jedittextarea.java

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/*
 * JEditTextArea.java - jEdit's text component
 * Copyright (C) 1999 Slava Pestov
 *
 * You may use and modify this package for any purpose. Redistribution is
 * permitted, in both source and binary form, provided that this notice
 * remains intact in all source distributions of this package.
 */

package org.syntax.jedit;

import org.syntax.jedit.tokenmarker.*;  
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.undo.*;
import javax.swing.*;
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.*;
import java.util.Enumeration;
import java.util.Vector;

/**
 * jEdit's text area component. It is more suited for editing program
 * source code than JEditorPane, because it drops the unnecessary features
 * (images, variable-width lines, and so on) and adds a whole bunch of
 * useful goodies such as:
 * <ul>
 * <li>More flexible key binding scheme
 * <li>Supports macro recorders
 * <li>Rectangular selection
 * <li>Bracket highlighting
 * <li>Syntax highlighting
 * <li>Command repetition
 * <li>Block caret can be enabled
 * </ul>
 * It is also faster and doesn't have as many problems. It can be used
 * in other applications; the only other part of jEdit it depends on is
 * the syntax package.<p>
 *
 * To use it in your app, treat it like any other component, for example:
 * <pre>JEditTextArea ta = new JEditTextArea();
 * ta.setTokenMarker(new JavaTokenMarker());
 * ta.setText("public class Test {\n"
 *     + "    public static void main(String[] args) {\n"
 *     + "        System.out.println(\"Hello World\");\n"
 *     + "    }\n"
 *     + "}");</pre>
 *
 * @author Slava Pestov
 * @version $Id: JEditTextArea.java,v 1.7 2004/07/15 12:11:16 gt78 Exp $
 */
public class JEditTextArea extends JComponent
{
	/**
	 * Adding components with this name to the text area will place
	 * them left of the horizontal scroll bar. In jEdit, the status
	 * bar is added this way.
	 */
	public static String LEFT_OF_SCROLLBAR = "los";

	/**
	 * Creates a new JEditTextArea with the default settings.
	 */
	public JEditTextArea()
	{
		this(TextAreaDefaults.getDefaults());
	}

	/**
	 * Creates a new JEditTextArea with the specified settings.
	 * @param defaults The default settings
	 */
	public JEditTextArea(TextAreaDefaults defaults)
	{
		// Enable the necessary events
		enableEvents(AWTEvent.KEY_EVENT_MASK);

		// Initialize some misc. stuff
		painter = new TextAreaPainter(this,defaults);
		documentHandler = new DocumentHandler();
		listenerList = new EventListenerList();
		caretEvent = new MutableCaretEvent();
		lineSegment = new Segment();
		bracketLine = bracketPosition = -1;
		blink = true;

		// Initialize the GUI
		setLayout(new ScrollLayout());
		add(CENTER,painter);
		add(RIGHT,vertical = new JScrollBar(JScrollBar.VERTICAL));
		add(BOTTOM,horizontal = new JScrollBar(JScrollBar.HORIZONTAL));
		// Add some event listeners
		vertical.addAdjustmentListener(new AdjustHandler());
		horizontal.addAdjustmentListener(new AdjustHandler());
		painter.addComponentListener(new ComponentHandler());
		painter.addMouseListener(new MouseHandler());
		painter.addMouseMotionListener(new DragHandler());
		addFocusListener(new FocusHandler());

		// Load the defaults
		setInputHandler(defaults.inputHandler);
		setDocument(defaults.document);
		editable = defaults.editable;
		caretVisible = defaults.caretVisible;
		caretBlinks = defaults.caretBlinks;
		electricScroll = defaults.electricScroll;

		popup = defaults.popup;

		// We don't seem to get the initial focus event?
		focusedComponent = this;
	}

	/**
	 * Returns if this component can be traversed by pressing
	 * the Tab key. This returns false.
	 */
	public final boolean isManagingFocus()
	{
		return true;
	}

	/**
	 * Returns the object responsible for painting this text area.
	 */
	public final TextAreaPainter getPainter()
	{
		return painter;
	}

	/**
	 * Returns the input handler.
	 */
	public final InputHandler getInputHandler()
	{
		return inputHandler;
	}

	/**
	 * Sets the input handler.
	 * @param inputHandler The new input handler
	 */
	public void setInputHandler(InputHandler inputHandler)
	{
		this.inputHandler = inputHandler;
	}

	/**
	 * Returns true if the caret is blinking, false otherwise.
	 */
	public final boolean isCaretBlinkEnabled()
	{
		return caretBlinks;
	}

	/**
	 * Toggles caret blinking.
	 * @param caretBlinks True if the caret should blink, false otherwise
	 */
	public void setCaretBlinkEnabled(boolean caretBlinks)
	{
		this.caretBlinks = caretBlinks;
		if(!caretBlinks)
			blink = false;

		painter.invalidateSelectedLines();
	}

	/**
	 * Returns true if the caret is visible, false otherwise.
	 */
	public final boolean isCaretVisible()
	{
		return (!caretBlinks || blink) && caretVisible;
	}

	/**
	 * Sets if the caret should be visible.
	 * @param caretVisible True if the caret should be visible, false
	 * otherwise
	 */
	public void setCaretVisible(boolean caretVisible)
	{
		this.caretVisible = caretVisible;
		blink = true;

		painter.invalidateSelectedLines();
	}

	/**
	 * Blinks the caret.
	 */
	public final void blinkCaret()
	{
		if(caretBlinks)
		{
			blink = !blink;
			painter.invalidateSelectedLines();
		}
		else
			blink = true;
	}

	/**
	 * Returns the number of lines from the top and button of the
	 * text area that are always visible.
	 */
	public final int getElectricScroll()
	{
		return electricScroll;
	}

	/**
	 * Sets the number of lines from the top and bottom of the text
	 * area that are always visible
	 * @param electricScroll The number of lines always visible from
	 * the top or bottom
	 */
	public final void setElectricScroll(int electricScroll)
	{
		this.electricScroll = electricScroll;
	}

	/**
	 * Updates the state of the scroll bars. This should be called
	 * if the number of lines in the document changes, or when the
	 * size of the text are changes.
	 */
	public void updateScrollBars()
	{
		if(vertical != null && visibleLines != 0)
		{
			vertical.setValues(firstLine,visibleLines,0,getLineCount());
			vertical.setUnitIncrement(2);
			vertical.setBlockIncrement(visibleLines);
		}

		int width = this.getWidth();
		if(horizontal != null && width != 0)
		{
			horizontal.setValues(-horizontalOffset,width,0,width * 5);
			horizontal.setUnitIncrement(painter.getFontMetrics()
				.charWidth('w'));
			horizontal.setBlockIncrement(width / 2);
		}
                
                if (this.getVisibleLines() <= this.getLineCount())
                {
                   if (!vertical.isVisible())
                   {
                       vertical.setPreferredSize(new Dimension(16,0));
                       vertical.setVisible(true);
                   }
                }
                else
                {
                    if (vertical.isVisible())
                   {
                       vertical.setPreferredSize(new Dimension(0,0));
                       vertical.setVisible(false);
                   }
                   
                }
                
                // Trova la riga piu' linga...
                int max = 0;
                int tmp_max = 0;
                for (int i=0 ; i<this.getLineCount(); ++i)
                {
                    tmp_max = this.getLineText(i).length(); //  getLineLength(i);
                    max = (max < tmp_max) ? tmp_max : max;
                    //System.out.println(this.getLineText(i));
                }
                if (max * painter.getFontMetrics().charWidth('w') > this.getWidth() )
                {
                   if (!horizontal.isVisible())
                   {
                       horizontal.setPreferredSize(new Dimension(20,16));
                       horizontal.setVisible(true);
                   }
                }
                else
                {
                    if (horizontal.isVisible())
                   {
                       horizontal.setPreferredSize(new Dimension(0,0));
                       horizontal.setVisible(false);
                   }
                   
                }
               // System.out.println(""+ this.getWidth() + "<" + this.getLineCount()+" "+max+" "+ painter.getFontMetrics().charWidth('w') );
	}

	/**
	 * Returns the line displayed at the text area's origin.
	 */
	public final int getFirstLine()
	{
		return firstLine;
	}

	/**
	 * Sets the line displayed at the text area's origin without
	 * updating the scroll bars.
	 */
	public void setFirstLine(int firstLine)
	{
		if(firstLine == this.firstLine)
			return;
		int oldFirstLine = this.firstLine;
		this.firstLine = firstLine;
		if(firstLine != vertical.getValue())
			updateScrollBars();
		painter.repaint();
	}

	/**
	 * Returns the number of lines visible in this text area.
	 */
	public final int getVisibleLines()
	{
		return visibleLines;
	}

	/**
	 * Recalculates the number of visible lines. This should not
	 * be called directly.
	 */
	public final void recalculateVisibleLines()
	{
		if(painter == null)
			return;
		int height = painter.getHeight();
		int lineHeight = painter.getFontMetrics().getHeight();
		int oldVisibleLines = visibleLines;
		visibleLines = height / lineHeight;
		updateScrollBars();
	}

	/**
	 * Returns the horizontal offset of drawn lines.
	 */
	public final int getHorizontalOffset()
	{
		return horizontalOffset;
	}

	/**
	 * Sets the horizontal offset of drawn lines. This can be used to
	 * implement horizontal scrolling.
	 * @param horizontalOffset offset The new horizontal offset
	 */
	public void setHorizontalOffset(int horizontalOffset)
	{
		if(horizontalOffset == this.horizontalOffset)
			return;
		this.horizontalOffset = horizontalOffset;
		if(horizontalOffset != horizontal.getValue())
			updateScrollBars();
		painter.repaint();
	}

	/**
	 * A fast way of changing both the first line and horizontal
	 * offset.
	 * @param firstLine The new first line
	 * @param horizontalOffset The new horizontal offset
	 * @return True if any of the values were changed, false otherwise
	 */
	public boolean setOrigin(int firstLine, int horizontalOffset)
	{
		boolean changed = false;
		int oldFirstLine = this.firstLine;

		if(horizontalOffset != this.horizontalOffset)
		{
			this.horizontalOffset = horizontalOffset;
			changed = true;
		}

		if(firstLine != this.firstLine)
		{
			this.firstLine = firstLine;
			changed = true;
		}

		if(changed)
		{
			updateScrollBars();
			painter.repaint();
		}

		return changed;
	}

	/**
	 * Ensures that the caret is visible by scrolling the text area if
	 * necessary.
	 * @return True if scrolling was actually performed, false if the
	 * caret was already visible
	 */
	public boolean scrollToCaret()
	{
		int line = getCaretLine();
		int lineStart = getLineStartOffset(line);
		int offset = Math.max(0,Math.min(getLineLength(line) - 1,
			getCaretPosition() - lineStart));

		return scrollTo(line,offset);
	}

	/**
	 * Ensures that the specified line and offset is visible by scrolling
	 * the text area if necessary.
	 * @param line The line to scroll to
	 * @param offset The offset in the line to scroll to
	 * @return True if scrolling was actually performed, false if the
	 * line and offset was already visible
	 */
	public boolean scrollTo(int line, int offset)
	{
		// visibleLines == 0 before the component is realized
		// we can't do any proper scrolling then, so we have
		// this hack...
		if(visibleLines == 0)
		{
			setFirstLine(Math.max(0,line - electricScroll));
			return true;
		}

		int newFirstLine = firstLine;
		int newHorizontalOffset = horizontalOffset;

		if(line < firstLine + electricScroll)
		{
			newFirstLine = Math.max(0,line - electricScroll);
		}
		else if(line + electricScroll >= firstLine + visibleLines)
		{
			newFirstLine = (line - visibleLines) + electricScroll + 1;
			if(newFirstLine + visibleLines >= getLineCount())
				newFirstLine = getLineCount() - visibleLines;
			if(newFirstLine < 0)
				newFirstLine = 0;
		}

		int x = _offsetToX(line,offset);
		int width = painter.getFontMetrics().charWidth('w');

		if(x < 0)
		{
			newHorizontalOffset = Math.min(0,horizontalOffset
				- x + width + 5);
		}
		else if(x + width >= painter.getWidth())
		{
			newHorizontalOffset = horizontalOffset +
				(painter.getWidth() - x) - width - 5;
		}

		return setOrigin(newFirstLine,newHorizontalOffset);
	}

	/**
	 * Converts a line index to a y co-ordinate.
	 * @param line The line
	 */
	public int lineToY(int line)
	{
		FontMetrics fm = painter.getFontMetrics();
		return (line - firstLine) * fm.getHeight()
			- (fm.getLeading() + fm.getMaxDescent());
	}

	/**
	 * Converts a y co-ordinate to a line index.
	 * @param y The y co-ordinate
	 */
	public int yToLine(int y)
	{
		FontMetrics fm = painter.getFontMetrics();
		int height = fm.getHeight();
		return Math.max(0,Math.min(getLineCount() - 1,
			y / height + firstLine));
	}

	/**
	 * Converts an offset in a line into an x co-ordinate. This is a
	 * slow version that can be used any time.
	 * @param line The line
	 * @param offset The offset, from the start of the line
	 */
	public final int offsetToX(int line, int offset)
	{
		// don't use cached tokens
		painter.currentLineTokens = null;
		return _offsetToX(line,offset);
	}

	/**
	 * Converts an offset in a line into an x co-ordinate. This is a
	 * fast version that should only be used if no changes were made
	 * to the text since the last repaint.
	 * @param line The line
	 * @param offset The offset, from the start of the line
	 */
	public int _offsetToX(int line, int offset)
	{
		TokenMarker tokenMarker = getTokenMarker();

		/* Use painter's cached info for speed */
		FontMetrics fm = painter.getFontMetrics();

		getLineText(line,lineSegment);

		int segmentOffset = lineSegment.offset;
		int x = horizontalOffset;

		/* If syntax coloring is disabled, do simple translation */
		if(tokenMarker == null)
		{
			lineSegment.count = offset;
			return x + Utilities.getTabbedTextWidth(lineSegment,
				fm,x,painter,0);
		}
		/* If syntax coloring is enabled, we have to do this because
		 * tokens can vary in width */
		else
		{
			Token tokens;
			if(painter.currentLineIndex == line
				&& painter.currentLineTokens != null)
				tokens = painter.currentLineTokens;
			else
			{
				painter.currentLineIndex = line;
				tokens = painter.currentLineTokens
					= tokenMarker.markTokens(lineSegment,line);
			}

			Toolkit toolkit = painter.getToolkit();
			Font defaultFont = painter.getFont();
			SyntaxStyle[] styles = painter.getStyles();