Qt 5.6 | Qt Widgets | Easing Curves Example | window.cpp Example File

Qt 5.6.2 Reference Documentation

# window.cpp Example File

animation/easing/window.cpp

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      #include "window.h"

      Window::Window(QWidget *parent)
          : QWidget(parent),
          m_iconSize(64, 64)
      {
          m_ui.setupUi(this);
          QButtonGroup *buttonGroup = findChild<QButtonGroup *>();     // ### workaround for uic in 4.4
          m_ui.easingCurvePicker->setIconSize(m_iconSize);
          m_ui.easingCurvePicker->setMinimumHeight(m_iconSize.height() + 50);
          buttonGroup->setId(m_ui.lineRadio, 0);
          buttonGroup->setId(m_ui.circleRadio, 1);

          QEasingCurve dummy;
          m_ui.periodSpinBox->setValue(dummy.period());
          m_ui.amplitudeSpinBox->setValue(dummy.amplitude());
          m_ui.overshootSpinBox->setValue(dummy.overshoot());

          connect(m_ui.easingCurvePicker, SIGNAL(currentRowChanged(int)), this, SLOT(curveChanged(int)));
          connect(buttonGroup, SIGNAL(buttonClicked(int)), this, SLOT(pathChanged(int)));
          connect(m_ui.periodSpinBox, SIGNAL(valueChanged(double)), this, SLOT(periodChanged(double)));
          connect(m_ui.amplitudeSpinBox, SIGNAL(valueChanged(double)), this, SLOT(amplitudeChanged(double)));
          connect(m_ui.overshootSpinBox, SIGNAL(valueChanged(double)), this, SLOT(overshootChanged(double)));
          createCurveIcons();

          QPixmap pix(QLatin1String(":/images/qt-logo.png"));
          m_item = new PixmapItem(pix);
          m_scene.addItem(m_item);
          m_ui.graphicsView->setScene(&m_scene);

          m_anim = new Animation(m_item, "pos");
          m_anim->setEasingCurve(QEasingCurve::OutBounce);
          m_ui.easingCurvePicker->setCurrentRow(int(QEasingCurve::OutBounce));

          startAnimation();
      }

      QEasingCurve createEasingCurve(QEasingCurve::Type curveType)
      {
          QEasingCurve curve(curveType);

          if (curveType == QEasingCurve::BezierSpline) {
              curve.addCubicBezierSegment(QPointF(0.4, 0.1), QPointF(0.6, 0.9), QPointF(1.0, 1.0));

          } else if (curveType == QEasingCurve::TCBSpline) {
              curve.addTCBSegment(QPointF(0.0, 0.0), 0, 0, 0);
              curve.addTCBSegment(QPointF(0.3, 0.4), 0.2, 1, -0.2);
              curve.addTCBSegment(QPointF(0.7, 0.6), -0.2, 1, 0.2);
              curve.addTCBSegment(QPointF(1.0, 1.0), 0, 0, 0);
          }

          return curve;
      }

      void Window::createCurveIcons()
      {
          QPixmap pix(m_iconSize);
          QPainter painter(&pix);
          QLinearGradient gradient(0,0, 0, m_iconSize.height());
          gradient.setColorAt(0.0, QColor(240, 240, 240));
          gradient.setColorAt(1.0, QColor(224, 224, 224));
          QBrush brush(gradient);
          const QMetaObject &mo = QEasingCurve::staticMetaObject;
          QMetaEnum metaEnum = mo.enumerator(mo.indexOfEnumerator("Type"));
          // Skip QEasingCurve::Custom
          for (int i = 0; i < QEasingCurve::NCurveTypes - 1; ++i) {
              painter.fillRect(QRect(QPoint(0, 0), m_iconSize), brush);
              QEasingCurve curve = createEasingCurve((QEasingCurve::Type) i);
              painter.setPen(QColor(0, 0, 255, 64));
              qreal xAxis = m_iconSize.height()/1.5;
              qreal yAxis = m_iconSize.width()/3;
              painter.drawLine(0, xAxis, m_iconSize.width(),  xAxis);
              painter.drawLine(yAxis, 0, yAxis, m_iconSize.height());

              qreal curveScale = m_iconSize.height()/2;

              painter.setPen(Qt::NoPen);

              // start point
              painter.setBrush(Qt::red);
              QPoint start(yAxis, xAxis - curveScale * curve.valueForProgress(0));
              painter.drawRect(start.x() - 1, start.y() - 1, 3, 3);

              // end point
              painter.setBrush(Qt::blue);
              QPoint end(yAxis + curveScale, xAxis - curveScale * curve.valueForProgress(1));
              painter.drawRect(end.x() - 1, end.y() - 1, 3, 3);

              QPainterPath curvePath;
              curvePath.moveTo(start);
              for (qreal t = 0; t <= 1.0; t+=1.0/curveScale) {
                  QPoint to;
                  to.setX(yAxis + curveScale * t);
                  to.setY(xAxis - curveScale * curve.valueForProgress(t));
                  curvePath.lineTo(to);
              }
              painter.setRenderHint(QPainter::Antialiasing, true);
              painter.strokePath(curvePath, QColor(32, 32, 32));
              painter.setRenderHint(QPainter::Antialiasing, false);
              QListWidgetItem *item = new QListWidgetItem;
              item->setIcon(QIcon(pix));
              item->setText(metaEnum.key(i));
              m_ui.easingCurvePicker->addItem(item);
          }
      }

      void Window::startAnimation()
      {
          m_anim->setStartValue(QPointF(0, 0));
          m_anim->setEndValue(QPointF(100, 100));
          m_anim->setDuration(2000);
          m_anim->setLoopCount(-1); // forever
          m_anim->start();
      }

      void Window::curveChanged(int row)
      {
          QEasingCurve::Type curveType = (QEasingCurve::Type)row;
          m_anim->setEasingCurve(createEasingCurve(curveType));
          m_anim->setCurrentTime(0);

          bool isElastic = curveType >= QEasingCurve::InElastic && curveType <= QEasingCurve::OutInElastic;
          bool isBounce = curveType >= QEasingCurve::InBounce && curveType <= QEasingCurve::OutInBounce;
          m_ui.periodSpinBox->setEnabled(isElastic);
          m_ui.amplitudeSpinBox->setEnabled(isElastic || isBounce);
          m_ui.overshootSpinBox->setEnabled(curveType >= QEasingCurve::InBack && curveType <= QEasingCurve::OutInBack);
      }

      void Window::pathChanged(int index)
      {
          m_anim->setPathType((Animation::PathType)index);
      }

      void Window::periodChanged(double value)
      {
          QEasingCurve curve = m_anim->easingCurve();
          curve.setPeriod(value);
          m_anim->setEasingCurve(curve);
      }

      void Window::amplitudeChanged(double value)
      {
          QEasingCurve curve = m_anim->easingCurve();
          curve.setAmplitude(value);
          m_anim->setEasingCurve(curve);
      }

      void Window::overshootChanged(double value)
      {
          QEasingCurve curve = m_anim->easingCurve();
          curve.setOvershoot(value);
          m_anim->setEasingCurve(curve);
      }