gcc/libjava/classpath/javax/swing/text/FieldView.java

/* FieldView.java --
   Copyright (C) 2004, 2006 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
WITHOUT ANY WARRANTY; without even the implied warranty of
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
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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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this exception to your version of the library, but you are not
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package javax.swing.text;

import java.awt.Component;
import java.awt.Container;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Shape;

import javax.swing.BoundedRangeModel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;

public class FieldView extends PlainView
{
  BoundedRangeModel horizontalVisibility;

  /** Caches the preferred span of the X axis. It is invalidated by
   * setting it to -1f. This is done when text in the document
   * is inserted, removed or changed. The value is corrected as
   * soon as calculateHorizontalSpan() is called.
   */
  float cachedSpan = -1f;

  public FieldView(Element elem)
  {
    super(elem);

  }

  /** Checks whether the given container is a JTextField. If so
   * it retrieves the textfield's horizontalVisibility instance.
   *
   * <p>This method should be only called when the view's container
   * is valid. Naturally that would be the setParent() method however
   * that method is not overridden in the RI and that is why we chose
   * paint() instead.</p>
   */
  private void checkContainer()
  {
    Container c = getContainer();

    if (c instanceof JTextField)
      {
        horizontalVisibility = ((JTextField) c).getHorizontalVisibility();

        // Provokes a repaint when the BoundedRangeModel's values change
        // (which is what the RI does).
        horizontalVisibility.addChangeListener(new ChangeListener(){
          public void stateChanged(ChangeEvent event) {
            getContainer().repaint();
          }
        });

        // It turned out that the span calculated at this point is wrong
        // and needs to be recalculated (e.g. a different font setting is
        // not taken into account).
        calculateHorizontalSpan();

        // Initializes the BoundedRangeModel properly.
        updateVisibility();
      }

  }

  private void updateVisibility()
  {
    JTextField tf = (JTextField) getContainer();
    Insets insets = tf.getInsets();

    int width = tf.getWidth() - insets.left - insets.right;

    horizontalVisibility.setMaximum(Math.max((int) ((cachedSpan != -1f)
                                                 ? cachedSpan
                                                 : calculateHorizontalSpan()),
                                             width));

    horizontalVisibility.setExtent(width - 1);
  }

  protected FontMetrics getFontMetrics()
  {
    Component container = getContainer();
    return container.getFontMetrics(container.getFont());
  }

  /**
   * Vertically centers the single line of text within the
   * bounds of the input shape. The returned Rectangle is centered
   * vertically within <code>shape</code> and has a height of the
   * preferred span along the Y axis. Horizontal adjustment is done according
   * to the horizontalAligment property of the component that is rendered.
   *
   * @param shape the shape within which the line is beeing centered
   */
  protected Shape adjustAllocation(Shape shape)
  {
    // Return null when the original allocation is null (like the RI).
    if (shape == null)
      return null;

    Rectangle rectIn = shape.getBounds();
    // vertical adjustment
    int height = (int) getPreferredSpan(Y_AXIS);
    int y = rectIn.y + (rectIn.height - height) / 2;
    // horizontal adjustment
    JTextField textField = (JTextField) getContainer();
    int width = (int) ((cachedSpan != -1f) ? cachedSpan : calculateHorizontalSpan());
    int x;
    if (horizontalVisibility != null && horizontalVisibility.getExtent() < width)
        x = rectIn.x - horizontalVisibility.getValue();
    else
      switch (textField.getHorizontalAlignment())
        {
        case JTextField.CENTER:
          x = rectIn.x + (rectIn.width - width) / 2;
          break;
        case JTextField.RIGHT:
          x = rectIn.x + (rectIn.width - width - 1);
          break;
        case JTextField.TRAILING:
          if (textField.getComponentOrientation().isLeftToRight())
            x = rectIn.x + (rectIn.width - width - 1);
          else
            x = rectIn.x;
          break;
        case JTextField.LEADING:
          if (textField.getComponentOrientation().isLeftToRight())
            x = rectIn.x;
          else
            x = rectIn.x + (rectIn.width - width - 1);
          break;
        case JTextField.LEFT:
        default:
          x = rectIn.x;
          break;
        }

    return new Rectangle(x, y, width, height);
  }

  public float getPreferredSpan(int axis)
  {
    if (axis != X_AXIS && axis != Y_AXIS)
      throw new IllegalArgumentException();


    if (axis == Y_AXIS)
      return super.getPreferredSpan(axis);

    if (cachedSpan != -1f)
      return cachedSpan;

    return calculateHorizontalSpan();
  }

  /** Calculates and sets the horizontal span and stores the value
   * in cachedSpan.
   */
  private float calculateHorizontalSpan()
  {
    Segment s = getLineBuffer();
    Element elem = getElement();

    try
      {
        elem.getDocument().getText(elem.getStartOffset(),
                                          elem.getEndOffset() - 1,
                                          s);

        return cachedSpan = Utilities.getTabbedTextWidth(s, getFontMetrics(), 0, this, s.offset);
      }
    catch (BadLocationException e)
      {
        // Should never happen
        AssertionError ae = new AssertionError();
        ae.initCause(e);
        throw ae;
      }
  }

  public int getResizeWeight(int axis)
  {
    return axis == X_AXIS ? 1 : 0;
  }

  public Shape modelToView(int pos, Shape a, Position.Bias bias)
    throws BadLocationException
  {
    Shape newAlloc = adjustAllocation(a);
    return super.modelToView(pos, newAlloc, bias);
  }

  public void paint(Graphics g, Shape s)
  {
    if (horizontalVisibility == null)
      checkContainer();

    Shape newAlloc = adjustAllocation(s);

    Shape clip = g.getClip();
    if (clip != null)
      {
        // Reason for this: The allocation area is always determined by the
        // size of the component (and its insets) regardless of whether
        // parts of the component are invisible or not (e.g. when the
        // component is part of a JScrollPane and partly moved out of
        // the user-visible range). However the clip of the Graphics
        // instance may be adjusted properly to that condition but
        // does not handle insets. By calculating the intersection
        // we get the correct clip to paint the text in all cases.
        Rectangle r = s.getBounds();
        Rectangle cb = clip.getBounds();
        SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, cb);

        g.setClip(cb);
      }
    else
      g.setClip(s);

    super.paint(g, newAlloc);
    g.setClip(clip);

  }

  public void insertUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
  {
    cachedSpan = -1f;

    if (horizontalVisibility != null)
      updateVisibility();

    Shape newAlloc = adjustAllocation(shape);

    super.insertUpdate(ev, newAlloc, vf);
    getContainer().repaint();
  }

  public void removeUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
  {
    cachedSpan = -1f;

    if (horizontalVisibility != null)
      updateVisibility();

    Shape newAlloc = adjustAllocation(shape);
    super.removeUpdate(ev, newAlloc, vf);
    getContainer().repaint();
  }

  public void changedUpdate(DocumentEvent ev, Shape shape, ViewFactory vf)
  {
    cachedSpan = -1f;

    if (horizontalVisibility != null)
      updateVisibility();

    Shape newAlloc = adjustAllocation(shape);
    super.changedUpdate(ev, newAlloc, vf);
    getContainer().repaint();
  }

  public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias)
  {
    return super.viewToModel(fx, fy, adjustAllocation(a), bias);
  }

}