All callout class from Qt examples
ADD
src/cachesim/cacheratioplotview.cpp
+#include "cacheratioplotview.h"
+
+CacheRatioPlotView::CacheRatioPlotView()
+{
+
+}

ADD
src/cachesim/cacheratioplotview.h
+#ifndef CACHERATIOPLOTVIEW_H
+#define CACHERATIOPLOTVIEW_H
+
+
+class CacheRatioPlotView
+{
+public:
+ CacheRatioPlotView();
+};
+
+#endif // CACHERATIOPLOTVIEW_H

ADD
src/cachesim/callout.cpp
+/****************************************************************************
+**
+** 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
+** a written agreement between you and The Qt Company. For licensing terms
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "callout.h"
+#include <QAction>
+#include <QMenu>
+#include <QtCharts/QChart>
+#include <QtGui/QFontMetrics>
+#include <QtGui/QMouseEvent>
+#include <QtGui/QPainter>
+#include <QtWidgets/QGraphicsSceneMouseEvent>
+
+Callout::Callout(QChart* chart) : QGraphicsItem(chart), m_chart(chart) {}
+
+QRectF Callout::boundingRect() const {
+ QPointF anchor = mapFromParent(m_chart->mapToPosition(m_anchor));
+ QRectF rect;
+ rect.setLeft(qMin(m_rect.left(), anchor.x()));
+ rect.setRight(qMax(m_rect.right(), anchor.x()));
+ rect.setTop(qMin(m_rect.top(), anchor.y()));
+ rect.setBottom(qMax(m_rect.bottom(), anchor.y()));
+ return rect;
+}
+
+void Callout::paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget) {
+ painter->save();
+ Q_UNUSED(option)
+ Q_UNUSED(widget)
+ QPainterPath path;
+ path.addRoundedRect(m_rect, 5, 5);
+
+ QPointF anchor = mapFromParent(m_chart->mapToPosition(m_anchor));
+ if (!m_rect.contains(anchor)) {
+ QPointF point1, point2;
+
+ // establish the position of the anchor point in relation to m_rect
+ bool above = anchor.y() <= m_rect.top();
+ bool aboveCenter = anchor.y() > m_rect.top() && anchor.y() <= m_rect.center().y();
+ bool belowCenter = anchor.y() > m_rect.center().y() && anchor.y() <= m_rect.bottom();
+ bool below = anchor.y() > m_rect.bottom();
+
+ bool onLeft = anchor.x() <= m_rect.left();
+ bool leftOfCenter = anchor.x() > m_rect.left() && anchor.x() <= m_rect.center().x();
+ bool rightOfCenter = anchor.x() > m_rect.center().x() && anchor.x() <= m_rect.right();
+ bool onRight = anchor.x() > m_rect.right();
+
+ // get the nearest m_rect corner.
+ qreal x = (onRight + rightOfCenter) * m_rect.width();
+ qreal y = (below + belowCenter) * m_rect.height();
+ bool cornerCase = (above && onLeft) || (above && onRight) || (below && onLeft) || (below && onRight);
+ bool vertical = qAbs(anchor.x() - x) > qAbs(anchor.y() - y);
+
+ qreal x1 = x + leftOfCenter * 10 - rightOfCenter * 20 + cornerCase * !vertical * (onLeft * 10 - onRight * 20);
+ qreal y1 = y + aboveCenter * 10 - belowCenter * 20 + cornerCase * vertical * (above * 10 - below * 20);
+
+ point1.setX(x1);
+ point1.setY(y1);
+
+ qreal x2 = x + leftOfCenter * 20 - rightOfCenter * 10 + cornerCase * !vertical * (onLeft * 20 - onRight * 10);
+ qreal y2 = y + aboveCenter * 20 - belowCenter * 10 + cornerCase * vertical * (above * 20 - below * 10);
+
+ point2.setX(x2);
+ point2.setY(y2);
+
+ path.moveTo(point1);
+ path.lineTo(anchor);
+ path.lineTo(point2);
+ path = path.simplified();
+ }
+ painter->setBrush(QColor(255, 255, 255));
+ painter->drawPath(path);
+ painter->drawText(m_textRect, m_text);
+ painter->restore();
+}
+
+void Callout::contextMenuEvent(QGraphicsSceneContextMenuEvent* event) {
+ delete this;
+}
+
+void Callout::mousePressEvent(QGraphicsSceneMouseEvent* event) {
+ event->setAccepted(true);
+}
+
+void Callout::mouseMoveEvent(QGraphicsSceneMouseEvent* event) {
+ if (event->buttons() & Qt::LeftButton) {
+ setPos(mapToParent(event->pos() - event->buttonDownPos(Qt::LeftButton)));
+ event->setAccepted(true);
+ } else {
+ event->setAccepted(false);
+ }
+}
+
+void Callout::setText(const QString& text) {
+ m_text = text;
+ QFontMetrics metrics(m_font);
+ m_textRect = metrics.boundingRect(QRect(0, 0, 150, 150), Qt::AlignLeft, m_text);
+ m_textRect.translate(5, 5);
+ prepareGeometryChange();
+ m_rect = m_textRect.adjusted(-5, -5, 5, 5);
+}
+
+void Callout::setAnchor(QPointF point) {
+ m_anchor = point;
+}
+
+void Callout::updateGeometry() {
+ prepareGeometryChange();
+ setPos(m_chart->mapToPosition(m_anchor) + QPoint(10, -50));
+}

ADD
src/cachesim/callout.h
+/****************************************************************************
+**
+** 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
+** a written agreement between you and The Qt Company. For licensing terms
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef CALLOUT_H
+#define CALLOUT_H
+
+#include <QtCharts/QChartGlobal>
+#include <QtGui/QFont>
+#include <QtWidgets/QGraphicsItem>
+
+QT_BEGIN_NAMESPACE
+class QGraphicsSceneMouseEvent;
+QT_END_NAMESPACE
+
+QT_CHARTS_BEGIN_NAMESPACE
+class QChart;
+QT_CHARTS_END_NAMESPACE
+
+QT_CHARTS_USE_NAMESPACE
+
+class Callout : public QGraphicsItem {
+public:
+ Callout(QChart* parent);
+
+ void setText(const QString& text);
+ void setAnchor(QPointF point);
+ void updateGeometry();
+
+ QRectF boundingRect() const override;
+ void paint(QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget) override;
+
+protected:
+ void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
+ void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
+ void contextMenuEvent(QGraphicsSceneContextMenuEvent* event) override;
+
+private:
+ QString m_text;
+ QRectF m_textRect;
+ QRectF m_rect;
+ QPointF m_anchor;
+ QFont m_font;
+ QChart* m_chart;
+};
+
+#endif // CALLOUT_H

All callout class from Qt examples