Qt 5.11 | Qt Widgets | Wiggly Example | wigglywidget.cpp Example File

Qt 5.11.3 Reference Documentation

# wigglywidget.cpp Example File

widgets/wiggly/wigglywidget.cpp

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      #include <QtWidgets>

      #include "wigglywidget.h"

      WigglyWidget::WigglyWidget(QWidget *parent)
          : QWidget(parent)
      {
          setBackgroundRole(QPalette::Midlight);
          setAutoFillBackground(true);

          QFont newFont = font();
          newFont.setPointSize(newFont.pointSize() + 20);
          setFont(newFont);

          step = 0;
          timer.start(60, this);
      }

      void WigglyWidget::paintEvent(QPaintEvent * /* event */)
      {
          static const int sineTable[16] = {
              0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92, -100, -92, -71, -38
          };

          QFontMetrics metrics(font());
          int x = (width() - metrics.horizontalAdvance(text)) / 2;
          int y = (height() + metrics.ascent() - metrics.descent()) / 2;
          QColor color;

          QPainter painter(this);
          for (int i = 0; i < text.size(); ++i) {
              int index = (step + i) % 16;
              color.setHsv((15 - index) * 16, 255, 191);
              painter.setPen(color);
              painter.drawText(x, y - ((sineTable[index] * metrics.height()) / 400),
                               QString(text[i]));
              x += metrics.horizontalAdvance(text[i]);
          }
      }

      void WigglyWidget::timerEvent(QTimerEvent *event)
      {
          if (event->timerId() == timer.timerId()) {
              ++step;
              update();
          } else {
              QWidget::timerEvent(event);
          }
      }