123 lines
4.6 KiB
Python
123 lines
4.6 KiB
Python
# -*- coding: utf-8 -*-
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from math import atan2, degrees
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from ..Qt import QtGui, QtCore
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from . import ArrowItem
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from ..functions import clip_scalar
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import weakref
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from .GraphicsObject import GraphicsObject
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__all__ = ['CurvePoint', 'CurveArrow']
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class CurvePoint(GraphicsObject):
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"""A GraphicsItem that sets its location to a point on a PlotCurveItem.
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Also rotates to be tangent to the curve.
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The position along the curve is a Qt property, and thus can be easily animated.
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Note: This class does not display anything; see CurveArrow for an applied example
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"""
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def __init__(self, curve, index=0, pos=None, rotate=True):
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"""Position can be set either as an index referring to the sample number or
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the position 0.0 - 1.0
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If *rotate* is True, then the item rotates to match the tangent of the curve.
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"""
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GraphicsObject.__init__(self)
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#QObjectWorkaround.__init__(self)
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self._rotate = rotate
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self.curve = weakref.ref(curve)
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self.setParentItem(curve)
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self.setProperty('position', 0.0)
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self.setProperty('index', 0)
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self.setFlags(self.flags() | self.GraphicsItemFlag.ItemHasNoContents)
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if pos is not None:
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self.setPos(pos)
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else:
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self.setIndex(index)
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def setPos(self, pos):
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self.setProperty('position', float(pos))## cannot use numpy types here, MUST be python float.
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def setIndex(self, index):
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self.setProperty('index', int(index)) ## cannot use numpy types here, MUST be python int.
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def event(self, ev):
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if not isinstance(ev, QtCore.QDynamicPropertyChangeEvent) or self.curve() is None:
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return False
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if ev.propertyName() == 'index':
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index = self.property('index')
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if 'QVariant' in repr(index):
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index = index.toInt()[0]
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elif ev.propertyName() == 'position':
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index = None
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else:
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return False
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(x, y) = self.curve().getData()
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if index is None:
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#print ev.propertyName(), self.property('position').toDouble()[0], self.property('position').typeName()
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pos = self.property('position')
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if 'QVariant' in repr(pos): ## need to support 2 APIs :(
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pos = pos.toDouble()[0]
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index = (len(x)-1) * clip_scalar(pos, 0.0, 1.0)
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if index != int(index): ## interpolate floating-point values
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i1 = int(index)
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i2 = clip_scalar(i1+1, 0, len(x)-1)
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s2 = index-i1
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s1 = 1.0-s2
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newPos = (x[i1]*s1+x[i2]*s2, y[i1]*s1+y[i2]*s2)
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else:
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index = int(index)
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i1 = clip_scalar(index-1, 0, len(x)-1)
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i2 = clip_scalar(index+1, 0, len(x)-1)
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newPos = (x[index], y[index])
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p1 = self.parentItem().mapToScene(QtCore.QPointF(x[i1], y[i1]))
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p2 = self.parentItem().mapToScene(QtCore.QPointF(x[i2], y[i2]))
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rads = atan2(p2.y()-p1.y(), p2.x()-p1.x()) ## returns radians
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self.resetTransform()
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if self._rotate:
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self.setRotation(180 + degrees(rads))
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QtGui.QGraphicsItem.setPos(self, *newPos)
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return True
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def boundingRect(self):
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return QtCore.QRectF()
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def paint(self, *args):
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pass
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def makeAnimation(self, prop='position', start=0.0, end=1.0, duration=10000, loop=1):
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# In Python 3, a bytes object needs to be used as a property name in
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# QPropertyAnimation. PyQt stopped automatically encoding a str when a
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# QByteArray was expected in v5.5 (see qbytearray.sip).
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if not isinstance(prop, bytes):
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prop = prop.encode('latin-1')
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anim = QtCore.QPropertyAnimation(self, prop)
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anim.setDuration(duration)
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anim.setStartValue(start)
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anim.setEndValue(end)
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anim.setLoopCount(loop)
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return anim
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class CurveArrow(CurvePoint):
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"""Provides an arrow that points to any specific sample on a PlotCurveItem.
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Provides properties that can be animated."""
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def __init__(self, curve, index=0, pos=None, **opts):
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CurvePoint.__init__(self, curve, index=index, pos=pos)
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if opts.get('pxMode', True):
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opts['pxMode'] = False
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self.setFlags(self.flags() | self.GraphicsItemFlag.ItemIgnoresTransformations)
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opts['angle'] = 0
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self.arrow = ArrowItem.ArrowItem(**opts)
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self.arrow.setParentItem(self)
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def setStyle(self, **opts):
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return self.arrow.setStyle(**opts)
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