qpainterpath_p.h File Reference

#include "QtGui/qpainterpath.h"
#include "QtGui/qregion.h"
#include "QtCore/qlist.h"
#include "QtCore/qvarlengtharray.h"
#include <qdebug.h>
#include <private/qvectorpath_p.h>
#include <private/qstroker_p.h>

Go to the source code of this file.

Classes
class	QPainterPathData
class	QPainterPathStrokerPrivate
class	QVectorPathConverter
struct	QVectorPathConverter::QVectorPathData

Macros
#define	KAPPA   qreal(0.5522847498)

Functions
void Q_GUI_EXPORT	qt_find_ellipse_coords (const QRectF &r, qreal angle, qreal length, QPointF *startPoint, QPointF *endPoint)

Macro Definition Documentation

KAPPA

#define KAPPA   qreal(0.5522847498)

Definition at line 273 of file qpainterpath_p.h.

Function Documentation

qt_find_ellipse_coords()

void Q_GUI_EXPORT qt_find_ellipse_coords	(	const QRectF &	r,
		qreal	angle,
		qreal	length,
		QPointF *	startPoint,
		QPointF *	endPoint
	)

Definition at line 97 of file qpainterpath.cpp.

Referenced by QVectorPath::convertToPainterPath().

{
    if (r.isNull()) {
        if (startPoint)
            *startPoint = QPointF();
        if (endPoint)
            *endPoint = QPointF();
        return;
    }

    qreal w2 = r.width() / 2;
    qreal h2 = r.height() / 2;

    qreal angles[2] = { angle, angle + length };
    QPointF *points[2] = { startPoint, endPoint };

    for (int i = 0; i < 2; ++i) {
        if (!points[i])
            continue;

        qreal theta = angles[i] - 360 * qFloor(angles[i] / 360);
        qreal t = theta / 90;
        // truncate
        int quadrant = int(t);
        t -= quadrant;

        t = qt_t_for_arc_angle(90 * t);

        // swap x and y?
        if (quadrant & 1)
            t = 1 - t;

        qreal a, b, c, d;
        QBezier::coefficients(t, a, b, c, d);
        QPointF p(a + b + c*QT_PATH_KAPPA, d + c + b*QT_PATH_KAPPA);

        // left quadrants
        if (quadrant == 1 || quadrant == 2)
            p.rx() = -p.x();

        // top quadrants
        if (quadrant == 0 || quadrant == 1)
            p.ry() = -p.y();

        *points[i] = r.center() + QPointF(w2 * p.x(), h2 * p.y());
    }
}