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 * 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

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package javax.swing.text.html;

import java.awt.*;

import javax.swing.SizeRequirements;

import javax.swing.event.DocumentEvent;

import javax.swing.text.Document;

import javax.swing.text.Element;

import javax.swing.text.AttributeSet;

import javax.swing.text.StyleConstants;

import javax.swing.text.View;

import javax.swing.text.ViewFactory;

import javax.swing.text.BadLocationException;

import javax.swing.text.JTextComponent;

/**

 * Displays the a paragraph, and uses css attributes for its

 * configuration.

 *

 * @author  Timothy Prinzing

 */

public class ParagraphView extends javax.swing.text.ParagraphView {

    /**

     * Constructs a ParagraphView for the given element.

     *

     * @param elem the element that this view is responsible for

     */

    public ParagraphView(Element elem) {

        super(elem);

    }

    /**

     * Establishes the parent view for this view.  This is

     * guaranteed to be called before any other methods if the

     * parent view is functioning properly.

     * <p>

     * This is implemented

     * to forward to the superclass as well as call the

     * {@link #setPropertiesFromAttributes setPropertiesFromAttributes}

     * method to set the paragraph properties from the css

     * attributes.  The call is made at this time to ensure

     * the ability to resolve upward through the parents

     * view attributes.

     *

     * @param parent the new parent, or null if the view is

     *  being removed from a parent it was previously added

     *  to

     */

    public void setParent(View parent) {

        super.setParent(parent);

        if (parent != null) {

            setPropertiesFromAttributes();

        }

    }

    /**

     * Fetches the attributes to use when rendering.  This is

     * implemented to multiplex the attributes specified in the

     * model with a StyleSheet.

     */

    public AttributeSet getAttributes() {

        if (attr == null) {

            StyleSheet sheet = getStyleSheet();

            attr = sheet.getViewAttributes(this);

        }

        return attr;

    }

    /**

     * Sets up the paragraph from css attributes instead of

     * the values found in StyleConstants (i.e. which are used

     * by the superclass).  Since

     */

    protected void setPropertiesFromAttributes() {

        StyleSheet sheet = getStyleSheet();

        attr = sheet.getViewAttributes(this);

        painter = sheet.getBoxPainter(attr);

        if (attr != null) {

            super.setPropertiesFromAttributes();

            setInsets((short) painter.getInset(TOP, this),

                      (short) painter.getInset(LEFT, this),

                      (short) painter.getInset(BOTTOM, this),

                      (short) painter.getInset(RIGHT, this));

            Object o = attr.getAttribute(CSS.Attribute.TEXT_ALIGN);

            if (o != null) {

                // set horizontal alignment

                String ta = o.toString();

                if (ta.equals("left")) {

                    setJustification(StyleConstants.ALIGN_LEFT);

                } else if (ta.equals("center")) {

                    setJustification(StyleConstants.ALIGN_CENTER);

                } else if (ta.equals("right")) {

                    setJustification(StyleConstants.ALIGN_RIGHT);

                } else if (ta.equals("justify")) {

                    setJustification(StyleConstants.ALIGN_JUSTIFIED);

                }

            }

            // Get the width/height

            cssWidth = (CSS.LengthValue)attr.getAttribute(

                                        CSS.Attribute.WIDTH);

            cssHeight = (CSS.LengthValue)attr.getAttribute(

                                         CSS.Attribute.HEIGHT);

        }

    }

    protected StyleSheet getStyleSheet() {

        HTMLDocument doc = (HTMLDocument) getDocument();

        return doc.getStyleSheet();

    }

    /**

     * Calculate the needs for the paragraph along the minor axis.

     *

     * <p>If size requirements are explicitly specified for the paragraph,

     * use that requirements.  Otherwise, use the requirements of the

     * superclass {@link javax.swing.text.ParagraphView}.</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

     */

    protected SizeRequirements calculateMinorAxisRequirements(

                                                int axis, SizeRequirements r) {

        r = super.calculateMinorAxisRequirements(axis, r);

        if (BlockView.spanSetFromAttributes(axis, r, cssWidth, cssHeight)) {

            // Offset by the margins so that pref/min/max return the

            // right value.

            int margin = (axis == X_AXIS) ? getLeftInset() + getRightInset() :

                                            getTopInset() + getBottomInset();

            r.minimum -= margin;

            r.preferred -= margin;

            r.maximum -= margin;

        }

        return r;

    }

    /**

     * Indicates whether or not this view should be

     * displayed.  If none of the children wish to be

     * displayed and the only visible child is the

     * break that ends the paragraph, the paragraph

     * will not be considered visible.  Otherwise,

     * it will be considered visible and return true.

     *

     * @return true if the paragraph should be displayed

     */

    public boolean isVisible() {

        int n = getLayoutViewCount() - 1;

        for (int i = 0; i < n; i++) {

            View v = getLayoutView(i);

            if (v.isVisible()) {

                return true;

            }

        }

        if (n > 0) {

            View v = getLayoutView(n);

            if ((v.getEndOffset() - v.getStartOffset()) == 1) {

                return false;

            }

        }

        // If it's the last paragraph and not editable, it shouldn't

        // be visible.

        if (getStartOffset() == getDocument().getLength()) {

            boolean editable = false;

            Component c = getContainer();

            if (c instanceof JTextComponent) {

                editable = ((JTextComponent)c).isEditable();

            }

            if (!editable) {

                return false;

            }

        }

        return true;

    }

    /**

     * Renders using the given rendering surface and area on that

     * surface.  This is implemented to delgate 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) {

        if (a == null) {

            return;

        }

        Rectangle r;

        if (a instanceof Rectangle) {

            r = (Rectangle) a;

        } else {

            r = a.getBounds();

        }

        painter.paint(g, r.x, r.y, r.width, r.height, this);

        super.paint(g, a);

    }

    /**

     * Determines the preferred span for this view.  Returns

     * 0 if the view is not visible, otherwise it calls the

     * superclass method to get the preferred span.

     * axis.

     *

     * @param axis may be either View.X_AXIS or View.Y_AXIS

     * @return   the span the view would like to be rendered into;

     *           typically the view is told to render into the span

     *           that is returned, although there is no guarantee;

     *           the parent may choose to resize or break the view

     * @see javax.swing.text.ParagraphView#getPreferredSpan

     */

    public float getPreferredSpan(int axis) {

        if (!isVisible()) {

            return 0;

        }

        return super.getPreferredSpan(axis);

    }

    /**

     * Determines the minimum span for this view along an

     * axis.  Returns 0 if the view is not visible, otherwise

     * it calls the superclass method to get the minimum span.

     *

     * @param axis may be either <code>View.X_AXIS</code> or

     *  <code>View.Y_AXIS</code>

     * @return  the minimum span the view can be rendered into

     * @see javax.swing.text.ParagraphView#getMinimumSpan

     */

    public float getMinimumSpan(int axis) {

        if (!isVisible()) {

            return 0;

        }

        return super.getMinimumSpan(axis);

    }

    /**

     * Determines the maximum span for this view along an

     * axis.  Returns 0 if the view is not visible, otherwise

     * it calls the superclass method ot get the maximum span.

     *

     * @param axis may be either <code>View.X_AXIS</code> or

     *  <code>View.Y_AXIS</code>

     * @return  the maximum span the view can be rendered into

     * @see javax.swing.text.ParagraphView#getMaximumSpan

     */

    public float getMaximumSpan(int axis) {

        if (!isVisible()) {

            return 0;

        }

        return super.getMaximumSpan(axis);

    }

    private AttributeSet attr;

    private StyleSheet.BoxPainter painter;

    private CSS.LengthValue cssWidth;

    private CSS.LengthValue cssHeight;

}