/* TextUI.java --
   Copyright (C) 2002, 2003, 2004  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package javax.swing.plaf;

import java.awt.Point;
import java.awt.Rectangle;

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

/**
 * An abstract base class for delegates that provide the user
 * interface for text editors.
 *
 * @see javax.swing.text.JTextComponent
 *
 * @author Ronald Veldema (rveldema@cs.vu.nl)
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public abstract class TextUI
  extends ComponentUI
{
  /**
   * Constructs a new <code>TextUI</code>.
   */  
  public TextUI()
  {
  }


  /**
   * Calculates the geometric extent of the character at the
   * given offset.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param pos the zero-based index of the character into the
   *        document model.
   *
   * @return the bounding box of the character at index
   *         <code>pos</code>, in view coordinates.
   *
   * @throws BadLocationException if <code>pos</code> does not
   *         designate a valid position in the document model.
   *
   * @see javax.swing.text.View#modelToView(int,
   *      javax.swing.text.Position.Bias, int,
   *      javax.swing.text.position.Bias, java.awt.Shape)
   */
  public abstract Rectangle modelToView(JTextComponent tc, int pos)
    throws BadLocationException;


  /**
   * Calculates the geometric extent of the character at the
   * given offset.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param pos the zero-based index of the character into the
   *        document model.
   *
   * @param bias whether to take the character before or after the
   *        caret position indicated by <code>pos</code>.  The value
   *        must be either {@link
   *        javax.swing.text.Position.Bias#Backward} or {@link
   *        javax.swing.text.Position.Bias#Forward}.
   *
   * @return the bounding box of the character at index
   *         <code>pos</code>, in view coordinates.
   *
   * @throws BadLocationException if <code>pos</code> does not
   *         designate a valid position in the document model.
   *
   * @see javax.swing.text.View#modelToView(int,
   *      javax.swing.text.Position.Bias, int,
   *      javax.swing.text.position.Bias, java.awt.Shape)
   */
  public abstract Rectangle modelToView(JTextComponent tc, int pos,
                                        Position.Bias bias)
    throws BadLocationException;


  /**
   * Finds the caret position which is closest to the specified visual
   * location.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param loc the position in view coordinates.
   *
   * @return the caret position which is closest to <code>loc</code>.
   *
   * @see #viewToModel(JTextComponent, Point, Position.Bias[])
   */
  public abstract int viewToModel(JTextComponent t, Point pt);


  /**
   * Finds the caret position which is closest to the specified visual
   * location.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param loc the position in view coordinates.
   *
   * @param outBias an array whose size must be at least one.
   *        After the call, <code>outBias[0]</code> will indicate
   *        whether <code>loc</code> is in the glyph before
   *        (<code>Position.Bias.Backward</code>) or after
   *        (<code>Position.Bias.Forward</code>) the returned
   *        caret position.
   *
   * @return the caret position which is closest to <code>loc</code>.
   */
  public abstract int viewToModel(JTextComponent tc, Point loc,
                                  Position.Bias[] outBias);
 


  /**
   * Calculates the caret position that is visually next to the given
   * position. This is useful to determine where to move the caret
   * after the user has pressed an arrow key.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param pos the current caret position, a zero-based index
   *        into the document model.
   *
   * @param bias whether to take the character before or after the
   *        caret position indicated by <code>pos</code>.  The value
   *        must be either {@link
   *        javax.swing.text.Position.Bias#Backward} or {@link
   *        javax.swing.text.Position.Bias#Forward}.
   *
   * @param direction the visual direction. Pass
   *        {@link javax.swing.SwingConstants#WEST} for the left
   *        arrow key, {@link javax.swing.SwingConstants#EAST}
   *        for the right arrow key, {@link
   *        javax.swing.SwingConstants#NORTH} for the up arrow
   *        key, or {@link javax.swing.SwingConstants#SOUTH}
   *        for the down arrow key.
   *
   * @throws BadLocationException if <code>pos</code> does not
   *         designate a valid position in the document model.
   *
   * @throws IllegalArgumentException if <code>direction</code>
   *         is not one of <code>Position.Bias.Forward</code>
   *         or <code>Position.Biad.Backward</code>.
   */
  public abstract int getNextVisualPositionFrom(JTextComponent tc,
                                                int pos,
                                                Position.Bias bias,
                                                int direction,
                                                Position.Bias[] outBias)
    throws BadLocationException;


  /**
   * Repaints a range of characters.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param start the first character in the range that needs
   *        painting, indicated as an index into the document model.
   *
   * @param end the last character in the range that needs
   *        painting, indicated as an index into the document model.
   *        <code>end</code> must be greater than or equal to
   *        <code>start</code>.
   */
  public abstract void damageRange(JTextComponent tc, int start, int end);


  /**
   * Repaints a range of characters, also specifying the bias for the
   * start and end of the range.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param start the first character in the range that needs
   *        painting, indicated as an index into the document model.
   *
   * @param end the last character in the range that needs
   *        painting, indicated as an index into the document model.
   *        <code>end</code> must be greater than or equal to
   *        <code>start</code>.
   */
  public abstract void damageRange(JTextComponent tc,
                                   int start, int end,
                                   Position.Bias startBias,
                                   Position.Bias endBias);

  
  /**
   * Retrieves the <code>EditorKit</code> managing policies and
   * persistent state.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @return the <code>EditorKit</code> used by <code>tc</code>.
   */
  public abstract EditorKit getEditorKit(JTextComponent tc);
  
  
  /**
   * Retrieves the root of the view tree that visually presents
   * the text.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @return the root <code>View</code> used by <code>tc</code>.
   */
  public abstract View getRootView(JTextComponent tc);


  /**
   * Returns a String for presenting a tool tip at the specified
   * location.
   *
   * @param tc the <code>JTextComponent</code> for which this
   *        delegate object provides the user interface.
   *
   * @param loc the location for which the tool tip is requested.
   *
   * @return the text for the tool tip, or <code>null</code> to
   *         display no tool tip.
   *
   * @since 1.4
   */
  public String getToolTipText(JTextComponent tc, Point loc)
  {
    return null;
  }
}
