source: other-projects/rsyntax-textarea/src/java/org/fife/ui/rtextarea/RTextScrollPane.java@ 25584

/*
 * 11/14/2003
 *
 * RTextScrollPane.java - A JScrollPane that will only accept RTextAreas
 * so that it can display line numbers, fold indicators, and icons.
 * 
 * This library is distributed under a modified BSD license.  See the included
 * RSyntaxTextArea.License.txt file for details.
 */
package org.fife.ui.rtextarea;

import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import javax.swing.JScrollPane;


/**
 * An extension of <code>javax.swing.JScrollPane</code> that will only take
 * <code>RTextArea</code>s for its view.  This class has the ability to show:
 * <ul>
 *    <li>Line numbers
 *    <li>Per-line icons (for bookmarks, debugging breakpoints, error markers, etc.)
 *    <li>+/- icons to denote code folding regions.
 * </ul>
 *
 * The actual "meat" of these extras is contained in the {@link Gutter} class.
 * Each <code>RTextScrollPane</code> has a <code>Gutter</code> instance that
 * it uses as its row header.  The gutter is only made visible when one of its
 * features is being used (line numbering, folding, and/or icons).
 *
 * @author Robert Futrell
 * @version 0.9
 */
public class RTextScrollPane extends JScrollPane {

    private RTextArea textArea;
    private Gutter gutter;


    /**
     * Constructor.  If you use this constructor, you must call
     * {@link #setViewportView(Component)} and pass in an {@link RTextArea}
     * for this scroll pane to render line numbers properly.
     */
    public RTextScrollPane() {
        this(null, true);
    }


    /**
     * Creates a scroll pane.  A default value will be used for line number
     * color (gray), and the current line's line number will be highlighted.
     *
     * @param textArea The text area this scroll pane will contain.
     */
    public RTextScrollPane(RTextArea textArea) {
        this(textArea, true);
    }


    /**
     * Creates a scroll pane.  A default value will be used for line number
     * color (gray), and the current line's line number will be highlighted.
     *
     * @param textArea The text area this scroll pane will contain.  If this is
     *        <code>null</code>, you must call
     *        {@link #setViewportView(Component)}, passing in an
     *        {@link RTextArea}.
     * @param lineNumbers Whether line numbers should be enabled.
     */
    public RTextScrollPane(RTextArea textArea, boolean lineNumbers) {
        this(textArea, lineNumbers, Color.GRAY);
    }


    /**
     * Creates a scroll pane with preferred size (width, height).
     *
     * @param area The text area this scroll pane will contain.  If this is
     *        <code>null</code>, you must call
     *        {@link #setViewportView(Component)}, passing in an
     *        {@link RTextArea}.
     * @param lineNumbers Whether line numbers are initially enabled.
     * @param lineNumberColor The color to use for line numbers.
     */
    public RTextScrollPane(RTextArea area, boolean lineNumbers,
                            Color lineNumberColor) {

        super(area);

        // Create the text area and set it inside this scroll bar area.
        textArea = area;

        // Create the gutter for this document.
        Font defaultFont = new Font("Monospaced", Font.PLAIN, 12);
        gutter = new Gutter(textArea);
        gutter.setLineNumberFont(defaultFont);
        gutter.setLineNumberColor(lineNumberColor);
        setLineNumbersEnabled(lineNumbers);

        // Set miscellaneous properties.
        setVerticalScrollBarPolicy(VERTICAL_SCROLLBAR_ALWAYS);
        setHorizontalScrollBarPolicy(HORIZONTAL_SCROLLBAR_AS_NEEDED);

    }


    /**
     * Ensures the gutter is visible if it's showing anything.
     */
    private void checkGutterVisibility() {
        int count = gutter.getComponentCount();
        if (count==0) {
            if (getRowHeader()!=null && getRowHeader().getView()==gutter) {
                setRowHeaderView(null);
            }
        }
        else {
            if (getRowHeader()==null || getRowHeader().getView()==null) {
                setRowHeaderView(gutter);
            }
        }
    }


    /**
     * Returns the gutter.
     *
     * @return The gutter.
     */
    public Gutter getGutter() {
        return gutter;
    }


    /**
     * Returns <code>true</code> if the line numbers are enabled and visible.
     *
     * @return Whether or not line numbers are visible.
     * @see #setLineNumbersEnabled(boolean)
     */
    public boolean getLineNumbersEnabled() {
        return gutter.getLineNumbersEnabled();
    }


    /**
     * Returns the text area being displayed.
     *
     * @return The text area.
     * @see #setViewportView(Component)
     */
    public RTextArea getTextArea() {
        return (RTextArea)getViewport().getView();
    }


    /**
     * Returns whether the fold indicator is enabled.
     *
     * @return Whether the fold indicator is enabled.
     * @see #setFoldIndicatorEnabled(boolean)
     */
    public boolean isFoldIndicatorEnabled() {
        return gutter.isFoldIndicatorEnabled();
    }


    /**
     * Returns whether the icon row header is enabled.
     *
     * @return Whether the icon row header is enabled.
     * @see #setIconRowHeaderEnabled(boolean)
     */
    public boolean isIconRowHeaderEnabled() {
        return gutter.isIconRowHeaderEnabled();
    }


    /**
     * Toggles whether the fold indicator is enabled.
     *
     * @param enabled Whether the fold indicator should be enabled.
     * @see #isFoldIndicatorEnabled()
     */
    public void setFoldIndicatorEnabled(boolean enabled) {
        gutter.setFoldIndicatorEnabled(enabled);
        checkGutterVisibility();
    }


    /**
     * Toggles whether the icon row header (used for breakpoints, bookmarks,
     * etc.) is enabled.
     *
     * @param enabled Whether the icon row header is enabled.
     * @see #isIconRowHeaderEnabled()
     */
    public void setIconRowHeaderEnabled(boolean enabled) {
        gutter.setIconRowHeaderEnabled(enabled);
        checkGutterVisibility();
    }


    /**
     * Toggles whether or not line numbers are visible.
     *
     * @param enabled Whether or not line numbers should be visible.
     * @see #getLineNumbersEnabled()
     */
    public void setLineNumbersEnabled(boolean enabled) {
        gutter.setLineNumbersEnabled(enabled);
        checkGutterVisibility();
    }


    /**
     * Sets the view for this scroll pane.  This must be an {@link RTextArea}.
     *
     * @param view The new view.
     * @see #getTextArea()
     */
    public void setViewportView(Component view) {
        if (!(view instanceof RTextArea)) {
            throw new IllegalArgumentException("view must be an RTextArea");
        }
        super.setViewportView(view);
        textArea = (RTextArea)view;
        if (gutter!=null) {
            gutter.setTextArea(textArea);
        }
    }


}