;

	    Rectangle alloc;
	    if (bounds instanceof Rectangle) {
		alloc = (Rectangle)bounds;
	    }
	    else {
		alloc = bounds.getBounds();
	    }
	    if (width == 0 || height == 0) {
		x = alloc.x;
		y = alloc.y;
		width = alloc.width;
		height = alloc.height;
	    }
	    else {
		width = Math.max(x + width, alloc.x + alloc.width);
		height = Math.max(y + height, alloc.y + alloc.height);
		x = Math.min(x, alloc.x);
		width -= x;
		y = Math.min(y, alloc.y);
		height -= y;
	    }
	}

	/**
	 * Restricts the region based on the receivers offsets and messages
	 * the painter to paint the region.
	 */
	void paintLayeredHighlights(Graphics g, int p0, int p1,
				    Shape viewBounds, JTextComponent editor,
				    View view) {
	    int start = getStartOffset();
	    int end = getEndOffset();
	    // Restrict the region to what we represent
	    p0 = Math.max(start, p0);
	    p1 = Math.min(end, p1);
	    // Paint the appropriate region using the painter and union
	    // the effected region with our bounds.
	    union(((LayeredHighlighter.LayerPainter)painter).paintLayer
		  (g, p0, p1, viewBounds, editor, view));
	}

	int x;
	int y;
	int width;
	int height;
    }

    /**
     * This class invokes <code>mapper.damageRange</code> in
     * EventDispatchThread. The only one instance per Highlighter
     * is cretaed. When a number of ranges should be damaged
     * it collects them into queue and damages
     * them in consecutive order in <code>run</code>
     * call.
     */
    class SafeDamager implements Runnable {
        private final List<Position> p0 = new ArrayList<Position>();
        private final List<Position> p1 = new ArrayList<Position>();
        private Document lastDoc = null;

        /**
         * Executes range(s) damage and cleans range queue.
         */
        public synchronized void run() {
            if (component != null) {
                TextUI mapper = component.getUI();
                if (mapper != null && lastDoc == component.getDocument()) {
                    // the Document should be the same to properly
                    // display highlights
                    int len = p0.size();
                    for (int i = 0; i < len; i++){
                        mapper.damageRange(component,
                                p0.get(i).getOffset(),
                                p1.get(i).getOffset());
                    }
                }
            }
            p0.clear();
            p1.clear();

            // release reference
            lastDoc = null;
        }

        /**
         * Adds the range to be damaged into the range queue. If the
         * range queue is empty (the first call or run() was already
         * invoked) then adds this class instance into EventDispatch
         * queue.
         *
         * The method also tracks if the current document changed or
         * component is null. In this case it removes all ranges added
         * before from range queue.
         */
        private synchronized void damageRange(Position pos0, Position pos1) {
            if (component == null) {
                p0.clear();
                lastDoc = null;
                return;
            }

            boolean addToQueue = p0.isEmpty();
            Document curDoc = component.getDocument();
            if (curDoc != lastDoc) {
                if (!p0.isEmpty()) {
                    p0.clear();
                    p1.clear();
                }
                lastDoc = curDoc;
            }
            p0.add(pos0);
            p1.add(pos1);

            if (addToQueue) {
                SwingUtilities.invokeLater(this);
            }
        }
    }
}
