Question

我查看了这个版本的pyqtgraph

git clone https://github.com/3rdcycle/pyqtgraph.git
git checkout origin/date-axis-item
pip uninstall pyqtgraph
python setup.py install

然后我运行这个程序。它看起来运行正常，除了我的x轴时间戳进入和退出视图而我没有做任何事情。不确定这是否是此程序或DateAxisItem中的错误。此外，毫秒总是100的倍数。例如，我看到00：00：00：900,00：00：01：200，但从不00：00：00：042？

# -*- coding: utf-8 -*-
"""
Created on Thu May 14 21:09:44 2015

@author: idf
"""

from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg
from PySide.QtCore import QTime, QTimer
from collections import deque

t = QTime()
t.start()
data = deque(maxlen=20)

class TimeAxisItem(pg.DateAxisItem):
    def __init__(self, *args, **kwargs):
        super(TimeAxisItem, self).__init__(*args, **kwargs)

    def tickStrings(self, values, scale, spacing):
        return [QTime().addMSecs(value).toString('hh:mm:ss.zzz') for value in values]

app = QtGui.QApplication([])

win = pg.GraphicsWindow(title="Basic time-plotting examples")
win.resize(1000,600)

plot = win.addPlot(title='Timed data', axisItems={'bottom': TimeAxisItem(orientation='bottom')})
curve = plot.plot()

def update():
    global plot, curve, data
    data.append({'x': t.elapsed(), 'y': np.random.randint(0, 100)})
    x = [item['x'] for item in data]
    y = [item['y'] for item in data]
    curve.setData(x=x, y=y)

tmr = QTimer()
tmr.timeout.connect(update)
tmr.start(800)

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

Answer 1

我不确定您的DateAxisItem会发生什么。如您所知，它尚未合并到PyQtGraph的主要开发分支中。但是，对于您的特定应用程序，从头开始并定义您自己的TimeAxisItem可能更容易？如果从以下代码开始，将缺少哪些功能？

class TimeAxisItem(AxisItem):

    def __init__(self, orientation, **kwargs):
        super().__init__(orientation, **kwargs)

    def tickStrings(self, values, scale, spacing):
        return [self.get_tick(v, spacing) for v in values]

    def get_tick(self, ts, spacing):
        dt = datetime.datetime.fromtimestamp(ts)
        # Here you can decide on the accuracy of the time data
        # displayed depending on the spacing.
        if spacing > 60:
            return "%02d:%02d" % (dt.hour, dt.minute)
        else:
            return "%02d:%02d:%02d" % (dt.hour, dt.minute, dt.second)

DateAxisItem有时会变得不可见

1 个答案: