(C++) QtPathArrowItem
January 25, 2018 · View on GitHub
(C++) QtPathArrowItem
QtPathArrowItem is a Qt QGraphicsItem class that displays an arrow that can have a multiple straight-line body.
Technical facts
./CppQtPathArrowItem/CppQtPathArrowItem.pri
INCLUDEPATH += \ ../../Classes/CppQtPathArrowItem SOURCES += \ ../../Classes/CppQtPathArrowItem/qtpatharrowitem.cpp HEADERS += \ ../../Classes/CppQtPathArrowItem/qtpatharrowitem.h OTHER_FILES += \ ../../Classes/CppQtPathArrowItem/Licence.txt
./CppQtPathArrowItem/qtpatharrowitem.h
//--------------------------------------------------------------------------- /* QtPathArrowItem, an arrow QGraphicsItem with one or more midpoints Copyright 2012-2015 Richel Bilderbeek This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program.If not, see <http://www.gnu.org/licenses/>. */ //--------------------------------------------------------------------------- //From http://www.richelbilderbeek.nl/CppQtPathArrowItem.htm //--------------------------------------------------------------------------- #ifndef QTPATHARROWITEM_H #define QTPATHARROWITEM_H #include <string> #include <vector> #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include <boost/signals2.hpp> #include <QGraphicsLineItem> #include <QPen> #pragma GCC diagnostic pop namespace ribi { ///An arrow item that has one or more midpoints struct QtPathArrowItem : public QGraphicsItem { typedef QtPathArrowItem This; QtPathArrowItem( const QPointF& tail_pos, const bool tail, const std::vector<QPointF>& mid_pos, const bool head, const QPointF& head_pos, QGraphicsItem *parent = 0); virtual ~QtPathArrowItem() noexcept {} ///Obtain the version of this class static std::string GetVersion() noexcept; ///Obtain the version history of this class static std::vector<std::string> GetVersionHistory() noexcept; ///Is there an arrow at the 'to' point (x2,y2)? bool HasHead() const noexcept { return m_head; } ///Is there an arrow at the 'from' point (x1,y1)? bool HasTail() const noexcept { return m_tail; } ///Respond to key presses void keyPressEvent(QKeyEvent *event); ///Set the path the arrow has to take void SetArrowPath( const QPointF& tail_pos, const std::vector<QPointF>& mid_pos, const QPointF& head_pos ); ///Set the pen used to show focus void SetFocusPen(const QPen& pen) noexcept { m_focus_pen = pen; } ///Set the regular pen used to draw the arrow void SetPen(const QPen& pen) noexcept { m_pen = pen; } ///Set if the arrow has a point at the head void SetHasHead(const bool has_head) noexcept { m_head = has_head; } ///Set if the arrow has a point at the tail void SetHasTail(const bool has_tail) noexcept { m_tail = has_tail; } ///Signal to request a scene update, because this item has moved/changed boost::signals2::signal<void (This*)> m_signal_item_requests_scene_update; protected: QRectF boundingRect() const; void hoverEnterEvent(QGraphicsSceneHoverEvent *); virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event); virtual void mousePressEvent(QGraphicsSceneMouseEvent *event); void paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *); QPainterPath shape() const; private: ///The extra width given to the line for easier clicking static const double m_click_easy_width; ///The arrow used for indicating focus QPen m_focus_pen; ///Show arrow at head bool m_head; ///The position of the head QPointF m_head_pos; ///The positions between tail (lower indices) and tail (higher indices) std::vector<QPointF> m_mid_pos; ///The regular pen QPen m_pen; ///Show arrow at tail bool m_tail; ///The position of the head QPointF m_tail_pos; ///Obtain the angle in radians between two deltas ///12 o'clock is 0.0 * pi /// 3 o'clock is 0.5 * pi /// 6 o'clock is 1.0 * pi /// 9 o'clock is 1.5 * pi //From www.richelbilderbeek.nl/CppGetAngle.htm //static double GetAngle(const double dx, const double dy); }; } //~namespace ribi #endif // QTPATHARROWITEM_H
./CppQtPathArrowItem/qtpatharrowitem.cpp
//--------------------------------------------------------------------------- /* QtPathArrowItem, an arrow QGraphicsItem with one or more midpoints Copyright 2012-2015 Richel Bilderbeek This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program.If not, see <http://www.gnu.org/licenses/>. */ //--------------------------------------------------------------------------- //From http://www.richelbilderbeek.nl/CppQtPathArrowItem.htm //--------------------------------------------------------------------------- #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include "qtpatharrowitem.h" #include <cassert> #include <cmath> #include <boost/math/constants/constants.hpp> #include <QCursor> #include <QGraphicsScene> #include <QGraphicsSceneMouseEvent> #include <QKeyEvent> #include <QPainter> #include "geometry.h" #pragma GCC diagnostic pop const double ribi::QtPathArrowItem::m_click_easy_width = 10.0; ribi::QtPathArrowItem::QtPathArrowItem( const QPointF& tail_pos, const bool tail, const std::vector<QPointF>& mid_pos, const bool head, const QPointF& head_pos, QGraphicsItem *parent) : QGraphicsItem(parent), //New since Qt5 m_signal_item_requests_scene_update{}, m_focus_pen(QPen(Qt::DashLine)), m_head(head), m_head_pos(head_pos), m_mid_pos(mid_pos), m_pen(QPen(QColor(0,0,0))), m_tail(tail), m_tail_pos(tail_pos) { assert(m_mid_pos.size() >= 1 && "There must be at least one midpos"); this->setFlags( QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable ); //Allow mouse tracking this->setAcceptHoverEvents(true); } QRectF ribi::QtPathArrowItem::boundingRect() const { return shape().boundingRect(); } std::string ribi::QtPathArrowItem::GetVersion() noexcept { return "1.0"; } std::vector<std::string> ribi::QtPathArrowItem::GetVersionHistory() noexcept { std::vector<std::string> v; v.push_back("2012-12-01: version 1.0: initial version"); return v; } void ribi::QtPathArrowItem::hoverEnterEvent(QGraphicsSceneHoverEvent *) { this->setCursor(QCursor(Qt::PointingHandCursor)); } void ribi::QtPathArrowItem::keyPressEvent(QKeyEvent *event) { switch (event->key()) { case Qt::Key_F1: case Qt::Key_1: case Qt::Key_T: case Qt::Key_Minus: m_tail = !m_tail; this->update(); break; case Qt::Key_F2: case Qt::Key_2: case Qt::Key_H: case Qt::Key_Plus: m_head = !m_head; this->update(); break; default: break; } QGraphicsItem::keyPressEvent(event); m_signal_item_requests_scene_update(this); } void ribi::QtPathArrowItem::mouseMoveEvent(QGraphicsSceneMouseEvent*) { m_signal_item_requests_scene_update(this); //QGraphicsLineItem::mouseMoveEvent(event); } void ribi::QtPathArrowItem::mousePressEvent(QGraphicsSceneMouseEvent *event) { if (event->modifiers() & Qt::ShiftModifier) { if ((event->pos() - m_tail_pos).manhattanLength() < 10.0) { m_tail = !m_tail; this->update(); } else if ((event->pos() - m_head_pos).manhattanLength() < 10.0) { m_head = !m_head; this->update(); } } QGraphicsItem::mousePressEvent(event); } void ribi::QtPathArrowItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *) { painter->setRenderHint(QPainter::Antialiasing); if (this->isSelected() || this->hasFocus()) { painter->setPen(m_focus_pen); } else { painter->setPen(m_pen); } { //Draw the lines painter->drawLine(m_tail_pos,m_mid_pos[0]); const std::size_t max = m_mid_pos.size() - 1; //-1, because the line goes to the next index for (std::size_t i = 0; i!= max; ++i) { painter->drawLine(m_mid_pos[i],m_mid_pos[i+1]); } painter->drawLine(m_mid_pos[ m_mid_pos.size() - 1 ],m_head_pos); } const double sz = 10.0; //pixels if (m_tail) { const double pi{boost::math::constants::pi<double>()}; const double dx{m_mid_pos[0].x() - m_tail_pos.x()}; const double dy{m_mid_pos[0].y() - m_tail_pos.y()}; double angle{Geometry().GetAngleClockScreen(dx,dy)}; if (dy >= 0.0) angle = (1.0 * pi) + angle; //const QPointF m_tail_pos(m_tail_x,m_tail_y); const QPointF p1{ m_tail_pos + QPointF( std::sin(angle + pi + (pi * 0.1)) * sz, -std::cos(angle + pi + (pi * 0.1)) * sz) }; const QPointF p2{ m_tail_pos + QPointF( std::sin(angle + pi - (pi * 0.1)) * sz, -std::cos(angle + pi - (pi * 0.1)) * sz) }; painter->drawPolygon(QPolygonF() << m_tail_pos << p1 << p2); } if (m_head) { const double pi = boost::math::constants::pi<double>(); const double dx = m_head_pos.x() - m_mid_pos[m_mid_pos.size() - 1].x(); const double dy = m_head_pos.y() - m_mid_pos[m_mid_pos.size() - 1].y(); double angle{Geometry().GetAngleClockScreen(dx,dy)}; if (dy >= 0.0) angle = (1.0 * pi) + angle; const QPointF p1 = m_head_pos + QPointF( std::sin(angle + 0.0 + (pi * 0.1)) * sz, -std::cos(angle + 0.0 + (pi * 0.1)) * sz); const QPointF p2 = m_head_pos + QPointF( std::sin(angle + 0.0 - (pi * 0.1)) * sz, -std::cos(angle + 0.0 - (pi * 0.1)) * sz); painter->drawPolygon(QPolygonF() << m_head_pos << p1 << p2); } } void ribi::QtPathArrowItem::SetArrowPath( const QPointF& tail_pos, const std::vector<QPointF>& mid_pos, const QPointF& head_pos) { m_tail_pos = tail_pos; m_mid_pos = mid_pos; m_head_pos = head_pos; assert(m_mid_pos.size() >= 1 && "There must be at least one midpos"); this->update(); } QPainterPath ribi::QtPathArrowItem::shape() const { //Thanks to norobro for posting this code at //http://www.qtcentre.org/threads/49201-Increase-margin-for-detecting-tooltip-events-of-QGraphicsLineItem QPainterPath path; QPainterPathStroker stroker; path.moveTo(m_tail_pos); const std::size_t sz = m_mid_pos.size(); for (std::size_t i = 0; i!= sz; ++i) { path.lineTo(m_mid_pos[i]); } path.lineTo(m_head_pos); stroker.setWidth(m_click_easy_width); return stroker.createStroke(path); }