Qt Reference Documentation

# qtbox.cpp Example File

demos/boxes/qtbox.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the demonstration applications of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:LGPL$
     ** GNU Lesser General Public License Usage
     ** This file may be used under the terms of the GNU Lesser General Public
     ** License version 2.1 as published by the Free Software Foundation and
     ** appearing in the file LICENSE.LGPL included in the packaging of this
     ** file. Please review the following information to ensure the GNU Lesser
     ** General Public License version 2.1 requirements will be met:
     ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
     **
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     ** rights. These rights are described in the Nokia Qt LGPL Exception
     ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
     **
     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU General
     ** Public License version 3.0 as published by the Free Software Foundation
     ** and appearing in the file LICENSE.GPL included in the packaging of this
     ** file. Please review the following information to ensure the GNU General
     ** Public License version 3.0 requirements will be met:
     ** http://www.gnu.org/copyleft/gpl.html.
     **
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     ** Alternatively, this file may be used in accordance with the terms and
     ** conditions contained in a signed written agreement between you and Nokia.
     **
     **
     **
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     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include "qtbox.h"

     const qreal ROTATE_SPEED_X = 30.0 / 1000.0;
     const qreal ROTATE_SPEED_Y = 20.0 / 1000.0;
     const qreal ROTATE_SPEED_Z = 40.0 / 1000.0;
     const int MAX_ITEM_SIZE = 512;
     const int MIN_ITEM_SIZE = 16;

     //============================================================================//
     //                                  ItemBase                                  //
     //============================================================================//

     ItemBase::ItemBase(int size, int x, int y) : m_size(size), m_isResizing(false)
     {
         setFlag(QGraphicsItem::ItemIsMovable, true);
         setFlag(QGraphicsItem::ItemIsSelectable, true);
         setFlag(QGraphicsItem::ItemIsFocusable, true);
         setAcceptHoverEvents(true);
         setPos(x, y);
         m_startTime = QTime::currentTime();
     }

     ItemBase::~ItemBase()
     {
     }

     QRectF ItemBase::boundingRect() const
     {
         return QRectF(-m_size / 2, -m_size / 2, m_size, m_size);
     }

     void ItemBase::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *)
     {
         if (option->state & QStyle::State_Selected) {
             painter->setRenderHint(QPainter::Antialiasing, true);
             if (option->state & QStyle::State_HasFocus)
                 painter->setPen(Qt::yellow);
             else
                 painter->setPen(Qt::white);
             painter->drawRect(boundingRect());

             painter->drawLine(m_size / 2 - 9, m_size / 2, m_size / 2, m_size / 2 - 9);
             painter->drawLine(m_size / 2 - 6, m_size / 2, m_size / 2, m_size / 2 - 6);
             painter->drawLine(m_size / 2 - 3, m_size / 2, m_size / 2, m_size / 2 - 3);

             painter->setRenderHint(QPainter::Antialiasing, false);
         }
     }

     void ItemBase::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
     {
         if (!isSelected() && scene()) {
             scene()->clearSelection();
             setSelected(true);
         }

         QMenu menu;
         QAction *delAction = menu.addAction("Delete");
         QAction *newAction = menu.addAction("New");
         QAction *growAction = menu.addAction("Grow");
         QAction *shrinkAction = menu.addAction("Shrink");

         QAction *selectedAction = menu.exec(event->screenPos());

         if (selectedAction == delAction)
             deleteSelectedItems(scene());
         else if (selectedAction == newAction)
             duplicateSelectedItems(scene());
         else if (selectedAction == growAction)
             growSelectedItems(scene());
         else if (selectedAction == shrinkAction)
             shrinkSelectedItems(scene());
     }

     void ItemBase::duplicateSelectedItems(QGraphicsScene *scene)
     {
         if (!scene)
             return;

         QList<QGraphicsItem *> selected;
         selected = scene->selectedItems();

         foreach (QGraphicsItem *item, selected) {
             ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
             if (itemBase)
                 scene->addItem(itemBase->createNew(itemBase->m_size, itemBase->pos().x() + itemBase->m_size, itemBase->pos().y()));
         }
     }

     void ItemBase::deleteSelectedItems(QGraphicsScene *scene)
     {
         if (!scene)
             return;

         QList<QGraphicsItem *> selected;
         selected = scene->selectedItems();

         foreach (QGraphicsItem *item, selected) {
             ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
             if (itemBase)
                 delete itemBase;
         }
     }

     void ItemBase::growSelectedItems(QGraphicsScene *scene)
     {
         if (!scene)
             return;

         QList<QGraphicsItem *> selected;
         selected = scene->selectedItems();

         foreach (QGraphicsItem *item, selected) {
             ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
             if (itemBase) {
                 itemBase->prepareGeometryChange();
                 itemBase->m_size *= 2;
                 if (itemBase->m_size > MAX_ITEM_SIZE)
                     itemBase->m_size = MAX_ITEM_SIZE;
             }
         }
     }

     void ItemBase::shrinkSelectedItems(QGraphicsScene *scene)
     {
         if (!scene)
             return;

         QList<QGraphicsItem *> selected;
         selected = scene->selectedItems();

         foreach (QGraphicsItem *item, selected) {
             ItemBase *itemBase = qgraphicsitem_cast<ItemBase *>(item);
             if (itemBase) {
                 itemBase->prepareGeometryChange();
                 itemBase->m_size /= 2;
                 if (itemBase->m_size < MIN_ITEM_SIZE)
                     itemBase->m_size = MIN_ITEM_SIZE;
             }
         }
     }

     void ItemBase::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
     {
         if (m_isResizing) {
             int dx = int(2.0 * event->pos().x());
             int dy = int(2.0 * event->pos().y());
             prepareGeometryChange();
             m_size = (dx > dy ? dx : dy);
             if (m_size < MIN_ITEM_SIZE)
                 m_size = MIN_ITEM_SIZE;
             else if (m_size > MAX_ITEM_SIZE)
                 m_size = MAX_ITEM_SIZE;
         } else {
             QGraphicsItem::mouseMoveEvent(event);
         }
     }

     void ItemBase::hoverMoveEvent(QGraphicsSceneHoverEvent *event)
     {
         if (m_isResizing || (isInResizeArea(event->pos()) && isSelected()))
             setCursor(Qt::SizeFDiagCursor);
         else
             setCursor(Qt::ArrowCursor);
         QGraphicsItem::hoverMoveEvent(event);
     }

     void ItemBase::mousePressEvent(QGraphicsSceneMouseEvent *event)
     {
         static qreal z = 0.0;
         setZValue(z += 1.0);
         if (event->button() == Qt::LeftButton && isInResizeArea(event->pos())) {
             m_isResizing = true;
         } else {
             QGraphicsItem::mousePressEvent(event);
         }
     }

     void ItemBase::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
     {
         if (event->button() == Qt::LeftButton && m_isResizing) {
             m_isResizing = false;
         } else {
             QGraphicsItem::mouseReleaseEvent(event);
         }
     }

     void ItemBase::keyPressEvent(QKeyEvent *event)
     {
         switch (event->key()) {
         case Qt::Key_Delete:
             deleteSelectedItems(scene());
             break;
         case Qt::Key_Insert:
             duplicateSelectedItems(scene());
             break;
         case Qt::Key_Plus:
             growSelectedItems(scene());
             break;
         case Qt::Key_Minus:
             shrinkSelectedItems(scene());
             break;
         default:
             QGraphicsItem::keyPressEvent(event);
             break;
         }
     }

     void ItemBase::wheelEvent(QGraphicsSceneWheelEvent *event)
     {
         prepareGeometryChange();
         m_size = int(m_size * exp(-event->delta() / 600.0));
         if (m_size > MAX_ITEM_SIZE)
             m_size = MAX_ITEM_SIZE;
         else if (m_size < MIN_ITEM_SIZE)
             m_size = MIN_ITEM_SIZE;
     }

     int ItemBase::type() const
     {
         return Type;
     }

     bool ItemBase::isInResizeArea(const QPointF &pos)
     {
         return (-pos.y() < pos.x() - m_size + 9);
     }

     //============================================================================//
     //                                    QtBox                                   //
     //============================================================================//

     QtBox::QtBox(int size, int x, int y) : ItemBase(size, x, y), m_texture(0)
     {
         for (int i = 0; i < 8; ++i) {
             m_vertices[i].setX(i & 1 ? 0.5f : -0.5f);
             m_vertices[i].setY(i & 2 ? 0.5f : -0.5f);
             m_vertices[i].setZ(i & 4 ? 0.5f : -0.5f);
         }
         for (int i = 0; i < 4; ++i) {
             m_texCoords[i].setX(i & 1 ? 1.0f : 0.0f);
             m_texCoords[i].setY(i & 2 ? 1.0f : 0.0f);
         }
         m_normals[0] = QVector3D(-1.0f, 0.0f, 0.0f);
         m_normals[1] = QVector3D(1.0f, 0.0f, 0.0f);
         m_normals[2] = QVector3D(0.0f, -1.0f, 0.0f);
         m_normals[3] = QVector3D(0.0f, 1.0f, 0.0f);
         m_normals[4] = QVector3D(0.0f, 0.0f, -1.0f);
         m_normals[5] = QVector3D(0.0f, 0.0f, 1.0f);
     }

     QtBox::~QtBox()
     {
         if (m_texture)
             delete m_texture;
     }

     ItemBase *QtBox::createNew(int size, int x, int y)
     {
         return new QtBox(size, x, y);
     }

     void QtBox::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
     {
         QRectF rect = boundingRect().translated(pos());
         float width = float(painter->device()->width());
         float height = float(painter->device()->height());

         float left = 2.0f * float(rect.left()) / width - 1.0f;
         float right = 2.0f * float(rect.right()) / width - 1.0f;
         float top = 1.0f - 2.0f * float(rect.top()) / height;
         float bottom = 1.0f - 2.0f * float(rect.bottom()) / height;
         float moveToRectMatrix[] = {
             0.5f * (right - left), 0.0f, 0.0f, 0.0f,
             0.0f, 0.5f * (bottom - top), 0.0f, 0.0f,
             0.0f, 0.0f, 1.0f, 0.0f,
             0.5f * (right + left), 0.5f * (bottom + top), 0.0f, 1.0f
         };

         painter->beginNativePainting();

         glMatrixMode(GL_PROJECTION);
         glPushMatrix();
         glLoadMatrixf(moveToRectMatrix);
         qgluPerspective(60.0, 1.0, 0.01, 10.0);

         glMatrixMode(GL_MODELVIEW);
         glPushMatrix();
         glLoadIdentity();

         //glEnable(GL_DEPTH_TEST);
         glEnable(GL_CULL_FACE);
         glEnable(GL_LIGHTING);
         glEnable(GL_COLOR_MATERIAL);
         glEnable(GL_NORMALIZE);

         if(m_texture == 0)
             m_texture = new GLTexture2D(":/res/boxes/qt-logo.jpg", 64, 64);
         m_texture->bind();
         glEnable(GL_TEXTURE_2D);

         glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
         float lightColour[] = {1.0f, 1.0f, 1.0f, 1.0f};
         float lightDir[] = {0.0f, 0.0f, 1.0f, 0.0f};
         glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColour);
         glLightfv(GL_LIGHT0, GL_POSITION, lightDir);
         glEnable(GL_LIGHT0);

         glTranslatef(0.0f, 0.0f, -1.5f);
         glRotatef(ROTATE_SPEED_X * m_startTime.msecsTo(QTime::currentTime()), 1.0f, 0.0f, 0.0f);
         glRotatef(ROTATE_SPEED_Y * m_startTime.msecsTo(QTime::currentTime()), 0.0f, 1.0f, 0.0f);
         glRotatef(ROTATE_SPEED_Z * m_startTime.msecsTo(QTime::currentTime()), 0.0f, 0.0f, 1.0f);
         int dt = m_startTime.msecsTo(QTime::currentTime());
         if (dt < 500)
             glScalef(dt / 500.0f, dt / 500.0f, dt / 500.0f);

         for (int dir = 0; dir < 3; ++dir) {
             glColor4f(1.0f, 1.0f, 1.0f, 1.0);

             glBegin(GL_TRIANGLE_STRIP);
             glNormal3fv(reinterpret_cast<float *>(&m_normals[2 * dir + 0]));
             for (int i = 0; i < 2; ++i) {
                 for (int j = 0; j < 2; ++j) {
                     glTexCoord2fv(reinterpret_cast<float *>(&m_texCoords[(j << 1) | i]));
                     glVertex3fv(reinterpret_cast<float *>(&m_vertices[(i << ((dir + 2) % 3)) | (j << ((dir + 1) % 3))]));
                 }
             }
             glEnd();

             glBegin(GL_TRIANGLE_STRIP);
             glNormal3fv(reinterpret_cast<float *>(&m_normals[2 * dir + 1]));
             for (int i = 0; i < 2; ++i) {
                 for (int j = 0; j < 2; ++j) {
                     glTexCoord2fv(reinterpret_cast<float *>(&m_texCoords[(j << 1) | i]));
                     glVertex3fv(reinterpret_cast<float *>(&m_vertices[(1 << dir) | (i << ((dir + 1) % 3)) | (j << ((dir + 2) % 3))]));
                 }
             }
             glEnd();
         }
         m_texture->unbind();

         //glDisable(GL_DEPTH_TEST);
         glDisable(GL_CULL_FACE);
         glDisable(GL_LIGHTING);
         glDisable(GL_COLOR_MATERIAL);
         glDisable(GL_TEXTURE_2D);
         glDisable(GL_LIGHT0);
         glDisable(GL_NORMALIZE);

         glPopMatrix();

         glMatrixMode(GL_PROJECTION);
         glPopMatrix();

         painter->endNativePainting();

         ItemBase::paint(painter, option, widget);
     }

     //============================================================================//
     //                                 CircleItem                                 //
     //============================================================================//

     CircleItem::CircleItem(int size, int x, int y) : ItemBase(size, x, y)
     {
          m_color = QColor::fromHsv(rand() % 360, 255, 255);
     }

     void CircleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
     {
         int dt = m_startTime.msecsTo(QTime::currentTime());

         qreal r0 = 0.5 * m_size * (1.0 - exp(-0.001 * ((dt + 3800) % 4000)));
         qreal r1 = 0.5 * m_size * (1.0 - exp(-0.001 * ((dt + 0) % 4000)));
         qreal r2 = 0.5 * m_size * (1.0 - exp(-0.001 * ((dt + 1800) % 4000)));
         qreal r3 = 0.5 * m_size * (1.0 - exp(-0.001 * ((dt + 2000) % 4000)));

         if (r0 > r1)
             r0 = 0.0;
         if (r2 > r3)
             r2 = 0.0;

         QPainterPath path;
         path.moveTo(r1, 0.0);
         path.arcTo(-r1, -r1, 2 * r1, 2 * r1, 0.0, 360.0);
         path.lineTo(r0, 0.0);
         path.arcTo(-r0, -r0, 2 * r0, 2 * r0, 0.0, -360.0);
         path.closeSubpath();
         path.moveTo(r3, 0.0);
         path.arcTo(-r3, -r3, 2 * r3, 2 * r3, 0.0, 360.0);
         path.lineTo(r0, 0.0);
         path.arcTo(-r2, -r2, 2 * r2, 2 * r2, 0.0, -360.0);
         path.closeSubpath();
         painter->setRenderHint(QPainter::Antialiasing, true);
         painter->setBrush(QBrush(m_color));
         painter->setPen(Qt::NoPen);
         painter->drawPath(path);
         painter->setBrush(Qt::NoBrush);
         painter->setPen(Qt::SolidLine);
         painter->setRenderHint(QPainter::Antialiasing, false);

         ItemBase::paint(painter, option, widget);
     }

     ItemBase *CircleItem::createNew(int size, int x, int y)
     {
         return new CircleItem(size, x, y);
     }

     //============================================================================//
     //                                 SquareItem                                 //
     //============================================================================//

     SquareItem::SquareItem(int size, int x, int y) : ItemBase(size, x, y)
     {
         m_image = QPixmap(":/res/boxes/square.jpg");
     }

     void SquareItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
     {
         int dt = m_startTime.msecsTo(QTime::currentTime());
         QTransform oldTransform = painter->worldTransform();
         int dtMod = dt % 2000;
         qreal amp = 0.002 * (dtMod < 1000 ? dtMod : 2000 - dtMod) - 1.0;

         qreal scale = 0.6 + 0.2 * amp * amp;
         painter->setWorldTransform(QTransform().rotate(15.0 * amp).scale(scale, scale), true);

         painter->drawPixmap(-m_size / 2, -m_size / 2, m_size, m_size, m_image);

         painter->setWorldTransform(oldTransform, false);
         ItemBase::paint(painter, option, widget);
     }

     ItemBase *SquareItem::createNew(int size, int x, int y)
     {
         return new SquareItem(size, x, y);
     }