plasma-framework/delegate.h

/*  
    Copyright 2007 Robert Knight <robertknight@gmail.com>
    Copyright 2008 Marco Martin <notmart@gmail.com>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

#ifndef DELEGATE_H
#define DELEGATE_H

// Qt
#include <QtGui/QAbstractItemDelegate>

// Plasma
#include <plasma/plasma_export.h>

namespace Plasma
{

/**
 * Item delegate for rendering items in Plasma menus implemented with item views.
 *
 * The delegate makes use of its own data roles that are:
 * SubTitleRole: the text of the subtitle
 * SubTitleMandatoryRole: if the subtitle is to always be displayed (as default the subtitle is displayed only on mouse over)
 * ColumnTypeRole: if the column is a main column (with title and subtitle)
 * or a secondary action column (only a little icon that appears on mouse over is displayed)
 */
class PLASMA_EXPORT Delegate : public QAbstractItemDelegate
{
    Q_OBJECT
public:

    enum SpecificRoles {
         SubTitleRole = Qt::UserRole + 1,
         SubTitleMandatoryRole = Qt::UserRole + 2,
         ColumnTypeRole = Qt::UserRole + 3
    };

    enum ColumnType {
         MainColumn = 1,
         SecondaryActionColumn = 2
    };

    Delegate(QObject *parent = 0);
    ~Delegate();

    /**
     * Maps an arbitrary role to a role belonging to SpecificRoles.
     * Using this function you can use any model with this delegate.
     *
     * @param role a role belonging to SpecificRoles
     * @param actual an arbitrary role of the model we are using
     */
    void setRoleMapping(SpecificRoles role, int actual);

    int roleMapping(SpecificRoles role) const;

    static const int ICON_TEXT_MARGIN = 10;
    static const int TEXT_RIGHT_MARGIN = 5;
    static const int ICON_SIZE = 32;
    static const int ACTION_ICON_SIZE = 22;

    static const int ITEM_LEFT_MARGIN = 5;
    static const int ITEM_RIGHT_MARGIN = 5;
    static const int ITEM_TOP_MARGIN = 5;
    static const int ITEM_BOTTOM_MARGIN = 5;

    /* give some space between icons */
    static const int ITEM_HEIGHT = ICON_SIZE + ITEM_TOP_MARGIN + ITEM_BOTTOM_MARGIN;

protected:
    /**
     * Returns the empty area after the title.
     * The height is the height of the subtitle.
     * It can be used by subclasses that wants to paint additional data after calling the paint function of the superclass.
     *
     * @param option options for the title text
     * @param index model index that we want to compute the free area
     */
    QRect rectAfterTitle(const QStyleOptionViewItem& option, const QModelIndex& index) const;

    /**
     * Returns the empty area after the subtitle.
     * The height is the height of the subtitle.
     * It can be used by subclasses, that wants to paint additional data.
     *
     * @param option options for the subtitle text
     * @param index model index that we want to compute the free area
     */
    QRect rectAfterSubTitle(const QStyleOptionViewItem& option, const QModelIndex& index) const;

    /**
     * Returns the empty area after both the title and the subtitle.
     * The height is the height of the item.
     * It can be used by subclasses that wants to paint additional data
     *
     * @param option options for the title and subtitle text
     * @param index model index that we want to compute the free area
     */
    QRect emptyRect(const QStyleOptionViewItem& option, const QModelIndex& index) const;

    //Reimplemented
    virtual void paint(QPainter *painter,const QStyleOptionViewItem& option,const QModelIndex& index) const;

    virtual QSize sizeHint(const QStyleOptionViewItem& option , const QModelIndex& index) const;

private:
    class Private;
    Private * const d;
};

}

#endif // ITEMDELEGATE_H