Source code for pyqtgraph.graphicsItems.CurvePoint

import weakref
from math import atan2, degrees

from ..functions import clip_scalar
from ..Qt import QtCore, QtWidgets
from . import ArrowItem
from .GraphicsObject import GraphicsObject

__all__ = ['CurvePoint', 'CurveArrow']
[docs] class CurvePoint(GraphicsObject): """A GraphicsItem that sets its location to a point on a PlotCurveItem. Also rotates to be tangent to the curve. The position along the curve is a Qt property, and thus can be easily animated. Note: This class does not display anything; see CurveArrow for an applied example """
[docs] def __init__(self, curve, index=0, pos=None, rotate=True): """Position can be set either as an index referring to the sample number or the position 0.0 - 1.0 If *rotate* is True, then the item rotates to match the tangent of the curve. """ GraphicsObject.__init__(self) #QObjectWorkaround.__init__(self) self._rotate = rotate self.curve = weakref.ref(curve) self.setParentItem(curve) self.setProperty('position', 0.0) self.setProperty('index', 0) self.setFlags(self.flags() | self.GraphicsItemFlag.ItemHasNoContents) if pos is not None: self.setPos(pos) else: self.setIndex(index)
def setPos(self, pos): self.setProperty('position', float(pos))## cannot use numpy types here, MUST be python float. def setIndex(self, index): self.setProperty('index', int(index)) ## cannot use numpy types here, MUST be python int. def event(self, ev): if not isinstance(ev, QtCore.QDynamicPropertyChangeEvent) or self.curve() is None: return False if ev.propertyName() == 'index': index ='index') if 'QVariant' in repr(index): index = index.toInt()[0] elif ev.propertyName() == 'position': index = None else: return False (x, y) = self.curve().getData() if index is None: #print ev.propertyName(),'position').toDouble()[0],'position').typeName() pos ='position') if 'QVariant' in repr(pos): ## need to support 2 APIs :( pos = pos.toDouble()[0] index = (len(x)-1) * clip_scalar(pos, 0.0, 1.0) if index != int(index): ## interpolate floating-point values i1 = int(index) i2 = clip_scalar(i1+1, 0, len(x)-1) s2 = index-i1 s1 = 1.0-s2 newPos = (x[i1]*s1+x[i2]*s2, y[i1]*s1+y[i2]*s2) else: index = int(index) i1 = clip_scalar(index-1, 0, len(x)-1) i2 = clip_scalar(index+1, 0, len(x)-1) newPos = (x[index], y[index]) p1 = self.parentItem().mapToScene(QtCore.QPointF(x[i1], y[i1])) p2 = self.parentItem().mapToScene(QtCore.QPointF(x[i2], y[i2])) rads = atan2(p2.y()-p1.y(), p2.x()-p1.x()) ## returns radians self.resetTransform() if self._rotate: self.setRotation(180 + degrees(rads)) QtWidgets.QGraphicsItem.setPos(self, *newPos) return True def boundingRect(self): return QtCore.QRectF() def paint(self, *args): pass def makeAnimation(self, prop='position', start=0.0, end=1.0, duration=10000, loop=1): # In Python 3, a bytes object needs to be used as a property name in # QPropertyAnimation. PyQt stopped automatically encoding a str when a # QByteArray was expected in v5.5 (see qbytearray.sip). if not isinstance(prop, bytes): prop = prop.encode('latin-1') anim = QtCore.QPropertyAnimation(self, prop) anim.setDuration(duration) anim.setStartValue(start) anim.setEndValue(end) anim.setLoopCount(loop) return anim
[docs] class CurveArrow(CurvePoint): """Provides an arrow that points to any specific sample on a PlotCurveItem. Provides properties that can be animated."""
[docs] def __init__(self, curve, index=0, pos=None, **opts): CurvePoint.__init__(self, curve, index=index, pos=pos) if opts.get('pxMode', True): opts['pxMode'] = False self.setFlags(self.flags() | self.GraphicsItemFlag.ItemIgnoresTransformations) opts['angle'] = 0 self.arrow = ArrowItem.ArrowItem(**opts) self.arrow.setParentItem(self)
def setStyle(self, **opts): return self.arrow.setStyle(**opts)