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splinechartitem.cpp
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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Charts module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
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** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
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** $QT_END_LICENSE$
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****************************************************************************/
#include <private/splinechartitem_p.h>
#include <private/qsplineseries_p.h>
#include <private/chartpresenter_p.h>
#include <private/splineanimation_p.h>
#include <private/polardomain_p.h>
#include <QtGui/QPainter>
#include <QtWidgets/QGraphicsSceneMouseEvent>
QT_CHARTS_BEGIN_NAMESPACE
SplineChartItem::SplineChartItem(QSplineSeries *series, QGraphicsItem *item)
: XYChart(series,item),
m_series(series),
m_pointsVisible(false),
m_animation(0),
m_pointLabelsVisible(false),
m_pointLabelsFormat(series->pointLabelsFormat()),
m_pointLabelsFont(series->pointLabelsFont()),
m_pointLabelsColor(series->pointLabelsColor()),
m_pointLabelsClipping(true),
m_mousePressed(false)
{
setAcceptHoverEvents(true);
setFlag(QGraphicsItem::ItemIsSelectable);
setZValue(ChartPresenter::SplineChartZValue);
QObject::connect(m_series->d_func(), SIGNAL(updated()), this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(visibleChanged()), this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(opacityChanged()), this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(pointLabelsFormatChanged(QString)),
this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(pointLabelsVisibilityChanged(bool)),
this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(pointLabelsFontChanged(QFont)), this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(pointLabelsColorChanged(QColor)), this, SLOT(handleUpdated()));
QObject::connect(series, SIGNAL(pointLabelsClippingChanged(bool)), this, SLOT(handleUpdated()));
handleUpdated();
}
QRectF SplineChartItem::boundingRect() const
{
return m_rect;
}
QPainterPath SplineChartItem::shape() const
{
return m_fullPath;
}
void SplineChartItem::setAnimation(SplineAnimation *animation)
{
m_animation = animation;
XYChart::setAnimation(animation);
}
ChartAnimation *SplineChartItem::animation() const
{
return m_animation;
}
void SplineChartItem::setControlGeometryPoints(QVector<QPointF>& points)
{
m_controlPoints = points;
}
QVector<QPointF> SplineChartItem::controlGeometryPoints() const
{
return m_controlPoints;
}
void SplineChartItem::updateChart(QVector<QPointF> &oldPoints, QVector<QPointF> &newPoints, int index)
{
QVector<QPointF> controlPoints;
if (newPoints.count() >= 2)
controlPoints = calculateControlPoints(newPoints);
if (m_animation)
m_animation->setup(oldPoints, newPoints, m_controlPoints, controlPoints, index);
m_points = newPoints;
m_controlPoints = controlPoints;
setDirty(false);
if (m_animation)
presenter()->startAnimation(m_animation);
else
updateGeometry();
}
void SplineChartItem::updateGeometry()
{
const QVector<QPointF> &points = m_points;
const QVector<QPointF> &controlPoints = m_controlPoints;
if ((points.size() < 2) || (controlPoints.size() < 2)) {
prepareGeometryChange();
m_path = QPainterPath();
m_rect = QRect();
return;
}
Q_ASSERT(points.count() * 2 - 2 == controlPoints.count());
QPainterPath splinePath;
QPainterPath fullPath;
// Use worst case scenario to determine required margin.
qreal margin = m_linePen.width() * 1.42;
if (m_series->chart()->chartType() == QChart::ChartTypePolar) {
QPainterPath splinePathLeft;
QPainterPath splinePathRight;
QPainterPath *currentSegmentPath = 0;
QPainterPath *previousSegmentPath = 0;
qreal minX = domain()->minX();
qreal maxX = domain()->maxX();
qreal minY = domain()->minY();
QPointF currentSeriesPoint = m_series->at(0);
QPointF currentGeometryPoint = points.at(0);
QPointF previousGeometryPoint = points.at(0);
bool pointOffGrid = false;
bool previousPointWasOffGrid = (currentSeriesPoint.x() < minX || currentSeriesPoint.x() > maxX);
m_visiblePoints.clear();
m_visiblePoints.reserve(points.size());
qreal domainRadius = domain()->size().height() / 2.0;
const QPointF centerPoint(domainRadius, domainRadius);
if (!previousPointWasOffGrid) {
fullPath.moveTo(points.at(0));
// Do not draw points for points below minimum Y.
if (m_pointsVisible && currentSeriesPoint.y() >= minY)
m_visiblePoints.append(currentGeometryPoint);
}
qreal leftMarginLine = centerPoint.x() - margin;
qreal rightMarginLine = centerPoint.x() + margin;
qreal horizontal = centerPoint.y();
// See ScatterChartItem::updateGeometry() for explanation why seriesLastIndex is needed
const int seriesLastIndex = m_series->count() - 1;
for (int i = 1; i < points.size(); i++) {
// Interpolating spline fragments accurately is not trivial, and would anyway be ugly
// when thick pen is used, so we work around it by utilizing three separate
// paths for spline segments and clip those with custom regions at paint time.
// "Right" path contains segments that cross the axis line with visible point on the
// right side of the axis line, as well as segments that have one point within the margin
// on the right side of the axis line and another point on the right side of the chart.
// "Left" path contains points with similarly on the left side.
// "Full" path contains rest of the points.
// This doesn't yield perfect results always. E.g. when segment covers more than 90
// degrees and both of the points are within the margin, one in the top half and one in the
// bottom half of the chart, the bottom one gets clipped incorrectly.
// However, this should be rare occurrence in any sensible chart.
currentSeriesPoint = m_series->at(qMin(seriesLastIndex, i));
currentGeometryPoint = points.at(i);
pointOffGrid = (currentSeriesPoint.x() < minX || currentSeriesPoint.x() > maxX);
// Draw something unless both off-grid
if (!pointOffGrid || !previousPointWasOffGrid) {
bool dummyOk; // We know points are ok, but this is needed
qreal currentAngle = static_cast<PolarDomain *>(domain())->toAngularCoordinate(currentSeriesPoint.x(), dummyOk);
qreal previousAngle = static_cast<PolarDomain *>(domain())->toAngularCoordinate(m_series->at(i - 1).x(), dummyOk);
if ((qAbs(currentAngle - previousAngle) > 180.0)) {
// If the angle between two points is over 180 degrees (half X range),
// any direct segment between them becomes meaningless.
// In this case two line segments are drawn instead, from previous
// point to the center and from center to current point.
if ((previousAngle < 0.0 || (previousAngle <= 180.0 && previousGeometryPoint.x() < rightMarginLine))
&& previousGeometryPoint.y() < horizontal) {
currentSegmentPath = &splinePathRight;
} else if ((previousAngle > 360.0 || (previousAngle > 180.0 && previousGeometryPoint.x() > leftMarginLine))
&& previousGeometryPoint.y() < horizontal) {
currentSegmentPath = &splinePathLeft;
} else if (previousAngle > 0.0 && previousAngle < 360.0) {
currentSegmentPath = &splinePath;
} else {
currentSegmentPath = 0;
}
if (currentSegmentPath) {
if (previousSegmentPath != currentSegmentPath)
currentSegmentPath->moveTo(previousGeometryPoint);
if (!previousSegmentPath)
fullPath.moveTo(previousGeometryPoint);
currentSegmentPath->lineTo(centerPoint);
fullPath.lineTo(centerPoint);
}
previousSegmentPath = currentSegmentPath;
if ((currentAngle < 0.0 || (currentAngle <= 180.0 && currentGeometryPoint.x() < rightMarginLine))
&& currentGeometryPoint.y() < horizontal) {
currentSegmentPath = &splinePathRight;
} else if ((currentAngle > 360.0 || (currentAngle > 180.0 &&currentGeometryPoint.x() > leftMarginLine))
&& currentGeometryPoint.y() < horizontal) {
currentSegmentPath = &splinePathLeft;
} else if (currentAngle > 0.0 && currentAngle < 360.0) {
currentSegmentPath = &splinePath;
} else {
currentSegmentPath = 0;
}
if (currentSegmentPath) {
if (previousSegmentPath != currentSegmentPath)
currentSegmentPath->moveTo(centerPoint);
if (!previousSegmentPath)
fullPath.moveTo(centerPoint);
currentSegmentPath->lineTo(currentGeometryPoint);
fullPath.lineTo(currentGeometryPoint);
}
} else {
QPointF cp1 = controlPoints[2 * (i - 1)];
QPointF cp2 = controlPoints[(2 * i) - 1];
if (previousAngle < 0.0 || currentAngle < 0.0
|| ((previousAngle <= 180.0 && currentAngle <= 180.0)
&& ((previousGeometryPoint.x() < rightMarginLine && previousGeometryPoint.y() < horizontal)
|| (currentGeometryPoint.x() < rightMarginLine && currentGeometryPoint.y() < horizontal)))) {
currentSegmentPath = &splinePathRight;
} else if (previousAngle > 360.0 || currentAngle > 360.0
|| ((previousAngle > 180.0 && currentAngle > 180.0)
&& ((previousGeometryPoint.x() > leftMarginLine && previousGeometryPoint.y() < horizontal)
|| (currentGeometryPoint.x() > leftMarginLine && currentGeometryPoint.y() < horizontal)))) {
currentSegmentPath = &splinePathLeft;
} else {
currentSegmentPath = &splinePath;
}
if (currentSegmentPath != previousSegmentPath)
currentSegmentPath->moveTo(previousGeometryPoint);
if (!previousSegmentPath)
fullPath.moveTo(previousGeometryPoint);
fullPath.cubicTo(cp1, cp2, currentGeometryPoint);
currentSegmentPath->cubicTo(cp1, cp2, currentGeometryPoint);
}
} else {
currentSegmentPath = 0;
}
previousPointWasOffGrid = pointOffGrid;
if (!pointOffGrid && m_pointsVisible && currentSeriesPoint.y() >= minY)
m_visiblePoints.append(currentGeometryPoint);
previousSegmentPath = currentSegmentPath;
previousGeometryPoint = currentGeometryPoint;
}
m_pathPolarRight = splinePathRight;
m_pathPolarLeft = splinePathLeft;
// Note: This construction of m_fullpath is not perfect. The partial segments that are
// outside left/right clip regions at axis boundary still generate hover/click events,
// because shape doesn't get clipped. It doesn't seem possible to do sensibly.
} else { // not polar
splinePath.moveTo(points.at(0));
for (int i = 0; i < points.size() - 1; i++) {
const QPointF &point = points.at(i + 1);
splinePath.cubicTo(controlPoints[2 * i], controlPoints[2 * i + 1], point);
}
fullPath = splinePath;
}
QPainterPathStroker stroker;
// The full path is comprised of three separate paths.
// This is why we are prepared for the "worst case" scenario, i.e. use always MiterJoin and
// multiply line width with square root of two when defining shape and bounding rectangle.
stroker.setWidth(margin);
stroker.setJoinStyle(Qt::MiterJoin);
stroker.setCapStyle(Qt::SquareCap);
stroker.setMiterLimit(m_linePen.miterLimit());
// Only zoom in if the bounding rects of the path fit inside int limits. QWidget::update() uses
// a region that has to be compatible with QRect.
QPainterPath checkShapePath = stroker.createStroke(fullPath);
if (checkShapePath.boundingRect().height() <= INT_MAX
&& checkShapePath.boundingRect().width() <= INT_MAX
&& splinePath.boundingRect().height() <= INT_MAX
&& splinePath.boundingRect().width() <= INT_MAX) {
m_path = splinePath;
prepareGeometryChange();
m_fullPath = checkShapePath;
m_rect = m_fullPath.boundingRect();
}
}
/*!
Calculates control points which are needed by QPainterPath.cubicTo function to draw the cubic Bezier cureve between two points.
*/
QVector<QPointF> SplineChartItem::calculateControlPoints(const QVector<QPointF> &points)
{
QVector<QPointF> controlPoints;
controlPoints.resize(points.count() * 2 - 2);
int n = points.count() - 1;
if (n == 1) {
//for n==1
controlPoints[0].setX((2 * points[0].x() + points[1].x()) / 3);
controlPoints[0].setY((2 * points[0].y() + points[1].y()) / 3);
controlPoints[1].setX(2 * controlPoints[0].x() - points[0].x());
controlPoints[1].setY(2 * controlPoints[0].y() - points[0].y());
return controlPoints;
}
// Calculate first Bezier control points
// Set of equations for P0 to Pn points.
//
// | 2 1 0 0 ... 0 0 0 ... 0 0 0 | | P1_1 | | P0 + 2 * P1 |
// | 1 4 1 0 ... 0 0 0 ... 0 0 0 | | P1_2 | | 4 * P1 + 2 * P2 |
// | 0 1 4 1 ... 0 0 0 ... 0 0 0 | | P1_3 | | 4 * P2 + 2 * P3 |
// | . . . . . . . . . . . . | | ... | | ... |
// | 0 0 0 0 ... 1 4 1 ... 0 0 0 | * | P1_i | = | 4 * P(i-1) + 2 * Pi |
// | . . . . . . . . . . . . | | ... | | ... |
// | 0 0 0 0 0 0 0 0 ... 1 4 1 | | P1_(n-1)| | 4 * P(n-2) + 2 * P(n-1) |
// | 0 0 0 0 0 0 0 0 ... 0 2 7 | | P1_n | | 8 * P(n-1) + Pn |
//
QVector<qreal> vector;
vector.resize(n);
vector[0] = points[0].x() + 2 * points[1].x();
for (int i = 1; i < n - 1; ++i)
vector[i] = 4 * points[i].x() + 2 * points[i + 1].x();
vector[n - 1] = (8 * points[n - 1].x() + points[n].x()) / 2.0;
QVector<qreal> xControl = firstControlPoints(vector);
vector[0] = points[0].y() + 2 * points[1].y();
for (int i = 1; i < n - 1; ++i)
vector[i] = 4 * points[i].y() + 2 * points[i + 1].y();
vector[n - 1] = (8 * points[n - 1].y() + points[n].y()) / 2.0;
QVector<qreal> yControl = firstControlPoints(vector);
for (int i = 0, j = 0; i < n; ++i, ++j) {
controlPoints[j].setX(xControl[i]);
controlPoints[j].setY(yControl[i]);
j++;
if (i < n - 1) {
controlPoints[j].setX(2 * points[i + 1].x() - xControl[i + 1]);
controlPoints[j].setY(2 * points[i + 1].y() - yControl[i + 1]);
} else {
controlPoints[j].setX((points[n].x() + xControl[n - 1]) / 2);
controlPoints[j].setY((points[n].y() + yControl[n - 1]) / 2);
}
}
return controlPoints;
}
QVector<qreal> SplineChartItem::firstControlPoints(const QVector<qreal>& vector)
{
QVector<qreal> result;
int count = vector.count();
result.resize(count);
result[0] = vector[0] / 2.0;
QVector<qreal> temp;
temp.resize(count);
temp[0] = 0;
qreal b = 2.0;
for (int i = 1; i < count; i++) {
temp[i] = 1 / b;
b = (i < count - 1 ? 4.0 : 3.5) - temp[i];
result[i] = (vector[i] - result[i - 1]) / b;
}
for (int i = 1; i < count; i++)
result[count - i - 1] -= temp[count - i] * result[count - i];
return result;
}
//handlers
void SplineChartItem::handleUpdated()
{
setVisible(m_series->isVisible());
setOpacity(m_series->opacity());
m_pointsVisible = m_series->pointsVisible();
m_linePen = m_series->pen();
m_pointPen = m_series->pen();
m_pointPen.setWidthF(2 * m_pointPen.width());
m_pointLabelsFormat = m_series->pointLabelsFormat();
m_pointLabelsVisible = m_series->pointLabelsVisible();
m_pointLabelsFont = m_series->pointLabelsFont();
m_pointLabelsColor = m_series->pointLabelsColor();
m_pointLabelsClipping = m_series->pointLabelsClipping();
update();
}
//painter
void SplineChartItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
Q_UNUSED(widget)
Q_UNUSED(option)
QRectF clipRect = QRectF(QPointF(0, 0), domain()->size());
painter->save();
painter->setPen(m_linePen);
painter->setBrush(Qt::NoBrush);
if (m_series->chart()->chartType() == QChart::ChartTypePolar) {
qreal halfWidth = domain()->size().width() / 2.0;
QRectF clipRectLeft = QRectF(0, 0, halfWidth, domain()->size().height());
QRectF clipRectRight = QRectF(halfWidth, 0, halfWidth, domain()->size().height());
QRegion fullPolarClipRegion(clipRect.toRect(), QRegion::Ellipse);
QRegion clipRegionLeft(fullPolarClipRegion.intersected(clipRectLeft.toRect()));
QRegion clipRegionRight(fullPolarClipRegion.intersected(clipRectRight.toRect()));
painter->setClipRegion(clipRegionLeft);
painter->drawPath(m_pathPolarLeft);
painter->setClipRegion(clipRegionRight);
painter->drawPath(m_pathPolarRight);
painter->setClipRegion(fullPolarClipRegion);
} else {
painter->setClipRect(clipRect);
}
reversePainter(painter, clipRect);
painter->drawPath(m_path);
if (m_pointsVisible) {
painter->setPen(m_pointPen);
if (m_series->chart()->chartType() == QChart::ChartTypePolar)
painter->drawPoints(m_visiblePoints);
else
painter->drawPoints(geometryPoints());
}
reversePainter(painter, clipRect);
if (m_pointLabelsVisible) {
if (m_pointLabelsClipping)
painter->setClipping(true);
else
painter->setClipping(false);
m_series->d_func()->drawSeriesPointLabels(painter, m_points, m_linePen.width() / 2);
}
painter->restore();
}
void SplineChartItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
emit XYChart::pressed(domain()->calculateDomainPoint(event->pos()));
m_lastMousePos = event->pos();
m_mousePressed = true;
QGraphicsItem::mousePressEvent(event);
}
void SplineChartItem::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
{
emit XYChart::hovered(domain()->calculateDomainPoint(event->pos()), true);
QGraphicsItem::hoverEnterEvent(event);
}
void SplineChartItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
emit XYChart::hovered(domain()->calculateDomainPoint(event->pos()), false);
QGraphicsItem::hoverLeaveEvent(event);
}
void SplineChartItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
emit XYChart::released(domain()->calculateDomainPoint(m_lastMousePos));
if (m_mousePressed)
emit XYChart::clicked(domain()->calculateDomainPoint(m_lastMousePos));
m_mousePressed = false;
QGraphicsItem::mouseReleaseEvent(event);
}
void SplineChartItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
emit XYChart::doubleClicked(domain()->calculateDomainPoint(m_lastMousePos));
QGraphicsItem::mouseDoubleClickEvent(event);
}
#include "moc_splinechartitem_p.cpp"
QT_CHARTS_END_NAMESPACE