How to create a ruler widget for a qcustomplot with a given ICSRulerWidget Class?

[mson9]

I am trying to create a ruler widget that I can use to measure customplot's keys or values. I found an existing thread that included the .cpp and .h file for the ICSRulerWidget Class. However, I do not quite know to use the given class' methods to create the ruler. Specifically, I'd like it to be placed at the place the mouse was pressed, and be able to be dragged to the spot to be measured until mouse released.

Can anyone help with a simple example of creating the ruler?

The icsrulerwidget.cpp file:

#include <QDebug>
#include <QIcon>
#include <QPen>
#include <QPaintEvent>
#include <QPainter>
#include "icsrulerwidget.h"
 
ICSRulerWidget::ICSRulerWidget(QWidget* pParent): QWidget(pParent) {}
 
int ICSRulerWidget::createMarker(bool pInverted) {
	auto pMarker = new QLabel(this);
 
	pMarker->installEventFilter(this);
	pMarker->setProperty("ICS_MarkerInverted", pInverted);
	pMarker->setProperty("ICS_MarkerValue", 0.0f);
	pMarker->setPixmap(
		m_nOrientation == Qt::Horizontal
            ? QIcon(":/resources/toolbar/rulerTool.png").pixmap(16, 16)
            : QIcon(":/resources/toolbar/rulerTool.png").pixmap(16, 16)
	);
 
	m_lstMarkers.append(pMarker);
	setMarkerRange(m_lstMarkers.length() - 1, 0.0f, m_fMaximum);
 
	return m_lstMarkers.length() - 1;
}
 
void ICSRulerWidget::setOrientation(Qt::Orientation pOrientation) {
	if(pOrientation == Qt::Horizontal)
		setMinimumSize(0, fontMetrics().height() + 16);
	else
		setMinimumSize(fontMetrics().height() + 16, 0);
 
	m_nOrientation = pOrientation;
 
	updateGeometry();
}
 
float ICSRulerWidget::markerValue(int pIndex) const { return m_lstMarkers[pIndex]->property("ICS_MarkerValue").toFloat(); }
 
void ICSRulerWidget::setMarkerValue(int pIndex, float pValue) {
	auto pMarker = m_lstMarkers[pIndex];
 
	pMarker->setProperty("ICS_MarkerValue", pValue);
 
	if(m_nOrientation == Qt::Horizontal)
		pMarker->move(
			pMarker->property("ICS_MarkerInverted").toBool()
				? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - pValue)
				: m_nOrigin + float(physicalDpiX()) / 25.4f * pValue,
			0
		);
	else
		pMarker->move(
			0,
			pMarker->property("ICS_MarkerInverted").toBool()
				? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - pValue)
				: m_nOrigin + float(physicalDpiY()) / 25.4f * pValue
		);
 
	emit markerValueChanged(pIndex, pValue);
}
 
void ICSRulerWidget::setMarkerRange(int pIndex, float pMinimum, float pMaximum) {
	m_lstMarkers[pIndex]->setProperty("ICS_MarkerRange", QVariant::fromValue<QPair<float, float> >(QPair<float, float>(pMinimum, pMaximum)));
}
 
bool ICSRulerWidget::eventFilter(QObject* pSender, QEvent* pEvent) {
	if(auto pMarker = dynamic_cast<QLabel*>(pSender))
		switch(pEvent->type()) {
		case QEvent::MouseButtonPress: {
				auto pMouseEvent = dynamic_cast<QMouseEvent*>(pEvent);
 
				if(!mouseGrabber() && pMouseEvent->button() == Qt::LeftButton) {
					pMarker->grabMouse();
					pMarker->setProperty("ICS_MouseGrabPoint", pMouseEvent->pos());
 
					emit markerValueAboutToBeChanged(m_lstMarkers.indexOf(pMarker));
					return true;
				}
			}
 
			break;
 
		case QEvent::MouseMove:
			if(mouseGrabber() == pMarker) {
				auto ptParent = pMarker->mapToParent(dynamic_cast<QMouseEvent*>(pEvent)->pos()) - pMarker->property("ICS_MouseGrabPoint").toPoint();
				auto cRange = pMarker->property("ICS_MarkerRange").value<QPair<float, float> >();
 
				if(m_nOrientation == Qt::Horizontal) {
					if(ptParent.x() >= physicalDpiX() / 25.4f * cRange.first && ptParent.x() <= m_nOrigin + physicalDpiX() / 25.4f * cRange.second) {
						pMarker->move(ptParent.x(), 0);
 
						emit markerValueChanging(
							m_lstMarkers.indexOf(pMarker),
							pMarker->property("ICS_MarkerInverted").toBool()
								? m_fMaximum - float(ptParent.x() - m_nOrigin) * 25.4f / float(physicalDpiX())
								: float(ptParent.x() + m_nOrigin) * 25.4f / float(physicalDpiX())
						);
 
						return true;
					}
				} else if(ptParent.y() >= physicalDpiY() / 25.4f * cRange.first && ptParent.y() <= m_nOrigin + physicalDpiY() / 25.4f * cRange.second) {
					pMarker->move(0, ptParent.y());
 
					emit markerValueChanging(
						m_lstMarkers.indexOf(pMarker),
						pMarker->property("ICS_MarkerInverted").toBool()
							? m_fMaximum - float(ptParent.y() - m_nOrigin) * 25.4f / float(physicalDpiY())
							: float(ptParent.y() + m_nOrigin) * 25.4f / float(physicalDpiY())
					);
 
					return true;
				}
			}
 
			break;
 
		case QEvent::MouseButtonRelease: {
				auto pMouseEvent = dynamic_cast<QMouseEvent*>(pEvent);
				auto cRange = pMarker->property("ICS_MarkerRange").value<QPair<float, float> >();
 
				if(mouseGrabber() == pMarker && pMouseEvent->button() == Qt::LeftButton) {
					auto ptParent = pMarker->mapToParent(pMouseEvent->pos()) - pMarker->property("ICS_MouseGrabPoint").toPoint();
 
					pMarker->releaseMouse();
 
					if(m_nOrientation == Qt::Horizontal) {
						if(ptParent.x() >= physicalDpiX() / 25.4f * cRange.first && ptParent.x() <= m_nOrigin + physicalDpiX() / 25.4f * cRange.second) {
							pMarker->move(ptParent.x(), 0);
							pMarker->setProperty(
								"ICS_MarkerValue",
								pMarker->property("ICS_MarkerInverted").toBool()
									? m_fMaximum - float(ptParent.x() - m_nOrigin) * 25.4f / float(physicalDpiX())
									: float(ptParent.x() + m_nOrigin) * 25.4f / float(physicalDpiX())
							);
						}
					} else if(ptParent.y() >= physicalDpiY() / 25.4f * cRange.first && ptParent.y() <= m_nOrigin + physicalDpiY() / 25.4f * cRange.second) {
						pMarker->move(0, ptParent.y());
						pMarker->setProperty(
							"ICS_MarkerValue",
							pMarker->property("ICS_MarkerInverted").toBool()
								? m_fMaximum - float(ptParent.y() - m_nOrigin) * 25.4f / float(physicalDpiY())
								: float(ptParent.y() + m_nOrigin) * 25.4f / float(physicalDpiY())
						);
					}
 
					emit markerValueChanged(m_lstMarkers.indexOf(pMarker), pMarker->property("ICS_MarkerValue").toFloat());
 
					return true;
				}
			}
 
			break;
 
		default:
			break;
		}
 
	return QWidget::eventFilter(pSender, pEvent);
}
 
void ICSRulerWidget::paintEvent(QPaintEvent* pEvent) {
	Q_UNUSED(pEvent);
 
	QPainter cPainter(this);
 
	cPainter.fillRect(0, 0, width(), height(), Qt::white);
	cPainter.setPen(Qt::lightGray);
	cPainter.drawRect(0, 0, width(), height());
 
	if(m_nOrientation == Qt::Horizontal) {
		float nX = 8.0f;
 
		cPainter.translate(m_nOrigin, 0.0f);
 
		for(int nValue = 0; nValue <= m_fMaximum; nValue += 2) {
			if(nX + m_nOrigin >= 0 && nX + m_nOrigin < width()) {
				if(nValue % 10 == 0) {
					auto strText = QString::number(nValue / 10);
 
					cPainter.setPen(QPen(QBrush(Qt::black), 2.0f));
					cPainter.drawLine(nX, height() - 2, nX, height() - fontMetrics().height() / 2 - 2);
					cPainter.drawText(nX - fontMetrics().width(strText) / 2, height() - fontMetrics().height() / 2 - 8, strText);
				} else {
					cPainter.setPen(Qt::black);
					cPainter.drawLine(nX, height() - 2, nX, height() - fontMetrics().height() / 3 - 2);
				}
			}
 
			nX += float(physicalDpiX()) / 12.7f;
		}
	} else {
		float nY = 8.0f;
 
		cPainter.translate(0.0f, m_nOrigin);
 
		for(int nValue = 0; nValue <= m_fMaximum; nValue += 2) {
			if(nY + m_nOrigin >= 0 && nY + m_nOrigin < height()) {
				if(nValue % 10 == 0) {
					auto strText = QString::number(nValue / 10);
 
					cPainter.setPen(QPen(QBrush(Qt::black), 2.0f));
					cPainter.drawLine(width() - 2, nY, width() - fontMetrics().height() / 2 - 2, nY);
					cPainter.drawText(4, nY + fontMetrics().height() / 3, strText);
				} else {
					cPainter.setPen(Qt::black);
					cPainter.drawLine(width() - 2, nY, width() - fontMetrics().height() / 3 - 2, nY);
				}
			}
 
			nY += float(physicalDpiY()) / 12.7f;
		}
	}
}
 
void ICSRulerWidget::setOrigin(int pOrigin) {
	m_nOrigin = -pOrigin;
 
	for(auto pMarker: m_lstMarkers) {
		auto fValue = pMarker->property("ICS_MarkerValue").toFloat();
 
		if(m_nOrientation == Qt::Horizontal)
			pMarker->move(
				pMarker->property("ICS_MarkerInverted").toBool()
					? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - fValue)
					: m_nOrigin + float(physicalDpiX()) / 25.4f * fValue,
				0
			);
		else
			pMarker->move(
				0,
				pMarker->property("ICS_MarkerInverted").toBool()
					? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - fValue)
					: m_nOrigin + float(physicalDpiY()) / 25.4f * fValue
			);
	}
 
	update();
}
 
void ICSRulerWidget::setMaximum(float pMaximum) {
	if(m_fMaximum != pMaximum) {
		m_fMaximum = pMaximum;
 
		for(int nIndex = 0; nIndex < m_lstMarkers.size(); nIndex++) {
			auto fValue = markerValue(nIndex);
 
			setMarkerRange(nIndex, 0, m_fMaximum);
 
			if(fValue > pMaximum)
				setMarkerValue(nIndex, pMaximum);
			else {
				if(m_nOrientation == Qt::Horizontal)
					m_lstMarkers[nIndex]->move(
						m_lstMarkers[nIndex]->property("ICS_MarkerInverted").toBool()
							? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - fValue)
							: m_nOrigin + float(physicalDpiX()) / 25.4f * fValue,
						0
					);
				else
					m_lstMarkers[nIndex]->move(
						0,
						m_lstMarkers[nIndex]->property("ICS_MarkerInverted").toBool()
							? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - fValue)
							: m_nOrigin + float(physicalDpiY()) / 25.4f * fValue
					);
			}
		}
 
		update();
	}
}
 
void ICSRulerWidget::clearMarkers(void) {
	qDeleteAll(m_lstMarkers);
	update();
}

#include <QDebug>
#include <QIcon>
#include <QPen>
#include <QPaintEvent>
#include <QPainter>
#include "icsrulerwidget.h"

ICSRulerWidget::ICSRulerWidget(QWidget* pParent): QWidget(pParent) {}

int ICSRulerWidget::createMarker(bool pInverted) {
	auto pMarker = new QLabel(this);

	pMarker->installEventFilter(this);
	pMarker->setProperty("ICS_MarkerInverted", pInverted);
	pMarker->setProperty("ICS_MarkerValue", 0.0f);
	pMarker->setPixmap(
		m_nOrientation == Qt::Horizontal
            ? QIcon(":/resources/toolbar/rulerTool.png").pixmap(16, 16)
            : QIcon(":/resources/toolbar/rulerTool.png").pixmap(16, 16)
	);

	m_lstMarkers.append(pMarker);
	setMarkerRange(m_lstMarkers.length() - 1, 0.0f, m_fMaximum);

	return m_lstMarkers.length() - 1;
}

void ICSRulerWidget::setOrientation(Qt::Orientation pOrientation) {
	if(pOrientation == Qt::Horizontal)
		setMinimumSize(0, fontMetrics().height() + 16);
	else
		setMinimumSize(fontMetrics().height() + 16, 0);

	m_nOrientation = pOrientation;

	updateGeometry();
}

float ICSRulerWidget::markerValue(int pIndex) const { return m_lstMarkers[pIndex]->property("ICS_MarkerValue").toFloat(); }

void ICSRulerWidget::setMarkerValue(int pIndex, float pValue) {
	auto pMarker = m_lstMarkers[pIndex];

	pMarker->setProperty("ICS_MarkerValue", pValue);

	if(m_nOrientation == Qt::Horizontal)
		pMarker->move(
			pMarker->property("ICS_MarkerInverted").toBool()
				? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - pValue)
				: m_nOrigin + float(physicalDpiX()) / 25.4f * pValue,
			0
		);
	else
		pMarker->move(
			0,
			pMarker->property("ICS_MarkerInverted").toBool()
				? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - pValue)
				: m_nOrigin + float(physicalDpiY()) / 25.4f * pValue
		);

	emit markerValueChanged(pIndex, pValue);
}

void ICSRulerWidget::setMarkerRange(int pIndex, float pMinimum, float pMaximum) {
	m_lstMarkers[pIndex]->setProperty("ICS_MarkerRange", QVariant::fromValue<QPair<float, float> >(QPair<float, float>(pMinimum, pMaximum)));
}

bool ICSRulerWidget::eventFilter(QObject* pSender, QEvent* pEvent) {
	if(auto pMarker = dynamic_cast<QLabel*>(pSender))
		switch(pEvent->type()) {
		case QEvent::MouseButtonPress: {
				auto pMouseEvent = dynamic_cast<QMouseEvent*>(pEvent);

				if(!mouseGrabber() && pMouseEvent->button() == Qt::LeftButton) {
					pMarker->grabMouse();
					pMarker->setProperty("ICS_MouseGrabPoint", pMouseEvent->pos());

					emit markerValueAboutToBeChanged(m_lstMarkers.indexOf(pMarker));
					return true;
				}
			}

			break;

		case QEvent::MouseMove:
			if(mouseGrabber() == pMarker) {
				auto ptParent = pMarker->mapToParent(dynamic_cast<QMouseEvent*>(pEvent)->pos()) - pMarker->property("ICS_MouseGrabPoint").toPoint();
				auto cRange = pMarker->property("ICS_MarkerRange").value<QPair<float, float> >();

				if(m_nOrientation == Qt::Horizontal) {
					if(ptParent.x() >= physicalDpiX() / 25.4f * cRange.first && ptParent.x() <= m_nOrigin + physicalDpiX() / 25.4f * cRange.second) {
						pMarker->move(ptParent.x(), 0);

						emit markerValueChanging(
							m_lstMarkers.indexOf(pMarker),
							pMarker->property("ICS_MarkerInverted").toBool()
								? m_fMaximum - float(ptParent.x() - m_nOrigin) * 25.4f / float(physicalDpiX())
								: float(ptParent.x() + m_nOrigin) * 25.4f / float(physicalDpiX())
						);

						return true;
					}
				} else if(ptParent.y() >= physicalDpiY() / 25.4f * cRange.first && ptParent.y() <= m_nOrigin + physicalDpiY() / 25.4f * cRange.second) {
					pMarker->move(0, ptParent.y());

					emit markerValueChanging(
						m_lstMarkers.indexOf(pMarker),
						pMarker->property("ICS_MarkerInverted").toBool()
							? m_fMaximum - float(ptParent.y() - m_nOrigin) * 25.4f / float(physicalDpiY())
							: float(ptParent.y() + m_nOrigin) * 25.4f / float(physicalDpiY())
					);

					return true;
				}
			}

			break;

		case QEvent::MouseButtonRelease: {
				auto pMouseEvent = dynamic_cast<QMouseEvent*>(pEvent);
				auto cRange = pMarker->property("ICS_MarkerRange").value<QPair<float, float> >();

				if(mouseGrabber() == pMarker && pMouseEvent->button() == Qt::LeftButton) {
					auto ptParent = pMarker->mapToParent(pMouseEvent->pos()) - pMarker->property("ICS_MouseGrabPoint").toPoint();

					pMarker->releaseMouse();

					if(m_nOrientation == Qt::Horizontal) {
						if(ptParent.x() >= physicalDpiX() / 25.4f * cRange.first && ptParent.x() <= m_nOrigin + physicalDpiX() / 25.4f * cRange.second) {
							pMarker->move(ptParent.x(), 0);
							pMarker->setProperty(
								"ICS_MarkerValue",
								pMarker->property("ICS_MarkerInverted").toBool()
									? m_fMaximum - float(ptParent.x() - m_nOrigin) * 25.4f / float(physicalDpiX())
									: float(ptParent.x() + m_nOrigin) * 25.4f / float(physicalDpiX())
							);
						}
					} else if(ptParent.y() >= physicalDpiY() / 25.4f * cRange.first && ptParent.y() <= m_nOrigin + physicalDpiY() / 25.4f * cRange.second) {
						pMarker->move(0, ptParent.y());
						pMarker->setProperty(
							"ICS_MarkerValue",
							pMarker->property("ICS_MarkerInverted").toBool()
								? m_fMaximum - float(ptParent.y() - m_nOrigin) * 25.4f / float(physicalDpiY())
								: float(ptParent.y() + m_nOrigin) * 25.4f / float(physicalDpiY())
						);
					}

					emit markerValueChanged(m_lstMarkers.indexOf(pMarker), pMarker->property("ICS_MarkerValue").toFloat());

					return true;
				}
			}

			break;

		default:
			break;
		}

	return QWidget::eventFilter(pSender, pEvent);
}

void ICSRulerWidget::paintEvent(QPaintEvent* pEvent) {
	Q_UNUSED(pEvent);

	QPainter cPainter(this);

	cPainter.fillRect(0, 0, width(), height(), Qt::white);
	cPainter.setPen(Qt::lightGray);
	cPainter.drawRect(0, 0, width(), height());

	if(m_nOrientation == Qt::Horizontal) {
		float nX = 8.0f;

		cPainter.translate(m_nOrigin, 0.0f);

		for(int nValue = 0; nValue <= m_fMaximum; nValue += 2) {
			if(nX + m_nOrigin >= 0 && nX + m_nOrigin < width()) {
				if(nValue % 10 == 0) {
					auto strText = QString::number(nValue / 10);

					cPainter.setPen(QPen(QBrush(Qt::black), 2.0f));
					cPainter.drawLine(nX, height() - 2, nX, height() - fontMetrics().height() / 2 - 2);
					cPainter.drawText(nX - fontMetrics().width(strText) / 2, height() - fontMetrics().height() / 2 - 8, strText);
				} else {
					cPainter.setPen(Qt::black);
					cPainter.drawLine(nX, height() - 2, nX, height() - fontMetrics().height() / 3 - 2);
				}
			}

			nX += float(physicalDpiX()) / 12.7f;
		}
	} else {
		float nY = 8.0f;

		cPainter.translate(0.0f, m_nOrigin);

		for(int nValue = 0; nValue <= m_fMaximum; nValue += 2) {
			if(nY + m_nOrigin >= 0 && nY + m_nOrigin < height()) {
				if(nValue % 10 == 0) {
					auto strText = QString::number(nValue / 10);

					cPainter.setPen(QPen(QBrush(Qt::black), 2.0f));
					cPainter.drawLine(width() - 2, nY, width() - fontMetrics().height() / 2 - 2, nY);
					cPainter.drawText(4, nY + fontMetrics().height() / 3, strText);
				} else {
					cPainter.setPen(Qt::black);
					cPainter.drawLine(width() - 2, nY, width() - fontMetrics().height() / 3 - 2, nY);
				}
			}

			nY += float(physicalDpiY()) / 12.7f;
		}
	}
}

void ICSRulerWidget::setOrigin(int pOrigin) {
	m_nOrigin = -pOrigin;

	for(auto pMarker: m_lstMarkers) {
		auto fValue = pMarker->property("ICS_MarkerValue").toFloat();

		if(m_nOrientation == Qt::Horizontal)
			pMarker->move(
				pMarker->property("ICS_MarkerInverted").toBool()
					? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - fValue)
					: m_nOrigin + float(physicalDpiX()) / 25.4f * fValue,
				0
			);
		else
			pMarker->move(
				0,
				pMarker->property("ICS_MarkerInverted").toBool()
					? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - fValue)
					: m_nOrigin + float(physicalDpiY()) / 25.4f * fValue
			);
	}

	update();
}

void ICSRulerWidget::setMaximum(float pMaximum) {
	if(m_fMaximum != pMaximum) {
		m_fMaximum = pMaximum;

		for(int nIndex = 0; nIndex < m_lstMarkers.size(); nIndex++) {
			auto fValue = markerValue(nIndex);

			setMarkerRange(nIndex, 0, m_fMaximum);

			if(fValue > pMaximum)
				setMarkerValue(nIndex, pMaximum);
			else {
				if(m_nOrientation == Qt::Horizontal)
					m_lstMarkers[nIndex]->move(
						m_lstMarkers[nIndex]->property("ICS_MarkerInverted").toBool()
							? m_nOrigin + float(physicalDpiX()) / 25.4f * (m_fMaximum - fValue)
							: m_nOrigin + float(physicalDpiX()) / 25.4f * fValue,
						0
					);
				else
					m_lstMarkers[nIndex]->move(
						0,
						m_lstMarkers[nIndex]->property("ICS_MarkerInverted").toBool()
							? m_nOrigin + float(physicalDpiY()) / 25.4f * (m_fMaximum - fValue)
							: m_nOrigin + float(physicalDpiY()) / 25.4f * fValue
					);
			}
		}

		update();
	}
}

void ICSRulerWidget::clearMarkers(void) {
	qDeleteAll(m_lstMarkers);
	update();
}

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I've attached the icsrulerwidget.h file: icsrulerwidget.h

The original Thread: http://www.qtcentre.org/threads/6054...implementation

[d_stranz]

I think you misunderstand what this widget does. It is not a ruler for measuring the distance between two points on the screen, it is like the bar you see at the top of Microsoft Word and other document editing programs. The picture below is from OpenOffice. I do not know how the ICSRulerWidget looks, but it is probably similar.

Capture.jpg