(C++) QtArrowItem

 

Technical facts

 

 

 

 

 

 

./CppQtArrowItem/CppQtArrowItem.pri

 

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INCLUDEPATH += \     ../../Classes/CppQtArrowItem SOURCES += \     ../../Classes/CppQtArrowItem/qtarrowitem.cpp HEADERS  += \     ../../Classes/CppQtArrowItem/qtarrowitem.h OTHER_FILES += \     ../../Classes/CppQtArrowItem/Licence.txt

 

 

 

 

 

./CppQtArrowItem/qtarrowitem.h

 

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//--------------------------------------------------------------------------- /* QtArrowItem, an arrow QGraphicsItem 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/CppQtArrowItem.htm //--------------------------------------------------------------------------- #ifndef QTARROWITEM_H #define QTARROWITEM_H #include <string> #include <vector> #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #pragma GCC diagnostic ignored "-Wunused-but-set-parameter" #include <boost/signals2.hpp> #include <QGraphicsLineItem> #include <QPen> #pragma GCC diagnostic pop namespace ribi { ///An arrow QGraphicsItem //From http://www.richelbilderbeek.nl/CppQtArrowItem.htm struct QtArrowItem : public QGraphicsLineItem {   typedef QtArrowItem This;   QtArrowItem(     const double x1,     const double y1,     const bool tail,     const double x2,     const double y2,     const bool head,     QGraphicsItem* parent = 0);   ///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 distance in pixels the user is allowed to be distance from the   ///arrow head/tail to change it   void SetArrowHeadClickingDistance(const double manhattan_distance) noexcept;   ///Set the pen used to show focus   void SetFocusPen(const QPen& pen) noexcept { m_focus_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; }   ///Set the position of the head   void SetHeadPos(const double x, const double y) noexcept;   ///Set the regular pen used to draw the arrow   void SetPen(const QPen& pen) noexcept { m_pen = pen; }   ///Set the position of the tail   void SetTailPos(const double x, const double y) noexcept;   ///Signal emitted when this item has changed and the scene needs to be updated   boost::signals2::signal<void (This*)> m_signal_item_requests_scene_update; protected:   virtual ~QtArrowItem() noexcept {}   QRectF boundingRect() const;   virtual void hoverEnterEvent(QGraphicsSceneHoverEvent *event);   virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event);   virtual void mousePressEvent(QGraphicsSceneMouseEvent *event);   virtual void paint(QPainter* painter, const QStyleOptionGraphicsItem *, QWidget *);   QPainterPath shape() const; private:   ///Set the distance in pixels the user is allowed to be distance from the   ///arrow head/tail to change it   double m_arrow_head_clicking_distance;   ///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 regular pen   QPen m_pen;   ///Show arrow at tail   bool m_tail;   #ifndef NDEBUG   static void Test() noexcept;   #endif }; } //~namespace ribi #endif // QTARROWITEM_H

 

 

 

 

 

./CppQtArrowItem/qtarrowitem.cpp

 

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//--------------------------------------------------------------------------- /* QtArrowItem, an arrow QGraphicsItem 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/CppQtArrowItem.htm //--------------------------------------------------------------------------- #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #include "qtarrowitem.h" #include <cassert> #include <cmath> #include <boost/math/constants/constants.hpp> #include <QCursor> #include <QGraphicsScene> #include <QGraphicsSceneMouseEvent> #include <QKeyEvent> #include <QPainter> #include "geometry.h" #include "trace.h" #pragma GCC diagnostic pop const double ribi::QtArrowItem::m_click_easy_width = 10.0; ribi::QtArrowItem::QtArrowItem(   const double x1,   const double y1,   const bool tail,   const double x2,   const double y2,   const bool head,   QGraphicsItem* parent)   : QGraphicsLineItem(x1,y1,x2,y2,parent),     m_signal_item_requests_scene_update{},     m_arrow_head_clicking_distance(20.0),     m_focus_pen(QPen(Qt::DashLine)),     m_head(head),     m_pen(QPen(QColor(0,0,0))),     m_tail(tail) {   this->setFlags(       QGraphicsItem::ItemIsFocusable     | QGraphicsItem::ItemIsMovable     | QGraphicsItem::ItemIsSelectable   );   //Allow mouse tracking   this->setAcceptHoverEvents(true);   assert(this->line().p1() == QPointF(x1,y1));   assert(this->line().p2() == QPointF(x2,y2)); } QRectF ribi::QtArrowItem::boundingRect() const {   return shape().boundingRect(); } std::string ribi::QtArrowItem::GetVersion() noexcept {   return "1.2"; } std::vector<std::string> ribi::QtArrowItem::GetVersionHistory() noexcept {   return {     "2012-11-18: version 1.0: initial version",     "2012-11-20: version 1.1: mouse cursor changes its shape when moving over this item",     "2012-12-19: version 1.2: allow changing pens"   }; } void ribi::QtArrowItem::hoverEnterEvent(QGraphicsSceneHoverEvent *) {   this->setCursor(QCursor(Qt::PointingHandCursor)); } void ribi::QtArrowItem::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;   }   QGraphicsLineItem::keyPressEvent(event);   m_signal_item_requests_scene_update(this); } void ribi::QtArrowItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event) {   m_signal_item_requests_scene_update(this);   QGraphicsLineItem::mouseMoveEvent(event); } void ribi::QtArrowItem::mousePressEvent(QGraphicsSceneMouseEvent *event) {   if (event->modifiers() & Qt::ShiftModifier)   {     if ((event->pos() - this->line().p1()).manhattanLength() < m_arrow_head_clicking_distance)     {       m_tail = !m_tail;       this->update();     }     else if ((event->pos() - this->line().p2()).manhattanLength() < m_arrow_head_clicking_distance)     {       m_head = !m_head;       this->update();     }   } } void ribi::QtArrowItem::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);   }   painter->drawLine(this->line());   const double pi{boost::math::constants::pi<double>()};   //The angle from tail to head   double angle{Geometry().GetAngleClockScreen(line().dx(),line().dy())};   if (line().dy() >= 0.0) angle = (1.0 * pi) + angle;   const double sz{10.0}; //pixels   if (m_tail)   {     const QPointF p0{this->line().p1()};     const QPointF p1{       p0 + QPointF(          std::sin(angle + pi + (pi * 0.1)) * sz,         -std::cos(angle + pi + (pi * 0.1)) * sz)};     const QPointF p2       = p0 + QPointF(          std::sin(angle + pi - (pi * 0.1)) * sz,         -std::cos(angle + pi - (pi * 0.1)) * sz);     painter->drawPolygon(QPolygonF() << p0 << p1 << p2);   }   if (m_head)   {     const QPointF p0 = this->line().p2();     const QPointF p1       = p0 + QPointF(          std::sin(angle +  0.0 + (pi * 0.1)) * sz,         -std::cos(angle +  0.0 + (pi * 0.1)) * sz);     const QPointF p2       = p0 + QPointF(          std::sin(angle +  0.0 - (pi * 0.1)) * sz,         -std::cos(angle +  0.0 - (pi * 0.1)) * sz);     painter->drawPolygon(QPolygonF() << p0 << p1 << p2);   } } void ribi::QtArrowItem::SetArrowHeadClickingDistance(const double manhattan_distance) noexcept {   m_arrow_head_clicking_distance = manhattan_distance; } void ribi::QtArrowItem::SetHeadPos(const double x, const double y) noexcept {   if (line().x2() != x || line().y2() != y)   {     QLineF line = this->line();     line.setP2(QPointF(x,y));     this->setLine(line);     this->update();   } } void ribi::QtArrowItem::SetTailPos(const double x, const double y) noexcept {   if (line().x1() != x || line().y1() != y)   {     QLineF line = this->line();     line.setP1(QPointF(x,y));     this->setLine(line);     this->update();   } } QPainterPath ribi::QtArrowItem::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(line().p1());   path.lineTo(line().p2());   stroker.setWidth(m_click_easy_width);   return stroker.createStroke(path); }