具有多个断点的可拖动线

Question

我有一个与以下问题非常相似的应用程序：Draw half infinite lines?

我想要一条具有多个阈值的无限线。

问题中提供的解决方案是一个很好的起点：https://stackoverflow.com/a/37836348/7163293

我试图通过修改__init__ 中的movable 属性来使线条可移动，并添加一个setMovable 方法，就像源代码中的源代码一样：

http://www.pyqtgraph.org/documentation/_modules/pyqtgraph/graphicsItems/InfiniteLine.html#InfiniteLine

from pyqtgraph.Qt import QtGui
import numpy as np
import pyqtgraph as pg

class InfiniteLineWithBreak(pg.GraphicsObject):

    def __init__(self, changeX, levelsY, pen=None):
        pg.GraphicsObject.__init__(self)

        self.changeX = changeX
        self.levelsY = levelsY

        self.maxRange = [None, None]
        self.moving = False
        self.movable = True
        self.setMovable(self.movable)
        self.mouseHovering = False

        pen = (200, 200, 100)
        self.setPen(pen)
        self.setHoverPen(color=(255,0,0), width=self.pen.width())
        self.currentPen = self.pen

    def setMovable(self, m):
        """Set whether the line is movable by the user."""
        self.movable = m
        self.setAcceptHoverEvents(m)


    def setBounds(self, bounds):
        self.maxRange = bounds
        self.setValue(self.value())

    def setPen(self, *args, **kwargs):
        self.pen = pg.fn.mkPen(*args, **kwargs)
        if not self.mouseHovering:
            self.currentPen = self.pen
            self.update()

    def setHoverPen(self, *args, **kwargs):
        self.hoverPen = pg.fn.mkPen(*args, **kwargs)
        if self.mouseHovering:
            self.currentPen = self.hoverPen
            self.update()

    def boundingRect(self):
        br = self.viewRect()
        return br.normalized()

    def paint(self, p, *args):
        br = self.boundingRect()
        p.setPen(self.currentPen)
        # three lines (left border to change point, change point vertical, change point to right)
        p.drawLine(pg.Point(br.left(), self.levelsY[0]), pg.Point(self.changeX, self.levelsY[0]))
        p.drawLine(pg.Point(self.changeX, self.levelsY[0]), pg.Point(self.changeX, self.levelsY[1]))
        p.drawLine(pg.Point(self.changeX, self.levelsY[1]), pg.Point(br.right(), self.levelsY[1]))

    def dataBounds(self, axis, frac=1.0, orthoRange=None):
        if axis == 0:
            return None   ## x axis should never be auto-scaled
        else:
            return (0,0)

    def setMouseHover(self, hover):
        pass

app = QtGui.QApplication([])
w = pg.GraphicsWindow()
w.resize(1000, 600)
v = w.addPlot(y=np.random.normal(size=100))
v.addItem(InfiniteLineWithBreak(changeX=50, levelsY=(-1, 1)))
app.exec_()

但是，修改后的线仍然无法移动。所以我有点卡在这里。有人能提供一些指点吗？

此外，理想情况下，应用程序上的线条应该可以分段移动。因此，当用户拖动一条线时，只有断点之间的部分在移动。所以理想情况下，我想要这样的东西：

Draggable line with draggable points

在我的应用程序中。理想情况下，它看起来像

阈值点水平（TH_Px_L1）可拖动，但不能定时（TH_Px_T1），所以点只能垂直移动。

如果有人也可以在第二个项目上提供帮助并提供一些非常有用的指示或解决方案。

Answer 1

基于来自文档的this example。

散点图类似于绘制图形，但连接线位于 i 点和它们连接的 i + 1 点之间。然后我们将运动限制在垂直轴上，因为这是作者的要求。

import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui

pg.setConfigOptions(antialias=True)

w = pg.GraphicsWindow()
w.setWindowTitle('Draggable')


class Graph(pg.GraphItem):
    def __init__(self):
        self.dragPoint = None
        self.dragOffset = None
        pg.GraphItem.__init__(self)

    def setData(self, **kwds):
        self.data = kwds
        if 'pos' in self.data:
            npts = self.data['pos'].shape[0]
            self.data['adj'] = np.column_stack((np.arange(0, npts-1), np.arange(1, npts)))
            self.data['data'] = np.empty(npts, dtype=[('index', int)])
            self.data['data']['index'] = np.arange(npts)
        self.updateGraph()

    def updateGraph(self):
        pg.GraphItem.setData(self, **self.data)

    def mouseDragEvent(self, ev):
        if ev.button() != QtCore.Qt.LeftButton:
            ev.ignore()
            return

        if ev.isStart():
            pos = ev.buttonDownPos()
            pts = self.scatter.pointsAt(pos)
            if len(pts) == 0:
                ev.ignore()
                return
            self.dragPoint = pts[0]
            ind = pts[0].data()[0]
            self.dragOffset = self.data['pos'][ind][1] - pos[1]
        elif ev.isFinish():
            self.dragPoint = None
            return
        else:
            if self.dragPoint is None:
                ev.ignore()
                return

        ind = self.dragPoint.data()[0]
        self.data['pos'][ind][1] = ev.pos()[1] + self.dragOffset
        self.updateGraph()
        ev.accept()


g = Graph()
v = w.addPlot()
v.addItem(g)

x = np.linspace(1, 100, 40)
pos = np.column_stack((x, np.sin(x)))

g.setData(pos=pos, size=10, pxMode=True)

if __name__ == '__main__':
    import sys

    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()