Dépôt officiel du code source de l'ERP OpenConcerto

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2011-2019 OpenConcerto, by ILM Informatique. All rights reserved.
 * 
 * The contents of this file are subject to the terms of the GNU General Public License Version 3
 * only ("GPL"). You may not use this file except in compliance with the License. You can obtain a
 * copy of the License at http://www.gnu.org/licenses/gpl-3.0.html See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each file.
 */
 
 package org.openconcerto.ui;

import java.awt.*;
import javax.swing.*;

/**
 * A panel that implements the Scrollable interface. This class allows you to customize the
 * scrollable features by using newly provided setter methods so you don't have to extend this class
 * every time.
 *
 * Scrollable amounts can be specifed as a percentage of the viewport size or as an actual pixel
 * value. The amount can be changed for both unit and block scrolling for both horizontal and
 * vertical scrollbars.
 *
 * The Scrollable interface only provides a boolean value for determining whether or not the
 * viewport size (width or height) should be used by the scrollpane when determining if scrollbars
 * should be made visible. This class supports the concept of dynamically changing this value based
 * on the size of the viewport. In this case the viewport size will only be used when it is larger
 * than the panels size. This has the effect of ensuring the viewport is always full as components
 * added to the panel will be size to fill the area available, based on the rules of the applicable
 * layout manager of course.
 */
public class ScrollablePanel extends JPanel implements Scrollable, SwingConstants {
    public enum ScrollableSizeHint {
        NONE, FIT, STRETCH;
    }

    public enum IncrementType {
        PERCENT, PIXELS;
    }

    private ScrollableSizeHint scrollableHeight = ScrollableSizeHint.NONE;
    private ScrollableSizeHint scrollableWidth = ScrollableSizeHint.NONE;

    private IncrementInfo horizontalBlock;
    private IncrementInfo horizontalUnit;
    private IncrementInfo verticalBlock;
    private IncrementInfo verticalUnit;

    /**
     * Default constructor that uses a FlowLayout
     */
    public ScrollablePanel() {
        this(new FlowLayout());
    }

    /**
     * Constuctor for specifying the LayoutManager of the panel.
     *
     * @param layout the LayountManger for the panel
     */
    public ScrollablePanel(LayoutManager layout) {
        super(layout);

        IncrementInfo block = new IncrementInfo(IncrementType.PERCENT, 100);
        IncrementInfo unit = new IncrementInfo(IncrementType.PERCENT, 10);

        setScrollableBlockIncrement(HORIZONTAL, block);
        setScrollableBlockIncrement(VERTICAL, block);
        setScrollableUnitIncrement(HORIZONTAL, unit);
        setScrollableUnitIncrement(VERTICAL, unit);
    }

    /**
     * Get the height ScrollableSizeHint enum
     *
     * @return the ScrollableSizeHint enum for the height
     */
    public ScrollableSizeHint getScrollableHeight() {
        return scrollableHeight;
    }

    /**
     * Set the ScrollableSizeHint enum for the height. The enum is used to determine the boolean
     * value that is returned by the getScrollableTracksViewportHeight() method. The valid values
     * are:
     *
     * ScrollableSizeHint.NONE - return "false", which causes the height of the panel to be used
     * when laying out the children ScrollableSizeHint.FIT - return "true", which causes the height
     * of the viewport to be used when laying out the children ScrollableSizeHint.STRETCH - return
     * "true" when the viewport height is greater than the height of the panel, "false" otherwise.
     *
     * @param scrollableHeight as represented by the ScrollableSizeHint enum.
     */
    public void setScrollableHeight(ScrollableSizeHint scrollableHeight) {
        this.scrollableHeight = scrollableHeight;
        revalidate();
    }

    /**
     * Get the width ScrollableSizeHint enum
     *
     * @return the ScrollableSizeHint enum for the width
     */
    public ScrollableSizeHint getScrollableWidth() {
        return scrollableWidth;
    }

    /**
     * Set the ScrollableSizeHint enum for the width. The enum is used to determine the boolean
     * value that is returned by the getScrollableTracksViewportWidth() method. The valid values
     * are:
     *
     * ScrollableSizeHint.NONE - return "false", which causes the width of the panel to be used when
     * laying out the children ScrollableSizeHint.FIT - return "true", which causes the width of the
     * viewport to be used when laying out the children ScrollableSizeHint.STRETCH - return "true"
     * when the viewport width is greater than the width of the panel, "false" otherwise.
     *
     * @param scrollableWidth as represented by the ScrollableSizeHint enum.
     */
    public void setScrollableWidth(ScrollableSizeHint scrollableWidth) {
        this.scrollableWidth = scrollableWidth;
        revalidate();
    }

    /**
     * Get the block IncrementInfo for the specified orientation
     *
     * @return the block IncrementInfo for the specified orientation
     */
    public IncrementInfo getScrollableBlockIncrement(int orientation) {
        return orientation == SwingConstants.HORIZONTAL ? horizontalBlock : verticalBlock;
    }

    /**
     * Specify the information needed to do block scrolling.
     *
     * @param orientation specify the scrolling orientation. Must be either:
     *        SwingContants.HORIZONTAL or SwingContants.VERTICAL.
     * @paran type specify how the amount parameter in the calculation of the scrollable amount.
     *        Valid values are: IncrementType.PERCENT - treat the amount as a % of the viewport size
     *        IncrementType.PIXEL - treat the amount as the scrollable amount
     * @param amount a value used with the IncrementType to determine the scrollable amount
     */
    public void setScrollableBlockIncrement(int orientation, IncrementType type, int amount) {
        IncrementInfo info = new IncrementInfo(type, amount);
        setScrollableBlockIncrement(orientation, info);
    }

    /**
     * Specify the information needed to do block scrolling.
     *
     * @param orientation specify the scrolling orientation. Must be either:
     *        SwingContants.HORIZONTAL or SwingContants.VERTICAL.
     * @param info An IncrementInfo object containing information of how to calculate the scrollable
     *        amount.
     */
    public void setScrollableBlockIncrement(int orientation, IncrementInfo info) {
        switch (orientation) {
        case SwingConstants.HORIZONTAL:
            horizontalBlock = info;
            break;
        case SwingConstants.VERTICAL:
            verticalBlock = info;
            break;
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }

    /**
     * Get the unit IncrementInfo for the specified orientation
     *
     * @return the unit IncrementInfo for the specified orientation
     */
    public IncrementInfo getScrollableUnitIncrement(int orientation) {
        return orientation == SwingConstants.HORIZONTAL ? horizontalUnit : verticalUnit;
    }

    /**
     * Specify the information needed to do unit scrolling.
     *
     * @param orientation specify the scrolling orientation. Must be either:
     *        SwingContants.HORIZONTAL or SwingContants.VERTICAL.
     * @paran type specify how the amount parameter in the calculation of the scrollable amount.
     *        Valid values are: IncrementType.PERCENT - treat the amount as a % of the viewport size
     *        IncrementType.PIXEL - treat the amount as the scrollable amount
     * @param amount a value used with the IncrementType to determine the scrollable amount
     */
    public void setScrollableUnitIncrement(int orientation, IncrementType type, int amount) {
        IncrementInfo info = new IncrementInfo(type, amount);
        setScrollableUnitIncrement(orientation, info);
    }

    /**
     * Specify the information needed to do unit scrolling.
     *
     * @param orientation specify the scrolling orientation. Must be either:
     *        SwingContants.HORIZONTAL or SwingContants.VERTICAL.
     * @param info An IncrementInfo object containing information of how to calculate the scrollable
     *        amount.
     */
    public void setScrollableUnitIncrement(int orientation, IncrementInfo info) {
        switch (orientation) {
        case SwingConstants.HORIZONTAL:
            horizontalUnit = info;
            break;
        case SwingConstants.VERTICAL:
            verticalUnit = info;
            break;
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }

    // Implement Scrollable interface

    public Dimension getPreferredScrollableViewportSize() {
        return super.getPreferredSize();
    }

    public int getScrollableUnitIncrement(Rectangle visible, int orientation, int direction) {
        switch (orientation) {
        case SwingConstants.HORIZONTAL:
            return getScrollableIncrement(horizontalUnit, visible.width);
        case SwingConstants.VERTICAL:
            return getScrollableIncrement(verticalUnit, visible.height);
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }

    public int getScrollableBlockIncrement(Rectangle visible, int orientation, int direction) {
        switch (orientation) {
        case SwingConstants.HORIZONTAL:
            return getScrollableIncrement(horizontalBlock, visible.width);
        case SwingConstants.VERTICAL:
            return getScrollableIncrement(verticalBlock, visible.height);
        default:
            throw new IllegalArgumentException("Invalid orientation: " + orientation);
        }
    }

    protected int getScrollableIncrement(IncrementInfo info, int distance) {
        if (info.getIncrement() == IncrementType.PIXELS)
            return info.getAmount();
        else
            return distance * info.getAmount() / 100;
    }

    public boolean getScrollableTracksViewportWidth() {
        if (scrollableWidth == ScrollableSizeHint.NONE)
            return false;

        if (scrollableWidth == ScrollableSizeHint.FIT)
            return true;

        // STRETCH sizing, use the greater of the panel or viewport width

        if (getParent() instanceof JViewport) {
            return (((JViewport) getParent()).getWidth() > getPreferredSize().width);
        }

        return false;
    }

    public boolean getScrollableTracksViewportHeight() {
        if (scrollableHeight == ScrollableSizeHint.NONE)
            return false;

        if (scrollableHeight == ScrollableSizeHint.FIT)
            return true;

        // STRETCH sizing, use the greater of the panel or viewport height

        if (getParent() instanceof JViewport) {
            return (((JViewport) getParent()).getHeight() > getPreferredSize().height);
        }

        return false;
    }

    /**
     * Helper class to hold the information required to calculate the scroll amount.
     */
    static class IncrementInfo {
        private IncrementType type;
        private int amount;

        public IncrementInfo(IncrementType type, int amount) {
            this.type = type;
            this.amount = amount;
        }

        public IncrementType getIncrement() {
            return type;
        }

        public int getAmount() {
            return amount;
        }

        public String toString() {
            return "ScrollablePanel[" + type + ", " + amount + "]";
        }
    }
}