source: sasview/src/sas/qtgui/Plotting/SlicerParameters.py @ 0239237

"""
Allows users to modify the box slicer parameters.
"""
import numpy
import functools

from PyQt5 import QtCore
from PyQt5 import QtGui
from PyQt5 import QtWidgets

import sas.qtgui.Utilities.GuiUtils as GuiUtils

# Local UI
from sas.qtgui.UI import main_resources_rc
from sas.qtgui.Plotting.UI.SlicerParametersUI import Ui_SlicerParametersUI

class SlicerParameters(QtWidgets.QDialog, Ui_SlicerParametersUI):
    """
    Interaction between the QTableView and the underlying model,
    passed from a slicer instance.
    """
    closeWidgetSignal = QtCore.pyqtSignal()
    def __init__(self, model=None, validate_method=None):
        super(SlicerParameters, self).__init__()

        self.setupUi(self)

        assert isinstance(model, QtGui.QStandardItemModel)

        self.model = model
        self.validate_method = validate_method

        # Define a proxy model so cell enablement can be finegrained.
        self.proxy = ProxyModel(self)
        self.proxy.setSourceModel(self.model)

        # Set the proxy model for display in the Table View.
        self.lstParams.setModel(self.proxy)

        # Disallow edit of the parameter name column.
        self.lstParams.model().setColumnReadOnly(0, True)

        # Specify the validator on the parameter value column.
        self.delegate = EditDelegate(self, validate_method=self.validate_method)
        self.lstParams.setItemDelegate(self.delegate)
        self.delegate.refocus_signal.connect(self.onFocus)

        # Display Help on clicking the button
        self.buttonBox.button(QtWidgets.QDialogButtonBox.Help).clicked.connect(self.onHelp)

        # Close doesn't trigger closeEvent automatically, so force it
        self.buttonBox.button(QtWidgets.QDialogButtonBox.Close).clicked.connect(functools.partial(self.closeEvent, None))

        # Disable row number display
        self.lstParams.verticalHeader().setVisible(False)
        self.lstParams.setAlternatingRowColors(True)
        self.lstParams.setSizePolicy(QtWidgets.QSizePolicy.MinimumExpanding, QtWidgets.QSizePolicy.Expanding)

        # Header properties for nicer display
        header = self.lstParams.horizontalHeader()
        header.setSectionResizeMode(QtWidgets.QHeaderView.Stretch)
        header.setStretchLastSection(True)

    def onFocus(self, row, column):
        """ Set the focus on the cell (row, column) """
        selection_model = self.lstParams.selectionModel()
        selection_model.select(self.model.index(row, column), QtGui.QItemSelectionModel.Select)
        self.lstParams.setSelectionModel(selection_model)
        self.lstParams.setCurrentIndex(self.model.index(row, column))

    def setModel(self, model):
        """ Model setter """
        self.model = model
        self.proxy.setSourceModel(self.model)

    def keyPressEvent(self, event):
         key = event.key()

         if key == QtCore.Qt.Key_Escape:
            self.closeWidgetSignal.emit()

    def closeEvent(self, event):
        """
        Overwritten close widget method in order to send the close
        signal to the parent.
        """
        self.closeWidgetSignal.emit()
        if event:
            event.accept()

    def onHelp(self):
        """
        Display generic data averaging help
        """
        url = "/user/qtgui/MainWindow/graph_help.html#d-data-averaging"
        GuiUtils.showHelp(url)

class ProxyModel(QtCore.QIdentityProxyModel):
    """
    Trivial proxy model with custom column edit flag
    """
    def __init__(self, parent=None):
        super(ProxyModel, self).__init__(parent)
        self._columns = set()

    def columnReadOnly(self, column):
        '''Returns True if column is read only, false otherwise'''
        return column in self._columns

    def setColumnReadOnly(self, column, readonly=True):
        '''Add/removes a column from the readonly list'''
        if readonly:
            self._columns.add(column)
        else:
            self._columns.discard(column)

    def flags(self, index):
        '''Sets column flags'''
        flags = super(ProxyModel, self).flags(index)
        if self.columnReadOnly(index.column()):
            flags &= ~QtCore.Qt.ItemIsEditable
        return flags

class PositiveDoubleEditor(QtWidgets.QLineEdit):
    # a signal to tell the delegate when we have finished editing
    editingFinished = QtCore.Signal()

    def __init__(self, parent=None):
            # Initialize the editor object
            super(PositiveDoubleEditor, self).__init__(parent)
            self.setAutoFillBackground(True)
            validator = GuiUtils.DoubleValidator()
            # Don't use the scientific notation, cause 'e'.
            validator.setNotation(GuiUtils.DoubleValidator.StandardNotation)

            self.setValidator(validator)

    def focusOutEvent(self, event):
            # Once focus is lost, tell the delegate we're done editing
            self.editingFinished.emit()


class EditDelegate(QtWidgets.QStyledItemDelegate):
    refocus_signal = QtCore.pyqtSignal(int, int)
    def __init__(self, parent=None, validate_method=None):
        super(EditDelegate, self).__init__(parent)
        self.editor = None
        self.index = None
        self.validate_method = validate_method

    def createEditor(self, parent, option, index):
        # Creates and returns the custom editor object we will use to edit the cell
        if not index.isValid():
            return 0

        result = index.column()
        if result==1:
                self.editor = PositiveDoubleEditor(parent)
                self.index = index
                return self.editor
        else:
                return QtWidgets.QStyledItemDelegate.createEditor(self, parent, option, index)

    def setModelData(self, editor, model, index):
        """
        Custom version of the model update, rejecting bad values
        """
        self.index = index

        # Find out the changed parameter name and proposed value
        new_value = GuiUtils.toDouble(self.editor.text())
        param_name = model.sourceModel().item(index.row(),0).text()

        validated = True
        if self.validate_method:
            # Validate the proposed value in the slicer
            value_accepted = self.validate_method(param_name, new_value)

        if value_accepted:
            # Update the model only if value accepted
            return super(EditDelegate, self).setModelData(editor, model, index)