Qt实现扇形图(1)

#include "pieview.h
#include <QtWidgets>

PieView::PieView(QWidget *parent)
    : QAbstractItemView(parent)
{
horizontalScrollBar()->setRange(0, 0);
verticalScrollBar()->setRange(0, 0);
}

void PieView::dataChanged(const QModelIndex &topLeft,
const QModelIndex &bottomRight,
const QVector<int> &roles)
{
QAbstractItemView::dataChanged(topLeft, bottomRight, roles);

if (!roles.contains(Qt::DisplayRole))
return;

validItems = 0;
totalValue = 0.0;

for (int row = 0; row < model()->rowCount(rootIndex()); ++row) {

QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index, Qt::DisplayRole).toDouble();

if (value > 0.0) {
totalValue += value;
validItems++;
        }
    }
viewport()->update();
}

bool PieView::edit(const QModelIndex &index, EditTrigger trigger, QEvent *event)
{
if (index.column() == 0)
return QAbstractItemView::edit(index, trigger, event);
else
return false;
}


QModelIndex PieView::indexAt(const QPoint &point) const
{
if (validItems == 0)
return QModelIndex();

// Transform the view coordinates into contents widget coordinates.
int wx = point.x() + horizontalScrollBar()->value();
int wy = point.y() + verticalScrollBar()->value();

if (wx < totalSize) {
double cx = w - totalSize / 2;
double cy = totalSize / 2 - wy; // positive cy for items above the center

// Determine the distance from the center point of the pie chart.
double d = std::sqrt(std::pow(cx, 2) + std::pow(cy, 2));

if (d == 0 || d > pieSize / 2)
return QModelIndex();

// Determine the angle of the point.
double angle = qRadiansToDegrees(std::atan2(cy, cx));
if (angle < 0)
angle = 360 + angle;

// Find the relevant slice of the pie.
double startAngle = 0.0;

for (int row = 0; row < model()->rowCount(rootIndex()); ++row) {

QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index).toDouble();

if (value > 0.0) {
double sliceAngle = 360 * value / totalValue;

if (angle >= startAngle && angle < (startAngle + sliceAngle))
return model()->index(row, 1, rootIndex());

startAngle += sliceAngle;
            }
        }
    } else {
double itemHeight = QFontMetrics(viewOptions().font).height();
int listItem = int((wy - margin) / itemHeight);
int validRow = 0;

for (int row = 0; row < model()->rowCount(rootIndex()); ++row) {

QModelIndex index = model()->index(row, 1, rootIndex());
if (model()->data(index).toDouble() > 0.0) {

if (listItem == validRow)
return model()->index(row, 0, rootIndex());

// Update the list index that corresponds to the next valid row.
++validRow;
            }
        }
    }

return QModelIndex();
}

bool PieView::isIndexHidden(const QModelIndex & /*index*/) const
{
return false;
}

QRect PieView::itemRect(const QModelIndex &index) const
{
if (!index.isValid())
return QRect();

// Check whether the index's row is in the list of rows represented
// by slices.
QModelIndex valueIndex;

if (index.column() != 1)
valueIndex = model()->index(index.row(), 1, rootIndex());
else
valueIndex = index;

if (model()->data(valueIndex).toDouble() <= 0.0)
return QRect();

int listItem = 0;
for (int row = index.row()-1; row >= 0; --row) {
if (model()->data(model()->index(row, 1, rootIndex())).toDouble() > 0.0)
listItem++;
    }

switch (index.column()) {
case 0: {
const qreal itemHeight = QFontMetricsF(viewOptions().font).height();

return QRect(totalSize,
qRound(margin + listItem * itemHeight),
totalSize - margin, qRound(itemHeight));
    }
case 1:
return viewport()->rect();
    }
return QRect();
}

QRegion PieView::itemRegion(const QModelIndex &index) const
{
if (!index.isValid())
return QRegion();

if (index.column() != 1)
return itemRect(index);

if (model()->data(index).toDouble() <= 0.0)
return QRegion();

double startAngle = 0.0;
for (int row = 0; row < model()->rowCount(rootIndex()); ++row) {

QModelIndex sliceIndex = model()->index(row, 1, rootIndex());
double value = model()->data(sliceIndex).toDouble();

if (value > 0.0) {
double angle = 360 * value / totalValue;

if (sliceIndex == index) {
QPainterPath slicePath;
slicePath.moveTo(totalSize / 2, totalSize / 2);
slicePath.arcTo(margin, margin, margin + pieSize, margin + pieSize,
startAngle, angle);
slicePath.closeSubpath();

return QRegion(slicePath.toFillPolygon().toPolygon());
            }

startAngle += angle;
        }
    }

return QRegion();
}

int PieView::horizontalOffset() const
{
return horizontalScrollBar()->value();
}

void PieView::mousePressEvent(QMouseEvent *event)
{
QAbstractItemView::mousePressEvent(event);
origin = event->pos();
if (!rubberBand)
rubberBand = new QRubberBand(QRubberBand::Rectangle, viewport());
rubberBand->setGeometry(QRect(origin, QSize()));
rubberBand->show();
}

void PieView::mouseMoveEvent(QMouseEvent *event)
{
if (rubberBand)
rubberBand->setGeometry(QRect(origin, event->pos()).normalized());
QAbstractItemView::mouseMoveEvent(event);
}

void PieView::mouseReleaseEvent(QMouseEvent *event)
{
QAbstractItemView::mouseReleaseEvent(event);
if (rubberBand)
rubberBand->hide();
viewport()->update();
}

QModelIndex PieView::moveCursor(QAbstractItemView::CursorAction cursorAction,
Qt::KeyboardModifiers /*modifiers*/)
{
QModelIndex current = currentIndex();

switch (cursorAction) {
case MoveLeft:
case MoveUp:
if (current.row() > 0)
current = model()->index(current.row() - 1, current.column(),
rootIndex());
else
current = model()->index(0, current.column(), rootIndex());
break;
case MoveRight:
case MoveDown:
if (current.row() < rows(current) - 1)
current = model()->index(current.row() + 1, current.column(),
rootIndex());
else
current = model()->index(rows(current) - 1, current.column(),
rootIndex());
break;
default:
break;
    }

viewport()->update();
return current;
}

void PieView::paintEvent(QPaintEvent *event)
{
QItemSelectionModel *selections = selectionModel();
QStyleOptionViewItem option = viewOptions();

QBrush background = option.palette.base();
QPen foreground(option.palette.color(QPalette::WindowText));

QPainter painter(viewport());
painter.setRenderHint(QPainter::Antialiasing);

painter.fillRect(event->rect(), background);
painter.setPen(foreground);

// Viewport rectangles
QRect pieRect = QRect(margin, margin, pieSize, pieSize);

if (validItems <= 0)
return;

painter.save();
painter.translate(pieRect.x() - horizontalScrollBar()->value(),
pieRect.y() - verticalScrollBar()->value());
painter.drawEllipse(0, 0, pieSize, pieSize);
double startAngle = 0.0;
int row;

for (row = 0; row < model()->rowCount(rootIndex()); ++row) {
QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index).toDouble();

if (value > 0.0) {
double angle = 360 * value / totalValue;

QModelIndex colorIndex = model()->index(row, 0, rootIndex());
QColor color = QColor(model()->data(colorIndex, Qt::DecorationRole).toString());

if (currentIndex() == index)
painter.setBrush(QBrush(color, Qt::Dense4Pattern));
else if (selections->isSelected(index))
painter.setBrush(QBrush(color, Qt::Dense3Pattern));
else
painter.setBrush(QBrush(color));

painter.drawPie(0, 0, pieSize, pieSize, int(startAngle*16), int(angle*16));

startAngle += angle;
        }
    }
painter.restore();

int keyNumber = 0;

for (row = 0; row < model()->rowCount(rootIndex()); ++row) {
QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index).toDouble();

if (value > 0.0) {
QModelIndex labelIndex = model()->index(row, 0, rootIndex());

QStyleOptionViewItem option = viewOptions();
option.rect = visualRect(labelIndex);
if (selections->isSelected(labelIndex))
option.state |= QStyle::State_Selected;
if (currentIndex() == labelIndex)
option.state |= QStyle::State_HasFocus;
itemDelegate()->paint(&painter, option, labelIndex);

++keyNumber;
        }
    }
}

void PieView::resizeEvent(QResizeEvent * /* event */)
{
updateGeometries();
}

int PieView::rows(const QModelIndex &index) const
{
return model()->rowCount(model()->parent(index));
}

void PieView::rowsInserted(const QModelIndex &parent, int start, int end)
{
for (int row = start; row <= end; ++row) {
QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index).toDouble();

if (value > 0.0) {
totalValue += value;
++validItems;
        }
    }

QAbstractItemView::rowsInserted(parent, start, end);
}

void PieView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
{
for (int row = start; row <= end; ++row) {
QModelIndex index = model()->index(row, 1, rootIndex());
double value = model()->data(index).toDouble();
if (value > 0.0) {
totalValue -= value;
--validItems;
        }
    }

QAbstractItemView::rowsAboutToBeRemoved(parent, start, end);
}

void PieView::scrollContentsBy(int dx, int dy)
{
viewport()->scroll(dx, dy);
}

void PieView::scrollTo(const QModelIndex &index, ScrollHint)
{
QRect area = viewport()->rect();
QRect rect = visualRect(index);

if (rect.left() < area.left()) {
horizontalScrollBar()->setValue(
horizontalScrollBar()->value() + rect.left() - area.left());
    } else if (rect.right() > area.right()) {
horizontalScrollBar()->setValue(
horizontalScrollBar()->value() + qMin(
rect.right() - area.right(), rect.left() - area.left()));
    }

if (rect.top() < area.top()) {
verticalScrollBar()->setValue(
verticalScrollBar()->value() + rect.top() - area.top());
    } else if (rect.bottom() > area.bottom()) {
verticalScrollBar()->setValue(
verticalScrollBar()->value() + qMin(
rect.bottom() - area.bottom(), rect.top() - area.top()));
    }

update();
}

/*
Find the indices corresponding to the extent of the selection.
*/

void PieView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
// Use content widget coordinates because we will use the itemRegion()
// function to check for intersections.

QRect contentsRect = rect.translated(
horizontalScrollBar()->value(),
verticalScrollBar()->value()).normalized();

int rows = model()->rowCount(rootIndex());
int columns = model()->columnCount(rootIndex());
QModelIndexList indexes;

for (int row = 0; row < rows; ++row) {
for (int column = 0; column < columns; ++column) {
QModelIndex index = model()->index(row, column, rootIndex());
QRegion region = itemRegion(index);
if (region.intersects(contentsRect))
indexes.append(index);
        }
    }

if (indexes.size() > 0) {
int firstRow = indexes.at(0).row();
int lastRow = firstRow;
int firstColumn = indexes.at(0).column();
int lastColumn = firstColumn;

for (int i = 1; i < indexes.size(); ++i) {
firstRow = qMin(firstRow, indexes.at(i).row());
lastRow = qMax(lastRow, indexes.at(i).row());
firstColumn = qMin(firstColumn, indexes.at(i).column());
lastColumn = qMax(lastColumn, indexes.at(i).column());
        }

QItemSelection selection(
model()->index(firstRow, firstColumn, rootIndex()),
model()->index(lastRow, lastColumn, rootIndex()));
selectionModel()->select(selection, command);
    } else {
QModelIndex noIndex;
QItemSelection selection(noIndex, noIndex);
selectionModel()->select(selection, command);
    }

update();
}

void PieView::updateGeometries()
{
horizontalScrollBar()->setPageStep(viewport()->width());
horizontalScrollBar()->setRange(0, qMax(0, 2 * totalSize - viewport()->width()));
verticalScrollBar()->setPageStep(viewport()->height());
verticalScrollBar()->setRange(0, qMax(0, totalSize - viewport()->height()));
}

int PieView::verticalOffset() const
{
return verticalScrollBar()->value();
}

QRect PieView::visualRect(const QModelIndex &index) const
{
QRect rect = itemRect(index);
if (!rect.isValid())
return rect;

return QRect(rect.left() - horizontalScrollBar()->value(),
rect.top() - verticalScrollBar()->value(),
rect.width(), rect.height());
}

/*
Returns a region corresponding to the selection in viewport coordinates.
*/

QRegion PieView::visualRegionForSelection(const QItemSelection &selection) const
{
int ranges = selection.count();

if (ranges == 0)
return QRect();

QRegion region;
for (int i = 0; i < ranges; ++i) {
const QItemSelectionRange &range = selection.at(i);
for (int row = range.top(); row <= range.bottom(); ++row) {
for (int col = range.left(); col <= range.right(); ++col) {
QModelIndex index = model()->index(row, col, rootIndex());
region += visualRect(index);
            }
        }
    }
return region;
}