drawlipse的PyQt实现到Matlab的转换

from PyQt4.QtGui import * def draw_ellipse(self, center, rad_x, rad_y, angle, color): qp = QtGui.QPainter() qp.begin(self) qp.translate(center) qp.rotate(math.degrees(angle)) qp.setPen(QtGui.QColor(color)) qp.drawEllipse(QPoint(0, 0), rad_x, rad_y) qp.end()

01052 void QPainterPath::addEllipse(const QRectF &boundingRect) 01053 { 01054 #ifndef QT_NO_DEBUG 01055 if (qIsNan(boundingRect.x()) || qIsNan(boundingRect.y()) 01056 || qIsNan(boundingRect.width()) || qIsNan(boundingRect.height())) 01057 qWarning("QPainterPath::addEllipse: Adding ellipse where a parameter is NaN, results are undefined"); 01058 #endif 01059 if (boundingRect.isNull()) 01060 return; 01061 01062 ensureData(); 01063 detach(); 01064 01065 Q_D(QPainterPath); 01066 d->elements.reserve(d->elements.size() + 13); 01067 01068 QPointF pts[12]; 01069 int point_count; 01070 QPointF start = qt_curves_for_arc(boundingRect, 0, 360, pts, &point_count); 01071 01072 moveTo(start); 01073 cubicTo(pts[0], pts[1], pts[2]); // 0 -> 270 01074 cubicTo(pts[3], pts[4], pts[5]); // 270 -> 180 01075 cubicTo(pts[6], pts[7], pts[8]); // 180 -> 90 01076 cubicTo(pts[9], pts[10], pts[11]); // 90 - >0 01077 d_func()->require_moveTo = true; 01078 }

00722 QPointF qt_curves_for_arc(const QRectF &rect, qreal startAngle, qreal sweepLength, 00723 QPointF *curves, int *point_count) 00724 { 00725 Q_ASSERT(point_count); 00726 Q_ASSERT(curves); 00727 00728 #ifndef QT_NO_DEBUG 00729 if (qIsNan(rect.x()) || qIsNan(rect.y()) || qIsNan(rect.width()) || qIsNan(rect.height()) 00730 || qIsNan(startAngle) || qIsNan(sweepLength)) 00731 qWarning("QPainterPath::arcTo: Adding arc where a parameter is NaN, results are undefined"); 00732 #endif 00733 *point_count = 0; 00734 00735 if (rect.isNull()) { 00736 return QPointF(); 00737 } 00738 00739 if (sweepLength > 360) sweepLength = 360; 00740 else if (sweepLength < -360) sweepLength = -360; 00741 00742 // Special case fast path 00743 if (startAngle == 0.0 && sweepLength == 360.0) { 00744 qreal x = rect.x(); 00745 qreal y = rect.y(); 00746 00747 qreal w = rect.width(); 00748 qreal w2 = rect.width() / 2; 00749 qreal w2k = w2 * QT_PATH_KAPPA; 00750 00751 qreal h = rect.height(); 00752 qreal h2 = rect.height() / 2; 00753 qreal h2k = h2 * QT_PATH_KAPPA; 00754 00755 // 0 -> 270 degrees 00756 curves[(*point_count)++] = QPointF(x + w, y + h2 + h2k); 00757 curves[(*point_count)++] = QPointF(x + w2 + w2k, y + h); 00758 curves[(*point_count)++] = QPointF(x + w2, y + h); 00759 00760 // 270 -> 180 degrees 00761 curves[(*point_count)++] = QPointF(x + w2 - w2k, y + h); 00762 curves[(*point_count)++] = QPointF(x, y + h2 + h2k); 00763 curves[(*point_count)++] = QPointF(x, y + h2); 00764 00765 // 180 -> 90 degrees 00766 curves[(*point_count)++] = QPointF(x, y + h2 - h2k); 00767 curves[(*point_count)++] = QPointF(x + w2 - w2k, y); 00768 curves[(*point_count)++] = QPointF(x + w2, y); 00769 00770 // 90 -> 0 degrees 00771 curves[(*point_count)++] = QPointF(x + w2 + w2k, y); 00772 curves[(*point_count)++] = QPointF(x + w, y + h2 - h2k); 00773 curves[(*point_count)++] = QPointF(x + w, y + h2); 00774 00775 return QPointF(x + w, y + h2); 00776 } 00777 00778 #define ANGLE(t) ((t) * 2 * Q_PI / 360.0) 00779 #define SIGN(t) (t > 0 ? 1 : -1) 00780 qreal a = rect.width() / 2.0; 00781 qreal b = rect.height() / 2.0; 00782 00783 qreal absSweepLength = (sweepLength < 0 ? -sweepLength : sweepLength); 00784 int iterations = (int)ceil((absSweepLength) / 90.0); 00785 00786 QPointF first_point; 00787 00788 if (iterations == 0) { 00789 first_point = rect.center() + QPointF(a * qCos(ANGLE(startAngle)), 00790 -b * qSin(ANGLE(startAngle))); 00791 } else { 00792 qreal clength = sweepLength / iterations; 00793 qreal cosangle1, sinangle1, cosangle2, sinangle2; 00794 00795 for (int i=0; i<iterations; ++i) { 00796 qreal cangle = startAngle + i * clength; 00797 00798 cosangle1 = qCos(ANGLE(cangle)); 00799 sinangle1 = qSin(ANGLE(cangle)); 00800 cosangle2 = qCos(ANGLE(cangle + clength)); 00801 sinangle2 = qSin(ANGLE(cangle + clength)); 00802 00803 // Find the start and end point of the curve. 00804 QPointF startPoint = rect.center() + QPointF(a * cosangle1, -b * sinangle1); 00805 QPointF endPoint = rect.center() + QPointF(a * cosangle2, -b * sinangle2); 00806 00807 // The derived at the start and end point. 00808 qreal sdx = -a * sinangle1; 00809 qreal sdy = -b * cosangle1; 00810 qreal edx = -a * sinangle2; 00811 qreal edy = -b * cosangle2; 00812 00813 // Creating the tangent lines. We need to reverse their direction if the 00814 // sweep is negative (clockwise) 00815 QLineF controlLine1(startPoint, startPoint + SIGN(sweepLength) * QPointF(sdx, sdy)); 00816 QLineF controlLine2(endPoint, endPoint - SIGN(sweepLength) * QPointF(edx, edy)); 00817 00818 // We need to scale down the control lines to match that of the current sweeplength. 00819 // qAbs because we only want to scale, not change direction. 00820 qreal kappa = QT_PATH_KAPPA * qAbs(clength) / 90.0; 00821 // Adjust their length to fit the magic KAPPA length. 00822 controlLine1.setLength(controlLine1.length() * kappa); 00823 controlLine2.setLength(controlLine2.length() * kappa); 00824 00825 curves[(*point_count)++] = controlLine1.p2(); 00826 curves[(*point_count)++] = controlLine2.p2(); 00827 curves[(*point_count)++] = endPoint; 00828 00829 if (i == 0) 00830 first_point = startPoint; 00831 } 00832 } 00833 00834 return first_point; 00835 }

a = rad_x; % horizontal radius b = rad_y; % vertical radius x0 = center_x; % x0, y0 ellipse centre coordinates y0 = center_y; steps = 50; t = linspace(0, 2*pi, steps); theta0 = angle; x = x0 + (a * sin(t - theta0)); y = y0 + (b * cos(t)); plot(x, y, '.-'),

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1楼 · 发布于 2024-09-28 20:46:30

这样的怎么样？在

a = rad_x;
b = rad_y;
r0 = center_x + i*center_y;  % <  origin of ellipse

theta0=angle;   % <  angle of rotation of ellipse

steps = 200;

t = linspace(0, 2*pi, steps);

r = a*sin(t) + i*b*cos(t);


R = exp(i*theta0);
r = R*r;
r = r0 + r;

figure(1), hold on 
plot(real(r), imag(r), '-r')

使用矩阵而不是复数：

^{pr2}$

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