Qt 5.11 | Qt Widgets | Fade Message Effect Example | fademessage.cpp Example File

Qt 5.11.3 Reference Documentation

# fademessage.cpp Example File

effects/fademessage/fademessage.cpp

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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.horizontalAdvance(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);
      }