pieview.cpp Example File
itemviews/chart/pieview.cpp
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**
** Copyright (C) 2004-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
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#include <math.h>
#include <QtGui>
#ifndef M_PI
#define M_PI 3.1415927
#endif
#include "pieview.h"
PieView::PieView(QWidget *parent)
: QAbstractItemView(parent)
{
horizontalScrollBar()->setRange(0, 0);
verticalScrollBar()->setRange(0, 0);
margin = 8;
totalSize = 300;
pieSize = totalSize - 2*margin;
validItems = 0;
totalValue = 0.0;
}
void PieView::dataChanged(const QModelIndex &topLeft,
const QModelIndex &bottomRight)
{
QAbstractItemView::dataChanged(topLeft, bottomRight);
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).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;
}
/*
Returns the item that covers the coordinate given in the view.
*/
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 = wx - 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 = pow(pow(cx, 2) + pow(cy, 2), 0.5);
if (d == 0 || d > pieSize/2)
return QModelIndex();
// Determine the angle of the point.
double angle = (180 / M_PI) * acos(cx/d);
if (cy < 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;
}
/*
Returns the rectangle of the item at position \a index in the
model. The rectangle is in contents coordinates.
*/
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) {
int listItem = 0;
for (int row = index.row()-1; row >= 0; --row) {
if (model()->data(model()->index(row, 1, rootIndex())).toDouble() > 0.0)
listItem++;
}
double itemHeight;
switch (index.column()) {
case 0:
itemHeight = QFontMetrics(viewOptions().font).height();
return QRect(totalSize,
int(margin + listItem*itemHeight),
totalSize - margin, int(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::mouseReleaseEvent(QMouseEvent *event)
{
QAbstractItemView::mouseReleaseEvent(event);
selectionRect = QRect();
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();
QStyle::State state = option.state;
QBrush background = option.palette.base();
QPen foreground(option.palette.color(QPalette::Foreground));
QPen textPen(option.palette.color(QPalette::Text));
QPen highlightedPen(option.palette.color(QPalette::HighlightedText));
QPainter painter(viewport());
painter.setRenderHint(QPainter::Antialiasing);
painter.fillRect(event->rect(), background);
painter.setPen(foreground);
// Viewport rectangles
QRect pieRect = QRect(margin, margin, pieSize, pieSize);
QPoint keyPoint = QPoint(totalSize - horizontalScrollBar()->value(),
margin - verticalScrollBar()->value());
if (validItems > 0) {
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());
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.intersect(contentsRect).isEmpty())
indexes.append(index);
}
}
if (indexes.size() > 0) {
int firstRow = indexes[0].row();
int lastRow = indexes[0].row();
int firstColumn = indexes[0].column();
int lastColumn = indexes[0].column();
for (int i = 1; i < indexes.size(); ++i) {
firstRow = qMin(firstRow, indexes[i].row());
lastRow = qMax(lastRow, indexes[i].row());
firstColumn = qMin(firstColumn, indexes[i].column());
lastColumn = qMax(lastColumn, indexes[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);
}
selectionRect = rect;
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();
}
/*
Returns the position of the item in viewport coordinates.
*/
QRect PieView::visualRect(const QModelIndex &index) const
{
QRect rect = itemRect(index);
if (rect.isValid())
return QRect(rect.left() - horizontalScrollBar()->value(),
rect.top() - verticalScrollBar()->value(),
rect.width(), rect.height());
else
return rect;
}
/*
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();
// 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, rootIndex());
QModelIndex lastItem = model()->index(qMax(firstRow, lastRow), 0, rootIndex());
QRect firstRect = visualRect(firstItem);
QRect lastRect = visualRect(lastItem);
return firstRect.unite(lastRect);
}
