Mastering GUI Programming with Python

Building the memory chart

We'll start this chart view object just like we started the others in the previous sections:

class MemoryChartView(qtch.QChartView):    chart_title = "Memory Usage"    num_data_points = 50    def __init__(self):        super().__init__()        chart = qtch.QChart(title=self.chart_title)        self.setChart(chart)        series = qtch.QStackedBarSeries()        chart.addSeries(series)        self.phys_set = qtch.QBarSet("Physical")        self.swap_set = qtch.QBarSet("Swap")        series.append(self.phys_set)        series.append(self.swap_set)

This class starts in a similar way to our disk usage chart – by subclassing QChartView, defining a chart, defining a series, and then defining some bar sets. This time, however, we are going to use QStackedBarSeries. The stacked bar is just ...