https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package javax.swing.text;

import java.util.Arrays;
import java.awt.*;
import java.awt.font.TextAttribute;
import javax.swing.event.*;
import javax.swing.SizeRequirements;


View of a simple line-wrapping paragraph that supports
multiple fonts, colors, components, icons, etc.  It is
basically a vertical box with a margin around it.  The
contents of the box are a bunch of rows which are special
horizontal boxes.  This view creates a collection of
views that represent the child elements of the paragraph
element.  Each of these views are placed into a row
directly if they will fit, otherwise the breakView
method is called to try and carve the view into pieces
that fit.

Author: Timothy Prinzing,  Scott Violet,  Igor Kushnirskiy
See Also:
/**
 * View of a simple line-wrapping paragraph that supports
 * multiple fonts, colors, components, icons, etc.  It is
 * basically a vertical box with a margin around it.  The
 * contents of the box are a bunch of rows which are special
 * horizontal boxes.  This view creates a collection of
 * views that represent the child elements of the paragraph
 * element.  Each of these views are placed into a row
 * directly if they will fit, otherwise the <code>breakView</code>
 * method is called to try and carve the view into pieces
 * that fit.
 *
 * @author  Timothy Prinzing
 * @author  Scott Violet
 * @author  Igor Kushnirskiy
 * @see     View
 */
public class ParagraphView extends FlowView implements TabExpander {

    
Constructs a ParagraphView for the given element.

Params:
  • elem – the element that this view is responsible for
/**
     * Constructs a <code>ParagraphView</code> for the given element.
     *
     * @param elem the element that this view is responsible for
     */
    public ParagraphView(Element elem) {
        super(elem, View.Y_AXIS);
        setPropertiesFromAttributes();
        Document doc = elem.getDocument();
        Object i18nFlag = doc.getProperty(AbstractDocument.I18NProperty);
        if ((i18nFlag != null) && i18nFlag.equals(Boolean.TRUE)) {
            try {
                if (i18nStrategy == null) {
                    // the classname should probably come from a property file.
                    String classname = "javax.swing.text.TextLayoutStrategy";
                    ClassLoader loader = getClass().getClassLoader();
                    if (loader != null) {
                        i18nStrategy = loader.loadClass(classname);
                    } else {
                        i18nStrategy = Class.forName(classname);
                    }
                }
                Object o = i18nStrategy.newInstance();
                if (o instanceof FlowStrategy) {
                    strategy = (FlowStrategy) o;
                }
            } catch (Throwable e) {
                throw new StateInvariantError("ParagraphView: Can't create i18n strategy: "
                                              + e.getMessage());
            }
        }
    }

    
Sets the type of justification.

Params:
  • j – one of the following values:

      

    • StyleConstants.ALIGN_LEFT

    • StyleConstants.ALIGN_CENTER

    • StyleConstants.ALIGN_RIGHT

/**
     * Sets the type of justification.
     *
     * @param j one of the following values:
     * <ul>
     * <li><code>StyleConstants.ALIGN_LEFT</code>
     * <li><code>StyleConstants.ALIGN_CENTER</code>
     * <li><code>StyleConstants.ALIGN_RIGHT</code>
     * </ul>
     */
    protected void setJustification(int j) {
        justification = j;
    }

    
Sets the line spacing.

Params:
  • ls – the value is a factor of the line hight
/**
     * Sets the line spacing.
     *
     * @param ls the value is a factor of the line hight
     */
    protected void setLineSpacing(float ls) {
        lineSpacing = ls;
    }

    
Sets the indent on the first line.

Params:
  • fi – the value in points
/**
     * Sets the indent on the first line.
     *
     * @param fi the value in points
     */
    protected void setFirstLineIndent(float fi) {
        firstLineIndent = (int) fi;
    }

    
Set the cached properties from the attributes.

/**
     * Set the cached properties from the attributes.
     */
    protected void setPropertiesFromAttributes() {
        AttributeSet attr = getAttributes();
        if (attr != null) {
            setParagraphInsets(attr);
            Integer a = (Integer)attr.getAttribute(StyleConstants.Alignment);
            int alignment;
            if (a == null) {
                Document doc = getElement().getDocument();
                Object o = doc.getProperty(TextAttribute.RUN_DIRECTION);
                if ((o != null) && o.equals(TextAttribute.RUN_DIRECTION_RTL)) {
                    alignment = StyleConstants.ALIGN_RIGHT;
                } else {
                    alignment = StyleConstants.ALIGN_LEFT;
                }
            } else {
                alignment = a.intValue();
            }
            setJustification(alignment);
            setLineSpacing(StyleConstants.getLineSpacing(attr));
            setFirstLineIndent(StyleConstants.getFirstLineIndent(attr));
        }
    }

    
Returns the number of views that this view is
responsible for.
The child views of the paragraph are rows which
have been used to arrange pieces of the Views
that represent the child elements.  This is the number
of views that have been tiled in two dimensions,
and should be equivalent to the number of child elements
to the element this view is responsible for.

Returns:the number of views that this ParagraphView
         is responsible for
/**
     * Returns the number of views that this view is
     * responsible for.
     * The child views of the paragraph are rows which
     * have been used to arrange pieces of the <code>View</code>s
     * that represent the child elements.  This is the number
     * of views that have been tiled in two dimensions,
     * and should be equivalent to the number of child elements
     * to the element this view is responsible for.
     *
     * @return the number of views that this <code>ParagraphView</code>
     *          is responsible for
     */
    protected int getLayoutViewCount() {
        return layoutPool.getViewCount();
    }

    
Returns the view at a given index.
The child views of the paragraph are rows which
have been used to arrange pieces of the Views
that represent the child elements.  This methods returns
the view responsible for the child element index
(prior to breaking).  These are the Views that were
produced from a factory (to represent the child
elements) and used for layout.

Params:
  • index – the index of the desired view
Returns:the view at index
/**
     * Returns the view at a given <code>index</code>.
     * The child views of the paragraph are rows which
     * have been used to arrange pieces of the <code>Views</code>
     * that represent the child elements.  This methods returns
     * the view responsible for the child element index
     * (prior to breaking).  These are the Views that were
     * produced from a factory (to represent the child
     * elements) and used for layout.
     *
     * @param index the <code>index</code> of the desired view
     * @return the view at <code>index</code>
     */
    protected View getLayoutView(int index) {
        return layoutPool.getView(index);
    }

    
Returns the next visual position for the cursor, in
either the east or west direction.
Overridden from CompositeView.

Params:
  • pos – position into the model
  • b – either Position.Bias.Forward or
         Position.Bias.Backward
  • a – the allocated region to render into
  • direction – either SwingConstants.NORTH
         or SwingConstants.SOUTH
  • biasRet – an array containing the bias that were checked
 in this method
Returns:the location in the model that represents the
 next location visual position
/**
     * Returns the next visual position for the cursor, in
     * either the east or west direction.
     * Overridden from <code>CompositeView</code>.
     * @param pos position into the model
     * @param b either <code>Position.Bias.Forward</code> or
     *          <code>Position.Bias.Backward</code>
     * @param a the allocated region to render into
     * @param direction either <code>SwingConstants.NORTH</code>
     *          or <code>SwingConstants.SOUTH</code>
     * @param biasRet an array containing the bias that were checked
     *  in this method
     * @return the location in the model that represents the
     *  next location visual position
     */
    protected int getNextNorthSouthVisualPositionFrom(int pos, Position.Bias b,
                                                      Shape a, int direction,
                                                      Position.Bias[] biasRet)
                                                throws BadLocationException {
        int vIndex;
        if(pos == -1) {
            vIndex = (direction == NORTH) ?
                     getViewCount() - 1 : 0;
        }
        else {
            if(b == Position.Bias.Backward && pos > 0) {
                vIndex = getViewIndexAtPosition(pos - 1);
            }
            else {
                vIndex = getViewIndexAtPosition(pos);
            }
            if(direction == NORTH) {
                if(vIndex == 0) {
                    return -1;
                }
                vIndex--;
            }
            else if(++vIndex >= getViewCount()) {
                return -1;
            }
        }
        // vIndex gives index of row to look in.
        JTextComponent text = (JTextComponent)getContainer();
        Caret c = text.getCaret();
        Point magicPoint;
        magicPoint = (c != null) ? c.getMagicCaretPosition() : null;
        int x;
        if(magicPoint == null) {
            Shape posBounds;
            try {
                posBounds = text.getUI().modelToView(text, pos, b);
            } catch (BadLocationException exc) {
                posBounds = null;
            }
            if(posBounds == null) {
                x = 0;
            }
            else {
                x = posBounds.getBounds().x;
            }
        }
        else {
            x = magicPoint.x;
        }
        return getClosestPositionTo(pos, b, a, direction, biasRet, vIndex, x);
    }

    
Returns the closest model position to x.
rowIndex gives the index of the view that corresponds
that should be looked in.

Params:
  • pos –  position into the model
  • a – the allocated region to render into
  • direction – one of the following values:

      

    • SwingConstants.NORTH

    • SwingConstants.SOUTH

  • biasRet – an array containing the bias that were checked
 in this method
  • rowIndex – the index of the view
  • x – the x coordinate of interest
Returns:the closest model position to x
/**
     * Returns the closest model position to <code>x</code>.
     * <code>rowIndex</code> gives the index of the view that corresponds
     * that should be looked in.
     * @param pos  position into the model
     * @param a the allocated region to render into
     * @param direction one of the following values:
     * <ul>
     * <li><code>SwingConstants.NORTH</code>
     * <li><code>SwingConstants.SOUTH</code>
     * </ul>
     * @param biasRet an array containing the bias that were checked
     *  in this method
     * @param rowIndex the index of the view
     * @param x the x coordinate of interest
     * @return the closest model position to <code>x</code>
     */
    // NOTE: This will not properly work if ParagraphView contains
    // other ParagraphViews. It won't raise, but this does not message
    // the children views with getNextVisualPositionFrom.
    protected int getClosestPositionTo(int pos, Position.Bias b, Shape a,
                                       int direction, Position.Bias[] biasRet,
                                       int rowIndex, int x)
              throws BadLocationException {
        JTextComponent text = (JTextComponent)getContainer();
        Document doc = getDocument();
        View row = getView(rowIndex);
        int lastPos = -1;
        // This could be made better to check backward positions too.
        biasRet[0] = Position.Bias.Forward;
        for(int vc = 0, numViews = row.getViewCount(); vc < numViews; vc++) {
            View v = row.getView(vc);
            int start = v.getStartOffset();
            boolean ltr = AbstractDocument.isLeftToRight(doc, start, start + 1);
            if(ltr) {
                lastPos = start;
                for(int end = v.getEndOffset(); lastPos < end; lastPos++) {
                    float xx = text.modelToView(lastPos).getBounds().x;
                    if(xx >= x) {
                        while (++lastPos < end &&
                               text.modelToView(lastPos).getBounds().x == xx) {
                        }
                        return --lastPos;
                    }
                }
                lastPos--;
            }
            else {
                for(lastPos = v.getEndOffset() - 1; lastPos >= start;
                    lastPos--) {
                    float xx = text.modelToView(lastPos).getBounds().x;
                    if(xx >= x) {
                        while (--lastPos >= start &&
                               text.modelToView(lastPos).getBounds().x == xx) {
                        }
                        return ++lastPos;
                    }
                }
                lastPos++;
            }
        }
        if(lastPos == -1) {
            return getStartOffset();
        }
        return lastPos;
    }

    
Determines in which direction the next view lays.
Consider the View at index n.
Typically the Views are layed out
from left to right, so that the View
to the EAST will be at index n + 1, and the
View to the WEST will be at index n - 1.
In certain situations, such as with bidirectional text,
it is possible that the View to EAST is not
at index n + 1, but rather at index n - 1,
or that the View to the WEST is not at
index n - 1, but index n + 1.  In this case this method
would return true, indicating the Views are
layed out in descending order.


This will return true if the text is layed out right
to left at position, otherwise false.

Params:
  • position – position into the model
  • bias – either Position.Bias.Forward or
         Position.Bias.Backward
Returns:true if the text is layed out right to left at
        position, otherwise false.
/**
     * Determines in which direction the next view lays.
     * Consider the <code>View</code> at index n.
     * Typically the <code>View</code>s are layed out
     * from left to right, so that the <code>View</code>
     * to the EAST will be at index n + 1, and the
     * <code>View</code> to the WEST will be at index n - 1.
     * In certain situations, such as with bidirectional text,
     * it is possible that the <code>View</code> to EAST is not
     * at index n + 1, but rather at index n - 1,
     * or that the <code>View</code> to the WEST is not at
     * index n - 1, but index n + 1.  In this case this method
     * would return true, indicating the <code>View</code>s are
     * layed out in descending order.
     * <p>
     * This will return true if the text is layed out right
     * to left at position, otherwise false.
     *
     * @param position position into the model
     * @param bias either <code>Position.Bias.Forward</code> or
     *          <code>Position.Bias.Backward</code>
     * @return true if the text is layed out right to left at
     *         position, otherwise false.
     */
    protected boolean flipEastAndWestAtEnds(int position,
                                            Position.Bias bias) {
        Document doc = getDocument();
        position = getStartOffset();
        return !AbstractDocument.isLeftToRight(doc, position, position + 1);
    }

    // --- FlowView methods ---------------------------------------------

    
Fetches the constraining span to flow against for
the given child index.

Params:
  • index – the index of the view being queried
Returns:the constraining span for the given view at
 index
Since:1.3
/**
     * Fetches the constraining span to flow against for
     * the given child index.
     * @param index the index of the view being queried
     * @return the constraining span for the given view at
     *  <code>index</code>
     * @since 1.3
     */
    public int getFlowSpan(int index) {
        View child = getView(index);
        int adjust = 0;
        if (child instanceof Row) {
            Row row = (Row) child;
            adjust = row.getLeftInset() + row.getRightInset();
        }
        return (layoutSpan == Integer.MAX_VALUE) ? layoutSpan
                                                 : (layoutSpan - adjust);
    }

    
Fetches the location along the flow axis that the
flow span will start at.

Params:
  • index – the index of the view being queried
Returns:the location for the given view at
 index
Since:1.3
/**
     * Fetches the location along the flow axis that the
     * flow span will start at.
     * @param index the index of the view being queried
     * @return the location for the given view at
     *  <code>index</code>
     * @since 1.3
     */
    public int getFlowStart(int index) {
        View child = getView(index);
        int adjust = 0;
        if (child instanceof Row) {
            Row row = (Row) child;
            adjust = row.getLeftInset();
        }
        return tabBase + adjust;
    }

    
Create a View that should be used to hold a
a row's worth of children in a flow.

Returns:the new View
Since:1.3
/**
     * Create a <code>View</code> that should be used to hold a
     * a row's worth of children in a flow.
     * @return the new <code>View</code>
     * @since 1.3
     */
    protected View createRow() {
        return new Row(getElement());
    }

    // --- TabExpander methods ------------------------------------------

    
Returns the next tab stop position given a reference position.
This view implements the tab coordinate system, and calls
getTabbedSpan on the logical children in the process
of layout to determine the desired span of the children.  The
logical children can delegate their tab expansion upward to
the paragraph which knows how to expand tabs.
LabelView is an example of a view that delegates
its tab expansion needs upward to the paragraph.


This is implemented to try and locate a TabSet
in the paragraph element's attribute set.  If one can be
found, its settings will be used, otherwise a default expansion
will be provided.  The base location for for tab expansion
is the left inset from the paragraphs most recent allocation
(which is what the layout of the children is based upon).

Params:
  • x – the X reference position
  • tabOffset – the position within the text stream
  that the tab occurred at >= 0
See Also:
Returns:the trailing end of the tab expansion >= 0
/**
     * Returns the next tab stop position given a reference position.
     * This view implements the tab coordinate system, and calls
     * <code>getTabbedSpan</code> on the logical children in the process
     * of layout to determine the desired span of the children.  The
     * logical children can delegate their tab expansion upward to
     * the paragraph which knows how to expand tabs.
     * <code>LabelView</code> is an example of a view that delegates
     * its tab expansion needs upward to the paragraph.
     * <p>
     * This is implemented to try and locate a <code>TabSet</code>
     * in the paragraph element's attribute set.  If one can be
     * found, its settings will be used, otherwise a default expansion
     * will be provided.  The base location for for tab expansion
     * is the left inset from the paragraphs most recent allocation
     * (which is what the layout of the children is based upon).
     *
     * @param x the X reference position
     * @param tabOffset the position within the text stream
     *   that the tab occurred at &gt;= 0
     * @return the trailing end of the tab expansion &gt;= 0
     * @see TabSet
     * @see TabStop
     * @see LabelView
     */
    public float nextTabStop(float x, int tabOffset) {
        // If the text isn't left justified, offset by 10 pixels!
        if(justification != StyleConstants.ALIGN_LEFT)
            return x + 10.0f;
        x -= tabBase;
        TabSet tabs = getTabSet();
        if(tabs == null) {
            // a tab every 72 pixels.
            return (float)(tabBase + (((int)x / 72 + 1) * 72));
        }
        TabStop tab = tabs.getTabAfter(x + .01f);
        if(tab == null) {
            // no tab, do a default of 5 pixels.
            // Should this cause a wrapping of the line?
            return tabBase + x + 5.0f;
        }
        int alignment = tab.getAlignment();
        int offset;
        switch(alignment) {
        default:
        case TabStop.ALIGN_LEFT:
            // Simple case, left tab.
            return tabBase + tab.getPosition();
        case TabStop.ALIGN_BAR:
            // PENDING: what does this mean?
            return tabBase + tab.getPosition();
        case TabStop.ALIGN_RIGHT:
        case TabStop.ALIGN_CENTER:
            offset = findOffsetToCharactersInString(tabChars,
                                                    tabOffset + 1);
            break;
        case TabStop.ALIGN_DECIMAL:
            offset = findOffsetToCharactersInString(tabDecimalChars,
                                                    tabOffset + 1);
            break;
        }
        if (offset == -1) {
            offset = getEndOffset();
        }
        float charsSize = getPartialSize(tabOffset + 1, offset);
        switch(alignment) {
        case TabStop.ALIGN_RIGHT:
        case TabStop.ALIGN_DECIMAL:
            // right and decimal are treated the same way, the new
            // position will be the location of the tab less the
            // partialSize.
            return tabBase + Math.max(x, tab.getPosition() - charsSize);
        case TabStop.ALIGN_CENTER:
            // Similar to right, but half the partialSize.
            return tabBase + Math.max(x, tab.getPosition() - charsSize / 2.0f);
        }
        // will never get here!
        return x;
    }

    
Gets the Tabset to be used in calculating tabs.

Returns:the TabSet
/**
     * Gets the <code>Tabset</code> to be used in calculating tabs.
     *
     * @return the <code>TabSet</code>
     */
    protected TabSet getTabSet() {
        return StyleConstants.getTabSet(getElement().getAttributes());
    }

    
Returns the size used by the views between
startOffset and endOffset.
This uses getPartialView to calculate the
size if the child view implements the
TabableView interface. If a
size is needed and a View does not implement
the TabableView interface,
the preferredSpan will be used.

Params:
  • startOffset – the starting document offset >= 0
  • endOffset – the ending document offset >= startOffset
Returns:the size >= 0
/**
     * Returns the size used by the views between
     * <code>startOffset</code> and <code>endOffset</code>.
     * This uses <code>getPartialView</code> to calculate the
     * size if the child view implements the
     * <code>TabableView</code> interface. If a
     * size is needed and a <code>View</code> does not implement
     * the <code>TabableView</code> interface,
     * the <code>preferredSpan</code> will be used.
     *
     * @param startOffset the starting document offset &gt;= 0
     * @param endOffset the ending document offset &gt;= startOffset
     * @return the size &gt;= 0
     */
    protected float getPartialSize(int startOffset, int endOffset) {
        float size = 0.0f;
        int viewIndex;
        int numViews = getViewCount();
        View view;
        int viewEnd;
        int tempEnd;

        // Have to search layoutPool!
        // PENDING: when ParagraphView supports breaking location
        // into layoutPool will have to change!
        viewIndex = getElement().getElementIndex(startOffset);
        numViews = layoutPool.getViewCount();
        while(startOffset < endOffset && viewIndex < numViews) {
            view = layoutPool.getView(viewIndex++);
            viewEnd = view.getEndOffset();
            tempEnd = Math.min(endOffset, viewEnd);
            if(view instanceof TabableView)
                size += ((TabableView)view).getPartialSpan(startOffset, tempEnd);
            else if(startOffset == view.getStartOffset() &&
                    tempEnd == view.getEndOffset())
                size += view.getPreferredSpan(View.X_AXIS);
            else
                // PENDING: should we handle this better?
                return 0.0f;
            startOffset = viewEnd;
        }
        return size;
    }

    
Finds the next character in the document with a character in
string, starting at offset start. If
there are no characters found, -1 will be returned.

Params:
  • string – the string of characters
  • start – where to start in the model >= 0
Returns:the document offset, or -1 if no characters found
/**
     * Finds the next character in the document with a character in
     * <code>string</code>, starting at offset <code>start</code>. If
     * there are no characters found, -1 will be returned.
     *
     * @param string the string of characters
     * @param start where to start in the model &gt;= 0
     * @return the document offset, or -1 if no characters found
     */
    protected int findOffsetToCharactersInString(char[] string,
                                                 int start) {
        int stringLength = string.length;
        int end = getEndOffset();
        Segment seg = new Segment();
        try {
            getDocument().getText(start, end - start, seg);
        } catch (BadLocationException ble) {
            return -1;
        }
        for(int counter = seg.offset, maxCounter = seg.offset + seg.count;
            counter < maxCounter; counter++) {
            char currentChar = seg.array[counter];
            for(int subCounter = 0; subCounter < stringLength;
                subCounter++) {
                if(currentChar == string[subCounter])
                    return counter - seg.offset + start;
            }
        }
        // No match.
        return -1;
    }

    
Returns where the tabs are calculated from.

Returns:where tabs are calculated from
/**
     * Returns where the tabs are calculated from.
     * @return where tabs are calculated from
     */
    protected float getTabBase() {
        return (float)tabBase;
    }

    // ---- View methods ----------------------------------------------------

    
Renders using the given rendering surface and area on that
surface.  This is implemented to delegate to the superclass
after stashing the base coordinate for tab calculations.

Params:
  • g – the rendering surface to use
  • a – the allocated region to render into
See Also:
/**
     * Renders using the given rendering surface and area on that
     * surface.  This is implemented to delegate to the superclass
     * after stashing the base coordinate for tab calculations.
     *
     * @param g the rendering surface to use
     * @param a the allocated region to render into
     * @see View#paint
     */
    public void paint(Graphics g, Shape a) {
        Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a : a.getBounds();
        tabBase = alloc.x + getLeftInset();
        super.paint(g, a);

        // line with the negative firstLineIndent value needs
        // special handling
        if (firstLineIndent < 0) {
            Shape sh = getChildAllocation(0, a);
            if ((sh != null) &&  sh.intersects(alloc)) {
                int x = alloc.x + getLeftInset() + firstLineIndent;
                int y = alloc.y + getTopInset();

                Rectangle clip = g.getClipBounds();
                tempRect.x = x + getOffset(X_AXIS, 0);
                tempRect.y = y + getOffset(Y_AXIS, 0);
                tempRect.width = getSpan(X_AXIS, 0) - firstLineIndent;
                tempRect.height = getSpan(Y_AXIS, 0);
                if (tempRect.intersects(clip)) {
                    tempRect.x = tempRect.x - firstLineIndent;
                    paintChild(g, tempRect, 0);
                }
            }
        }
    }

    
Determines the desired alignment for this view along an
axis.  This is implemented to give the alignment to the
center of the first row along the y axis, and the default
along the x axis.

Params:
  • axis – may be either View.X_AXIS or
  View.Y_AXIS
Returns:the desired alignment.  This should be a value
  between 0.0 and 1.0 inclusive, where 0 indicates alignment at the
  origin and 1.0 indicates alignment to the full span
  away from the origin.  An alignment of 0.5 would be the
  center of the view.
/**
     * Determines the desired alignment for this view along an
     * axis.  This is implemented to give the alignment to the
     * center of the first row along the y axis, and the default
     * along the x axis.
     *
     * @param axis may be either <code>View.X_AXIS</code> or
     *   <code>View.Y_AXIS</code>
     * @return the desired alignment.  This should be a value
     *   between 0.0 and 1.0 inclusive, where 0 indicates alignment at the
     *   origin and 1.0 indicates alignment to the full span
     *   away from the origin.  An alignment of 0.5 would be the
     *   center of the view.
     */
    public float getAlignment(int axis) {
        switch (axis) {
        case Y_AXIS:
            float a = 0.5f;
            if (getViewCount() != 0) {
                int paragraphSpan = (int) getPreferredSpan(View.Y_AXIS);
                View v = getView(0);
                int rowSpan = (int) v.getPreferredSpan(View.Y_AXIS);
                a = (paragraphSpan != 0) ? ((float)(rowSpan / 2)) / paragraphSpan : 0;
            }
            return a;
        case X_AXIS:
            return 0.5f;
        default:
            throw new IllegalArgumentException("Invalid axis: " + axis);
        }
    }

    
Breaks this view on the given axis at the given length.


ParagraphView instances are breakable
along the Y_AXIS only, and only if
len is after the first line.

Params:
  • axis – may be either View.X_AXIS
 or View.Y_AXIS
  • len – specifies where a potential break is desired
 along the given axis >= 0
  • a – the current allocation of the view
See Also:
Returns:the fragment of the view that represents the
 given span, if the view can be broken; if the view
 doesn't support breaking behavior, the view itself is
 returned
/**
     * Breaks this view on the given axis at the given length.
     * <p>
     * <code>ParagraphView</code> instances are breakable
     * along the <code>Y_AXIS</code> only, and only if
     * <code>len</code> is after the first line.
     *
     * @param axis may be either <code>View.X_AXIS</code>
     *  or <code>View.Y_AXIS</code>
     * @param len specifies where a potential break is desired
     *  along the given axis &gt;= 0
     * @param a the current allocation of the view
     * @return the fragment of the view that represents the
     *  given span, if the view can be broken; if the view
     *  doesn't support breaking behavior, the view itself is
     *  returned
     * @see View#breakView
     */
    public View breakView(int axis, float len, Shape a) {
        if(axis == View.Y_AXIS) {
            if(a != null) {
                Rectangle alloc = a.getBounds();
                setSize(alloc.width, alloc.height);
            }
            // Determine what row to break on.

            // PENDING(prinz) add break support
            return this;
        }
        return this;
    }

    
Gets the break weight for a given location.


ParagraphView instances are breakable
along the Y_AXIS only, and only if
len is after the first row.  If the length
is less than one row, a value of BadBreakWeight
is returned.

Params:
  • axis – may be either View.X_AXIS
 or View.Y_AXIS
  • len – specifies where a potential break is desired >= 0
See Also:
Returns:a value indicating the attractiveness of breaking here;
 either GoodBreakWeight or BadBreakWeight
/**
     * Gets the break weight for a given location.
     * <p>
     * <code>ParagraphView</code> instances are breakable
     * along the <code>Y_AXIS</code> only, and only if
     * <code>len</code> is after the first row.  If the length
     * is less than one row, a value of <code>BadBreakWeight</code>
     * is returned.
     *
     * @param axis may be either <code>View.X_AXIS</code>
     *  or <code>View.Y_AXIS</code>
     * @param len specifies where a potential break is desired &gt;= 0
     * @return a value indicating the attractiveness of breaking here;
     *  either <code>GoodBreakWeight</code> or <code>BadBreakWeight</code>
     * @see View#getBreakWeight
     */
    public int getBreakWeight(int axis, float len) {
        if(axis == View.Y_AXIS) {
            // PENDING(prinz) make this return a reasonable value
            // when paragraph breaking support is re-implemented.
            // If less than one row, bad weight value should be
            // returned.
            //return GoodBreakWeight;
            return BadBreakWeight;
        }
        return BadBreakWeight;
    }

    
Calculate the needs for the paragraph along the minor axis.

This uses size requirements of the superclass, modified to take into
account the non-breakable areas at the adjacent views edges.  The minimal
size requirements for such views should be no less than the sum of all
adjacent fragments.


If the axis parameter is neither View.X_AXIS nor View.Y_AXIS, IllegalArgumentException is thrown. If the r parameter is null, a new SizeRequirements object is created, otherwise the supplied SizeRequirements object is returned.


Params:
  • axis –  the minor axis
  • r –  the input SizeRequirements object
Throws:
Returns: the new or adjusted SizeRequirements object
/**
     * Calculate the needs for the paragraph along the minor axis.
     *
     * <p>This uses size requirements of the superclass, modified to take into
     * account the non-breakable areas at the adjacent views edges.  The minimal
     * size requirements for such views should be no less than the sum of all
     * adjacent fragments.</p>
     *
     * <p>If the {@code axis} parameter is neither {@code View.X_AXIS} nor
     * {@code View.Y_AXIS}, {@link IllegalArgumentException} is thrown.  If the
     * {@code r} parameter is {@code null,} a new {@code SizeRequirements}
     * object is created, otherwise the supplied {@code SizeRequirements}
     * object is returned.</p>
     *
     * @param axis  the minor axis
     * @param r     the input {@code SizeRequirements} object
     * @return      the new or adjusted {@code SizeRequirements} object
     * @throws IllegalArgumentException  if the {@code axis} parameter is invalid
     */
    @Override
    protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                        SizeRequirements r) {
        r = super.calculateMinorAxisRequirements(axis, r);

        float min = 0;
        float glue = 0;
        int n = getLayoutViewCount();
        for (int i = 0; i < n; i++) {
            View v = getLayoutView(i);
            float span = v.getMinimumSpan(axis);
            if (v.getBreakWeight(axis, 0, v.getMaximumSpan(axis)) > View.BadBreakWeight) {
                // find the longest non-breakable fragments at the view edges
                int p0 = v.getStartOffset();
                int p1 = v.getEndOffset();
                float start = findEdgeSpan(v, axis, p0, p0, p1);
                float end = findEdgeSpan(v, axis, p1, p0, p1);
                glue += start;
                min = Math.max(min, Math.max(span, glue));
                glue = end;
            } else {
                // non-breakable view
                glue += span;
                min = Math.max(min, glue);
            }
        }
        r.minimum = Math.max(r.minimum, (int) min);
        r.preferred = Math.max(r.minimum, r.preferred);
        r.maximum = Math.max(r.preferred, r.maximum);

        return r;
    }

    
Binary search for the longest non-breakable fragment at the view edge.

/**
     * Binary search for the longest non-breakable fragment at the view edge.
     */
    private float findEdgeSpan(View v, int axis, int fp, int p0, int p1) {
        int len = p1 - p0;
        if (len <= 1) {
            // further fragmentation is not possible
            return v.getMinimumSpan(axis);
        } else {
            int mid = p0 + len / 2;
            boolean startEdge = mid > fp;
            // initial view is breakable hence must support fragmentation
            View f = startEdge ?
                v.createFragment(fp, mid) : v.createFragment(mid, fp);
            boolean breakable = f.getBreakWeight(
                    axis, 0, f.getMaximumSpan(axis)) > View.BadBreakWeight;
            if (breakable == startEdge) {
                p1 = mid;
            } else {
                p0 = mid;
            }
            return findEdgeSpan(f, axis, fp, p0, p1);
        }
    }

    
Gives notification from the document that attributes were changed
in a location that this view is responsible for.

Params:
  • changes – the change information from the
 associated document
  • a – the current allocation of the view
  • f – the factory to use to rebuild if the view has children
See Also:
/**
     * Gives notification from the document that attributes were changed
     * in a location that this view is responsible for.
     *
     * @param changes 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 changes, Shape a, ViewFactory f) {
        // update any property settings stored, and layout should be
        // recomputed
        setPropertiesFromAttributes();
        layoutChanged(X_AXIS);
        layoutChanged(Y_AXIS);
        super.changedUpdate(changes, a, f);
    }


    // --- variables -----------------------------------------------

    private int justification;
    private float lineSpacing;
    
Indentation for the first line, from the left inset. 
/** Indentation for the first line, from the left inset. */
    protected int firstLineIndent = 0;

    
Used by the TabExpander functionality to determine
where to base the tab calculations.  This is basically
the location of the left side of the paragraph.

/**
     * Used by the TabExpander functionality to determine
     * where to base the tab calculations.  This is basically
     * the location of the left side of the paragraph.
     */
    private int tabBase;

    
Used to create an i18n-based layout strategy

/**
     * Used to create an i18n-based layout strategy
     */
    static Class i18nStrategy;

    
Used for searching for a tab. 
/** Used for searching for a tab. */
    static char[] tabChars;
    
Used for searching for a tab or decimal character. 
/** Used for searching for a tab or decimal character. */
    static char[] tabDecimalChars;

    static {
        tabChars = new char[1];
        tabChars[0] = '\t';
        tabDecimalChars = new char[2];
        tabDecimalChars[0] = '\t';
        tabDecimalChars[1] = '.';
    }

    
Internally created view that has the purpose of holding
the views that represent the children of the paragraph
that have been arranged in rows.

/**
     * Internally created view that has the purpose of holding
     * the views that represent the children of the paragraph
     * that have been arranged in rows.
     */
    class Row extends BoxView {

        Row(Element elem) {
            super(elem, View.X_AXIS);
        }

        
This is reimplemented to do nothing since the
paragraph fills in the row with its needed
children.

/**
         * This is reimplemented to do nothing since the
         * paragraph fills in the row with its needed
         * children.
         */
        protected void loadChildren(ViewFactory f) {
        }

        
Fetches the attributes to use when rendering.  This view
isn't directly responsible for an element so it returns
the outer classes attributes.

/**
         * Fetches the attributes to use when rendering.  This view
         * isn't directly responsible for an element so it returns
         * the outer classes attributes.
         */
        public AttributeSet getAttributes() {
            View p = getParent();
            return (p != null) ? p.getAttributes() : null;
        }

        public float getAlignment(int axis) {
            if (axis == View.X_AXIS) {
                switch (justification) {
                case StyleConstants.ALIGN_LEFT:
                    return 0;
                case StyleConstants.ALIGN_RIGHT:
                    return 1;
                case StyleConstants.ALIGN_CENTER:
                    return 0.5f;
                case StyleConstants.ALIGN_JUSTIFIED:
                    float rv = 0.5f;
                    //if we can justifiy the content always align to
                    //the left.
                    if (isJustifiableDocument()) {
                        rv = 0f;
                    }
                    return rv;
                }
            }
            return super.getAlignment(axis);
        }

        
Provides a mapping from the document model coordinate space
to the coordinate space of the view mapped to it.  This is
implemented to let the superclass find the position along
the major axis and the allocation of the row is used
along the minor axis, so that even though the children
are different heights they all get the same caret height.

Params:
  • pos – the position to convert
  • a – the allocated region to render into
Throws:
  • BadLocationException –  if the given position does not represent a
  valid location in the associated document
See Also:
Returns:the bounding box of the given position
/**
         * Provides a mapping from the document model coordinate space
         * to the coordinate space of the view mapped to it.  This is
         * implemented to let the superclass find the position along
         * the major axis and the allocation of the row is used
         * along the minor axis, so that even though the children
         * are different heights they all get the same caret height.
         *
         * @param pos the position to convert
         * @param a the allocated region to render into
         * @return the bounding box of the given position
         * @exception BadLocationException  if the given position does not represent a
         *   valid location in the associated document
         * @see View#modelToView
         */
        public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
            Rectangle r = a.getBounds();
            View v = getViewAtPosition(pos, r);
            if ((v != null) && (!v.getElement().isLeaf())) {
                // Don't adjust the height if the view represents a branch.
                return super.modelToView(pos, a, b);
            }
            r = a.getBounds();
            int height = r.height;
            int y = r.y;
            Shape loc = super.modelToView(pos, a, b);
            r = loc.getBounds();
            r.height = height;
            r.y = y;
            return r;
        }

        
Range represented by a row in the paragraph is only
a subset of the total range of the paragraph element.

See Also:
  • getRange.getRange
/**
         * Range represented by a row in the paragraph is only
         * a subset of the total range of the paragraph element.
         * @see View#getRange
         */
        public int getStartOffset() {
            int offs = Integer.MAX_VALUE;
            int n = getViewCount();
            for (int i = 0; i < n; i++) {
                View v = getView(i);
                offs = Math.min(offs, v.getStartOffset());
            }
            return offs;
        }

        public int getEndOffset() {
            int offs = 0;
            int n = getViewCount();
            for (int i = 0; i < n; i++) {
                View v = getView(i);
                offs = Math.max(offs, v.getEndOffset());
            }
            return offs;
        }

        
Perform layout for the minor axis of the box (i.e. the
axis orthogonal to the axis that it represents).  The results
of the layout should be placed in the given arrays which represent
the allocations to the children along the minor axis.


This is implemented to do a baseline layout of the children
by calling BoxView.baselineLayout.

Params:
  • targetSpan – the total span given to the view, which
 would be used to layout the children.
  • axis – the axis being layed out.
  • offsets – the offsets from the origin of the view for
 each of the child views.  This is a return value and is
 filled in by the implementation of this method.
  • spans – the span of each child view.  This is a return
 value and is filled in by the implementation of this method.
Returns:the offset and span for each child view in the
 offsets and spans parameters
/**
         * Perform layout for the minor axis of the box (i.e. the
         * axis orthogonal to the axis that it represents).  The results
         * of the layout should be placed in the given arrays which represent
         * the allocations to the children along the minor axis.
         * <p>
         * This is implemented to do a baseline layout of the children
         * by calling BoxView.baselineLayout.
         *
         * @param targetSpan the total span given to the view, which
         *  would be used to layout the children.
         * @param axis the axis being layed out.
         * @param offsets the offsets from the origin of the view for
         *  each of the child views.  This is a return value and is
         *  filled in by the implementation of this method.
         * @param spans the span of each child view.  This is a return
         *  value and is filled in by the implementation of this method.
         * @return the offset and span for each child view in the
         *  offsets and spans parameters
         */
        protected void layoutMinorAxis(int targetSpan, int axis, int[] offsets, int[] spans) {
            baselineLayout(targetSpan, axis, offsets, spans);
        }

        protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                                  SizeRequirements r) {
            return baselineRequirements(axis, r);
        }


        private boolean isLastRow() {
            View parent;
            return ((parent = getParent()) == null
                    || this == parent.getView(parent.getViewCount() - 1));
        }

        private boolean isBrokenRow() {
            boolean rv = false;
            int viewsCount = getViewCount();
            if (viewsCount > 0) {
                View lastView = getView(viewsCount - 1);
                if (lastView.getBreakWeight(X_AXIS, 0, 0) >=
                      ForcedBreakWeight) {
                    rv = true;
                }
            }
            return rv;
        }

        private boolean isJustifiableDocument() {
            return (! Boolean.TRUE.equals(getDocument().getProperty(
                          AbstractDocument.I18NProperty)));
        }

        
Whether we need to justify this Row. At this time (jdk1.6) we support justification on for non 18n text. 
Returns:true if this Row should be justified.
/**
         * Whether we need to justify this {@code Row}.
         * At this time (jdk1.6) we support justification on for non
         * 18n text.
         *
         * @return {@code true} if this {@code Row} should be justified.
         */
        private boolean isJustifyEnabled() {
            boolean ret = (justification == StyleConstants.ALIGN_JUSTIFIED);

            //no justification for i18n documents
            ret = ret && isJustifiableDocument();

            //no justification for the last row
            ret = ret && ! isLastRow();

            //no justification for the broken rows
            ret = ret && ! isBrokenRow();

            return ret;
        }


        //Calls super method after setting spaceAddon to 0.
        //Justification should not affect MajorAxisRequirements
        @Override
        protected SizeRequirements calculateMajorAxisRequirements(int axis,
                SizeRequirements r) {
            int oldJustficationData[] = justificationData;
            justificationData = null;
            SizeRequirements ret = super.calculateMajorAxisRequirements(axis, r);
            if (isJustifyEnabled()) {
                justificationData = oldJustficationData;
            }
            return ret;
        }

        @Override
        protected void layoutMajorAxis(int targetSpan, int axis,
                                       int[] offsets, int[] spans) {
            int oldJustficationData[] = justificationData;
            justificationData = null;
            super.layoutMajorAxis(targetSpan, axis, offsets, spans);
            if (! isJustifyEnabled()) {
                return;
            }

            int currentSpan = 0;
            for (int span : spans) {
                currentSpan += span;
            }
            if (currentSpan == targetSpan) {
                //no need to justify
                return;
            }

            // we justify text by enlarging spaces by the {@code spaceAddon}.
            // justification is started to the right of the rightmost TAB.
            // leading and trailing spaces are not extendable.
            //
            // GlyphPainter1 uses
            // justificationData
            // for all painting and measurement.

            int extendableSpaces = 0;
            int startJustifiableContent = -1;
            int endJustifiableContent = -1;
            int lastLeadingSpaces = 0;

            int rowStartOffset = getStartOffset();
            int rowEndOffset = getEndOffset();
            int spaceMap[] = new int[rowEndOffset - rowStartOffset];
            Arrays.fill(spaceMap, 0);
            for (int i = getViewCount() - 1; i >= 0 ; i--) {
                View view = getView(i);
                if (view instanceof GlyphView) {
                    GlyphView.JustificationInfo justificationInfo =
                        ((GlyphView) view).getJustificationInfo(rowStartOffset);
                    final int viewStartOffset = view.getStartOffset();
                    final int offset = viewStartOffset - rowStartOffset;
                    for (int j = 0; j < justificationInfo.spaceMap.length(); j++) {
                        if (justificationInfo.spaceMap.get(j)) {
                            spaceMap[j + offset] = 1;
                        }
                    }
                    if (startJustifiableContent > 0) {
                        if (justificationInfo.end >= 0) {
                            extendableSpaces += justificationInfo.trailingSpaces;
                        } else {
                            lastLeadingSpaces += justificationInfo.trailingSpaces;
                        }
                    }
                    if (justificationInfo.start >= 0) {
                        startJustifiableContent =
                            justificationInfo.start + viewStartOffset;
                        extendableSpaces += lastLeadingSpaces;
                    }
                    if (justificationInfo.end >= 0
                          && endJustifiableContent < 0) {
                        endJustifiableContent =
                            justificationInfo.end + viewStartOffset;
                    }
                    extendableSpaces += justificationInfo.contentSpaces;
                    lastLeadingSpaces = justificationInfo.leadingSpaces;
                    if (justificationInfo.hasTab) {
                        break;
                    }
                }
            }
            if (extendableSpaces <= 0) {
                //there is nothing we can do to justify
                return;
            }
            int adjustment = (targetSpan - currentSpan);
            int spaceAddon = (extendableSpaces > 0)
                ?  adjustment / extendableSpaces
                : 0;
            int spaceAddonLeftoverEnd = -1;
            for (int i = startJustifiableContent - rowStartOffset,
                     leftover = adjustment - spaceAddon * extendableSpaces;
                     leftover > 0;
                     leftover -= spaceMap[i],
                     i++) {
                spaceAddonLeftoverEnd = i;
            }
            if (spaceAddon > 0 || spaceAddonLeftoverEnd >= 0) {
                justificationData = (oldJustficationData != null)
                    ? oldJustficationData
                    : new int[END_JUSTIFIABLE + 1];
                justificationData[SPACE_ADDON] = spaceAddon;
                justificationData[SPACE_ADDON_LEFTOVER_END] =
                    spaceAddonLeftoverEnd;
                justificationData[START_JUSTIFIABLE] =
                    startJustifiableContent - rowStartOffset;
                justificationData[END_JUSTIFIABLE] =
                    endJustifiableContent - rowStartOffset;
                super.layoutMajorAxis(targetSpan, axis, offsets, spans);
            }
        }

        //for justified row we assume the maximum horizontal span
        //is MAX_VALUE.
        @Override
        public float getMaximumSpan(int axis) {
            float ret;
            if (View.X_AXIS == axis
                  && isJustifyEnabled()) {
                ret = Float.MAX_VALUE;
            } else {
              ret = super.getMaximumSpan(axis);
            }
            return ret;
        }

        
Fetches the child view index representing the given position in
the model.

Params:
  • pos – the position >= 0
Returns: index of the view representing the given position, or
  -1 if no view represents that position
/**
         * Fetches the child view index representing the given position in
         * the model.
         *
         * @param pos the position &gt;= 0
         * @return  index of the view representing the given position, or
         *   -1 if no view represents that position
         */
        protected int getViewIndexAtPosition(int pos) {
            // This is expensive, but are views are not necessarily layed
            // out in model order.
            if(pos < getStartOffset() || pos >= getEndOffset())
                return -1;
            for(int counter = getViewCount() - 1; counter >= 0; counter--) {
                View v = getView(counter);
                if(pos >= v.getStartOffset() &&
                   pos < v.getEndOffset()) {
                    return counter;
                }
            }
            return -1;
        }

        
Gets the left inset.

Returns:the inset
/**
         * Gets the left inset.
         *
         * @return the inset
         */
        protected short getLeftInset() {
            View parentView;
            int adjustment = 0;
            if ((parentView = getParent()) != null) { //use firstLineIdent for the first row
                if (this == parentView.getView(0)) {
                    adjustment = firstLineIndent;
                }
            }
            return (short)(super.getLeftInset() + adjustment);
        }

        protected short getBottomInset() {
            return (short)(super.getBottomInset() +
                           ((minorRequest != null) ? minorRequest.preferred : 0) *
                           lineSpacing);
        }

        final static int SPACE_ADDON = 0;
        final static int SPACE_ADDON_LEFTOVER_END = 1;
        final static int START_JUSTIFIABLE = 2;
        //this should be the last index in justificationData
        final static int END_JUSTIFIABLE = 3;

        int justificationData[] = null;
    }

}