How to put dates on the x qwtplot axis in python? - python-2.7

Question

I visited tons of pages in the internet but only have examples in C and I dont understand how to make this in python. Can someone helpme.
I use Pyqt designer and Python 2.7. I need plot data whith dates on a GUI using qwtplot.

Answer 1

you need a QwtScaleDraw class e.g.:
class TimeScaleDraw(QwtScaleDraw):
def __init__(self, baseTime, *args):
QwtScaleDraw.__init__(self, *args)
self.baseTime = baseTime
def label(self, value):
upTime = self.baseTime.addSecs(int(value))
return QwtText(upTime.toString())
then you modify your x axis with this code:
self.setAxisScaleDraw(
QwtPlot.xBottom, TimeScaleDraw(self.cpuStat.upTime()))
where self's base class is QwtPlot. cpuStat.upTime() returns a QTime instance. value represents one of your time data points. This code is from the cpuDemo example code.
To get this example cpuDemo working with python xy 2.7. make these changes to the imported modules:
import os
import sys
import numpy as np
from PyQt4.QtGui import (QApplication, QColor, QBrush, QWidget, QVBoxLayout,
QLabel)
from PyQt4.QtCore import QRect, QTime
from PyQt4.QtCore import Qt
from PyQt4.Qwt5 import (QwtPlot, QwtPlotMarker, QwtScaleDraw, QwtLegend, QwtPlotCurve,
QwtPlotItem, QwtText)#, QwtLegendData
then comment out all legend lines.
I adopted this code to use the QDateTime class. Here is a snippet:
from PyQt4 import QtCore, QtGui, Qt
from PyQt4 import Qwt5
class TimeScaleDraw(Qwt5.QwtScaleDraw):
def __init__(self, *args):
Qwt5.QwtScaleDraw.__init__(self,unixBaseTime *args)
self.basetime=unixBaseTime
self.fmt='h:mm\nd-MMM-yyyy'
def label(self, value):
dt = QtCore.QDateTime.fromMSecsSinceEpoch((value+self.basetime))
return Qwt5.QwtText(dt.toString(self.fmt))
...
class Ui_TabWidget(object):
def setupUi(self, TabWidget):
self.qwtPlot = Qwt5.QwtPlot()
self.qwtPlot.setAxisScaleDraw(Qwt5.QwtPlot.xBottom, TimeScaleDraw(unixBaseTime))
admire pretty picture