layoutitem.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #include "layoutitem.h"

  #include <QGradient>
  #include <QGraphicsLinearLayout>
  #include <QPainter>

  LayoutItem::LayoutItem(QGraphicsItem *parent/* = 0*/)
      : QGraphicsLayoutItem(), QGraphicsItem(parent)
  {
      m_pix = new QPixmap(QLatin1String(":/images/block.png"));
      setGraphicsItem(this);
  }

  LayoutItem::~LayoutItem()
  {
      delete m_pix;
  }

  void LayoutItem::paint(QPainter *painter,
      const QStyleOptionGraphicsItem *option, QWidget *widget /*= 0*/)
  {
      Q_UNUSED(widget);
      Q_UNUSED(option);

      QRectF frame(QPointF(0,0), geometry().size());
      qreal w = m_pix->width();
      qreal h = m_pix->height();
      QGradientStops stops;

      // paint a background rect (with gradient)
      QLinearGradient gradient(frame.topLeft(), frame.topLeft() + QPointF(200,200));
      stops << QGradientStop(0.0, QColor(60, 60,  60));
      stops << QGradientStop(frame.height() / 2 / frame.height(), QColor(102, 176, 54));

      //stops << QGradientStop(((frame.height() + h)/2 )/frame.height(), QColor(157, 195,  55));
      stops << QGradientStop(1.0, QColor(215, 215, 215));
      gradient.setStops(stops);
      painter->setBrush(QBrush(gradient));
      painter->drawRoundedRect(frame, 10.0, 10.0);

      // paint a rect around the pixmap (with gradient)
      QPointF pixpos = frame.center() - (QPointF(w, h) / 2);
      QRectF innerFrame(pixpos, QSizeF(w, h));
      innerFrame.adjust(-4, -4, 4, 4);
      gradient.setStart(innerFrame.topLeft());
      gradient.setFinalStop(innerFrame.bottomRight());
      stops.clear();
      stops << QGradientStop(0.0, QColor(215, 255, 200));
      stops << QGradientStop(0.5, QColor(102, 176, 54));
      stops << QGradientStop(1.0, QColor(0, 0,  0));
      gradient.setStops(stops);
      painter->setBrush(QBrush(gradient));
      painter->drawRoundedRect(innerFrame, 10.0, 10.0);
      painter->drawPixmap(pixpos, *m_pix);
  }

  QRectF LayoutItem::boundingRect() const
  {
      return QRectF(QPointF(0,0), geometry().size());
  }

  void LayoutItem::setGeometry(const QRectF &geom)
  {
      prepareGeometryChange();
      QGraphicsLayoutItem::setGeometry(geom);
      setPos(geom.topLeft());
  }

  QSizeF LayoutItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
  {
      switch (which) {
      case Qt::MinimumSize:
      case Qt::PreferredSize:
          // Do not allow a size smaller than the pixmap with two frames around it.
          return m_pix->size() + QSize(12, 12);
      case Qt::MaximumSize:
          return QSizeF(1000,1000);
      default:
          break;
      }
      return constraint;
  }