QCustomPlot之鼠标悬浮显示值

参考：https://www.jianshu.com/p/9f2763469030

参考中有一些函数声明了，没实现。我这里补充了部分。

使用到qcustomplot，想在鼠标停在某个点时，显示该点的值。从网上找到例子，加入到工程中。

qcustomplot源码下载：https://www.qcustomplot.com/index.php/download

工程中，点击按钮调出对话框，在对话框中显示折线。

对话框类

DlgPlot1.h

#ifndef DLGPLOT1_H
#define DLGPLOT1_H

#include <QDialog>
#include "qcustomplot.h"
#include "CustomPlotTooltip.h"

namespace Ui {
class DlgPlot1;
}

class DlgPlot1 : public QDialog
{
    Q_OBJECT

public:
    explicit DlgPlot1(QWidget *parent = nullptr);
    ~DlgPlot1();

public:

private:
    void setupScatterStyleDemo(QCustomPlot *customPlot);
private slots:
    void on_btnRefresh_clicked();
private:
    Ui::DlgPlot1 *ui;
    QCPToolTip* m_pCpTip;
};

#endif // DLGPLOT1_H

DlgPlot1.cpp

 1 #include "DlgPlot1.h"
 2 #include "ui_DlgPlot1.h"
 3 #include "CustomPlotTooltip.h"
 4 
 5 DlgPlot1::DlgPlot1(QWidget *parent) :
 6     QDialog(parent),
 7     ui(new Ui::DlgPlot1)
 8 {
 9     ui->setupUi(this);
10     QString demoName = "Scatter Style Demo";
11     this->setWindowTitle(demoName);
12     setupScatterStyleDemo(ui->customPlot);
13 
14     m_pCpTip = new QCPToolTip(ui->customPlot);
15 }
16 
17 DlgPlot1::~DlgPlot1()
18 {
19     delete ui;
20 }
21 
22 void DlgPlot1::on_btnRefresh_clicked()
23 {
24 
25 }
26 
27 void DlgPlot1::setupScatterStyleDemo(QCustomPlot *customPlot)
28 {
29     customPlot->legend->setVisible(true);
30     customPlot->legend->setFont(QFont("Helvetica", 9));
31     customPlot->legend->setRowSpacing(-3);
32     QVector<QCPScatterStyle::ScatterShape> shapes;
33     QVector<QColor> colors;
34     colors << Qt::blue;
35     colors << Qt::red;
36     colors << Qt::green;
37 //    shapes << QCPScatterStyle::ssCross;
38 //    shapes << QCPScatterStyle::ssPlus;
39 //    shapes << QCPScatterStyle::ssCircle;
40     shapes << QCPScatterStyle::ssDisc;
41     shapes << QCPScatterStyle::ssDisc;
42 //    shapes << QCPScatterStyle::ssSquare;
43 //    shapes << QCPScatterStyle::ssDiamond;
44 //    shapes << QCPScatterStyle::ssStar;
45 //    shapes << QCPScatterStyle::ssTriangle;
46 //    shapes << QCPScatterStyle::ssTriangleInverted;
47 //    shapes << QCPScatterStyle::ssCrossSquare;
48 //    shapes << QCPScatterStyle::ssPlusSquare;
49 //    shapes << QCPScatterStyle::ssCrossCircle;
50 //    shapes << QCPScatterStyle::ssPlusCircle;
51 //    shapes << QCPScatterStyle::ssPeace;
52 //    shapes << QCPScatterStyle::ssCustom;
53 //    shapes << QCPScatterStyle::ssDot;
54 
55     QPen pen;
56     // add graphs with different scatter styles:
57     for (int i=0; i<shapes.size(); ++i)
58     {
59       customPlot->addGraph();
60       pen.setColor(colors.at(i));
61       // generate data:
62       QVector<double> x, y;
63       if(i == 0){
64           x  << 2005 << 2006 << 2007 << 2008  << 2009  << 2010 << 2011;
65           y << 2.17 << 3.42 << 4.94 << 10.38 << 15.86 << 29.33 << 52.1;
66       }
67       else if(i == 1){
68           x  << 2005 << 2006 << 2007 << 2008  << 2009  << 2010 << 2011;
69           y << 2 << 9 << 6 << 15 << 89 << 11 << 20;
70       }
71       customPlot->graph()->setData(x, y);
72       customPlot->graph()->rescaleAxes(true);
73       customPlot->graph()->setPen(pen);
74       customPlot->graph()->setName(QCPScatterStyle::staticMetaObject.enumerator(QCPScatterStyle::staticMetaObject.indexOfEnumerator("ScatterShape")).valueToKey(shapes.at(i)));
75       customPlot->graph()->setLineStyle(QCPGraph::lsLine);
76       // set scatter style:
77       if (shapes.at(i) != QCPScatterStyle::ssCustom)
78       {
79         customPlot->graph()->setScatterStyle(QCPScatterStyle(shapes.at(i), 10));
80       }
81       else
82       {
83         QPainterPath customScatterPath;
84         for (int i=0; i<3; ++i)
85           customScatterPath.cubicTo(qCos(2*M_PI*i/3.0)*9, qSin(2*M_PI*i/3.0)*9, qCos(2*M_PI*(i+0.9)/3.0)*9, qSin(2*M_PI*(i+0.9)/3.0)*9, 0, 0);
86         customPlot->graph()->setScatterStyle(QCPScatterStyle(customScatterPath, QPen(Qt::black, 0), QColor(255, 255, 255, 50), 10));
87       }
88     }
89 
90     // set blank axis lines:
91     customPlot->rescaleAxes();
92     customPlot->xAxis->setTicks(true);
93     customPlot->yAxis->setTicks(true);
94     customPlot->xAxis->setTickLabels(true);
95     customPlot->yAxis->setTickLabels(true);
96     // make top right axes clones of bottom left axes:
97     customPlot->axisRect()->setupFullAxesBox();
98 }

DlgPlot1.ui

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <ui version="4.0">
 3  <class>DlgPlot1</class>
 4  <widget class="QDialog" name="DlgPlot1">
 5   <property name="geometry">
 6    <rect>
 7     <x>0</x>
 8     <y>0</y>
 9     <width>400</width>
10     <height>300</height>
11    </rect>
12   </property>
13   <property name="windowTitle">
14    <string>Dialog</string>
15   </property>
16   <layout class="QGridLayout" name="gridLayout">
17    <item row="0" column="0" colspan="2">
18     <widget class="QCustomPlot" name="customPlot" native="true"/>
19    </item>
20    <item row="1" column="0">
21     <spacer name="horizontalSpacer">
22      <property name="orientation">
23       <enum>Qt::Horizontal</enum>
24      </property>
25      <property name="sizeHint" stdset="0">
26       <size>
27        <width>293</width>
28        <height>20</height>
29       </size>
30      </property>
31     </spacer>
32    </item>
33    <item row="1" column="1">
34     <widget class="QPushButton" name="btnRefresh">
35      <property name="text">
36       <string>刷  新</string>
37      </property>
38     </widget>
39    </item>
40   </layout>
41  </widget>
42  <customwidgets>
43   <customwidget>
44    <class>QCustomPlot</class>
45    <extends>QWidget</extends>
46    <header location="global">qcustomplot.h</header>
47    <container>1</container>
48   </customwidget>
49  </customwidgets>
50  <resources/>
51  <connections/>
52 </ui>

CustomPlotTooltip.h

 1 #ifndef CUSTOMPLOTTOOLTIP_H
 2 #define CUSTOMPLOTTOOLTIP_H
 3 #include "qcustomplot.h"
 4 
 5 class QCPToolTip : public QCPAbstractItem
 6 {
 7     Q_OBJECT
 8 public:
 9     explicit QCPToolTip(QCustomPlot *parentPlot);
10 
11     void setText(const QString &text);
12     void setFont(const QFont &font);
13     void setTextColor(const QColor &color);
14     void setBorderPen(const QPen &pen);
15     void setBrush(const QBrush &brush);
16     void setRadius(double xRadius, double yRadius, Qt::SizeMode mode = Qt::AbsoluteSize);
17     void setOffset(double xOffset, double yOffset);
18     void setPadding(const QMargins &paddings);
19 
20     Q_SLOT void handleTriggerEvent(QMouseEvent *event);
21     void updatePosition(const QPointF &newPos, bool replot = false);
22 
23     void update();
24 
25     virtual double selectTest(const QPointF &pos, bool onlySelectable, QVariant *details) const Q_DECL_OVERRIDE;
26 
27     QCPItemPosition * const position;
28 protected:
29     bool mPlotReplot;    // 表明是由QCustomPlot刷新的，需要更新位置
30     QString mText;
31     Qt::Alignment mTextAlignment;
32     QFont mFont;
33     QColor mTextColor;
34     QPen mBorderPen;
35     QBrush mBrush;
36 
37     QPointF mRadius;
38     Qt::SizeMode mSizeMode;
39 
40     QPointF mOffset;     // 偏移鼠标的距离
41     QMargins mPadding;
42 
43     QCPGraph *mHighlightGraph;
44     QPointF mGraphDataPos;
45 
46     virtual void draw(QCPPainter *painter) Q_DECL_OVERRIDE;
47     virtual void drawGraphScatterPlot(QCPPainter *painter, QCPGraph *graph, const QPointF &pos);
48 
49     int pickClosest(double target, const QVector<double> &vector);
50 };
51 #endif // CUSTOMPLOTTOOLTIP_H

CustomPlotTooltip.cpp

  1 #include "CustomPlotTooltip.h"
  2 #include <QToolTip>
  3 #include <QCursor>
  4 
  5 QCPToolTip::QCPToolTip(QCustomPlot *parentPlot)
  6     : QCPAbstractItem(parentPlot),
  7       position(createPosition(QLatin1String("position"))),
  8       mPlotReplot(true),
  9       mTextAlignment(Qt::AlignLeft | Qt::AlignVCenter),
 10       mRadius(6, 6),
 11       mSizeMode(Qt::AbsoluteSize),
 12       mHighlightGraph(nullptr)
 13 {
 14     position->setType(QCPItemPosition::ptAbsolute);
 15     setSelectable(false);
 16     setLayer("overlay");
 17 
 18     setBorderPen(Qt::NoPen);
 19     setBrush(QColor(87, 98, 93, 180));
 20     setTextColor(Qt::white);
 21     setOffset(10, 0);
 22     setPadding(QMargins(6, 6, 6, 6));
 23     connect(mParentPlot, SIGNAL(mouseMove(QMouseEvent *)), this, SLOT(handleTriggerEvent(QMouseEvent *)));
 24 }
 25 
 26 void QCPToolTip::setText(const QString &text)
 27 {
 28     mText = text;
 29 //    QToolTip::showText(mParentPlot->cursor().pos(), text, mParentPlot);
 30 }
 31 
 32 void QCPToolTip::setFont(const QFont &font)
 33 {
 34     mFont = font;
 35 }
 36 
 37 void QCPToolTip::setTextColor(const QColor &color)
 38 {
 39     mTextColor = color;
 40 }
 41 
 42 void QCPToolTip::setBorderPen(const QPen &pen)
 43 {
 44     mBorderPen = pen;
 45 }
 46 
 47 void QCPToolTip::setBrush(const QBrush &brush)
 48 {
 49     mBrush = brush;
 50 }
 51 
 52 void QCPToolTip::setRadius(double xRadius, double yRadius, Qt::SizeMode mode)
 53 {
 54     mRadius.setX(xRadius);
 55     mRadius.setY(yRadius);
 56     mSizeMode = mode;
 57 }
 58 
 59 void QCPToolTip::setOffset(double xOffset, double yOffset)
 60 {
 61     mOffset.setX(xOffset);
 62     mOffset.setY(yOffset);
 63 }
 64 
 65 void QCPToolTip::setPadding(const QMargins &paddings)
 66 {
 67     mPadding = paddings;
 68 }
 69 
 70 void QCPToolTip::handleTriggerEvent(QMouseEvent *event)
 71 {
 72     updatePosition(event->pos(), true);   // true 表示需要单独刷新，将调用update函数
 73 }
 74 
 75 void QCPToolTip::update()
 76 {
 77     mPlotReplot = false;    // 表明单独刷新
 78     layer()->replot();
 79     mPlotReplot = true;    // 单独刷新完毕
 80 }
 81 
 82 // 不需要鼠标点击测试，因为ToolTip是跟随鼠标的，鼠标点击不到
 83 double QCPToolTip::selectTest(const QPointF &pos, bool onlySelectable, QVariant *details) const
 84 {
 85     Q_UNUSED(pos)
 86     Q_UNUSED(onlySelectable)
 87     Q_UNUSED(details)
 88     return -1;
 89 }
 90 
 91 int QCPToolTip::pickClosest(double target, const QVector<double> &vector)
 92 {
 93     if (vector.size() < 2)
 94         return 0;
 95 
 96     // 查找第一个大于或等于target的位置
 97     auto it = std::lower_bound(vector.constBegin(), vector.constEnd(), target);
 98 
 99     if (it == vector.constEnd()) return vector.size() - 1;
100     else if (it == vector.constBegin()) return 0;
101     else return target - *(it - 1) < *it - target ? (it - vector.constBegin() - 1): (it - vector.constBegin());
102 }
103 
104 void QCPToolTip::updatePosition(const QPointF &newPos, bool replot)
105 {
106     mHighlightGraph = nullptr;
107     double tolerance = mParentPlot->selectionTolerance();
108 
109     for (int i = mParentPlot->graphCount() - 1; i >= 0; --i) {
110         QCPGraph *graph = mParentPlot->graph(i);
111         if (!graph->realVisibility() || graph->scatterStyle().isNone())   // graph不可见或者scatter style 为空的时候，不显示ToolTip
112             continue;
113 
114         double limitDistance = tolerance;   // limitDistance 用于选择的范围
115         double penWidth = graph->pen().widthF();
116         QCPScatterStyle scatterStyle = graph->scatterStyle();
117 
118         limitDistance = qMax(scatterStyle.size(), tolerance);
119         penWidth = scatterStyle.isPenDefined() ? scatterStyle.pen().widthF() : penWidth;
120 
121         QVariant details;
122         double currentDistance = graph->selectTest(newPos, false, &details);   // details会返回最接近的一个数据点，selectTest是不精确的，所以后面还要判断
123 
124         QCPDataSelection selection = details.value<QCPDataSelection>();
125         if (currentDistance >= 0 && currentDistance < limitDistance + penWidth && !selection.isEmpty()) {
126             // 取出当前key和value值，并且转换为像素位置
127             double key = graph->dataMainKey(selection.dataRange().begin());
128             double value = graph->dataMainValue(selection.dataRange().begin());
129             QPointF pos = graph->coordsToPixels(key, value);
130 
131             QRectF rect(pos.x() - limitDistance * 0.5, pos.y() - limitDistance * 0.5, limitDistance, limitDistance);
132             rect = rect.adjusted(-penWidth, -penWidth, penWidth, penWidth);
133 
134             if (rect.contains(newPos)) {    // 通过矩形判断，鼠标位置是否在数据点上
135 //                // 解开以下注释，可以使得我们的文字跟轴标签的文字是一样的（但跟轴标签实际的显示效果可能是不一样的，这里要注意，例如对于科学计数法，轴可能会使用美化），同时要注意当轴标签不显示的时候tickVectorLabels返回的是空的，所以我们要做一下判断
136 //                // 注意这里的方式是不精确的，适用于文字轴这种类型的
137 //                int keyIndex = pickClosest(key, graph->keyAxis()->tickVector());
138 //                setText(QString("%1:%2").arg(graph->keyAxis()->tickVectorLabels().at(keyIndex),
139 //                                         QString::number(value)));
140                 setText(QString("%1:%2").arg(QString::number(key), QString::number(value)));
141                 mHighlightGraph = graph;
142                 mGraphDataPos = pos;
143 
144                 mParentPlot->setCursor(Qt::PointingHandCursor);
145                 position->setPixelPosition(newPos);  // 更新位置
146                 setVisible(true);
147 
148                 if (replot) update();
149                 break;
150             }
151         }
152     }
153 
154     if (!mHighlightGraph && visible()) {
155         mParentPlot->setCursor(Qt::ArrowCursor);
156         setVisible(false);
157         if (replot) update();
158     }
159 }
160 
161 void QCPToolTip::draw(QCPPainter *painter)
162 {
163     if (mPlotReplot) {  // 当前是由QCustomPlot的replot函数刷新的，所以要更新位置
164         updatePosition(position->pixelPosition(), false);  // 传入false表明不刷新
165         if (!visible()) return;   // 由于位置更新之后，ToolTip可能会隐藏掉了，所以此处直接返回
166     }
167 
168     drawGraphScatterPlot(painter, mHighlightGraph, mGraphDataPos);
169 
170     QPointF pos = position->pixelPosition() + mOffset;
171     painter->translate(pos);  // 移动painter的绘制原点位置
172 
173     QFontMetrics fontMetrics(mFont);
174     QRect textRect = fontMetrics.boundingRect(0, 0, 0, 0, Qt::TextDontClip | mTextAlignment, mText);
175     textRect.moveTopLeft(QPoint(mPadding.left(), mPadding.top()));
176 
177     QRect textBoxRect = textRect.adjusted(-mPadding.left(), -mPadding.top(), mPadding.right(), mPadding.bottom());
178     textBoxRect.moveTopLeft(QPoint());
179 
180     // 限制ToolTip不超过QCustomPlot的范围
181     if (pos.x() + textBoxRect.width() >= mParentPlot->viewport().right())
182         painter->translate(-mOffset.x() * 2 - textBoxRect.width(), 0);
183     if (pos.y() + textBoxRect.height() * 2 >= mParentPlot->viewport().bottom())
184         painter->translate(0, -mOffset.y() * 2 - textBoxRect.height());
185 
186     // 绘制背景和边框
187     if ((mBrush != Qt::NoBrush && mBrush.color().alpha() != 0) ||
188             (mBorderPen != Qt::NoPen && mBorderPen.color().alpha() != 0)) {
189         double clipPad = mBorderPen.widthF();
190         QRect boundingRect = textBoxRect.adjusted(-clipPad, -clipPad, clipPad, clipPad);
191 
192         painter->setPen(mBorderPen);
193         painter->setBrush(mBrush);
194         painter->drawRoundedRect(boundingRect, mRadius.x(), mRadius.y(), mSizeMode);
195     }
196 
197     // 绘制文字
198     painter->setFont(mFont);
199     painter->setPen(mTextColor);
200     painter->setBrush(Qt::NoBrush);
201     painter->drawText(textRect, Qt::TextDontClip | mTextAlignment, mText);
202 }
203 
204 void QCPToolTip::drawGraphScatterPlot(QCPPainter *painter, QCPGraph *graph, const QPointF &pos)
205 {
206     if (!graph) return;
207 
208     QCPScatterStyle style = graph->scatterStyle();
209     if (style.isNone()) return;
210 
211     if (graph->selectionDecorator())  // 如果有select decorator，则使用修饰器的风格
212         style = graph->selectionDecorator()->getFinalScatterStyle(style);
213 
214     style.applyTo(painter, graph->pen());
215     style.setSize(style.size() * 1.2); // 放大一点
216     style.drawShape(painter, pos);
217 }

 

posted @ 2020-07-03 10:32  阳光下的小土豆  阅读(3932)  评论(0)  编辑  收藏  举报