/* ============================================================
 *
 * This file is a part of digiKam project
 * http://www.digikam.org
 *
 * Date        : 2010-08-26
 * Description : Tag region formatting
 *
 * Copyright (C) 2010-2011 by Marcel Wiesweg <marcel dot wiesweg at gmx dot de>
 *
 * This program is free software; you can redistribute it
 * and/or modify it under the terms of the GNU General
 * Public License as published by the Free Software Foundation;
 * either version 2, or (at your option)
 * any later version.
 *
 * This program 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 for more details.
 *
 * ============================================================ */

#ifndef TAGREGION_H
#define TAGREGION_H

// Qt includes

#include <QRect>
#include <QString>
#include <QVariant>

// Local includes

#include "digikam_export.h"

class QDebug;

namespace Digikam
{

class DImg;

class DIGIKAM_EXPORT TagRegion
{

public:
    
    enum Type
    {
        Invalid,
        Rect
    };
    
public:

    /**
     * Use this small class to convert between the formatted
     * textual representation of a tag region in the database
     * and the corresponding object.
     */

    /// Invalid region
    TagRegion();
    /// Construct with the textual descriptor
    explicit TagRegion(const QString& descriptor);
    /// Construct with the region
    explicit TagRegion(const QRect& rect);

    Type type() const;
    bool isValid() const;

    bool operator==(const TagRegion& other) const;
    bool operator!=(const TagRegion& other) const
    {
        return !operator==(other);
    }

    /// Returns an XML textual representation of this region
    QString toXml() const;
    /// If type is Rect, returns the contained rectangle
    QRect toRect() const;

    /// Stores in / loads from a variant. Will only use native QVariant types.
    QVariant toVariant() const;
    static TagRegion fromVariant(const QVariant& var);

    /**
     * Returns true if this and the other region intersect.
     * fraction describes the relative overlap area needed to return true:
     * If fraction is 0, returns true if the regions intersect at all.
     * If fraction is 1, returns true only if other is completely contained in this region.
     * If fraction is x, 0 < x < 1, returns true if the area of this region
     * covered by the other is greater than x.
     * Invalid areas never intersect.
     */
    bool intersects(const TagRegion& other, double fraction = 0);

    /**
     * Converts detail rectangles taken from a reduced size image to the original size, and vice versa
     */
    static QRect mapToOriginalSize(const QSize& fullImageSize, const QSize& reducedImageSize, const QRect& reducedSizeDetail);
    static QRect mapFromOriginalSize(const QSize& fullImageSize, const QSize& reducedImageSize, const QRect& fullSizeDetail);
    /// Takes the original and reduced size from the DImg
    static QRect mapToOriginalSize(const DImg& reducedSizeImage, const QRect& reducedSizeDetail);
    static QRect mapFromOriginalSize(const DImg& reducedSizeImage, const QRect& fullSizeDetail);

    /**
     * Takes a relative region and a full size and returns the absolute region
     */
    static QRect relativeToAbsolute(const QRectF& region, const QSize& fullSize);
    /// Takes the original and reduced size from the DImg, maps to original size
    static QRect relativeToAbsolute(const QRectF& region, const DImg& reducedSizeImage);

    /**
     *  Takes absolute region and full size to return the original relative region
     * Used to write back rectangles into image's XMP. see MetadataHub::write
     */
    static QRectF absoluteToRelative(const QRect& region, const QSize& fullSize);

    /** When images is rotated, rectangles are off-position, ajust them using
     *  image's current size and rotation(left,right supported only)
     */
    static QRect ajustToRotatedImg(const QRect& region, const QSize& fullSize, int rotation);

protected:

    QVariant m_value;
    Type     m_type;
};

QDebug DIGIKAM_EXPORT operator<<(QDebug dbg, const TagRegion& r);

} // namespace Digikam

#endif // TAGREGION_H
