jtextarea.java

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    }

    /**
     * Implements the abstract method in charva.awt.Component.
     */
    public void draw() {
	Point tempCaret = null;
	Point caret = _caret;

	/* Get the absolute origin of this component.
	 */
	Point origin = getLocationOnScreen();

	Toolkit term = Toolkit.getDefaultToolkit();
	int colorpair = getCursesColor();

	/* Start by blanking out the text area 
	 */
	term.blankBox(origin, getSize(), colorpair);
	term.setCursor(origin);

	/* Scan through the entire document, drawing each character in it.
	 */
	ScrollEvent scrollevent = null;
	int row = 0, col = 0;
outerloop:
	for (int i=0; i<super._document.length(); i++) {

	    /* At some point during the scan of the document, the
	     * caret position should match the scan index, unless the caret
	     * position is after the last character of the document.
	     */
	    if (_caretPosition == i) {
		tempCaret = new Point(col, row);

		/* If the caret has changed, generate a ScrollEvent. Note
		 * that this method may be called multiple times during the
		 * scan; however, we must post only the last event generated.
		 */
		if (tempCaret.equals(caret) == false) {
		    scrollevent = generateScrollEvent(tempCaret, 
			    new Point(col, row));
		    caret = tempCaret;
		}
	    }

	    char chr = super._document.charAt(i);
	    if (col < _columns) {
		if (chr == '\n') {
		    col = 0;
		    row++;
		    if (row >= _rows)
			_rows++;
		    term.setCursor(origin.addOffset(col, row));
		}
		else {
		    term.addChar(chr, 0, colorpair);
		    col++;
		}
	    }
	    else {	// We have reached the right-hand column.
		if (_lineWrap == false) {
		    if (chr == '\n') {
			col = 0;
			row++;
			if (row >= _rows)
			    _rows++;
			term.setCursor(origin.addOffset(col, row));
		    }
		    else {
			term.addChar(chr, 0, colorpair);
			col++;
			_columns++;
		    }
		}
		else {	// line-wrap is true
		    if (_wrapStyleWord == false) {
			col = 0;
			row++;
			if (row >= _rows)
			    _rows++;
			term.setCursor(origin.addOffset(col, row));
			if (chr != '\n')    // thanks to Chris Rogers for this
			    term.addChar(chr, 0, colorpair);
		    }
		    else {
			/* We must back-track until we get to whitespace, so
			 * that we can move the word to the next line.
			 */
			int j;
			for (j=0; j<_columns; j++) {
			    char tmpchr = super._document.charAt(i-j);
			    if (tmpchr == ' ' || tmpchr == '\t') {
				deleteEOL(term, col-j, row, colorpair);
				col = 0;
				row++;
				if (row >= _rows)
				    _rows++;
				i -= j;
				term.setCursor(origin.addOffset(col, row));
				break;
			    }
			}
			if (j == _columns) {	// the word was too long
			    if (chr == ' ' || chr == '\n' || chr == '\t') {
				col = 0;
				row++;
				if (row >= _rows)
				    _rows++;
				term.setCursor(origin.addOffset(col, row));
			    }
			}
		    }
		}	// end if line-wrap is true
	    }		// end if we have reached the right-hand column
	}		// end FOR loop.

	/* Check for the case where the caret position is after the last
	 * character of the document.
	 */
	if (_caretPosition == super._document.length()) {
	    tempCaret = new Point(col, row);

	    /* If the caret has changed, generate a ScrollEvent
	     */
	    if (tempCaret.equals(caret) == false) {
		scrollevent = generateScrollEvent(tempCaret, 
			new Point(col, row));
	    }
	    caret = tempCaret;
	}

	/* Post a ScrollEvent, if one was generated; but only if the
	 * caret has really changed.  We have to be careful to avoid an
	 * endless loop, where a ScrollEvent triggers a draw(), which
	 * triggers an unnecessary ScrollEvent and so on.
	 */
	if ((_caret.equals(caret) == false) && scrollevent != null) {
	    term.getSystemEventQueue().postEvent(scrollevent);
	    _caret = caret;
	}
    }

    public void requestFocus() {
	/* Generate the FOCUS_GAINED event.
	 */
	super.requestFocus();

	/* Get the absolute origin of this component.
	 */
	Point origin = getLocationOnScreen();
	Toolkit.getDefaultToolkit().setCursor(origin.addOffset(_caret));
    }

    /**
     * Register a ScrollListener object for this JTextArea.
     */
    public void addScrollListener(ScrollListener sl_) {
	if (_scrollListeners == null)
	    _scrollListeners = new Vector();
	_scrollListeners.add(sl_);
    }

    /**
     * Remove a ScrollListener object that is registered for this JTextArea.
     */
    public void removeScrollListener(ScrollListener sl_) {
	if (_scrollListeners == null)
	    return;
	_scrollListeners.remove(sl_);
    }

    /** Process scroll events generated by this JTextArea.
     */
    public void processScrollEvent(ScrollEvent e_) {
	if (_scrollListeners != null) {
	    for (Enumeration e = _scrollListeners.elements(); 
		    e.hasMoreElements(); ) {

		ScrollListener sl = (ScrollListener) e.nextElement();
		sl.scroll(e_);
	    }
	}
    }

    /** Returns the preferred size of the viewport for this JTextArea
     * when it is in a JScrollPane (this method implements the 
     * Scrollable interface). The size is determined by the number of
     * rows and columns set for this JTextArea (either in the constructor
     * or in the setColumns() and setRows() methods).
     */
    public Dimension getPreferredScrollableViewportSize() {
	return new Dimension(_preferredColumns, _preferredRows);
    }

    public void debug(int level_)
    {
	for (int i=0; i<level_; i++)
	    System.err.print("    ");
	System.err.println("JTextArea origin=" + _origin + 
	    " size=" + getSize());
    }

    /** A private helper method to delete from a specified position
     * until the end of the line.
     */
    private void deleteEOL(Toolkit term_, int col_, int row_, int colorpair_)
    {
	Point origin = getLocationOnScreen();
	term_.setCursor(origin.addOffset(col_, row_));
	for (int i=col_; i<_columns ; i++)
	    term_.addChar(' ', 0, colorpair_);
    }

    /** This helper method converts offset to line number and
     * vice versa.
     */
    private int offsetCalc(int mode_, int value_)
    {
	int lineOfOffset=0;
	int row = 0;

	if (mode_ == LINE_START_OFFSET && value_ == 0)
	    return 0;

	for (int col=0, i=0; 
		i<super._document.length(); 
		i++) {

	    if (mode_ == LINE_OF_OFFSET && value_ == i) {
		lineOfOffset = row;
	    }

	    char chr = super._document.charAt(i);
	    if (col < _columns) {
		if (chr == '\n') {
		    col = 0;
		    row++;
		}
		else {
		    col++;
		}
	    }
	    else {	// We have reached the right-hand column.
		if (_lineWrap == false) {
		    if (chr == '\n') {
			col = 0;
			row++;
		    }
		}
		else {	// line-wrap is true
		    if (_wrapStyleWord == false) {
			col = 0;
			row++;
		    }
		    else {
			/* We must back-track until we get to whitespace, so
			 * that we can move the word to the next line.
			 */
			int j;
			for (j=0; j<_columns; j++) {
			    char tmpchr = super._document.charAt(i-j);
			    if (tmpchr == ' ' || tmpchr == '\t') {
				col = 0;
				row++;
				i -= j;
				break;
			    }
			}
			if (j == _columns) {	// the word was too long
			    if (chr == ' ' || chr == '\n' || chr == '\t') {
				col = 0;
				row++;
			    }
			}
		    }
		}	// end if line-wrap is true
	    }		// end if we have reached the right-hand column

	    if (mode_ == LINE_START_OFFSET && col == 0 && row == value_) {
		return i+1;
	    }
	    else if (mode_ == LINE_END_OFFSET && col == 0 && row == value_+1) {
		return i;
	    }

	}		// end FOR loop.

	if (mode_ == LINE_OF_OFFSET) {
	    if (value_ == super._document.length()) {
		return row;
	    }
	    else
		return lineOfOffset;
	}
	else if (mode_ == LINE_COUNT) {
	    return row+1;
	}
	else if (mode_ == LINE_END_OFFSET && row == value_) {
	    return super._document.length();
	}
	else {
	    throw new IndexOutOfBoundsException(
		"Invalid offset or line number: mode=" + mode_ + 
		" value=" + value_ + " row=" + row + " doc=\"" + _document + "\"");
	}
    }

    /* Private helper method used to redraw the component if its state
     * has changed.
     */
    private void refresh()
    {
	/* If this JTextArea is contained in a JViewport, the PaintEvent
	 * that we post must request a redraw of the JViewport, so that
	 * the JViewport can set the clipping rectangle before calling the
	 * draw() method of this JTextArea.
	 */
	Component todraw; 
	if (getParent() instanceof JViewport)
	    todraw = getParent();
	else
	    todraw = this;
	    
	/* If this component is already displayed, generate a PaintEvent
	 * and post it onto the queue.
	 */
	todraw.repaint();
    }

    /** Private method, called whenever the caret changes.
     */
    private ScrollEvent generateScrollEvent(Point tempCaret_, Point col_row_)
    {
	int direction;

	/* Determine the direction of scrolling
	 */
	if (tempCaret_.y > _caret.y) {
	    if (tempCaret_.x > _caret.x)
		direction = ScrollEvent.UP_LEFT;
	    else if (tempCaret_.x < _caret.x)
		direction = ScrollEvent.UP_RIGHT;
	    else
		direction = ScrollEvent.UP;
	}
	else if (tempCaret_.y < _caret.y) {
	    if (tempCaret_.x > _caret.x)
		direction = ScrollEvent.DOWN_LEFT;
	    else if (tempCaret_.x < _caret.x)
		direction = ScrollEvent.DOWN_RIGHT;
	    else
		direction = ScrollEvent.DOWN;
	}
	else {
	    if (tempCaret_.x > _caret.x)
		direction = ScrollEvent.LEFT;
	    else
		direction = ScrollEvent.RIGHT;
	}
	return new ScrollEvent(this, direction, col_row_);

    }

    //====================================================================
    // INSTANCE VARIABLES

    private int _rows;
    private int _columns;

    private int _preferredRows;
    private int _preferredColumns;

    /** The caret is updated only when the component is drawn.
     */
    private Point _caret = new Point(0,0);

    private boolean _lineWrap;
    private boolean _wrapStyleWord = false;

    /** A list of ScrollListeners registered for this JTextArea.
     */
    private Vector _scrollListeners = null;

    private static final int LINE_COUNT = 1;
    private static final int LINE_START_OFFSET = 2;
    private static final int LINE_END_OFFSET = 3;
    private static final int LINE_OF_OFFSET = 4;
}