Question

我不知道如何操作要缩放的绘图该图实时绘制随机函数我想实时缩放指定区域的情节此代码是pyqtgraph中的示例代码。此代码适用于固定数据情节是否无法实时移动以进行缩放？你能帮帮我吗？

# -*- coding: utf-8 -*-

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

win = pg.GraphicsWindow()
win.setWindowTitle('Scroll and Zoomed Plot')

plotScroll = win.addPlot()
plotScroll.setDownsampling(mode='peak')
plotScroll.setClipToView(True)
curveScroll = plotScroll.plot()

dataRnd = np.empty(100)
ptrDataRnd = 0

def updateScroll():
    global dataRnd, ptrDataRnd
    dataRnd[ptrDataRnd] = np.random.normal()
    ptrDataRnd += 1
    if ptrDataRnd >= dataRnd.shape[0]:
        tmp = dataRnd
        dataRnd = np.empty(dataRnd.shape[0] * 2)
        dataRnd[:tmp.shape[0]] = tmp
    curveScroll.setData(dataRnd[:ptrDataRnd])

LinRegionItem = pg.LinearRegionItem([0,100])
LinRegionItem.setZValue(-10)
plotScroll.addItem(LinRegionItem)

win.nextRow()

plotZoom = win.addPlot(title="Zoomed graph for Random plot ")
plotZoom.plot(dataRnd, pen=(255,255,255,200))

def updatePlot():
    plotZoom.setXRange(*LinRegionItem.getRegion(), padding=0)
def updateRegion():
    LinRegionItem.setRegion(plotZoom.getViewBox().viewRange()[0])
LinRegionItem.sigRegionChanged.connect(updatePlot)
plotZoom.sigXRangeChanged.connect(updateRegion)
updatePlot()

# update all plots
def update():
    updateScroll()

timer = pg.QtCore.QTimer()
timer.timeout.connect(update)
timer.start(50)

## 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_()

Answer 1

我通过添加标记为“＃added ..”的“updateZoom（）”函数解决了这个问题修订的代码如下所示并且下面的控制台消息发生了另一个问题是什么原因？
你能帮帮我吗？

控制台消息：

C：\ Python27 \ lib \ site-packages \ pyqtgraph \ graphicsItems \ AxisItem.py:841：RuntimeWarning：在double_scalars中遇到溢出   xScale = -bounds.height（）/ dif
C：\ Python27 \ lib \ site-packages \ pyqtgraph \ graphicsItems \ AxisItem.py:847：RuntimeWarning：double_scalars中遇到无效值   xRange = [x * xScale - 自我范围中x的偏移量]
C：\ Python27 \ lib \ site-packages \ pyqtgraph \ graphicsItems \ AxisItem.py:871:RuntimeWarning：double_scalars中遇到无效值   x =（v * xScale） - 偏移量

处理完成，退出代码为0

# -*- coding: utf-8 -*-

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

app = QtGui.QApplication([])
gui = QtGui.QMainWindow()
area = DockArea()
gui.setCentralWidget(area)
gui.resize(1000,500)
gui.setWindowTitle("Scroll and Zoomed Plot")

dockCtrl = Dock("Plot Control", size=(200, 500))
dockCtrl.setFixedWidth(200)
area.addDock(dockCtrl, 'left')
winCtrl = pg.LayoutWidget()
dockCtrl.addWidget(winCtrl)

restartBttn = QtGui.QPushButton("Restart")
restartBttn.setMinimumSize(100,40)
winCtrl.addWidget(restartBttn)

def RestartPlot():
    global dataRnd,ptrDataRnd
    timer.stop()
    dataRnd = np.empty(100)
    ptrDataRnd = 0
    timer.start(50)

restartBttn.clicked.connect(RestartPlot)

dockScroll = Dock("Scrolling plot", size=(800,250))
area.addDock(dockScroll, 'right')
winScroll = pg.GraphicsWindow()
dockScroll.addWidget(winScroll)

dockZoom = Dock("Zoomed plot", size=(800,250))
area.addDock(dockZoom, 'right')
winZoom = pg.GraphicsWindow()
dockZoom.addWidget(winZoom)
area.moveDock(dockScroll, 'top', dockZoom)

plotScroll = winScroll.addPlot()
plotScroll.setDownsampling(mode='peak')
plotScroll.setClipToView(True)
curveScroll = plotScroll.plot()

dataRnd = np.empty(100)
ptrDataRnd = 0

def updateScroll():
    global dataRnd, ptrDataRnd
    dataRnd[ptrDataRnd] = np.random.normal()
    ptrDataRnd += 1
    if ptrDataRnd >= dataRnd.shape[0]:
        tmp = dataRnd
        dataRnd = np.empty(dataRnd.shape[0] * 2)
        dataRnd[:tmp.shape[0]] = tmp
    curveScroll.setData(dataRnd[:ptrDataRnd])

LinRegionItem = pg.LinearRegionItem([0,100])
LinRegionItem.setZValue(-10)
plotScroll.addItem(LinRegionItem)

plotZoom = winZoom.addPlot()
curveZoom = plotZoom.plot(dataRnd, pen=(255,255,255,200))

def updatePlot():
    plotZoom.setXRange(*LinRegionItem.getRegion(), padding=0)
def updateRegion():
    LinRegionItem.setRegion(plotZoom.getViewBox().viewRange()[0])

LinRegionItem.sigRegionChanged.connect(updatePlot)
plotZoom.sigXRangeChanged.connect(updateRegion)
updatePlot()

# added lines
def updateZoom():
    curveZoom.setData(dataRnd[:ptrDataRnd])

# update all plots
def update():
    updateScroll()
    # added line
    updateZoom()

timer = pg.QtCore.QTimer()
timer.timeout.connect(update)
timer.start(50)

gui.show()

if __name__ == '__main__':
    import sys

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

Answer 2

我也解决了这个问题。我修改了代码，如下图所示。

修订前：

curveZoom.setData(dataRnd[:ptrDataRnd])

修改后的代码：

curveZoom.setData(dataRnd[0:ptrDataRnd])

我想知道numpy数组的约定。 “dataRnd [：ptrDataRnd]”的含义是指定从0th到ptrDataRnd的范围。我错了吗？请说实话。

如何在pyqtgraph中缩放图

2 个答案: