inlineview.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

/*
 * @(#)InlineView.java	1.27 06/05/12
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package javax.swing.text.html;

import java.awt.*;
import java.text.BreakIterator;
import javax.swing.event.DocumentEvent;
import javax.swing.text.*;

/**
 * Displays the <dfn>inline element</dfn> styles
 * based upon css attributes.
 *
 * @author  Timothy Prinzing
 * @version 1.27 05/12/06
 */
public class InlineView extends LabelView {

    /**
     * Constructs a new view wrapped on an element.
     *
     * @param elem the element
     */
    public InlineView(Element elem) {
	super(elem);
	StyleSheet sheet = getStyleSheet();
	attr = sheet.getViewAttributes(this);
    }

    /**
     * Gives notification that something was inserted into 
     * the document in a location that this view is responsible for.
     * If either parameter is <code>null</code>, behavior of this method is
     * implementation dependent.
     *  
     * @param e the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @since 1.5
     * @see View#insertUpdate
     */
    public void insertUpdate(DocumentEvent e, Shape a, ViewFactory f) {
	super.insertUpdate(e, a, f);
        longestWordSpan = -1.0f;
    }

    /**
     * Gives notification that something was removed from the document
     * in a location that this view is responsible for.
     * If either parameter is <code>null</code>, behavior of this method is
     * implementation dependent. 
     *
     * @param e the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @since 1.5
     * @see View#removeUpdate
     */
    public void removeUpdate(DocumentEvent e, Shape a, ViewFactory f) {
        super.removeUpdate(e, a, f);
        longestWordSpan = -1.0f;
    }

    /**
     * Gives notification from the document that attributes were changed
     * in a location that this view is responsible for.
     *
     * @param e the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @see View#changedUpdate
     */
    public void changedUpdate(DocumentEvent e, Shape a, ViewFactory f) {
	super.changedUpdate(e, a, f);
	StyleSheet sheet = getStyleSheet();
	attr = sheet.getViewAttributes(this);
        longestWordSpan = -1.0f;
	preferenceChanged(null, true, true);
    }

    /**
     * Fetches the attributes to use when rendering.  This is
     * implemented to multiplex the attributes specified in the
     * model with a StyleSheet.
     */
    public AttributeSet getAttributes() {
	return attr;
    }

    /**
     * Determines how attractive a break opportunity in 
     * this view is.  This can be used for determining which
     * view is the most attractive to call <code>breakView</code>
     * on in the process of formatting.  A view that represents
     * text that has whitespace in it might be more attractive
     * than a view that has no whitespace, for example.  The
     * higher the weight, the more attractive the break.  A
     * value equal to or lower than <code>BadBreakWeight</code>
     * should not be considered for a break.  A value greater
     * than or equal to <code>ForcedBreakWeight</code> should
     * be broken.
     * <p>
     * This is implemented to provide the default behavior
     * of returning <code>BadBreakWeight</code> unless the length
     * is greater than the length of the view in which case the 
     * entire view represents the fragment.  Unless a view has
     * been written to support breaking behavior, it is not
     * attractive to try and break the view.  An example of
     * a view that does support breaking is <code>LabelView</code>.
     * An example of a view that uses break weight is 
     * <code>ParagraphView</code>.
     *
     * @param axis may be either View.X_AXIS or View.Y_AXIS
     * @param pos the potential location of the start of the 
     *   broken view >= 0.  This may be useful for calculating tab
     *   positions.
     * @param len specifies the relative length from <em>pos</em>
     *   where a potential break is desired >= 0.
     * @return the weight, which should be a value between
     *   ForcedBreakWeight and BadBreakWeight.
     * @see LabelView
     * @see ParagraphView
     * @see javax.swing.text.View#BadBreakWeight
     * @see javax.swing.text.View#GoodBreakWeight
     * @see javax.swing.text.View#ExcellentBreakWeight
     * @see javax.swing.text.View#ForcedBreakWeight
     */
    public int getBreakWeight(int axis, float pos, float len) {
	if (nowrap) {
	    return BadBreakWeight;
	}
	return super.getBreakWeight(axis, pos, len);
    }

    /**
     * Tries to break this view on the given axis. Refer to
     * {@link javax.swing.text.View#breakView} for a complete
     * description of this method.
     * <p>Behavior of this method is unspecified in case <code>axis</code>
     * is neither <code>View.X_AXIS</code> nor <code>View.Y_AXIS</code>, and
     * in case <code>offset</code>, <code>pos</code>, or <code>len</code>
     * is null.
     *   
     * @param axis may be either <code>View.X_AXIS</code> or
     *		<code>View.Y_AXIS</code>
     * @param offset the location in the document model
     *   that a broken fragment would occupy >= 0.  This
     *   would be the starting offset of the fragment
     *   returned
     * @param pos the position along the axis that the
     *  broken view would occupy >= 0.  This may be useful for
     *  things like tab calculations
     * @param len specifies the distance along the axis
     *  where a potential break is desired >= 0
     * @return the fragment of the view that represents the
     *  given span.
     * @since 1.5 
     * @see javax.swing.text.View#breakView
     */
    public View breakView(int axis, int offset, float pos, float len) {
        InlineView view = (InlineView)super.breakView(axis, offset, pos, len);
        if (view != this) {
            view.longestWordSpan = -1;
        }
        return view;
    }

    /**
     * Fetch the span of the longest word in the view.
     */
    float getLongestWordSpan() {
        if (longestWordSpan < 0.0f) {
            longestWordSpan = calculateLongestWordSpan();
        }
        return longestWordSpan; 
    }
    
    float calculateLongestWordSpan() {
        float rv = 0f;
        Document doc = getDocument();
        //AbstractDocument.MultiByteProperty
        final Object MultiByteProperty = "multiByte";
        if (doc != null && 
              Boolean.TRUE.equals(doc.getProperty(MultiByteProperty))) {
            rv = calculateLongestWordSpanUseBreakIterator();
        } else {
            rv = calculateLongestWordSpanUseWhitespace();
        }
        return rv;
    }

    float calculateLongestWordSpanUseBreakIterator() {
        float span = 0;
        Document doc = getDocument();
        int p0 = getStartOffset();
        int p1 = getEndOffset();
        if (p1 > p0) {
            try {
                FontMetrics metrics = getFontMetrics();
                Segment segment = new Segment();
                doc.getText(p0, p1 - p0, segment);
                Container c = getContainer();
                BreakIterator line;
                if (c != null) {
                    line = BreakIterator.getLineInstance(c.getLocale());
                } else {
                    line = BreakIterator.getLineInstance();
                }
                line.setText(segment);
                int start = line.first();
                for (int end = line.next();
                     end != BreakIterator.DONE;
                     start = end, end = line.next()) {
                    if (end > start) {
                        span = Math.max(span,
                            metrics.charsWidth(segment.array, start,
                                               end - start)); 
                    }
                }
            } catch (BadLocationException ble) {
                // If the text can't be retrieved, it can't influence the size.
            }
        }
        return span;
    }

    
    float calculateLongestWordSpanUseWhitespace() {
        float span = 0;
        Document doc = getDocument();
        int p0 = getStartOffset();
        int p1 = getEndOffset();
        if (p1 > p0) {
            try {
                Segment segment = new Segment();
                doc.getText(p0, p1 - p0, segment);
                final int CONTENT = 0;
                final int SPACES = 1;
                int state = CONTENT;
                int start = segment.offset;
                int end = start;
                FontMetrics metrics = getFontMetrics();
                final int lastIndex = segment.offset + segment.count - 1;
                for (int i = segment.offset; i <= lastIndex; i++) {
                    boolean updateSpan = false;
                    if (Character.isWhitespace(segment.array[i])) {
                        if (state == CONTENT) {
                            //we got a word
                            updateSpan = true;
                            state = SPACES;
                        }
                    } else {
                        if (state == SPACES) {
                            //first non space
                            start = i;
                            end = start;
                            state = CONTENT;
                        } else {
                            end = i;
                        }
                        //handle last word
                        if (i == lastIndex) {
                            updateSpan = true;
                        }
                    }
                    if (updateSpan) {
                        if (end > start) {
                            span = Math.max(span,
                                metrics.charsWidth(segment.array, start, 
                                                   end - start + 1)); 
                        }
                    }

                }
            } catch (BadLocationException ble) {
                // If the text can't be retrieved, it can't influence the size.
            }
        }
        return span;
    }
    /**
     * Set the cached properties from the attributes.
     */
    protected void setPropertiesFromAttributes() {
	super.setPropertiesFromAttributes();
	AttributeSet a = getAttributes();
	Object decor = a.getAttribute(CSS.Attribute.TEXT_DECORATION);
	boolean u = (decor != null) ? 
	  (decor.toString().indexOf("underline") >= 0) : false;
	setUnderline(u);
	boolean s = (decor != null) ? 
	  (decor.toString().indexOf("line-through") >= 0) : false;
	setStrikeThrough(s);
        Object vAlign = a.getAttribute(CSS.Attribute.VERTICAL_ALIGN);
	s = (vAlign != null) ? (vAlign.toString().indexOf("sup") >= 0) : false;
	setSuperscript(s);
	s = (vAlign != null) ? (vAlign.toString().indexOf("sub") >= 0) : false;
	setSubscript(s);

	Object whitespace = a.getAttribute(CSS.Attribute.WHITE_SPACE);
	if ((whitespace != null) && whitespace.equals("nowrap")) {
	    nowrap = true;
	} else {
	    nowrap = false;
	}

	HTMLDocument doc = (HTMLDocument)getDocument();
	// fetches background color from stylesheet if specified
	Color bg = doc.getBackground(a);
	if (bg != null) {
	    setBackground(bg);
	}
    }


    protected StyleSheet getStyleSheet() {
	HTMLDocument doc = (HTMLDocument) getDocument();
	return doc.getStyleSheet();
    }

    private boolean nowrap;
    private AttributeSet attr;
    private float longestWordSpan = -1.0f;
}