I am just learning OOP and PySide. I have created a code as below. The application doesn't do anything much (it's a development project in learning stages).
import numpy as np
import sys
from qtpy.QtWidgets import (
QWidget,
QMainWindow,
QVBoxLayout,
QAction,
QMenu,
QLabel,
QApplication,
QMessageBox,
QDesktopWidget,
)
from qtpy.QtCore import Qt, Slot, QPoint, QObject
from qwt import (
QwtPlot,
QwtPlotMarker,
QwtPlotGrid,
QwtLegend,
QwtPlotCurve,
QwtLegendData,
)
class contexMenuHelper(QObject):
def __init__(self, plot, legend, legendItem):
super(contexMenuHelper, self).__init__()
self.plot = plot
self.legend = legend
self.legendItem = legendItem
@Slot(QPoint)
def contextMenuSlot(self, pos):
context = QMenu(self.legendItem)
context.addAction(QAction("Delete", self))
context.exec_(self.legendItem.mapToGlobal(pos))
class Plot(QwtPlot, QMainWindow):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.setAxisTitle(QwtPlot.xBottom, "X-axis")
self.setAxisTitle(QwtPlot.yLeft, "Y-axis")
self.setCanvasBackground(Qt.white)
self.setAxisScale(QwtPlot.yLeft, -2, 2)
QwtPlotGrid.make(self, color=Qt.lightGray, width=0, style=Qt.DotLine)
legend = QwtLegend()
legend.setDefaultItemMode(QwtLegendData.Checkable)
self.insertLegend(legend, QwtPlot.RightLegend)
x = np.arange(-5.0, 5.0, 0.1)
curves = []
curves.append(
QwtPlotCurve.make(
x, np.cos(x), "Cosinus", self, linecolor="red", antialiased=True
)
)
curves.append(
QwtPlotCurve.make(
x, np.sin(x), "Sinus", self, linecolor="blue", antialiased=True
)
)
self.helpers = dict()
for a in curves:
legend.legendWidget(a).setContextMenuPolicy(Qt.CustomContextMenu)
h = contexMenuHelper(self, legend, legend.legendWidget(a))
self.helpers[a] = h
legend.legendWidget(a).customContextMenuRequested.connect(h.contextMenuSlot)
QwtPlotMarker.make(
align=Qt.AlignRight | Qt.AlignTop,
linestyle=QwtPlotMarker.HLine,
color="black",
plot=self,
)
for keys, value in self.helpers.items():
print(keys)
print(value)
# insert a vertical marker at x = 0
QwtPlotMarker.make(
align=Qt.AlignRight | Qt.AlignTop,
linestyle=QwtPlotMarker.VLine,
color="black",
plot=self,
)
legend.checked.connect(self.showCurve)
self.replot()
@Slot(object, bool, int)
def showCurve(self, obj, condition, num):
obj.setVisible(not condition)
self.replot()
@Slot(object, bool, int)
def __del__(self, obj, condition):
print('Destructor called, vehicle deleted.')
class SimplePlot(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
layout = QVBoxLayout()
self.setLayout(layout)
plot = Plot()
plot.setTitle("Trigonometric")
self.setWindowTitle("Trigonometric")
layout.addWidget(plot)
label = QLabel("Press the legend to en/disable a curve")
layout.addWidget(label)
self.center()
def center(self):
qr = self.frameGeometry()
cp = QDesktopWidget().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
def closeEvent(self, event):
reply = QMessageBox.question(
self,
"Message",
"Are you sure to quit?",
QMessageBox.Yes | QMessageBox.No,
QMessageBox.No,
)
if reply == QMessageBox.Yes:
event.accept()
else:
event.ignore()
if __name__ == "__main__":
app = QApplication(sys.argv)
window = SimplePlot()
window.show()
window.resize(800, 600)
sys.exit(app.exec_())
I made the active legend and the context menu:
I want to make it so that when I select "Delete" from the context menu, the corresponding function waveform in the graph and the corresponding object in the legend will be deleted.
I have implemented it as follows. Perhaps someone will find my thinking useful. It works correctly and as I expected although there is a tiny error in the operation itself .
Do you see what error I mean?