| Цитата(airens @ 29.6.2009, 18:48) | | но каким образом можно вычислить координаты пар точек, через которые строить риски? |
Можно вот так, например:
| Код |
#ifndef WIDGET_H
#define WIDGET_H
#include <QtGui/QWidget>
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = 0);
~Widget();
protected:
void paintEvent(QPaintEvent *event);
private:
void circleScale(QPainter *painter, qreal radius, qreal tickLength, int numTicks);
};
#endif // WIDGET_H
|
| Код |
#include "widget.h"
#include <math.h>
#include <QPainter>
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
setMinimumSize(100, 100);
}
Widget::~Widget()
{
}
void Widget::paintEvent(QPaintEvent *event)
{
QWidget::paintEvent(event);
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.translate(0.5 * width(), 0.5 * height());
qreal radius = 0.35 * qMin(width(), height());
qreal tickLength = 0.15 * radius;
circleScale(&painter, radius, tickLength, 16);
}
void Widget::circleScale(QPainter *painter, qreal radius, qreal tickLength, int numTicks)
{
QPen pen(QBrush(Qt::blue), 2.0);
QFont font("Arial");
font.setPixelSize((int)tickLength);
painter->setPen(pen);
painter->setFont(font);
painter->drawEllipse(QPointF(0, 0), radius, radius);
for (int i = 0; i < numTicks; ++i) {
qreal angle = 2 * M_PI * i / numTicks;
qreal cs = cos(angle);
qreal sn = -sin(angle);
qreal x = radius * cs;
qreal y = radius * sn;
qreal dx = 0.5 * tickLength *cs;
qreal dy = 0.5 * tickLength *sn;
painter->drawLine(QPointF(x - dx, y - dy), QPointF(x + dx, y + dy));
QString text = QString("%1").arg(i);
QTextOption textOption(Qt::AlignCenter);
QRectF rect(x + dx, y + dy, 3 * dx, 3 * dy);
rect = painter->boundingRect(rect, text, textOption);
painter->drawText(rect, text, textOption);
}
}
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| Код |
#include <QtGui/QApplication>
#include "widget.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget w;
w.resize(400, 300);
w.show();
return a.exec();
}
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