/****************************************************************************

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the Qt3Support module of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

#include "qwidget.h"

#ifndef QT_NO_SCROLLVIEW

#include "qscrollbar.h"

#include "qpainter.h"

#include "qpixmap.h"

#include "qcursor.h"

#include "q3scrollview.h"

#include "q3ptrdict.h"

#include "qapplication.h"

#include "qtimer.h"

#include "qstyle.h"

#include "q3ptrlist.h"

#include "qevent.h"

#include "q3listview.h"

#ifdef Q_WS_MAC

# include "private/qt_mac_p.h"

#endif

QT_BEGIN_NAMESPACE

using namespace Qt;

static const int coord_limit = 4000;

static const int autoscroll_margin = 16;

static const int initialScrollTime = 30;

static const int initialScrollAccel = 5;

struct QSVChildRec {

    QSVChildRec(QWidget* c, int xx, int yy) :

        child(c),

        x(xx), y(yy)

    {

    }

    void hideOrShow(Q3ScrollView* sv, QWidget* clipped_viewport);

    void moveTo(Q3ScrollView* sv, int xx, int yy, QWidget* clipped_viewport)

    {

        if (x != xx || y != yy) {

            x = xx;

            y = yy;

            hideOrShow(sv,clipped_viewport);

        }

    }

    QWidget* child;

    int x, y;

};

void QSVChildRec::hideOrShow(Q3ScrollView* sv, QWidget* clipped_viewport)

{

    if (clipped_viewport) {

        if (x+child->width() < sv->contentsX()+clipped_viewport->x()

             || x > sv->contentsX()+clipped_viewport->width()

             || y+child->height() < sv->contentsY()+clipped_viewport->y()

             || y > sv->contentsY()+clipped_viewport->height()) {

            child->move(clipped_viewport->width(),

                        clipped_viewport->height());

        } else {

            child->move(x-sv->contentsX()-clipped_viewport->x(),

                        y-sv->contentsY()-clipped_viewport->y());

        }

    } else {

        child->move(x-sv->contentsX(), y-sv->contentsY());

    }

}

class QAbstractScrollAreaWidget : public QWidget

{

    Q_OBJECT

public:

    QAbstractScrollAreaWidget(Q3ScrollView* parent=0, const char* name=0, Qt::WindowFlags f = 0)

        : QWidget(parent, name, f)

    {

        setAutoFillBackground(true);

    }

};

class QClipperWidget : public QWidget

{

    Q_OBJECT

public:

    QClipperWidget(QWidget * parent=0, const char * name=0, Qt::WindowFlags f=0)

        : QWidget (parent,name,f) {}

};

QT_BEGIN_INCLUDE_NAMESPACE

#include "q3scrollview.moc"

QT_END_INCLUDE_NAMESPACE

class Q3ScrollViewData {

public:

    Q3ScrollViewData(Q3ScrollView* parent, int vpwflags) :

        hbar(new QScrollBar(Qt::Horizontal, parent, "qt_hbar")),

        vbar(new QScrollBar(Qt::Vertical, parent, "qt_vbar")),

        viewport(new QAbstractScrollAreaWidget(parent, "qt_viewport", QFlag(vpwflags))),

        clipped_viewport(0),

        flags(vpwflags),

        vx(0), vy(0), vwidth(1), vheight(1),

#ifndef QT_NO_DRAGANDDROP

        autoscroll_timer(parent, "scrollview autoscroll timer"),

        drag_autoscroll(true),

#endif

        scrollbar_timer(parent, "scrollview scrollbar timer"),

        inresize(false), use_cached_size_hint(true)

    {

        l_marg = r_marg = t_marg = b_marg = 0;

        viewport->polish();

        vMode = Q3ScrollView::Auto;

        hMode = Q3ScrollView::Auto;

        corner = 0;

        vbar->setSteps(20, 1/*set later*/);

        hbar->setSteps(20, 1/*set later*/);

        policy = Q3ScrollView::Default;

        signal_choke = false;

        static_bg = false;

        fake_scroll = false;

        hbarPressed = false;

        vbarPressed = false;

        hbar->setLayoutDirection(Qt::LeftToRight);

    }

    ~Q3ScrollViewData();

    QSVChildRec* rec(QWidget* w) { return childDict.find(w); }

    QSVChildRec* ancestorRec(QWidget* w);

    QSVChildRec* addChildRec(QWidget* w, int x, int y)

    {

        QSVChildRec *r = new QSVChildRec(w,x,y);

        children.append(r);

        childDict.insert(w, r);

        return r;

    }

    void deleteChildRec(QSVChildRec* r)

    {

        childDict.remove(r->child);

        children.removeRef(r);

        delete r;

    }

    void hideOrShowAll(Q3ScrollView* sv, bool isScroll = false);

    void moveAllBy(int dx, int dy);

    bool anyVisibleChildren();

    void autoMove(Q3ScrollView* sv);

    void autoResize(Q3ScrollView* sv);

    void autoResizeHint(Q3ScrollView* sv);

    void viewportResized(int w, int h);

    QScrollBar*  hbar;

    QScrollBar*  vbar;

    bool hbarPressed;

    bool vbarPressed;

    QAbstractScrollAreaWidget*    viewport;

    QClipperWidget*     clipped_viewport;

    int         flags;

    Q3PtrList<QSVChildRec>       children;

    Q3PtrDict<QSVChildRec>       childDict;

    QWidget*    corner;

    int         vx, vy, vwidth, vheight; // for drawContents-style usage

    int         l_marg, r_marg, t_marg, b_marg;

    Q3ScrollView::ResizePolicy policy;

    Q3ScrollView::ScrollBarMode  vMode;

    Q3ScrollView::ScrollBarMode  hMode;

#ifndef QT_NO_DRAGANDDROP

    QPoint cpDragStart;

    QTimer autoscroll_timer;

    int autoscroll_time;

    int autoscroll_accel;

    bool drag_autoscroll;

#endif

    QTimer scrollbar_timer;

    uint static_bg : 1;

    uint fake_scroll : 1;

    // This variable allows ensureVisible to move the contents then

    // update both the sliders.  Otherwise, updating the sliders would

    // cause two image scrolls, creating ugly flashing.

    //

    uint signal_choke : 1;

    // This variables indicates in updateScrollBars() that we are

    // in a resizeEvent() and thus don't want to flash scroll bars

    uint inresize : 1;

    uint use_cached_size_hint : 1;

    QSize cachedSizeHint;

    inline int contentsX() const { return -vx; }

    inline int contentsY() const { return -vy; }

    inline int contentsWidth() const { return vwidth; }

};

inline Q3ScrollViewData::~Q3ScrollViewData()

{

    children.setAutoDelete(true);

}

QSVChildRec* Q3ScrollViewData::ancestorRec(QWidget* w)

{

    if (clipped_viewport) {

        while (w->parentWidget() != clipped_viewport) {

            w = w->parentWidget();

            if (!w) return 0;

        }

    } else {

        while (w->parentWidget() != viewport) {

            w = w->parentWidget();

            if (!w) return 0;

        }

    }

    return rec(w);

}

void Q3ScrollViewData::hideOrShowAll(Q3ScrollView* sv, bool isScroll)

{

    if (!clipped_viewport)

        return;

    if (clipped_viewport->x() <= 0

         && clipped_viewport->y() <= 0

         && clipped_viewport->width()+clipped_viewport->x() >=

         viewport->width()

         && clipped_viewport->height()+clipped_viewport->y() >=

         viewport->height()) {

        // clipped_viewport still covers viewport

        if(static_bg)

            clipped_viewport->repaint(true);

        else if ((!isScroll && !clipped_viewport->testAttribute(Qt::WA_StaticContents)) || static_bg)

            clipped_viewport->update();

    } else {

        // Re-center

        int nx = (viewport->width() - clipped_viewport->width()) / 2;

        int ny = (viewport->height() - clipped_viewport->height()) / 2;

        clipped_viewport->move(nx,ny);

        clipped_viewport->update();

    }

    for (QSVChildRec *r = children.first(); r; r=children.next()) {

        r->hideOrShow(sv, clipped_viewport);

    }

}

void Q3ScrollViewData::moveAllBy(int dx, int dy)

{

    if (clipped_viewport && !static_bg) {

        clipped_viewport->move(clipped_viewport->x()+dx,

                                clipped_viewport->y()+dy);

    } else {

        for (QSVChildRec *r = children.first(); r; r=children.next()) {

            r->child->move(r->child->x()+dx,r->child->y()+dy);

        }

        if (static_bg)

            viewport->repaint(true);

    }

}

bool Q3ScrollViewData::anyVisibleChildren()

{

    for (QSVChildRec *r = children.first(); r; r=children.next()) {

        if (r->child->isVisible()) return true;

    }

    return false;

}

void Q3ScrollViewData::autoMove(Q3ScrollView* sv)

{

    if (policy == Q3ScrollView::AutoOne) {

        QSVChildRec* r = children.first();

        if (r)

            sv->setContentsPos(-r->child->x(),-r->child->y());

    }

}

void Q3ScrollViewData::autoResize(Q3ScrollView* sv)

{

    if (policy == Q3ScrollView::AutoOne) {

        QSVChildRec* r = children.first();

        if (r)

            sv->resizeContents(r->child->width(),r->child->height());

    }

}

void Q3ScrollViewData::autoResizeHint(Q3ScrollView* sv)

{

    if (policy == Q3ScrollView::AutoOne) {

        QSVChildRec* r = children.first();

        if (r) {

            QSize s = r->child->sizeHint();

            if (s.isValid())

                r->child->resize(s);

        }

    } else if (policy == Q3ScrollView::AutoOneFit) {

        QSVChildRec* r = children.first();

        if (r) {

            QSize sh = r->child->sizeHint();

            sh = sh.boundedTo(r->child->maximumSize());

            sv->resizeContents(sh.width(), sh.height());

        }

    }

}

void Q3ScrollViewData::viewportResized(int w, int h)

{

    if (policy == Q3ScrollView::AutoOneFit) {

        QSVChildRec* r = children.first();

        if (r) {

            QSize sh = r->child->sizeHint();

            sh = sh.boundedTo(r->child->maximumSize());

            r->child->resize(QMAX(w,sh.width()), QMAX(h,sh.height()));

        }

    }

}

/*!

    \class Q3ScrollView

    \brief The Q3ScrollView widget provides a scrolling area with on-demand scroll bars.

    \compat

    The Q3ScrollView is a large canvas - potentially larger than the

    coordinate system normally supported by the underlying window

    system. This is important because it is quite easy to go beyond

    these limitations (e.g. many web pages are more than 32000 pixels

    high). Additionally, the Q3ScrollView can have QWidgets positioned

    on it that scroll around with the drawn content. These sub-widgets

    can also have positions outside the normal coordinate range (but

    they are still limited in size).

    To provide content for the widget, inherit from Q3ScrollView,

    reimplement drawContents() and use resizeContents() to set the

    size of the viewed area. Use addChild() and moveChild() to

    position widgets on the view.

    To use Q3ScrollView effectively it is important to understand its

    widget structure in the three styles of use: a single large child

    widget, a large panning area with some widgets and a large panning

    area with many widgets.

    \section1 Using One Big Widget

    \img qscrollview-vp2.png

    The first, simplest usage of Q3ScrollView (depicted above), is

    appropriate for scrolling areas that are never more than about

    4000 pixels in either dimension (this is about the maximum

    reliable size on X11 servers). In this usage, you just make one

    large child in the Q3ScrollView. The child should be a child of the

    viewport() of the scrollview and be added with addChild():

    \snippet doc/src/snippets/code/src_qt3support_widgets_q3scrollview.cpp 0

    You can go on to add arbitrary child widgets to the single child

    in the scrollview as you would with any widget:

    \snippet doc/src/snippets/code/src_qt3support_widgets_q3scrollview.cpp 1

    Here the Q3ScrollView has four children: the viewport(), the

    verticalScrollBar(), the horizontalScrollBar() and a small

    cornerWidget(). The viewport() has one child: the QWidget. The

    QWidget has the three QLabel objects as child widgets. When the view

    is scrolled, the QWidget is moved; its children move with it as

    child widgets normally do.

    \section1 Using a Very Big View with Some Widgets

    \img qscrollview-vp.png

    The second usage of Q3ScrollView (depicted above) is appropriate

    when few, if any, widgets are on a very large scrolling area that

    is potentially larger than 4000 pixels in either dimension. In

    this usage you call resizeContents() to set the size of the area

    and reimplement drawContents() to paint the contents. You may also

    add some widgets by making them children of the viewport() and

    adding them with addChild() (this is the same as the process for

    the single large widget in the previous example):

    \snippet doc/src/snippets/code/src_qt3support_widgets_q3scrollview.cpp 2

    Here, the Q3ScrollView has the same four children: the viewport(),

    the verticalScrollBar(), the horizontalScrollBar() and a small

    cornerWidget(). The viewport() has the three QLabel objects as

    child widgets. When the view is scrolled, the scrollview moves the

    child widgets individually.

    \section1 Using a Very Big View with Many Widgets

    \img qscrollview-cl.png

    The final usage of Q3ScrollView (depicted above) is appropriate

    when many widgets are on a very large scrolling area that is

    potentially larger than 4000 pixels in either dimension. In this

    usage you call resizeContents() to set the size of the area and

    reimplement drawContents() to paint the contents. You then call

    enableClipper(true) and add widgets, again by making them children

    of the viewport(), and adding them with addChild():

    \snippet doc/src/snippets/code/src_qt3support_widgets_q3scrollview.cpp 3

    Here, the Q3ScrollView has four children:  the clipper() (not the

    viewport() this time), the verticalScrollBar(), the

    horizontalScrollBar() and a small cornerWidget(). The clipper()

    has one child: the viewport(). The viewport() has the same three

    labels as child widgets. When the view is scrolled the viewport()

    is moved; its children move with it as child widgets normally do.

    \target allviews

    \section1 Details Relevant for All Views

    Normally you will use the first or third method if you want any

    child widgets in the view.

    Note that the widget you see in the scrolled area is the

    viewport() widget, not the Q3ScrollView itself. So to turn mouse

    tracking on, for example, use viewport()->setMouseTracking(true).

    To enable drag-and-drop, you would setAcceptDrops(true) on the

    Q3ScrollView (because drag-and-drop events propagate to the

    parent). But to work out the logical position in the view, you

    would need to map the drop co-ordinate from being relative to the

    Q3ScrollView to being relative to the contents; use the function

    viewportToContents() for this.

    To handle mouse events on the scrolling area, subclass scrollview

    as you would subclass other widgets, but rather than

    reimplementing mousePressEvent(), reimplement

    contentsMousePressEvent() instead. The contents specific event

    handlers provide translated events in the coordinate system of the

    scrollview. If you reimplement mousePressEvent(), you'll get

    called only when part of the Q3ScrollView is clicked: and the only

    such part is the "corner" (if you don't set a cornerWidget()) and

    the frame; everything else is covered up by the viewport, clipper

    or scroll bars.

    When you construct a Q3ScrollView, some of the window flags apply

    to the viewport() instead of being sent to the QWidget constructor

    for the Q3ScrollView.

    \list

    \i An image-manipulation widget would use \c

    WNoAutoErase|WStaticContents because the widget draws all pixels

    itself, and when its size increases, it only needs a paint event

    for the new part because the old part remains unchanged.

    \i A scrolling game widget in which the background scrolls as the

    characters move might use \c WNoAutoErase (in addition to \c

    WStaticContents) so that the window system background does not

    flash in and out during scrolling.

    \i A word processing widget might use \c WNoAutoErase and repaint

    itself line by line to get a less-flickery resizing. If the widget

    is in a mode in which no text justification can take place, it

    might use \c WStaticContents too, so that it would only get a

    repaint for the newly visible parts.

    \endlist

    Child widgets may be moved using addChild() or moveChild(). Use

    childX() and childY() to get the position of a child widget.

    A widget may be placed in the corner between the vertical and

    horizontal scroll bars with setCornerWidget(). You can get access

    to the scroll bars using horizontalScrollBar() and

    verticalScrollBar(), and to the viewport with viewport(). The

    scroll view can be scrolled using scrollBy(), ensureVisible(),

    setContentsPos() or center().

    The visible area is given by visibleWidth() and visibleHeight(),

    and the contents area by contentsWidth() and contentsHeight(). The

    contents may be repainted using one of the repaintContents() or

    updateContents() functions.

    Coordinate conversion is provided by contentsToViewport() and

    viewportToContents().

    The contentsMoving() signal is emitted just before the contents

    are moved to a new position.

    \warning Q3ScrollView currently does not erase the background when

    resized, i.e. you must always clear the background manually in

    scrollview subclasses. This will change in a future version of Qt

    and we recommend specifying the \c WNoAutoErase flag explicitly.

*/

/*!

    \enum Q3ScrollView::ResizePolicy

    This enum type is used to control a Q3ScrollView's reaction to

    resize events.

    \value Default  the Q3ScrollView selects one of the other settings

    automatically when it has to. In this version of Qt, Q3ScrollView

    changes to \c Manual if you resize the contents with