fademessage.cpp Example File

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  #include "fademessage.h"

  #include <QtWidgets>

  FadeMessage::FadeMessage(QWidget *parent): QGraphicsView(parent)
  {
      setScene(&m_scene);
      setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
      setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

      setupScene();

      m_animation = new QPropertyAnimation(m_effect, "strength", this);
      m_animation->setDuration(500);
      m_animation->setEasingCurve(QEasingCurve::InOutSine);
      m_animation->setStartValue(0);
      m_animation->setEndValue(1);

      setRenderHint(QPainter::Antialiasing, true);
      setFrameStyle(QFrame::NoFrame);
  }

  void FadeMessage::togglePopup()
  {
      if (m_message->isVisible()) {
          m_message->setVisible(false);
          m_animation->setDirection(QAbstractAnimation::Backward);
      } else {
          m_message->setVisible(true);
          m_animation->setDirection(QAbstractAnimation::Forward);
      }
      m_animation->start();
  }

  void FadeMessage::setupScene()
  {
      QGraphicsRectItem *parent = m_scene.addRect(0, 0, 800, 600);
      parent->setPen(Qt::NoPen);
      parent->setZValue(0);

      QGraphicsPixmapItem *bg = m_scene.addPixmap(QPixmap(":/background.jpg"));
      bg->setParentItem(parent);
      bg->setZValue(-1);

      for (int i = 1; i < 5; ++i)
          for (int j = 2; j < 5; ++j) {
              QGraphicsRectItem *item = m_scene.addRect(i * 50, (j - 1) * 50, 38, 38);
              item->setParentItem(parent);
              item->setZValue(1);
              int hue = 12 * (i * 5 + j);
              item->setBrush(QColor::fromHsv(hue, 128, 128));
          }

      QFont font;
      font.setPointSize(font.pointSize() * 2);
      font.setBold(true);
      QFontMetrics fontMetrics(font);
      int fh = fontMetrics.height();

      QString sceneText = "Qt Everywhere!";
      int sceneTextWidth = fontMetrics.width(sceneText);

      QGraphicsRectItem *block = m_scene.addRect(50, 300, sceneTextWidth, fh + 3);
      block->setPen(Qt::NoPen);
      block->setBrush(QColor(102, 153, 51));

      QGraphicsTextItem *text = m_scene.addText(sceneText, font);
      text->setDefaultTextColor(Qt::white);
      text->setPos(50, 300);
      block->setZValue(2);
      block->hide();

      text->setParentItem(block);
      m_message = block;

      m_effect = new QGraphicsColorizeEffect;
      m_effect->setColor(QColor(122, 193, 66));
      m_effect->setStrength(0);
      m_effect->setEnabled(true);
      parent->setGraphicsEffect(m_effect);

      QPushButton *press = new QPushButton;
      press->setText(tr("Press me"));
      connect(press, SIGNAL(clicked()), SLOT(togglePopup()));
      m_scene.addWidget(press);

      press->move(300, 500);
  }