pyqtgraph：同步不同图中轴的缩放

Question

我想同步几个 pyqtgraph 图的 X 轴。当用户使用鼠标交互（例如鼠标在 x 轴上时滚动滚轮）重新调整 X 轴时，我想将相同的更改分配给所有其他绘图。那么我该怎么做呢？

我从下面的基本示例中导出了一个最小化的代码。

我一定要覆盖viewRangeChanged()的功能w1和w2？

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

from pyqtgraph.dockarea import *


win = QtGui.QMainWindow()
area = DockArea()
win.setCentralWidget(area)
win.resize(1000,500)
win.setWindowTitle('pyqtgraph example: dockarea')


d1 = Dock("Dock1")
d2 = Dock("Dock2")
area.addDock(d1, 'bottom')
area.addDock(d2, 'bottom', d1)

w1 = pg.PlotWidget(title="Dock 1 plot")
w1.plot(np.random.normal(size=100))
d1.addWidget(w1)

w2 = pg.PlotWidget(title="Dock 2 plot")
w2.plot(np.random.normal(size=100))
d2.addWidget(w2)

win.show()

## Start Qt event loop unless running in interactive mode or using pyside.
if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

这个问题有一个跟进here，另一个答案是这个问题。

Answer 1

我们需要使用 sigRangeChanged 信号并将其连接到一个插槽，问题是另一个项目的范围变化会产生信号 sigRangeChanged 等等，从而产生无限循环，要解决这个问题，您必须在进行修改之前断开这些信号并将它们重新连接到决赛。

w1.sigRangeChanged.connect(onSigRangeChanged)
w2.sigRangeChanged.connect(onSigRangeChanged)

def onSigRangeChanged(r):
    w1.sigRangeChanged.disconnect(onSigRangeChanged)
    w2.sigRangeChanged.disconnect(onSigRangeChanged)
    if w1 == r:
        w2.setRange(xRange=r.getAxis('bottom').range)
    elif w2 == r:
        w1.setRange(xRange=r.getAxis('bottom').range)

    w1.sigRangeChanged.connect(onSigRangeChanged)
    w2.sigRangeChanged.connect(onSigRangeChanged)

例子：

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


def onSigRangeChanged(r):
    w1.sigRangeChanged.disconnect(onSigRangeChanged)
    w2.sigRangeChanged.disconnect(onSigRangeChanged)
    if w1==r:
        w2.setRange(xRange=r.getAxis('bottom').range)
    elif w2 == r:
        w1.setRange(xRange=r.getAxis('bottom').range)

    w1.sigRangeChanged.connect(onSigRangeChanged)
    w2.sigRangeChanged.connect(onSigRangeChanged)

app = QtGui.QApplication(sys.argv)

win = QtGui.QMainWindow()
area = DockArea()
win.setCentralWidget(area)
win.resize(1000,500)
win.setWindowTitle('pyqtgraph example: dockarea')


d1 = Dock("Dock1")
d2 = Dock("Dock2")
area.addDock(d1, 'bottom')
area.addDock(d2, 'bottom', d1)

w1 = pg.PlotWidget(title="Dock 1 plot")
it=w1.plot(np.random.normal(size=100))

d1.addWidget(w1)

w2 = pg.PlotWidget(title="Dock 2 plot")
w2.plot(np.random.normal(size=100))
d2.addWidget(w2)

w1.sigRangeChanged.connect(onSigRangeChanged)
w2.sigRangeChanged.connect(onSigRangeChanged)

win.show()

sys.exit(app.exec_())

Answer 2

更好的是，

可以使用 blockSignals，而不是断开然后重新连接信号。

这是同步任意数量绘图的通用方法：

syncedPlots = [w1, w2, w3] # put as many plots as you wish

def onSigRangeChanged(r):
    for g in syncedPlots:
        if g !=r :
            g.blockSignals(True)
            g.setRange(xRange=r.getAxis('bottom').range)
            g.blockSignals(False)

for g in syncedPlots:
     g.sigRangeChanged.connect(onSigRangeChanged)

Answer 3

这个问题有一个更好的答案：

我们可以通过 w2.setXLink(w1) 直接链接轴刻度，而不是连接到 sigRangeChanged 事件。