def drawSteps(self, painter, xMap, yMap, canvasRect, from_, to):
"""
Draw steps
:param QPainter painter: Painter
:param qwt.scale_map.QwtScaleMap xMap: Maps x-values into pixel coordinates.
:param qwt.scale_map.QwtScaleMap yMap: Maps y-values into pixel coordinates.
:param QRectF canvasRect: Contents rectangle of the canvas
:param int from_: Index of the first point to be painted
:param int to: Index of the last point to be painted. If to < 0 the curve will be painted to its last point.
.. seealso::
:py:meth:`draw()`, :py:meth:`drawSticks()`,
:py:meth:`drawDots()`, :py:meth:`drawLines()`
"""
size = 2 * (to - from_) + 1
if QT_API == "pyside6":
polygon = QPolygonF()
polygon.resize(size)
elif QT_API == "pyqt6":
polygon = QPolygonF([QPointF(0, 0)] * size)
else:
polygon = QPolygonF(size)
inverted = self.orientation() == Qt.Vertical
if self.__data.attributes & self.Inverted:
inverted = not inverted
series = self.data()
ip = 0
for i in range(from_, to + 1):
sample = series.sample(i)
xi = xMap.transform(sample.x())
yi = yMap.transform(sample.y())
if ip > 0:
p0 = polygon[ip - 2]
if inverted:
polygon[ip - 1] = QPointF(p0.x(), yi)
else:
polygon[ip - 1] = QPointF(xi, p0.y())
polygon[ip] = QPointF(xi, yi)
ip += 2
painter.drawPolyline(polygon)
if self.__data.brush.style() != Qt.NoBrush:
self.fillCurve(painter, xMap, yMap, canvasRect, polygon)
def array2d_to_qpolygonf(xdata, ydata):
"""
Utility function to convert two 1D-NumPy arrays representing curve data
(X-axis, Y-axis data) into a single polyline (QtGui.PolygonF object).
This feature is compatible with PyQt4, PyQt5 and PySide2 (requires QtPy).
License/copyright: MIT License © Pierre Raybaut 2020-2021.
:param numpy.ndarray xdata: 1D-NumPy array
:param numpy.ndarray ydata: 1D-NumPy array
:return: Polyline
:rtype: QtGui.QPolygonF
"""
if not (xdata.size == ydata.size == xdata.shape[0] == ydata.shape[0]):
raise ValueError("Arguments must be 1D NumPy arrays with same size")
size = xdata.size
if QT_API.startswith("pyside"): # PySide (obviously...)
if QT_API == "pyside2":
polyline = QPolygonF(size)
else:
polyline = QPolygonF()
polyline.resize(size)
address = shiboken.getCppPointer(polyline.data())[0]
buffer = (ctypes.c_double * 2 * size).from_address(address)
else: # PyQt4, PyQt5
if QT_API == "pyqt6":
polyline = QPolygonF([QPointF(0, 0)] * size)
else:
polyline = QPolygonF(size)
buffer = polyline.data()
buffer.setsize(
16 * size) # 16 bytes per point: 8 bytes per X,Y value (float64)
memory = np.frombuffer(buffer, np.float64)
memory[:(size - 1) * 2 + 1:2] = np.array(xdata,
dtype=np.float64,
copy=False)
memory[1:(size - 1) * 2 + 2:2] = np.array(ydata,
dtype=np.float64,
copy=False)
return polyline
