- Qt 5.5
- Qt Widgets
- Wiggly Example
- wigglywidget.cpp Example File
- Qt 5.5.1 Reference Documentation

# wigglywidget.cpp Example File

widgets/wiggly/wigglywidget.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** 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
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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.width(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.width(text[i]);
        }
    }

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