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/*!

    view.cpp

    Provides a view to represent a one-dimensional sequence of integers

    obtained from a list model as a series of rows.

*/

#include <QAbstractItemModel>

#include <QBrush>

#include <QItemSelection>

#include <QPainter>

#include <QPaintEvent>

#include <QPen>

#include <QPoint>

#include <QResizeEvent>

#include <QScrollBar>

#include <QSizePolicy>

#include "view.h"

LinearView::LinearView(QWidget *parent)

    : QAbstractItemView(parent)

{

    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);

}

/*!

    Returns the position of the item in viewport coordinates.

*/

QRect LinearView::itemViewportRect(const QModelIndex &index) const

{

    QRect rect = itemRect(index);

    QRect result(rect.left() - horizontalScrollBar()->value(),

                 rect.top() - verticalScrollBar()->value(),

                 rect.width(), viewport()->height());

    return result;

}

/*!

    Returns the rectangle of the item at position \a index in the

    model. The rectangle is in contents coordinates.

*/

QRect LinearView::itemRect(const QModelIndex &index) const

{

    if (!index.isValid())

        return QRect();

    else

        return QRect(index.row(), 0, 1, 1);

}

void LinearView::ensureVisible(const QModelIndex &index)

{

    QRect area = viewport()->rect();

    QRect rect = itemViewportRect(index);

    if (rect.left() < area.left())

        horizontalScrollBar()->setValue(

            horizontalScrollBar()->value() - rect.left());

    else if (rect.right() > area.right())

        horizontalScrollBar()->setValue(

            horizontalScrollBar()->value() + rect.left() - area.width());

}

/*!

    Returns the item that covers the coordinate given in the view.

*/

QModelIndex LinearView::itemAt(int x, int /* y */) const

{

    int row = x + horizontalScrollBar()->value();

    return model()->index(row, 0, QModelIndex());

}

//void LinearView::dataChanged(const QModelIndex &/* topLeft */,

//    const QModelIndex &/* bottomRight */)

//{

//    updateGeometries();

//    if (isVisible())

//        repaint();

//}

void LinearView::rowsInserted(const QModelIndex &/* parent */, int /* start */,

    int /* end */)

{

    updateGeometries();

    if (isVisible())

        repaint();

}

void LinearView::rowsRemoved(const QModelIndex &/* parent */, int /* start */,

    int /* end */)

{

    updateGeometries();

    if (isVisible())

        repaint();

}

/*

void LinearView::verticalScrollbarAction(int action)

{

}

void LinearView::horizontalScrollbarAction(int action)

{

}

*/

/*!

    Select the items in the model that lie within the rectangle specified by

    \a rect, using the selection \a command.

*/

void LinearView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)

{

    QModelIndex leftIndex = itemAt(rect.left(), 0);

    QModelIndex rightIndex = itemAt(rect.right(), 0);

    QItemSelection selection(leftIndex, rightIndex);

    selectionModel()->select(selection, command);

}

QModelIndex LinearView::moveCursor(QAbstractItemView::CursorAction cursorAction,

                                   Qt::KeyboardModifiers)

{

    QModelIndex current = currentIndex();

    switch (cursorAction) {

    case MoveLeft:{

        if (current.row() > 0)

            return model()->index(current.row() - 1, 0, QModelIndex());

        else

            return model()->index(0, 0, QModelIndex());

        break;}

    case MoveRight:{

        if (current.row() < rows(current) - 1)

            return model()->index(current.row() + 1, 0, QModelIndex());

        else

            return model()->index(rows(current) - 1, 0,QModelIndex());

        break;}

    case MoveUp:

        return current;

    case MoveDown:

        return current;

    case MovePageUp:

        return current;

    case MovePageDown:

        return current;

    case MoveHome:

        return model()->index(0, 0, QModelIndex());

    case MoveEnd:

        return model()->index(rows(current) - 1, 0, QModelIndex());

    default:

        return current;

    }

}

int LinearView::horizontalOffset() const

{

    return horizontalScrollBar()->value();

}

int LinearView::verticalOffset() const

{

    return verticalScrollBar()->value();

}

/*!

    Returns a rectangle corresponding to the selection in viewport cooridinates.

*/

QRect LinearView::selectionViewportRect(const QItemSelection &selection) const

{

    int ranges = selection.count();

    if (ranges == 0)

        return QRect();

    // Note that we use the top and bottom functions of the selection range

    // since the data is stored in rows.

    int firstRow = selection.at(0).top();

    int lastRow = selection.at(0).top();

    for (int i = 0; i < ranges; ++i) {

        firstRow = qMin(firstRow, selection.at(i).top());

        lastRow = qMax(lastRow, selection.at(i).bottom());

    }

    QModelIndex firstItem = model()->index(qMin(firstRow, lastRow), 0,

        QModelIndex());

    QModelIndex lastItem = model()->index(qMax(firstRow, lastRow), 0,

        QModelIndex());

    QRect firstRect = itemViewportRect(firstItem);

    QRect lastRect = itemViewportRect(lastItem);

    return QRect(firstRect.left(), firstRect.top(),

        lastRect.right() - firstRect.left(), firstRect.height());

}

void LinearView::paintEvent(QPaintEvent *event)

{

    QPainter painter(viewport());

    QRect updateRect = event->rect();

    QBrush background(Qt::black);

    QPen foreground(Qt::white);

    painter.fillRect(updateRect, background);

    painter.setPen(foreground);

    QModelIndex firstItem = itemAt(updateRect.left(), updateRect.top());

    if (!firstItem.isValid())

        firstItem = model()->index(0, 0, QModelIndex());

    QModelIndex lastItem = itemAt(updateRect.right(), updateRect.bottom());

    if (!lastItem.isValid())

        lastItem = model()->index(rows() - 1, 0, QModelIndex());

    int x = updateRect.left();

    //int top = updateRect.top();

    //int bottom = updateRect.bottom();

    int row = firstItem.row();

    QModelIndex index = model()->index(row, 0, QModelIndex());

    int value = model()->data(index, Qt::DisplayRole).toInt();

    int midPoint = viewport()->height()/2;

    int y2 = midPoint - int(value * midPoint/255.0);

    while (row <= lastItem.row()) {

        QModelIndex index = model()->index(row, 0, QModelIndex());

        int value = model()->data(index, Qt::DisplayRole).toInt();

        int y1 = y2;

        y2 = midPoint - int(value * midPoint/255.0);

        painter.drawLine(x-1, y1, x, y2);

        ++row; ++x;

    }

}

void LinearView::resizeEvent(QResizeEvent * /* event */)

{

    updateGeometries();

}

void LinearView::updateGeometries()

{

    if (viewport()->width() < rows()) {

        horizontalScrollBar()->setPageStep(viewport()->width());

        horizontalScrollBar()->setRange(0, rows() - viewport()->width() - 1);

    }

}

QSize LinearView::sizeHint() const

{

    return QSize(rows(), 200);

}

int LinearView::rows(const QModelIndex &index) const

{

    return model()->rowCount(model()->parent(index));

}

bool LinearView::isIndexHidden(const QModelIndex &index) const

{

    return false;

}