/* This file is part of the KDE project
   Copyright (C) 2001 Andrea Rizzi <rizzi@kde.org>
	              Ulrich Kuettler <ulrich.kuettler@mailbox.tu-dresden.de>

   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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#ifndef __KFORMULAVIEW_H
#define __KFORMULAVIEW_H

#include <qevent.h>
#include <qobject.h>
#include <qrect.h>

#include "formuladefs.h"

class QColorGroup;

KFORMULA_NAMESPACE_BEGIN

class BasicElement;
class FormulaCursor;
class FormulaElement;
class KFormulaContainer;


/**
 * The view that shows the formula. Its main purpose is to handle
 * the cursor. There are methods
 * to move the cursor around. To edit the formula use the document.
 *
 * The view is meant to be easy embeddable into a widget or
 * to be used alone if there is a bigger widget the formula
 * is to be drawn into.
 */
class KFormulaView : public QObject {
    Q_OBJECT

public:
    KFormulaView(KFormulaContainer*);
    ~KFormulaView();

    /**
     * @returns the point inside the formula view where the cursor is.
     */
    QPoint getCursorPoint() const;

    /**
     * @returns the area the cursor is currently on.
     */
    QRect getDirtyArea() const;

    /**
     * Puts the widget in read only mode.
     */
    void setReadOnly(bool ro);

    void mousePressEvent(QMouseEvent* event);
    void mouseReleaseEvent(QMouseEvent* event);
    void mouseDoubleClickEvent(QMouseEvent* event);
    void mouseMoveEvent(QMouseEvent* event);
    void wheelEvent(QWheelEvent* event);

    //void paintEvent(QPaintEvent* event);
    void keyPressEvent(QKeyEvent* event);
    void focusInEvent(QFocusEvent* event);
    void focusOutEvent(QFocusEvent* event);

    void draw(QPainter& painter, const QRect& rect, const QColorGroup& cg);

    /**
     * The document we show.
     */
    KFormulaContainer* getDocument() const { return container(); }

    /**
     * Our cursor.
     */
    FormulaCursor* getCursor() const { return cursor(); }

    void setSmallCursor(bool small);

    /** @returns whether the cursor is at the first position. */
    bool isHome() const;

    /** @returns whether the cursor is at the last position. */
    bool isEnd() const;

signals:

    /**
     * Is emitted everytime the cursor might have changed.
     */
    void cursorChanged(bool visible, bool selecting);

public slots:

    void slotSelectAll();

    void slotMoveLeft(MoveFlag flag);
    void slotMoveRight(MoveFlag flag);
    void slotMoveUp(MoveFlag flag);
    void slotMoveDown(MoveFlag flag);
    void slotMoveHome(MoveFlag flag);
    void slotMoveEnd(MoveFlag flag);

protected slots:

    /**
     * The cursor has been moved by the container.
     * We need to repaint if it was ours.
     */
    void slotCursorMoved(FormulaCursor* cursor);

    /**
     * There was a major change that included a cursor move.
     * We need to recalc it so it gets drawn correctly.
     */
    void slotCursorChanged(FormulaCursor* cursor);

    /**
     * A new formula has been loaded.
     */
    void slotFormulaLoaded(FormulaElement*);

    /**
     * There is an element that will disappear from the tree.
     * our cursor must not be inside it.
     */
    void slotElementWillVanish(BasicElement*);

protected:

    /**
     * Convert Qt style key state modifiers to local
     * movement flags.
     */
    MoveFlag movementFlag(int state);

private:

    /**
     * Tell everybody that our cursor has changed if so.
     */
    void emitCursorChanged();

    struct KFormulaView_Impl;
    KFormulaView_Impl* impl;

    FormulaCursor* cursor() const;
    bool& cursorHasChanged();
    bool& cursorVisible();
    bool& smallCursor();
    KFormulaContainer* container() const;
};

KFORMULA_NAMESPACE_END

#endif // __KFORMULAVIEW_H

.