helper.cpp Example File
opengl/2dpainting/helper.cpp
/****************************************************************************
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** Copyright (C) 2006-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the example classes of the Qt Toolkit.
**
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** accordance with the Qt Preview License Agreement provided with the
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/
#include <QtGui>
#include "helper.h"
Helper::Helper()
{
QLinearGradient gradient(QPointF(50, -20), QPointF(80, 20));
gradient.setColorAt(0.0, Qt::white);
gradient.setColorAt(1.0, QColor(0xa6, 0xce, 0x39));
background = QBrush(QColor(64, 32, 64));
circleBrush = QBrush(gradient);
circlePen = QPen(Qt::black);
circlePen.setWidth(1);
textPen = QPen(Qt::white);
textFont.setPixelSize(50);
}
void Helper::paint(QPainter *painter, QPaintEvent *event, int elapsed)
{
painter->fillRect(event->rect(), background);
painter->translate(100, 100);
painter->save();
painter->setBrush(circleBrush);
painter->setPen(circlePen);
painter->rotate(elapsed * 0.030);
qreal r = elapsed/1000.0;
int n = 30;
for (int i = 0; i < n; ++i) {
painter->rotate(30);
qreal radius = 0 + 120.0*((i+r)/n);
qreal circleRadius = 1 + ((i+r)/n)*20;
painter->drawEllipse(QRectF(radius, -circleRadius,
circleRadius*2, circleRadius*2));
}
painter->restore();
painter->setPen(textPen);
painter->setFont(textFont);
painter->drawText(QRect(-50, -50, 100, 100), Qt::AlignCenter, "Qt");
}