### Navigation

- index
- modules |
- SamSifter 0.5.6 documentation »
- Module code »

# Source code for samsifter.gui.composites

    # -*- coding: utf-8 -*-
    """
    Composed widgets used to visualize filter parameters in a vertical form layout.

    .. moduleauthor:: Florian Aldehoff <faldehoff@student.uni-tuebingen.de>
    """

    import os
    from os.path import expanduser, isfile

    """ Qt4 imports """
    from PyQt4.QtGui import (
        QWidget, QSlider, QHBoxLayout, QLineEdit, QPushButton, QFileDialog, QIcon,
        QRadioButton, QButtonGroup, QLabel, QDoubleSpinBox
    )
    from PyQt4.QtCore import Qt

    class SliderSpinboxCombo(QWidget):
        """
        Slider coupled with Spinbox for setting numerical values between a minimum
        and maximum.
        """

        def __init__(self, parent=None, minimum=0.0, maximum=100.0, default=0.0,
                     precision=2):
            """Initialize a new instance of a SliderSpinboxCombo widget.

            Parameters
            ----------
            parent : QWidget, optional
                Parent Qt4 widget this widget belongs to, defaults to None.
            minimum : float, optional
                Minimum value of the permitted value range, defaults to 0.
            maximum : float, optional
                Maximum value of the permitted value range, defaults to 100.
            default : float, optional
                Default used as preset value in slider and spinbox, defaults to 0.
            precision : int, optional
                Number of decimals for the selected value, defaults to 2
                (eg. ``0.12`` for precision 2 vs. ``0.1`` for precision 1).
            """
            super(QWidget, self).__init__(parent)
            self.minimum = minimum
            self.maximum = maximum
            self.default = default
            if default < minimum:
                self.value = minimum
            elif default > maximum:
                self.value = maximum
            else:
                self.value = default
            self.precision = precision

            self.slider = QSlider(self)
            self.slider.setOrientation(Qt.Horizontal)
            self.slider.setTickPosition(QSlider.TicksBelow)
            self.slider.setObjectName("slider")
            self.slider.setMinimum(0)
            self.slider.setMaximum(10000)
            self.slider.setSingleStep(1)
            self.slider.setTickInterval(max(1000,
                                            10000 / (self.maximum - self.minimum)))
            self.slider.setValue(self.normalize(self.value))

            self.spinner = QDoubleSpinBox()
            self.spinner.setDecimals(self.precision)
            self.spinner.setSingleStep(10 ** (-1 * self.precision))
            self.spinner.setMinimum(self.minimum)
            self.spinner.setMaximum(self.maximum)
            self.spinner.setValue(self.value)
            self.spinner.setObjectName("spinner")

            self.spinner.valueChanged.connect(self.on_spinner_value_change)
            self.slider.valueChanged.connect(self.on_slider_value_change)

            layout = QHBoxLayout(self)
            layout.setMargin(0)
            layout.addWidget(self.slider)
            layout.addWidget(self.spinner)
            self.setLayout(layout)

        def on_spinner_value_change(self, value):
            """Handle changes to the spinbox value.

            Parameters
            ----------
            value : float
                New value of spinbox widget.
            """
            self.value = value
            self.slider.setValue(self.normalize(value))

        def on_slider_value_change(self, value):
            """Handle changes to the slider value.

            Parameters
            ----------
            value : float
                New value of slider widget.
            """
            self.spinner.setValue(self.denormalize(value))

        def normalize(self, value):
            """Translates absolute spinbox values to normalized slider values.

            Parameters
            ----------
            value : float
                Current value of spinbox widget.
            """
            delta = self.maximum - self.minimum
            assert delta > 0
            normalized = ((value - self.minimum) * (10000)) / delta
            return normalized

        def denormalize(self, value):
            """Translates normalized slider values to absolute spinbox values.

            Parameters
            ----------
            value : float
                Current value of slider widget.
            """
            delta = self.maximum - self.minimum
            assert delta > 0
            denormalized = ((value * delta) / (10000)) + self.minimum
            return denormalized

        """ Getters & Setters """

        def get_value(self):
            return self.value

        def set_value(self, value):
            if self.precision == 0:
                self.value = int(value)
            else:
                self.value = value
            # no need to set slider, it is coupled to spinbox
            self.spinner.setValue(value)

    class FileChooser(QWidget):
        """
        Combined LineEdit and Pushbutton for standard file dialog to select a file.
        """

        def __init__(self, parent=None, suffix_string="CSV files (*.csv *.CSV)"):
            """Initialize a new instance of a FileChooser.

            Parameters
            ----------
            parent : QWidget, optional
                Parent Qt4 widget this widget belongs to, defaults to None.
            suffix_string : str, optional
                String specifying the default file extensions to be displayed in
                the OS-specific file selection dialog. Should contain a short
                file type description and a list of space-separated file extensions
                with asterisks. The default value of ``CSV files (*.csv *.CSV)``
                sets the dialog to display CSV files only.
            """
            super(QWidget, self).__init__(parent)
            self.suffix_string = suffix_string
            self.filename = None

            self.lineedit = QLineEdit(self)

            self.button = QPushButton(QIcon.fromTheme('document-open'),
                                      "Select file...", self)
            self.button.pressed.connect(self.show_dialog)

            layout = QHBoxLayout(self)
            layout.setMargin(0)
            layout.addWidget(self.lineedit)
            layout.addWidget(self.button)
            self.setLayout(layout)

        def highlight(self, boolean=True):
            """Indicates errors or pending actions by changing background color.

            Parameters
            ----------
            boolean : bool, optional
                Enable highlighting of the QlineEdit widget, defaults to True.
            """
            css = "QLineEdit {background-color: #ffe08c;}"
            if boolean:
                self.lineedit.setStyleSheet(css)
            else:
                self.lineedit.setStyleSheet(None)

        def show_dialog(self):
            """Opens OS-specific file selection dialog in user's home directory."""
            dialog = QFileDialog()
            dialog.setDefaultSuffix(self.suffix_string)
            fname = dialog.getOpenFileName(self, 'Open file',
                                           expanduser("~"),
                                           self.suffix_string + ";;All files (*)"
                                           )
            self.lineedit.setText(fname)
            self.set_filename(fname)

        """ Getters & Setters """

        def get_suffix_string(self):
            return self.suffix_string

        def set_suffix_string(self, suffix_string):
            self.suffix_string = suffix_string

        def get_filename(self):
            return self.filename

        def set_filename(self, filename):
            """Sets a new filename.

            Maintains cursor position and validates the input on the fly. Tooltips
            and highlights of the QLineEdit widget are set to help resolving
            potential errors.

            Parameters
            ----------
            filename : str
                Path to existing and readable input file.
            """

            self.filename = filename

            # validate file
            if not (isfile(filename) and os.access(filename, os.R_OK)):
                self.highlight(True)
                self.lineedit.setToolTip(
                    "file either not existing or not readable"
                )
            else:
                self.highlight(False)
                self.lineedit.setToolTip(None)

            cursor = self.lineedit.cursorPosition()
            self.lineedit.setText(filename)
            self.lineedit.setCursorPosition(cursor)

    class OptionSwitcher(QWidget):
        """
        Group of coupled radio buttons to choose between exclusive options.

        Defaults to a simple True or False switch but arbitrary lists of options
        are supported and their options internally referenced by list indices. The
        first option in a list is considered the default value.
        """
        def __init__(self, parent=None, options=[True, False]):
            """Initialize a new instance of an optionSwitcher.

            Parameters
            ----------
            parent : QWidget, optional
                Parent Qt4 widget this widget belongs to, defaults to None.
            options : list
                Arbitrary list of options to choose between. Supports any data type
                like numbers, strings, etc. However the list objects have to
                provide short string representations to be properly displayed in
                the GUI form. Defaults to a list with the two options True or
                False.

            """
            super(QWidget, self).__init__(parent)
            self.options = options
            self.current_index = 0
            self.group = QButtonGroup(self)

            layout = QHBoxLayout(self)
            layout.setMargin(0)

            for idx, option in enumerate(self.options):
                lbl = QLabel(str(option), self)
                btn = QRadioButton(self)
                btn.setChecked(idx == self.current_index)
                self.group.addButton(btn, idx)
                layout.addWidget(btn)
                layout.addWidget(lbl)

            self.setLayout(layout)

        """ Getters & Setters """

        def get_options(self):
            return self.options

        def set_options(self, options):
            self.options = options

        def get_current_index(self):
            return self.current_index

        def set_current_index(self, index):
            if 0 <= index and index < len(self.options):
                self.current_index = index
                self.group.button(index).setChecked(True)

### Navigation

- index
- modules |
- SamSifter 0.5.6 documentation »
- Module code »