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#include "grid_p.h"

#include <QtCore/QString>

#include <QtCore/QVector>

#include <QtGui/QPainter>

#include <QtGui/QWidget>

#include <QtGui/qevent.h>

QT_BEGIN_NAMESPACE

static const bool defaultSnap = true;

static const bool defaultVisible = true;

static const int DEFAULT_GRID = 10;

static const char* KEY_VISIBLE = "gridVisible";

static const char* KEY_SNAPX =  "gridSnapX";

static const char* KEY_SNAPY =  "gridSnapY";

static const char* KEY_DELTAX =  "gridDeltaX";

static const char* KEY_DELTAY =  "gridDeltaY";

// Insert a value into the serialization map unless default

template <class T>

    static inline void valueToVariantMap(T value, T defaultValue, const QString &key, QVariantMap &v, bool forceKey) {

        if (forceKey || value != defaultValue)

            v.insert(key, QVariant(value));

    }

// Obtain a value form QVariantMap

template <class T>

    static inline bool valueFromVariantMap(const QVariantMap &v, const QString &key, T &value) {

        const QVariantMap::const_iterator it = v.constFind(key);

        const bool found = it != v.constEnd();

        if (found)

            value = qVariantValue<T>(it.value());

        return found;

    }

namespace qdesigner_internal

{

Grid::Grid() :

    m_visible(defaultVisible),

    m_snapX(defaultSnap),

    m_snapY(defaultSnap),

    m_deltaX(DEFAULT_GRID),

    m_deltaY(DEFAULT_GRID)

{

}

bool Grid::fromVariantMap(const QVariantMap& vm)

{

    *this = Grid();

    valueFromVariantMap(vm, QLatin1String(KEY_VISIBLE), m_visible);

    valueFromVariantMap(vm, QLatin1String(KEY_SNAPX), m_snapX);

    valueFromVariantMap(vm, QLatin1String(KEY_SNAPY), m_snapY);

    valueFromVariantMap(vm, QLatin1String(KEY_DELTAX), m_deltaX);

    return valueFromVariantMap(vm, QLatin1String(KEY_DELTAY), m_deltaY);

}

QVariantMap Grid::toVariantMap(bool forceKeys) const

{

    QVariantMap rc;

    addToVariantMap(rc, forceKeys);

    return rc;

}

void  Grid::addToVariantMap(QVariantMap& vm, bool forceKeys) const

{

    valueToVariantMap(m_visible, defaultVisible, QLatin1String(KEY_VISIBLE), vm, forceKeys);

    valueToVariantMap(m_snapX, defaultSnap, QLatin1String(KEY_SNAPX), vm, forceKeys);

    valueToVariantMap(m_snapY, defaultSnap, QLatin1String(KEY_SNAPY), vm, forceKeys);

    valueToVariantMap(m_deltaX, DEFAULT_GRID, QLatin1String(KEY_DELTAX), vm, forceKeys);

    valueToVariantMap(m_deltaY, DEFAULT_GRID, QLatin1String(KEY_DELTAY), vm, forceKeys);

}

void Grid::paint(QWidget *widget, QPaintEvent *e) const

{

    QPainter p(widget);

    paint(p, widget, e);

}

void Grid::paint(QPainter &p, const QWidget *widget, QPaintEvent *e) const

{

    p.setPen(widget->palette().dark().color());

    if (m_visible) {

        const int xstart = (e->rect().x() / m_deltaX) * m_deltaX;

        const int ystart = (e->rect().y() / m_deltaY) * m_deltaY;

        const int xend = e->rect().right();

        const int yend = e->rect().bottom();

        typedef QVector<QPointF> Points;

        static Points points;

        points.clear();

        for (int x = xstart; x <= xend; x += m_deltaX) {

            points.reserve((yend - ystart) / m_deltaY + 1);

            for (int y = ystart; y <= yend; y += m_deltaY)

                points.push_back(QPointF(x, y));

            p.drawPoints( &(*points.begin()), points.count());

            points.clear();

        }

    }

}

int Grid::snapValue(int value, int grid) const

{

    const int rest = value % grid;

    const int absRest = (rest < 0) ? -rest : rest;

    int offset = 0;

    if (2 * absRest > grid)

        offset = 1;

    if (rest < 0)

        offset *= -1;

    return (value / grid + offset) * grid;

}

QPoint Grid::snapPoint(const QPoint &p) const

{

    const int sx = m_snapX ? snapValue(p.x(), m_deltaX) : p.x();

    const int sy = m_snapY ? snapValue(p.y(), m_deltaY) : p.y();

    return QPoint(sx, sy);

}

int Grid::widgetHandleAdjustX(int x) const

{

    return m_snapX ? (x / m_deltaX) * m_deltaX + 1 : x;

}

int Grid::widgetHandleAdjustY(int y) const

{

    return m_snapY ? (y / m_deltaY) * m_deltaY + 1 : y;

}

bool Grid::equals(const Grid &rhs) const

{

    return m_visible == rhs.m_visible &&

           m_snapX   == rhs.m_snapX &&

           m_snapY   == rhs.m_snapY &&

           m_deltaX  == rhs.m_deltaX &&

           m_deltaY  == rhs.m_deltaY;

}

}

QT_END_NAMESPACE