示例#1
0
class SelectFilter(QWidget):
    """
    Construct and read combo boxes for selecting the filter, consisting of the
    following hierarchy:

    1. Response Type rt (LP, HP, Hilbert, ...)
    2. Filter Type ft (IIR, FIR, CIC ...)
    3. Filter Class (Butterworth, ...)

    Every time a combo box is changed manually, the filter tree for the selected
    response resp. filter type is read and the combo box(es) further down in
    the hierarchy are populated according to the available combinations.

    sig_tx({'filt_changed'}) is emitted and propagated to input_filter_specs.py
    where it triggers the recreation of all subwidgets.
    """
    sig_tx = pyqtSignal(object)  # outgoing
    from pyfda.libs.pyfda_qt_lib import emit

    def __init__(self, parent=None):
        super(SelectFilter, self).__init__(parent)

        self.fc_last = ''  # previous filter class

        self._construct_UI()

        self._set_response_type()  # first time initialization

    def _construct_UI(self):
        """
        Construct UI with comboboxes for selecting filter:

        - cmbResponseType for selecting response type rt (LP, HP, ...)

        - cmbFilterType for selection of filter type (IIR, FIR, ...)

        - cmbFilterClass for selection of design design class (Chebyshev, ...)

        and populate them from the "filterTree" dict during the initial run.
        Later, calling _set_response_type() updates the three combo boxes.

        See filterbroker.py for structure and content of "filterTree" dict

        """
        # ----------------------------------------------------------------------
        # Combo boxes for filter selection
        # ----------------------------------------------------------------------
        self.cmbResponseType = QComboBox(self)
        self.cmbResponseType.setObjectName("comboResponseType")
        self.cmbResponseType.setToolTip("Select filter response type.")
        self.cmbFilterType = QComboBox(self)
        self.cmbFilterType.setObjectName("comboFilterType")
        self.cmbFilterType.setToolTip(
            "<span>Choose filter type, either recursive (Infinite Impulse Response) "
            "or transversal (Finite Impulse Response).</span>")
        self.cmbFilterClass = QComboBox(self)
        self.cmbFilterClass.setObjectName("comboFilterClass")
        self.cmbFilterClass.setToolTip("Select the filter design class.")

        # Adapt comboboxes size dynamically to largest element
        self.cmbResponseType.setSizeAdjustPolicy(QComboBox.AdjustToContents)
        self.cmbFilterType.setSizeAdjustPolicy(QComboBox.AdjustToContents)
        self.cmbFilterClass.setSizeAdjustPolicy(QComboBox.AdjustToContents)

        # ----------------------------------------------------------------------
        # Populate combo box with initial settings from fb.fil_tree
        # ----------------------------------------------------------------------
        # Translate short response type ("LP") to displayed names ("Lowpass")
        # (correspondence is defined in pyfda_rc.py) and populate rt combo box
        #
        rt_list = sorted(list(fb.fil_tree.keys()))

        for rt in rt_list:
            try:
                self.cmbResponseType.addItem(rc.rt_names[rt], rt)
            except KeyError as e:
                logger.warning(
                    f"KeyError: {e} has no corresponding full name in rc.rt_names."
                )
        idx = self.cmbResponseType.findData('LP')  # find index for 'LP'

        if idx == -1:  # Key 'LP' does not exist, use first entry instead
            idx = 0

        self.cmbResponseType.setCurrentIndex(idx)  # set initial index
        rt = qget_cmb_box(self.cmbResponseType)

        for ft in fb.fil_tree[rt]:
            self.cmbFilterType.addItem(rc.ft_names[ft], ft)
        self.cmbFilterType.setCurrentIndex(0)  # set initial index
        ft = qget_cmb_box(self.cmbFilterType)

        for fc in fb.fil_tree[rt][ft]:
            self.cmbFilterClass.addItem(fb.filter_classes[fc]['name'], fc)
        self.cmbFilterClass.setCurrentIndex(0)  # set initial index

        # ----------------------------------------------------------------------
        # Layout for Filter Type Subwidgets
        # ----------------------------------------------------------------------

        layHFilWdg = QHBoxLayout()  # container for filter subwidgets
        layHFilWdg.addWidget(self.cmbResponseType)  # LP, HP, BP, etc.
        layHFilWdg.addStretch()
        layHFilWdg.addWidget(self.cmbFilterType)  # FIR, IIR
        layHFilWdg.addStretch()
        layHFilWdg.addWidget(self.cmbFilterClass)  # bessel, elliptic, etc.

        # ----------------------------------------------------------------------
        # Layout for dynamic filter subwidgets (empty frame)
        # ----------------------------------------------------------------------
        # see Summerfield p. 278
        self.layHDynWdg = QHBoxLayout()  # for additional dynamic subwidgets

        # ----------------------------------------------------------------------
        # Filter Order Subwidgets
        # ----------------------------------------------------------------------
        self.lblOrder = QLabel("<b>Order:</b>")
        self.chkMinOrder = QCheckBox("Minimum", self)
        self.chkMinOrder.setToolTip(
            "<span>Minimum filter order / # of taps is determined automatically.</span>"
        )
        self.lblOrderN = QLabel("<b><i>N =</i></b>")
        self.ledOrderN = QLineEdit(str(fb.fil[0]['N']), self)
        self.ledOrderN.setToolTip("Filter order (# of taps - 1).")

        # --------------------------------------------------
        #  Layout for filter order subwidgets
        # --------------------------------------------------
        layHOrdWdg = QHBoxLayout()
        layHOrdWdg.addWidget(self.lblOrder)
        layHOrdWdg.addWidget(self.chkMinOrder)
        layHOrdWdg.addStretch()
        layHOrdWdg.addWidget(self.lblOrderN)
        layHOrdWdg.addWidget(self.ledOrderN)

        # ----------------------------------------------------------------------
        # OVERALL LAYOUT (stack standard + dynamic subwidgets vertically)
        # ----------------------------------------------------------------------
        self.layVAllWdg = QVBoxLayout()
        self.layVAllWdg.addLayout(layHFilWdg)
        self.layVAllWdg.addLayout(self.layHDynWdg)
        self.layVAllWdg.addLayout(layHOrdWdg)

        # ==============================================================================
        frmMain = QFrame(self)
        frmMain.setLayout(self.layVAllWdg)

        layHMain = QHBoxLayout()
        layHMain.addWidget(frmMain)
        layHMain.setContentsMargins(*rc.params['wdg_margins'])

        self.setLayout(layHMain)

        # ==============================================================================

        # ------------------------------------------------------------
        # SIGNALS & SLOTS
        # ------------------------------------------------------------
        # Connect comboBoxes and setters, propgate change events hierarchically
        #  through all widget methods and emit 'filt_changed' in the end.
        self.cmbResponseType.currentIndexChanged.connect(
            lambda: self._set_response_type(enb_signal=True))  # 'LP'
        self.cmbFilterType.currentIndexChanged.connect(
            lambda: self._set_filter_type(enb_signal=True))  # 'IIR'
        self.cmbFilterClass.currentIndexChanged.connect(
            lambda: self._set_design_method(enb_signal=True))  # 'cheby1'
        self.chkMinOrder.clicked.connect(
            lambda: self._set_filter_order(enb_signal=True))  # Min. Order
        self.ledOrderN.editingFinished.connect(
            lambda: self._set_filter_order(enb_signal=True))  # Manual Order
        # ------------------------------------------------------------

# ------------------------------------------------------------------------------

    def load_dict(self):
        """
        Reload comboboxes from filter dictionary to update changed settings
        after loading a filter design from disk.
        `load_dict` uses the automatism of _set_response_type etc.
        of checking whether the previously selected filter design method is
        also available for the new combination.
        """
        # find index for response type:
        rt_idx = self.cmbResponseType.findData(fb.fil[0]['rt'])
        self.cmbResponseType.setCurrentIndex(rt_idx)
        self._set_response_type()

# ------------------------------------------------------------------------------

    def _set_response_type(self, enb_signal=False):
        """
        Triggered when cmbResponseType (LP, HP, ...) is changed:
        Copy selection to self.rt and fb.fil[0] and reconstruct filter type combo

        If previous filter type (FIR, IIR, ...) exists for new rt, set the
        filter type combo box to the old setting
        """
        # Read current setting of comboBox as string and store it in the filter dict
        fb.fil[0]['rt'] = self.rt = qget_cmb_box(self.cmbResponseType)

        # Get list of available filter types for new rt
        ft_list = list(
            fb.fil_tree[self.rt].keys())  # explicit list() needed for Py3
        # ---------------------------------------------------------------
        # Rebuild filter type combobox entries for new rt setting
        self.cmbFilterType.blockSignals(
            True)  # don't fire when changed programmatically
        self.cmbFilterType.clear()
        for ft in fb.fil_tree[self.rt]:
            self.cmbFilterType.addItem(rc.ft_names[ft], ft)

        # Is current filter type (e.g. IIR) in list for new rt?
        if fb.fil[0]['ft'] in ft_list:
            ft_idx = self.cmbFilterType.findText(fb.fil[0]['ft'])
            self.cmbFilterType.setCurrentIndex(
                ft_idx)  # yes, set same ft as before
        else:
            self.cmbFilterType.setCurrentIndex(0)  # no, set index 0

        self.cmbFilterType.blockSignals(False)
        # ---------------------------------------------------------------

        self._set_filter_type(enb_signal)

# ------------------------------------------------------------------------------

    def _set_filter_type(self, enb_signal=False):
        """"
        Triggered when cmbFilterType (IIR, FIR, ...) is changed:
        - read filter type ft and copy it to fb.fil[0]['ft'] and self.ft
        - (re)construct design method combo, adding
          displayed text (e.g. "Chebyshev 1") and hidden data (e.g. "cheby1")
        """
        # Read out current setting of comboBox and convert to string
        fb.fil[0]['ft'] = self.ft = qget_cmb_box(self.cmbFilterType)
        #
        logger.debug("InputFilter.set_filter_type triggered: {0}".format(
            self.ft))

        # ---------------------------------------------------------------
        # Get all available design methods for new ft from fil_tree and
        # - Collect them in fc_list
        # - Rebuild design method combobox entries for new ft setting:
        #    The combobox is populated with the "long name",
        #    the internal name is stored in comboBox.itemData
        self.cmbFilterClass.blockSignals(True)
        self.cmbFilterClass.clear()
        fc_list = []

        for fc in sorted(fb.fil_tree[self.rt][self.ft]):
            self.cmbFilterClass.addItem(fb.filter_classes[fc]['name'], fc)
            fc_list.append(fc)

        logger.debug("fc_list: {0}\n{1}".format(fc_list, fb.fil[0]['fc']))

        # Does new ft also provide the previous design method (e.g. ellip)?
        # Has filter been instantiated?
        if fb.fil[0]['fc'] in fc_list and ff.fil_inst:
            # yes, set same fc as before
            fc_idx = self.cmbFilterClass.findText(
                fb.filter_classes[fb.fil[0]['fc']]['name'])
            logger.debug("fc_idx : %s", fc_idx)
            self.cmbFilterClass.setCurrentIndex(fc_idx)
        else:
            self.cmbFilterClass.setCurrentIndex(0)  # no, set index 0

        self.cmbFilterClass.blockSignals(False)

        self._set_design_method(enb_signal)

# ------------------------------------------------------------------------------

    def _set_design_method(self, enb_signal=False):
        """
        Triggered when cmbFilterClass (cheby1, ...) is changed:
        - read design method fc and copy it to fb.fil[0]
        - create / update global filter instance fb.fil_inst of fc class
        - update dynamic widgets (if fc has changed and if there are any)
        - call load filter order
        """
        fb.fil[0]['fc'] = fc = qget_cmb_box(self.cmbFilterClass)

        if fc != self.fc_last:  # fc has changed:

            # when filter has been changed, try to destroy dynamic widgets of last fc:
            if self.fc_last:
                self._destruct_dyn_widgets()

            # ==================================================================
            """
            Create new instance of the selected filter class, accessible via
            its handle fb.fil_inst
            """
            err = ff.fil_factory.create_fil_inst(fc)
            logger.debug(f"InputFilter.set_design_method triggered: {fc}\n"
                         f"Returned error code {err}")
            # ==================================================================

            # Check whether new design method also provides the old filter order
            # method. If yes, don't change it, else set first available
            # filter order method
            if fb.fil[0]['fo'] not in fb.fil_tree[self.rt][self.ft][fc].keys():
                fb.fil[0].update({'fo': {}})
                # explicit list(dict.keys()) needed for Python 3
                fb.fil[0]['fo'] = list(
                    fb.fil_tree[self.rt][self.ft][fc].keys())[0]

# =============================================================================
#             logger.debug("selFilter = %s"
#                    "filterTree[fc] = %s"
#                    "filterTree[fc].keys() = %s"
#                   %(fb.fil[0], fb.fil_tree[self.rt][self.ft][fc],\
#                     fb.fil_tree[self.rt][self.ft][fc].keys()
#                     ))
#
# =============================================================================
# construct dyn. subwidgets if available
            if hasattr(ff.fil_inst, 'construct_UI'):
                self._construct_dyn_widgets()

            self.fc_last = fb.fil[0]['fc']

        self.load_filter_order(enb_signal)

# ------------------------------------------------------------------------------

    def load_filter_order(self, enb_signal=False):
        """
        Called by set_design_method or from InputSpecs (with enb_signal = False),
          load filter order setting from fb.fil[0] and update widgets

        """
        # collect dict_keys of available filter order [fo] methods for selected
        # design method [fc] from fil_tree (explicit list() needed for Python 3)
        fo_dict = fb.fil_tree[fb.fil[0]['rt']][fb.fil[0]['ft']][fb.fil[0]
                                                                ['fc']]
        fo_list = list(fo_dict.keys())

        # is currently selected fo setting available for (new) fc ?
        if fb.fil[0]['fo'] in fo_list:
            self.fo = fb.fil[0]['fo']  # keep current setting
        else:
            self.fo = fo_list[0]  # use first list entry from filterTree
            fb.fil[0]['fo'] = self.fo  # and update fo method

        # check whether fo widget is active, disabled or invisible
        if 'fo' in fo_dict[self.fo] and len(fo_dict[self.fo]['fo']) > 1:
            status = fo_dict[self.fo]['fo'][0]
        else:
            status = 'i'

        # Determine which subwidgets are __visible__
        self.chkMinOrder.setVisible('min' in fo_list)
        self.ledOrderN.setVisible(status in {'a', 'd'})
        self.lblOrderN.setVisible(status in {'a', 'd'})

        # Determine which subwidgets are __enabled__
        self.chkMinOrder.setChecked(fb.fil[0]['fo'] == 'min')
        self.ledOrderN.setText(str(fb.fil[0]['N']))
        self.ledOrderN.setEnabled(not self.chkMinOrder.isChecked()
                                  and status == 'a')
        self.lblOrderN.setEnabled(not self.chkMinOrder.isChecked()
                                  and status == 'a')

        if enb_signal:
            logger.debug("Emit 'filt_changed'")
            self.emit({'filt_changed': 'filter_type'})

# ------------------------------------------------------------------------------

    def _set_filter_order(self, enb_signal=False):
        """
        Triggered when either ledOrderN or chkMinOrder are edited:
        - copy settings to fb.fil[0]
        - emit 'filt_changed' if enb_signal is True
        """
        # Determine which subwidgets are _enabled_
        if self.chkMinOrder.isVisible():
            self.ledOrderN.setEnabled(not self.chkMinOrder.isChecked())
            self.lblOrderN.setEnabled(not self.chkMinOrder.isChecked())

            if self.chkMinOrder.isChecked() is True:
                # update in case N has been changed outside this class
                self.ledOrderN.setText(str(fb.fil[0]['N']))
                fb.fil[0].update({'fo': 'min'})

            else:
                fb.fil[0].update({'fo': 'man'})

        else:
            self.lblOrderN.setEnabled(self.fo == 'man')
            self.ledOrderN.setEnabled(self.fo == 'man')

        # read manual filter order, convert to positive integer and store it
        # in filter dictionary.
        ordn = safe_eval(self.ledOrderN.text(),
                         fb.fil[0]['N'],
                         return_type='int',
                         sign='pos')
        ordn = ordn if ordn > 0 else 1
        self.ledOrderN.setText(str(ordn))
        fb.fil[0].update({'N': ordn})

        if enb_signal:
            logger.debug("Emit 'filt_changed'")
            self.emit({'filt_changed': 'filter_order_widget'})

# ------------------------------------------------------------------------------

    def _destruct_dyn_widgets(self):
        """
        Delete the dynamically created filter design subwidget (if there is one)

        see http://stackoverflow.com/questions/13827798/proper-way-to-cleanup-
        widgets-in-pyqt

        This does NOT work when the subwidgets to be deleted and created are
        identical, as the deletion is only performed when the current scope has
        been left (?)! Hence, it is necessary to skip this method when the new
        design method is the same as the old one.
        """

        if hasattr(ff.fil_inst, 'wdg_fil'):
            # not needed, connection is destroyed automatically
            # ff.fil_inst.sig_tx.disconnect()
            try:
                # remove widget from layout
                self.layHDynWdg.removeWidget(self.dyn_wdg_fil)
                # delete UI widget when scope has been left
                self.dyn_wdg_fil.deleteLater()

            except AttributeError as e:
                logger.error("Could not destruct_UI!\n{0}".format(e))

            ff.fil_inst.deleteLater(
            )  # delete QWidget when scope has been left

# ------------------------------------------------------------------------------

    def _construct_dyn_widgets(self):
        """
        Create filter widget UI dynamically (if the filter routine has one) and
        connect its sig_tx signal to sig_tx in this scope.
        """
        ff.fil_inst.construct_UI()
        if hasattr(ff.fil_inst, 'wdg_fil'):
            try:
                self.dyn_wdg_fil = getattr(ff.fil_inst, 'wdg_fil')
                self.layHDynWdg.addWidget(self.dyn_wdg_fil, stretch=1)
            except AttributeError as e:
                logger.warning(e)

        if hasattr(ff.fil_inst, 'sig_tx'):
            ff.fil_inst.sig_tx.connect(self.sig_tx)
示例#2
0
class Input_Fixpoint_Specs(QWidget):
    """
    Create the widget that holds the dynamically loaded fixpoint filter ui
    """

    # sig_resize = pyqtSignal()  # emit a signal when the image has been resized
    sig_rx_local = pyqtSignal(object)  # incoming from subwidgets -> process_sig_rx_local
    sig_rx = pyqtSignal(object)  # incoming, connected to input_tab_widget.sig_rx
    sig_tx = pyqtSignal(object)  # outcgoing
    from pyfda.libs.pyfda_qt_lib import emit

    def __init__(self, parent=None):
        super(Input_Fixpoint_Specs, self).__init__(parent)

        self.tab_label = 'Fixpoint'
        self.tool_tip = ("<span>Select a fixpoint implementation for the filter,"
                         " simulate it or generate a Verilog netlist.</span>")
        self.parent = parent
        self.fx_path = os.path.realpath(
            os.path.join(dirs.INSTALL_DIR, 'fixpoint_widgets'))

        self.no_fx_filter_img = os.path.join(self.fx_path, "no_fx_filter.png")
        if not os.path.isfile(self.no_fx_filter_img):
            logger.error("Image {0:s} not found!".format(self.no_fx_filter_img))

        self.default_fx_img = os.path.join(self.fx_path, "default_fx_img.png")
        if not os.path.isfile(self.default_fx_img):
            logger.error("Image {0:s} not found!".format(self.default_fx_img))

        self._construct_UI()
        inst_wdg_list = self._update_filter_cmb()
        if len(inst_wdg_list) == 0:
            logger.warning("No fixpoint filter found for this type of filter!")
        else:
            logger.debug("Imported {0:d} fixpoint filters:\n{1}"
                         .format(len(inst_wdg_list.split("\n"))-1, inst_wdg_list))
        self._update_fixp_widget()

# ------------------------------------------------------------------------------
    def process_sig_rx_local(self, dict_sig: dict = None) -> None:
        """
        Process signals coming in from input and output quantizer subwidget and the
        dynamically instantiated subwidget and emit {'fx_sim': 'specs_changed'} in
        the end.
        """
        if dict_sig['id'] == id(self):
            logger.warning(f'RX_LOCAL - Stopped infinite loop: "{first_item(dict_sig)}"')
            return

        elif 'fx_sim' in dict_sig and dict_sig['fx_sim'] == 'specs_changed':
            self.wdg_dict2ui()  # update wordlengths in UI and set RUN button to 'changed'
            dict_sig.update({'id': id(self)})  # propagate 'specs_changed' with self 'id'
            self.emit(dict_sig)
            return

        # ---- Process input and output quantizer settings ('ui' in dict_sig) --
        elif 'ui' in dict_sig:
            if 'wdg_name' not in dict_sig:
                logger.warning(f"No key 'wdg_name' in dict_sig:\n{pprint_log(dict_sig)}")
                return

            elif dict_sig['wdg_name'] == 'w_input':
                """
                Input fixpoint format has been changed or butLock has been clicked.
                When I/O lock is active, copy input fixpoint word format to output
                word format.
                """
                if dict_sig['ui'] == 'butLock'\
                        and not self.wdg_w_input.butLock.isChecked():
                    # butLock was deactivitated, don't do anything
                    return
                elif self.wdg_w_input.butLock.isChecked():
                    # but lock was activated or wordlength setting have been changed
                    fb.fil[0]['fxqc']['QO']['WI'] = fb.fil[0]['fxqc']['QI']['WI']
                    fb.fil[0]['fxqc']['QO']['WF'] = fb.fil[0]['fxqc']['QI']['WF']
                    fb.fil[0]['fxqc']['QO']['W'] = fb.fil[0]['fxqc']['QI']['W']

            elif dict_sig['wdg_name'] == 'w_output':
                """
                Output fixpoint format has been changed. When I/O lock is active, copy
                output fixpoint word format to input word format.
                """
                if self.wdg_w_input.butLock.isChecked():
                    fb.fil[0]['fxqc']['QI']['WI'] = fb.fil[0]['fxqc']['QO']['WI']
                    fb.fil[0]['fxqc']['QI']['WF'] = fb.fil[0]['fxqc']['QO']['WF']
                    fb.fil[0]['fxqc']['QI']['W'] = fb.fil[0]['fxqc']['QO']['W']

            elif dict_sig['wdg_name'] in {'q_output', 'q_input'}:
                pass
            else:
                logger.error("Unknown wdg_name '{0}' in dict_sig:\n{1}"
                             .format(dict_sig['wdg_name'], pprint_log(dict_sig)))
                return

            if dict_sig['ui'] not in {'WI', 'WF', 'ovfl', 'quant', 'cmbW', 'butLock'}:
                logger.warning("Unknown value '{0}' for key 'ui'".format(dict_sig['ui']))

            self.wdg_dict2ui()  # update wordlengths in UI and set RUN button to 'changed'
            self.emit({'fx_sim': 'specs_changed'})  # propagate 'specs_changed'

        else:
            logger.error(f"Unknown key/value in 'dict_sig':\n{pprint_log(dict_sig)}")

# ------------------------------------------------------------------------------
    def process_sig_rx(self, dict_sig: dict = None) -> None:
        """
        Process signals coming in via `sig_rx` from other widgets.

        Trigger fx simulation:

        1. ``fx_sim': 'init'``: Start fixpoint simulation by sending
           'fx_sim':'start_fx_response_calculation'

        2. ``fx_sim_calc_response()``: Receive stimulus from widget in
            'fx_sim':'calc_frame_fx_response' and pass it to fixpoint simulation method

        3. Store fixpoint response in `fb.fx_result` and return to initiating routine
        """

        # logger.info(
        #     "SIG_RX(): vis={0}\n{1}".format(self.isVisible(), pprint_log(dict_sig)))
        # logger.debug(f'SIG_RX():  "{first_item(dict_sig)}"')

        if dict_sig['id'] == id(self):
            # logger.warning(f'Stopped infinite loop: "{first_item(dict_sig)}"')
            return

        elif 'data_changed' in dict_sig and dict_sig['data_changed'] == "filter_designed":
            # New filter has been designed, update list of available filter topologies
            self._update_filter_cmb()
            return

        elif 'data_changed' in dict_sig or\
             ('view_changed' in dict_sig and dict_sig['view_changed'] == 'q_coeff'):
            # Filter data has changed (but not the filter type) or the coefficient
            # format / wordlength have been changed in `input_coeffs`. The latter means
            # the view / display has been changed (wordlength) but not the actual
            # coefficients in the `input_coeffs` widget. However, the wordlength setting
            # is copied to the fxqc dict and from there to the fixpoint widget.
            # - update fields in the fixpoint filter widget - wordlength may have
            #   been changed.
            # - Set RUN button to "changed" in wdg_dict2ui()
            self.wdg_dict2ui()

        # --------------- FX Simulation -------------------------------------------
        elif 'fx_sim' in dict_sig:
            if dict_sig['fx_sim'] == 'init':
                # fixpoint simulation has been started externally, e.g. by
                # `impz.impz_init()`, return a handle to the fixpoint filter function
                # via signal-slot connection
                if not self.fx_wdg_found:
                    logger.error("No fixpoint widget found!")
                    qstyle_widget(self.butSimFx, "error")
                    self.emit({'fx_sim': 'error'})
                elif self.fx_sim_init() != 0:  # returned an error
                    qstyle_widget(self.butSimFx, "error")
                    self.emit({'fx_sim': 'error'})
                else:
                    self.emit({'fx_sim': 'start_fx_response_calculation',
                               'fxfilter_func': self.fx_filt_ui.fxfilter})

            elif dict_sig['fx_sim'] == 'calc_frame_fx_response':
                self.fx_sim_calc_response(dict_sig)
                # return to the routine collecting the response frame by frame
                return

            elif dict_sig['fx_sim'] == 'specs_changed':
                # fixpoint specification have been changed somewhere, update ui
                # and set run button to "changed" in wdg_dict2ui()
                self.wdg_dict2ui()
            elif dict_sig['fx_sim'] == 'finish':
                qstyle_widget(self.butSimFx, "normal")
            else:
                logger.error('Unknown "fx_sim" command option "{0}"\n'
                             '\treceived from "{1}".'
                             .format(dict_sig['fx_sim'], dict_sig['class']))

        # ---- resize image when "Fixpoint" tab is selected or widget size is changed:
        elif 'ui_changed' in dict_sig and dict_sig['ui_changed'] in {'resized', 'tab'}\
                and self.isVisible():
            self.resize_img()

# ------------------------------------------------------------------------------
    def _construct_UI(self) -> None:
        """
        Intitialize the main GUI, consisting of:

        - A combo box to select the filter topology and an image of the topology

        - The input quantizer

        - The UI of the fixpoint filter widget

        - Simulation and export buttons
        """
# ------------------------------------------------------------------------------
        # Define frame and layout for the dynamically updated filter widget
        # The actual filter widget is instantiated in self.set_fixp_widget() later on

        self.layH_fx_wdg = QHBoxLayout()
        # self.layH_fx_wdg.setContentsMargins(*params['wdg_margins'])
        frmHDL_wdg = QFrame(self)
        frmHDL_wdg.setLayout(self.layH_fx_wdg)
        # frmHDL_wdg.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)

# ------------------------------------------------------------------------------
#       Initialize fixpoint filter combobox, title and description
# ------------------------------------------------------------------------------
        self.cmb_fx_wdg = QComboBox(self)
        self.cmb_fx_wdg.setSizeAdjustPolicy(QComboBox.AdjustToContents)

        self.lblTitle = QLabel("not set", self)
        self.lblTitle.setWordWrap(True)
        self.lblTitle.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Fixed)
        layHTitle = QHBoxLayout()
        layHTitle.addWidget(self.cmb_fx_wdg)
        layHTitle.addWidget(self.lblTitle)

        self.frmTitle = QFrame(self)
        self.frmTitle.setLayout(layHTitle)
        self.frmTitle.setContentsMargins(*params['wdg_margins'])

# ------------------------------------------------------------------------------
#       Input and Output Quantizer
# ------------------------------------------------------------------------------
#       - instantiate widgets for input and output quantizer
#       - pass the quantization (sub-?) dictionary to the constructor
# ------------------------------------------------------------------------------

        self.wdg_w_input = UI_W(self, q_dict=fb.fil[0]['fxqc']['QI'],
                                wdg_name='w_input', label='', lock_visible=True)
        self.wdg_w_input.sig_tx.connect(self.process_sig_rx_local)

        cmb_q = ['round', 'floor', 'fix']

        self.wdg_w_output = UI_W(self, q_dict=fb.fil[0]['fxqc']['QO'],
                                 wdg_name='w_output', label='')
        self.wdg_w_output.sig_tx.connect(self.process_sig_rx_local)

        self.wdg_q_output = UI_Q(self, q_dict=fb.fil[0]['fxqc']['QO'],
                                 wdg_name='q_output',
                                 label='Output Format <i>Q<sub>Y&nbsp;</sub></i>:',
                                 cmb_q=cmb_q, cmb_ov=['wrap', 'sat'])
        self.wdg_q_output.sig_tx.connect(self.sig_rx_local)

        if HAS_DS:
            cmb_q.append('dsm')
        self.wdg_q_input = UI_Q(self, q_dict=fb.fil[0]['fxqc']['QI'],
                                wdg_name='q_input',
                                label='Input Format <i>Q<sub>X&nbsp;</sub></i>:',
                                cmb_q=cmb_q)
        self.wdg_q_input.sig_tx.connect(self.sig_rx_local)

        # Layout and frame for input quantization
        layVQiWdg = QVBoxLayout()
        layVQiWdg.addWidget(self.wdg_q_input)
        layVQiWdg.addWidget(self.wdg_w_input)
        frmQiWdg = QFrame(self)
        # frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmQiWdg.setLayout(layVQiWdg)
        frmQiWdg.setContentsMargins(*params['wdg_margins'])

        # Layout and frame for output quantization
        layVQoWdg = QVBoxLayout()
        layVQoWdg.addWidget(self.wdg_q_output)
        layVQoWdg.addWidget(self.wdg_w_output)
        frmQoWdg = QFrame(self)
        # frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmQoWdg.setLayout(layVQoWdg)
        frmQoWdg.setContentsMargins(*params['wdg_margins'])

# ------------------------------------------------------------------------------
#       Dynamically updated image of filter topology (label as placeholder)
# ------------------------------------------------------------------------------
        # allow setting background color
        # lbl_fixp_img_palette = QPalette()
        # lbl_fixp_img_palette.setColor(QPalette(window, Qt: white))
        # lbl_fixp_img_palette.setBrush(self.backgroundRole(), QColor(150, 0, 0))
        # lbl_fixp_img_palette.setColor(QPalette: WindowText, Qt: blue)

        self.lbl_fixp_img = QLabel("img not set", self)
        self.lbl_fixp_img.setAutoFillBackground(True)
        # self.lbl_fixp_img.setPalette(lbl_fixp_img_palette)
        # self.lbl_fixp_img.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)

        self.embed_fixp_img(self.no_fx_filter_img)
        layHImg = QHBoxLayout()
        layHImg.setContentsMargins(0, 0, 0, 0)
        layHImg.addWidget(self.lbl_fixp_img)  # , Qt.AlignCenter)
        self.frmImg = QFrame(self)
        self.frmImg.setLayout(layHImg)
        self.frmImg.setContentsMargins(*params['wdg_margins'])

# ------------------------------------------------------------------------------
#       Simulation and export Buttons
# ------------------------------------------------------------------------------
        self.butExportHDL = QPushButton(self)
        self.butExportHDL.setToolTip(
            "Create Verilog or VHDL netlist for fixpoint filter.")
        self.butExportHDL.setText("Create HDL")

        self.butSimFx = QPushButton(self)
        self.butSimFx.setToolTip("Start fixpoint simulation.")
        self.butSimFx.setText("Sim. FX")

        self.layHHdlBtns = QHBoxLayout()
        self.layHHdlBtns.addWidget(self.butSimFx)
        self.layHHdlBtns.addWidget(self.butExportHDL)
        # This frame encompasses the HDL buttons sim and convert
        frmHdlBtns = QFrame(self)
        # frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmHdlBtns.setLayout(self.layHHdlBtns)
        frmHdlBtns.setContentsMargins(*params['wdg_margins'])

# -------------------------------------------------------------------
#       Top level layout
# -------------------------------------------------------------------
        splitter = QSplitter(self)
        splitter.setOrientation(Qt.Vertical)
        splitter.addWidget(frmHDL_wdg)
        splitter.addWidget(frmQoWdg)
        splitter.addWidget(self.frmImg)

        # setSizes uses absolute pixel values, but can be "misused" by specifying values
        # that are way too large: in this case, the space is distributed according
        # to the _ratio_ of the values:
        splitter.setSizes([3000, 3000, 5000])

        layVMain = QVBoxLayout()
        layVMain.addWidget(self.frmTitle)
        layVMain.addWidget(frmHdlBtns)
        layVMain.addWidget(frmQiWdg)
        layVMain.addWidget(splitter)
        layVMain.addStretch()
        layVMain.setContentsMargins(*params['wdg_margins'])

        self.setLayout(layVMain)

        # ----------------------------------------------------------------------
        # GLOBAL SIGNALS & SLOTs
        # ----------------------------------------------------------------------
        self.sig_rx.connect(self.process_sig_rx)
        self.sig_rx_local.connect(self.process_sig_rx_local)
        # dynamic connection in `self._update_fixp_widget()`:
        # -----
        # if hasattr(self.fx_filt_ui, "sig_rx"):
        #     self.sig_rx.connect(self.fx_filt_ui.sig_rx)
        # if hasattr(self.fx_filt_ui, "sig_tx"):
        #     self.fx_filt_ui.sig_tx.connect(self.sig_rx_local)
        # ----
        # ----------------------------------------------------------------------
        # LOCAL SIGNALS & SLOTs
        # ----------------------------------------------------------------------
        self.cmb_fx_wdg.currentIndexChanged.connect(self._update_fixp_widget)
        self.butExportHDL.clicked.connect(self.exportHDL)
        self.butSimFx.clicked.connect(lambda x: self.emit({'fx_sim': 'start'}))
        # ----------------------------------------------------------------------
        # EVENT FILTER
        # ----------------------------------------------------------------------
        # # monitor events and generate sig_resize event when resized
        # self.lbl_fixp_img.installEventFilter(self)
        # # ... then redraw image when resized
        # self.sig_resize.connect(self.resize_img)

# ------------------------------------------------------------------------------
    def _update_filter_cmb(self) -> str:
        """
        (Re-)Read list of available fixpoint filters for a given filter design
        every time a new filter design is selected.

        Then try to import the fixpoint designs in the list and populate the
        fixpoint implementation combo box `self.cmb_fx_wdg` when successfull.

        Returns
        -------
        inst_wdg_str: str
          string with all fixpoint widgets that could be instantiated successfully
        """
        inst_wdg_str = ""  # full names of successfully instantiated widgets for logging
        # remember last fx widget setting:
        last_fx_wdg = qget_cmb_box(self.cmb_fx_wdg, data=False)
        self.cmb_fx_wdg.clear()
        fc = fb.fil[0]['fc']

        if 'fix' in fb.filter_classes[fc]:
            self.cmb_fx_wdg.blockSignals(True)
            for class_name in fb.filter_classes[fc]['fix']:  # get class name
                try:   # construct module + class name ...
                    mod_class_name = fb.fixpoint_classes[class_name]['mod'] + '.'\
                        + class_name
                    # ... and display name
                    disp_name = fb.fixpoint_classes[class_name]['name']
                    self.cmb_fx_wdg.addItem(disp_name, mod_class_name)
                    inst_wdg_str += '\t' + class_name + ' : ' + mod_class_name + '\n'
                except AttributeError as e:
                    logger.warning('Widget "{0}":\n{1}'.format(class_name, e))
                    self.embed_fixp_img(self.no_fx_filter_img)
                    continue  # with next `class_name` of for loop
                except KeyError as e:
                    logger.warning("No fixpoint filter for filter type {0} available."
                                   .format(e))
                    self.embed_fixp_img(self.no_fx_filter_img)
                    continue  # with next `class_name` of for loop

            # restore last fx widget if possible
            idx = self.cmb_fx_wdg.findText(last_fx_wdg)
            # set to idx 0 if not found (returned -1)
            self.cmb_fx_wdg.setCurrentIndex(max(idx, 0))
            self.cmb_fx_wdg.blockSignals(False)
        else:  # no fixpoint widget
            self.embed_fixp_img(self.no_fx_filter_img)
        self._update_fixp_widget()
        return inst_wdg_str

# # ------------------------------------------------------------------------------
#     def eventFilter(self, source, event):
#         """
#         Filter all events generated by monitored QLabel, only resize events are
#         processed here, generating a `sig_resize` signal. All other events
#         are passed on to the next hierarchy level.
#         """
#         if event.type() == QEvent.Resize:
#             logger.warning("resize event!")
#             self.sig_resize.emit()

#         # Call base class method to continue normal event processing:
#         return super(Input_Fixpoint_Specs, self).eventFilter(source, event)

# ------------------------------------------------------------------------------
    def embed_fixp_img(self, img_file: str) -> QPixmap:
        """
        Embed `img_file` in png format as `self.img_fixp`

        Parameters
        ----------
        img_file: str
            path and file name to image file

        Returns
        -------
        self.img_fixp: QPixmap object
            pixmap containing the passed img_file
        """
        if not os.path.isfile(img_file):
            logger.warning("Image file {0} doesn't exist.".format(img_file))
            img_file = self.default_fx_img

        _, file_extension = os.path.splitext(img_file)
        if file_extension != '.png':
            logger.error('Unknown file extension "{0}"!'.format(file_extension))
            img_file = self.default_fx_img

        self.img_fixp = QPixmap(img_file)
        # logger.warning(f"img_fixp = {img_file}")
        # logger.warning(f"_embed_fixp_img(): {self.img_fixp.__class__.__name__}")
        return self.img_fixp

# ------------------------------------------------------------------------------
    def resize_img(self) -> None:
        """
        Triggered when `self` (the widget) is selected or resized. The method resizes
        the image inside QLabel to completely fill the label while keeping
        the aspect ratio. An offset of some pixels is needed, otherwise the image
        is clipped.
        """
        # logger.warning(f"resize_img(): img_fixp = {self.img_fixp.__class__.__name__}")

        if self.parent is None:  # parent is QApplication, has no width or height
            par_w, par_h = 300, 700  # fixed size for module level test
        else:  # widget parent is InputTabWidget()
            par_w, par_h = self.parent.width(), self.parent.height()

        img_w, img_h = self.img_fixp.width(), self.img_fixp.height()

        if img_w > 10:
            max_h = int(max(np.floor(img_h * par_w/img_w) - 5, 20))
        else:
            max_h = 200
        logger.debug("img size: {0},{1}, frm size: {2},{3}, max_h: {4}"
                     .format(img_w, img_h, par_w, par_h, max_h))

        # The following doesn't work because the width of the parent widget can grow
        # with the image size
        # img_scaled = self.img_fixp.scaled(self.lbl_fixp_img.size(),
        # Qt.KeepAspectRatio, Qt.SmoothTransformation)
        img_scaled = self.img_fixp.scaledToHeight(max_h, Qt.SmoothTransformation)

        self.lbl_fixp_img.setPixmap(img_scaled)

# ------------------------------------------------------------------------------
    def _update_fixp_widget(self):
        """
        This method is called at the initialization of the widget and when
        a new fixpoint filter implementation is selected from the combo box:

        - Destruct old instance of fixpoint filter widget `self.fx_filt_ui`
        - Import and instantiate new fixpoint filter widget e.g. after changing the
          filter topology as
        - Try to load image for filter topology
        - Update the UI of the widget
        - Try to instantiate HDL filter as `self.fx_filt_ui.fixp_filter` with
            dummy data
        - emit {'fx_sim': 'specs_changed'} when successful
        """
        def _disable_fx_wdg(self) -> None:

            if hasattr(self, "fx_filt_ui") and self.fx_filt_ui is not None:
                # is a fixpoint widget loaded?
                try:
                    # try to remove widget from layout
                    self.layH_fx_wdg.removeWidget(self.fx_filt_ui)
                    # delete QWidget when scope has been left
                    self.fx_filt_ui.deleteLater()
                except AttributeError as e:
                    logger.error("Destructing UI failed!\n{0}".format(e))

            self.fx_wdg_found = False
            self.butSimFx.setEnabled(False)
            self.butExportHDL.setVisible(False)
            # self.layH_fx_wdg.setVisible(False)
            self.img_fixp = self.embed_fixp_img(self.no_fx_filter_img)
            self.resize_img()
            self.lblTitle.setText("")

            self.fx_filt_ui = None
        # -----------------------------------------------------------
        _disable_fx_wdg(self)  # destruct old fixpoint widget instance:

        # instantiate new fixpoint widget class as self.fx_filt_ui
        cmb_wdg_fx_cur = qget_cmb_box(self.cmb_fx_wdg, data=False)
        if cmb_wdg_fx_cur:  # at least one valid fixpoint widget found
            self.fx_wdg_found = True
            # get list [module name and path, class name]
            fx_mod_class_name = qget_cmb_box(self.cmb_fx_wdg, data=True).rsplit('.', 1)
            fx_mod = importlib.import_module(fx_mod_class_name[0])  # get module
            fx_filt_ui_class = getattr(fx_mod, fx_mod_class_name[1])  # get class
            logger.info("Instantiating new FX widget\n\t"
                        f"{fx_mod.__name__}.{fx_filt_ui_class.__name__}")
            # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            self.fx_filt_ui = fx_filt_ui_class()  # instantiate the fixpoint widget
            # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            # and add it to layout:
            self.layH_fx_wdg.addWidget(self.fx_filt_ui, stretch=1)
            self.fx_filt_ui.setVisible(True)
            self.wdg_dict2ui()  # initialize the fixpoint subwidgets from the fxqc_dict

            # ---- connect signals to fx_filt_ui ----
            if hasattr(self.fx_filt_ui, "sig_rx"):
                self.sig_rx.connect(self.fx_filt_ui.sig_rx)
            if hasattr(self.fx_filt_ui, "sig_tx"):
                self.fx_filt_ui.sig_tx.connect(self.sig_rx_local)

            # ---- get name of new fixpoint filter image ----
            if not (hasattr(self.fx_filt_ui, "img_name") and self.fx_filt_ui.img_name):
                # no image name defined, use default image
                img_file = self.default_fx_img
            else:
                # get path of imported fixpoint widget ...
                file_path = os.path.dirname(fx_mod.__file__)
                # ... and construct full image name from it
                img_file = os.path.join(file_path, self.fx_filt_ui.img_name)

            # ---- instantiate and scale graphic of filter topology ----
            self.embed_fixp_img(img_file)
            self.resize_img()

            # ---- set title and description for filter
            self.lblTitle.setText(self.fx_filt_ui.title)

            # Check which methods the fixpoint widget provides and enable
            # corresponding buttons:
            self.butExportHDL.setVisible(hasattr(self.fx_filt_ui, "to_hdl"))
            self.butSimFx.setEnabled(hasattr(self.fx_filt_ui, "fxfilter"))
            self.update_fxqc_dict()
            self.emit({'fx_sim': 'specs_changed'})

# ------------------------------------------------------------------------------
    def wdg_dict2ui(self):
        """
        Trigger an update of the fixpoint widget UI when view (i.e. fixpoint
        coefficient format) or data have been changed outside this class. Additionally,
        pass the fixpoint quantization widget to update / restore other subwidget
        settings.

        Set the RUN button to "changed".
        """
#        fb.fil[0]['fxqc']['QCB'].update({'scale':(1 << fb.fil[0]['fxqc']['QCB']['W'])})
        self.wdg_q_input.dict2ui(fb.fil[0]['fxqc']['QI'])
        self.wdg_q_output.dict2ui(fb.fil[0]['fxqc']['QO'])
        self.wdg_w_input.dict2ui(fb.fil[0]['fxqc']['QI'])
        self.wdg_w_output.dict2ui(fb.fil[0]['fxqc']['QO'])
        if self.fx_wdg_found and hasattr(self.fx_filt_ui, "dict2ui"):
            self.fx_filt_ui.dict2ui()
#            dict_sig = {'fx_sim':'specs_changed'}
#            self.emit(dict_sig)

        qstyle_widget(self.butSimFx, "changed")

# ------------------------------------------------------------------------------
    def update_fxqc_dict(self):
        """
        Update the fxqc dictionary before simulation / HDL generation starts.
        """
        if self.fx_wdg_found:
            # get a dict with the coefficients and fixpoint settings from fixpoint widget
            if hasattr(self.fx_filt_ui, "ui2dict"):
                fb.fil[0]['fxqc'].update(self.fx_filt_ui.ui2dict())
                logger.debug("update fxqc: \n{0}".format(pprint_log(fb.fil[0]['fxqc'])))
        else:
            logger.error("No fixpoint widget found!")

# ------------------------------------------------------------------------------
    def exportHDL(self):
        """
        Synthesize HDL description of filter
        """
        dlg = QFD(self)  # instantiate file dialog object

        file_types = "Verilog (*.v)"
        # needed for overwrite confirmation when name is entered without suffix:
        dlg.setDefaultSuffix('v')
        dlg.setWindowTitle('Export Verilog')
        dlg.setNameFilter(file_types)
        dlg.setDirectory(dirs.save_dir)
        # set mode "save file" instead "open file":
        dlg.setAcceptMode(QFD.AcceptSave)
        dlg.setOption(QFD.DontConfirmOverwrite, False)
        if dlg.exec_() == QFD.Accepted:
            hdl_file = qstr(dlg.selectedFiles()[0])
            # hdl_type = extract_file_ext(qstr(dlg.selectedNameFilter()))[0]

# =============================================================================
#       # static method getSaveFileName_() is simple but unflexible
#         hdl_file, hdl_filter = dlg.getSaveFileName_(
#                 caption="Save Verilog netlist as (this also defines the module name)",
#                 directory=dirs.save_dir, filter=file_types)
#         hdl_file = qstr(hdl_file)
#         if hdl_file != "": # "operation cancelled" returns an empty string
#             # return '.v' or '.vhd' depending on filetype selection:
#             # hdl_type = extract_file_ext(qstr(hdl_filter))[0]
#             # sanitized dir + filename + suffix. The filename suffix is replaced
#             # by `v` later.
#             hdl_file = os.path.normpath(hdl_file) # complete path + file name
# =============================================================================
            hdl_dir_name = os.path.dirname(hdl_file)  # extract the directory path
            if not os.path.isdir(hdl_dir_name):  # create directory if it doesn't exist
                os.mkdir(hdl_dir_name)
            dirs.save_dir = hdl_dir_name  # make this directory the new default / base dir
            hdl_file_name = os.path.splitext(os.path.basename(hdl_file))[0]
            hdl_full_name = os.path.join(hdl_dir_name, hdl_file_name + ".v")
            # remove all non-alphanumeric chars:
            vlog_mod_name = re.sub(r'\W+', '', hdl_file_name).lower()

            logger.info('Creating hdl_file "{0}"\n\twith top level module "{1}"'
                        .format(hdl_full_name, vlog_mod_name))
            try:
                self.update_fxqc_dict()
                self.fx_filt_ui.construct_fixp_filter()
                code = self.fx_filt_ui.to_hdl(name=vlog_mod_name)
                # logger.info(str(code)) # print verilog code to console
                with io.open(hdl_full_name, 'w', encoding="utf8") as f:
                    f.write(str(code))

                logger.info("HDL conversion finished!")
            except (IOError, TypeError) as e:
                logger.warning(e)

    # --------------------------------------------------------------------------
    def fx_sim_init(self):
        """
        Initialize fix-point simulation:

        - Update the `fxqc_dict` containing all quantization information
        - Setup a filter instance for fixpoint simulation
        - Request a stimulus signal

        Returns
        -------
        error: int
            0 for sucessful fx widget construction, -1 for error
        """
        try:
            self.update_fxqc_dict()
            self.fx_filt_ui.init_filter()   # setup filter instance
            return 0

        except ValueError as e:
            logger.error('Fixpoint stimulus generation failed during "init"'
                         '\nwith "{0} "'.format(e))
        return -1

# ------------------------------------------------------------------------------
    def fx_sim_calc_response(self, dict_sig) -> None:
        """
        - Read fixpoint stimulus from `dict_sig` in integer format
        - Pass it to the fixpoint filter which calculates the fixpoint response
        - Store the result in `fb.fx_results` and return. In case of an error,
          `fb.fx_results == None`

        Returns
        -------
        None
        """
        try:
            # logger.info(
            #     'Simulate fixpoint frame with "{0}" stimulus:\n\t{1}'.format(
            #         dict_sig['class'],
            #         pprint_log(dict_sig['fx_stimulus'], tab=" "),
            #         ))

            # Run fixpoint simulation and store the results as integer values:
            fb.fx_results = self.fx_filt_ui.fxfilter(dict_sig['fx_stimulus'])

            if len(fb.fx_results) == 0:
                logger.error("Fixpoint simulation returned empty results!")
            # else:
            #     # logger.debug("fx_results: {0}"\
            #     #            .format(pprint_log(fb.fx_results, tab= " ")))
            #     logger.info(
            #         f'Fixpoint simulation successful for dict\n{pprint_log(dict_sig)}'
            #         f'\tStimuli: Shape {np.shape(dict_sig["fx_stimulus"])}'
            #         f' of type "{dict_sig["fx_stimulus"].dtype}"'
            #         f'\n\tResponse: Shape {np.shape(fb.fx_results)}'
            #         f' of type "{type(fb.fx_results).__name__} "'
            #         f' ("{type(fb.fx_results[0]).__name__}")'
            #     )

        except ValueError as e:
            logger.error("Simulator error {0}".format(e))
            fb.fx_results = None

        except AssertionError as e:
            logger.error('Fixpoint simulation failed for dict\n{0}'
                         '\twith msg. "{1}"\n\tStimuli: Shape {2} of type "{3}"'
                         '\n\tResponse: Shape {4} of type "{5}"'.format(
                            pprint_log(dict_sig), e,
                            np.shape(dict_sig['fx_stimulus']),
                            dict_sig['fx_stimulus'].dtype,
                            np.shape(fb.fx_results),
                            type(fb.fx_results)
                                ))
            fb.fx_results = None

        if fb.fx_results is None:
            qstyle_widget(self.butSimFx, "error")
        else:
            pass # everything ok, return 
            # logger.debug("Sending fixpoint results")
        return
示例#3
0
class Input_Fixpoint_Specs(QWidget):
    """
    Create the widget that holds the dynamically loaded fixpoint filter ui 
    """
    # emit a signal when the image has been resized
    sig_resize = pyqtSignal()
    # incoming from subwidgets -> process_sig_rx_local
    sig_rx_local = pyqtSignal(object)
    # incoming, connected to input_tab_widget.sig_rx
    sig_rx = pyqtSignal(object)
    # outcgoing
    sig_tx = pyqtSignal(object)

    def __init__(self, parent):
        super(Input_Fixpoint_Specs, self).__init__(parent)

        self.tab_label = 'Fixpoint'
        self.tool_tip = (
            "<span>Select a fixpoint implementation for the filter,"
            " simulate it or generate a Verilog netlist.</span>")
        self.parent = parent
        self.fx_path = os.path.realpath(
            os.path.join(dirs.INSTALL_DIR, 'fixpoint_widgets'))
        self.no_fx_filter_img = os.path.join(self.fx_path, "no_fx_filter.png")
        if not os.path.isfile(self.no_fx_filter_img):
            logger.error("Image {0:s} not found!".format(
                self.no_fx_filter_img))

        self.default_fx_img = os.path.join(self.fx_path, "default_fx_img.png")
        if not os.path.isfile(self.default_fx_img):
            logger.error("Image {0:s} not found!".format(self.default_fx_img))

        if HAS_MIGEN:
            self._construct_UI()
        else:
            self.state = "deactivated"  # "invisible", "disabled"

#------------------------------------------------------------------------------

    def process_sig_rx(self, dict_sig=None):
        """
        Process signals coming in via subwidgets and sig_rx
		
		Play PingPong with a stimulus & plot widget:
        
		2. ``fx_sim_init()``: Request stimulus by sending 'fx_sim':'get_stimulus'
		
		3. ``fx_sim_set_stimulus()``: Receive stimulus from widget in 'fx_sim':'send_stimulus'
			and pass it to HDL object for simulation
		   
		4. Send back HDL response to widget via 'fx_sim':'set_response'

        """

        logger.debug("process_sig_rx(): vis={0}\n{1}"\
                    .format(self.isVisible(), pprint_log(dict_sig)))
        if dict_sig['sender'] == __name__:
            logger.debug("Stopped infinite loop\n{0}".format(
                pprint_log(dict_sig)))
            return
        elif 'data_changed' in dict_sig and dict_sig[
                'data_changed'] == "filter_designed":
            # New filter has been designed, update list of available filter topologies here
            self._update_filter_cmb()
            return
        elif 'data_changed' in dict_sig or\
            ('view_changed' in dict_sig and dict_sig['view_changed'] == 'q_coeff'):
            # update fields in the filter topology widget - wordlength may have
            # been changed. Also set RUN button to "changed" in wdg_dict2ui()
            self.wdg_dict2ui()
            #self.sig_tx.emit({'sender':__name__, 'fx_sim':'specs_changed'})
        elif 'fx_sim' in dict_sig:
            if dict_sig['fx_sim'] == 'init':
                if self.fx_wdg_found:
                    self.fx_sim_init()
                else:
                    logger.error("No fixpoint widget found!")
                    qstyle_widget(self.butSimHDL, "error")
                    self.sig_tx.emit({'sender': __name__, 'fx_sim': 'error'})

            elif dict_sig['fx_sim'] == 'send_stimulus':
                self.fx_sim_set_stimulus(dict_sig)
            elif dict_sig['fx_sim'] == 'specs_changed':
                # fixpoint specification have been changed somewhere, update ui
                # and set run button to "changed" in wdg_dict2ui()
                self.wdg_dict2ui()
            elif dict_sig['fx_sim'] == 'finish':
                qstyle_widget(self.butSimHDL, "normal")
                logger.info('Fixpoint simulation [{0:5.3g} ms]: Plotting finished'\
                            .format((time.process_time() - self.t_resp)*1000))
            else:
                logger.error('Unknown "fx_sim" command option "{0}"\n'
                             '\treceived from "{1}".'.format(
                                 dict_sig['fx_sim'], dict_sig['sender']))
        # ---- Process local widget signals
        elif 'ui' in dict_sig:
            if 'id' in dict_sig and dict_sig['id'] == 'w_input':
                """
                Input fixpoint format has been changed or butLock has been clicked.
                When I/O lock is active, copy input fixpoint word format to output 
                word format.
                """
                if dict_sig[
                        'ui'] == 'butLock' and not self.wdg_w_input.butLock.isChecked(
                        ):
                    # butLock was deactivitated, don't do anything
                    return
                elif self.wdg_w_input.butLock.isChecked():
                    # but lock was activated or wordlength setting have been changed
                    fb.fil[0]['fxqc']['QO']['WI'] = fb.fil[0]['fxqc']['QI'][
                        'WI']
                    fb.fil[0]['fxqc']['QO']['WF'] = fb.fil[0]['fxqc']['QI'][
                        'WF']
                    fb.fil[0]['fxqc']['QO']['W'] = fb.fil[0]['fxqc']['QI']['W']

            elif 'id' in dict_sig and dict_sig['id'] == 'w_output':
                """
                Output fixpoint format has been changed. When I/O lock is active, copy
                output fixpoint word format to input word format.
                """
                if self.wdg_w_input.butLock.isChecked():
                    fb.fil[0]['fxqc']['QI']['WI'] = fb.fil[0]['fxqc']['QO'][
                        'WI']
                    fb.fil[0]['fxqc']['QI']['WF'] = fb.fil[0]['fxqc']['QO'][
                        'WF']
                    fb.fil[0]['fxqc']['QI']['W'] = fb.fil[0]['fxqc']['QO']['W']

            elif 'id' in dict_sig and dict_sig['id'] in \
                {'w_coeff', 'q_input', 'q_output', 'w_accu', 'q_accu'}:
                pass  # nothing to do for now

            else:
                if not "id" in dict_sig:
                    logger.warning("No id in dict_sig:\n{0}".format(
                        pprint_log(dict_sig)))
                else:
                    logger.warning('Unknown id "{0}" in dict_sig:\n{1}'\
                                   .format(dict_sig['id'], pprint_log(dict_sig)))

            if not dict_sig['ui'] in {
                    'WI', 'WF', 'ovfl', 'quant', 'cmbW', 'butLock'
            }:
                logger.warning("Unknown value '{0}' for key 'ui'".format(
                    dict_sig['ui']))
            self.wdg_dict2ui(
            )  # update wordlengths in UI and set RUN button to 'changed'
            self.sig_tx.emit({'sender': __name__, 'fx_sim': 'specs_changed'})

            return

#------------------------------------------------------------------------------

    def _construct_UI(self):
        """
        Intitialize the main GUI, consisting of:
            
        - A combo box to select the filter topology and an image of the topology
        
        - The input quantizer
        
        - The UI of the fixpoint filter widget
        
        - Simulation and export buttons
        """
        #------------------------------------------------------------------------------
        # Define frame and layout for the dynamically updated filter widget
        # The actual filter widget is instantiated in self.set_fixp_widget() later on

        self.layH_fx_wdg = QHBoxLayout()
        #self.layH_fx_wdg.setContentsMargins(*params['wdg_margins'])
        frmHDL_wdg = QFrame(self)
        frmHDL_wdg.setLayout(self.layH_fx_wdg)
        #frmHDL_wdg.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)

        #------------------------------------------------------------------------------
        #       Initialize fixpoint filter combobox, title and description
        #------------------------------------------------------------------------------
        self.cmb_wdg_fixp = QComboBox(self)
        self.cmb_wdg_fixp.setSizeAdjustPolicy(QComboBox.AdjustToContents)

        self.lblTitle = QLabel("not set", self)
        self.lblTitle.setWordWrap(True)
        self.lblTitle.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Fixed)
        layHTitle = QHBoxLayout()
        layHTitle.addWidget(self.cmb_wdg_fixp)
        layHTitle.addWidget(self.lblTitle)

        self.frmTitle = QFrame(self)
        self.frmTitle.setLayout(layHTitle)
        self.frmTitle.setContentsMargins(*params['wdg_margins'])

        #------------------------------------------------------------------------------
        #       Input and Output Quantizer
        #------------------------------------------------------------------------------
        #       - instantiate widgets for input and output quantizer
        #       - pass the quantization (sub-?) dictionary to the constructor
        #------------------------------------------------------------------------------

        self.wdg_w_input = UI_W(self,
                                q_dict=fb.fil[0]['fxqc']['QI'],
                                id='w_input',
                                label='',
                                lock_visible=True)
        self.wdg_w_input.sig_tx.connect(self.process_sig_rx)

        cmb_q = ['round', 'floor', 'fix']

        self.wdg_w_output = UI_W(self,
                                 q_dict=fb.fil[0]['fxqc']['QO'],
                                 id='w_output',
                                 label='')
        self.wdg_w_output.sig_tx.connect(self.process_sig_rx)

        self.wdg_q_output = UI_Q(
            self,
            q_dict=fb.fil[0]['fxqc']['QO'],
            id='q_output',
            label='Output Format <i>Q<sub>Y&nbsp;</sub></i>:',
            cmb_q=cmb_q,
            cmb_ov=['wrap', 'sat'])
        self.wdg_q_output.sig_tx.connect(self.sig_rx)

        if HAS_DS:
            cmb_q.append('dsm')
        self.wdg_q_input = UI_Q(
            self,
            q_dict=fb.fil[0]['fxqc']['QI'],
            id='q_input',
            label='Input Format <i>Q<sub>X&nbsp;</sub></i>:',
            cmb_q=cmb_q)
        self.wdg_q_input.sig_tx.connect(self.sig_rx)

        # Layout and frame for input quantization
        layVQiWdg = QVBoxLayout()
        layVQiWdg.addWidget(self.wdg_q_input)
        layVQiWdg.addWidget(self.wdg_w_input)
        frmQiWdg = QFrame(self)
        #frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmQiWdg.setLayout(layVQiWdg)
        frmQiWdg.setContentsMargins(*params['wdg_margins'])

        # Layout and frame for output quantization
        layVQoWdg = QVBoxLayout()
        layVQoWdg.addWidget(self.wdg_q_output)
        layVQoWdg.addWidget(self.wdg_w_output)
        frmQoWdg = QFrame(self)
        #frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmQoWdg.setLayout(layVQoWdg)
        frmQoWdg.setContentsMargins(*params['wdg_margins'])

        #------------------------------------------------------------------------------
        #       Dynamically updated image of filter topology
        #------------------------------------------------------------------------------
        # label is a placeholder for image
        self.lbl_fixp_img = QLabel("img not set", self)
        #self.lbl_fixp_img.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)

        self.embed_fixp_img(self.no_fx_filter_img)

        layHImg = QHBoxLayout()
        layHImg.setContentsMargins(0, 0, 0, 0)
        layHImg.addWidget(self.lbl_fixp_img)  #, Qt.AlignCenter)
        self.frmImg = QFrame(self)
        self.frmImg.setLayout(layHImg)
        self.frmImg.setContentsMargins(*params['wdg_margins'])
        self.resize_img()
        #------------------------------------------------------------------------------
        #       Simulation and export Buttons
        #------------------------------------------------------------------------------
        self.butExportHDL = QPushButton(self)
        self.butExportHDL.setToolTip(
            "Export fixpoint filter in Verilog format.")
        self.butExportHDL.setText("Create HDL")

        self.butSimHDL = QPushButton(self)
        self.butSimHDL.setToolTip("Start migen fixpoint simulation.")
        self.butSimHDL.setText("Sim. HDL")

        self.butSimFxPy = QPushButton(self)
        self.butSimFxPy.setToolTip("Simulate filter with fixpoint effects.")
        self.butSimFxPy.setText("Sim. FixPy")

        self.layHHdlBtns = QHBoxLayout()
        self.layHHdlBtns.addWidget(self.butSimFxPy)
        self.layHHdlBtns.addWidget(self.butSimHDL)
        self.layHHdlBtns.addWidget(self.butExportHDL)
        # This frame encompasses the HDL buttons sim and convert
        frmHdlBtns = QFrame(self)
        #frmBtns.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        frmHdlBtns.setLayout(self.layHHdlBtns)
        frmHdlBtns.setContentsMargins(*params['wdg_margins'])

        # -------------------------------------------------------------------
        #       Top level layout
        # -------------------------------------------------------------------
        splitter = QSplitter(self)
        splitter.setOrientation(Qt.Vertical)
        splitter.addWidget(frmHDL_wdg)
        splitter.addWidget(frmQoWdg)
        splitter.addWidget(self.frmImg)

        # setSizes uses absolute pixel values, but can be "misused" by specifying values
        # that are way too large: in this case, the space is distributed according
        # to the _ratio_ of the values:
        splitter.setSizes([3000, 3000, 5000])

        layVMain = QVBoxLayout()
        layVMain.addWidget(self.frmTitle)
        layVMain.addWidget(frmHdlBtns)
        layVMain.addWidget(frmQiWdg)
        layVMain.addWidget(splitter)
        layVMain.addStretch()
        layVMain.setContentsMargins(*params['wdg_margins'])

        self.setLayout(layVMain)

        #----------------------------------------------------------------------
        # GLOBAL SIGNALS & SLOTs
        #----------------------------------------------------------------------
        self.sig_rx.connect(self.process_sig_rx)
        #----------------------------------------------------------------------
        # LOCAL SIGNALS & SLOTs & EVENTFILTERS
        #----------------------------------------------------------------------
        # monitor events and generate sig_resize event when resized
        self.lbl_fixp_img.installEventFilter(self)
        # ... then redraw image when resized
        self.sig_resize.connect(self.resize_img)

        self.cmb_wdg_fixp.currentIndexChanged.connect(self._update_fixp_widget)

        self.butExportHDL.clicked.connect(self.exportHDL)
        self.butSimHDL.clicked.connect(self.fx_sim_init)
        #----------------------------------------------------------------------
        inst_wdg_list = self._update_filter_cmb()
        if len(inst_wdg_list) == 0:
            logger.warning("No fixpoint filters found!")
        else:
            logger.debug("Imported {0:d} fixpoint filters:\n{1}".format(
                len(inst_wdg_list.split("\n")) - 1, inst_wdg_list))

        self._update_fixp_widget()

#------------------------------------------------------------------------------

    def _update_filter_cmb(self):
        """
        (Re-)Read list of available fixpoint filters for a given filter design 
        every time a new filter design is selected. 
        
        Then try to import the fixpoint designs in the list and populate the 
        fixpoint implementation combo box `self.cmb_wdg_fixp` when successfull. 
        """
        inst_wdg_str = ""  # full names of successfully instantiated widgets for logging
        last_fx_wdg = qget_cmb_box(
            self.cmb_wdg_fixp, data=False)  # remember last fx widget setting
        self.cmb_wdg_fixp.clear()
        fc = fb.fil[0]['fc']
        if 'fix' in fb.filter_classes[fc]:
            for class_name in fb.filter_classes[fc]['fix']:  # get class name
                try:
                    # construct module + class name
                    mod_class_name = fb.fixpoint_classes[class_name][
                        'mod'] + '.' + class_name
                    disp_name = fb.fixpoint_classes[class_name][
                        'name']  # # and display name
                    self.cmb_wdg_fixp.addItem(disp_name, mod_class_name)
                    inst_wdg_str += '\t' + class_name + ' : ' + mod_class_name + '\n'
                except AttributeError as e:
                    logger.warning('Widget "{0}":\n{1}'.format(class_name, e))
                    self.embed_fixp_img(self.no_fx_filter_img)
                    continue
                except KeyError as e:
                    logger.warning(
                        "No fixpoint filter for filter type {0} available.".
                        format(e))
                    self.embed_fixp_img(self.no_fx_filter_img)
                    continue

        # restore last fxp widget if possible
            idx = self.cmb_wdg_fixp.findText(last_fx_wdg)
            # set to idx 0 if not found (returned -1)
            self.cmb_wdg_fixp.setCurrentIndex(max(idx, 0))
        else:  # no fixpoint widget
            self.embed_fixp_img(self.no_fx_filter_img)
        return inst_wdg_str

#------------------------------------------------------------------------------

    def eventFilter(self, source, event):
        """
        Filter all events generated by monitored QLabel, only resize events are
        processed here, generating a `sig_resize` signal. All other events
        are passed on to the next hierarchy level.
        """
        if event.type() == QEvent.Resize:
            self.sig_resize.emit()

        # Call base class method to continue normal event processing:
        return super(Input_Fixpoint_Specs, self).eventFilter(source, event)
#------------------------------------------------------------------------------

    def embed_fixp_img(self, img_file):
        """ 
        Embed image as self.img_fixp, either in png or svg format
        
        Parameters:
            
            img_file: str
            path and file name to image file
        """
        if not os.path.isfile(img_file):
            logger.warning("Image file {0} doesn't exist.".format(img_file))
            img_file = self.default_fx_img

#        _, file_extension = os.path.splitext(self.fx_wdg_inst.img_name)
        _, file_extension = os.path.splitext(img_file)
        if file_extension == '.png':
            self.img_fixp = QPixmap(img_file)
            #self.lbl_fixp_img.setPixmap(QPixmap(self.img_fixp)) # fixed size
        # elif file_extension == '.svg':
        #     self.img_fixp = QtSvg.QSvgWidget(img_file)

        else:
            logger.error(
                'Unknown file extension "{0}"!'.format(file_extension))

        self.resize_img()

#------------------------------------------------------------------------------

    def resize_img(self):
        """ 
        Triggered when self (the widget) is resized, consequently the image
        inside QLabel is resized to completely fill the label while keeping 
        the aspect ratio.
        
        This doesn't really work at the moment.
        """

        if hasattr(self.parent, "width"):  # needed for module test
            par_w, par_h = self.parent.width(), self.parent.height()
        else:
            par_w, par_h = 300, 700  # fixed size for module testself.lbl_img_fixp
        lbl_w, lbl_h = self.lbl_fixp_img.width(), self.lbl_fixp_img.height()
        img_w, img_h = self.img_fixp.width(), self.img_fixp.height()

        if img_w > 10:
            max_h = int(max(np.floor(img_h * par_w / img_w) - 15, 20))
        else:
            max_h = 200
        logger.debug("img size: {0},{1}, frm size: {2},{3}, max_h: {4}".format(
            img_w, img_h, par_w, par_h, max_h))

        # The following doesn't work because the width of the parent widget can grow
        # with the image size
        # img_scaled = self.img_fixp.scaled(self.lbl_fixp_img.size(), Qt.KeepAspectRatio, Qt.SmoothTransformation)
        img_scaled = self.img_fixp.scaledToHeight(max_h,
                                                  Qt.SmoothTransformation)
        #img_scaled = self.img_fixp.scaledToHeight(max_h)

        self.lbl_fixp_img.setPixmap(img_scaled)

#------------------------------------------------------------------------------

    def _update_fixp_widget(self):
        """
        This method is called at the initialization of the widget and when
        a new fixpoint filter implementation is selected from the combo box:

        - Destruct old instance of fixpoint filter widget `self.fx_wdg_inst`

        - Import and instantiate new fixpoint filter widget e.g. after changing the 
          filter topology as 

        - Try to load image for filter topology

        - Update the UI of the widget

        - Try to instantiate HDL filter as `self.fx_wdg_inst.fixp_filter` with 
            dummy data
        """
        def _disable_fx_wdg(self):

            if hasattr(
                    self, "fx_wdg_inst"
            ) and self.fx_wdg_inst is not None:  # is a fixpoint widget loaded?
                try:
                    self.layH_fx_wdg.removeWidget(
                        self.fx_wdg_inst)  # remove widget from layout
                    self.fx_wdg_inst.deleteLater(
                    )  # delete QWidget when scope has been left
                except AttributeError as e:
                    logger.error("Destructing UI failed!\n{0}".format(e))

            self.fx_wdg_found = False
            self.butSimFxPy.setVisible(False)
            self.butSimHDL.setEnabled(False)
            self.butExportHDL.setEnabled(False)
            #self.layH_fx_wdg.setVisible(False)
            self.img_fixp = self.embed_fixp_img(self.no_fx_filter_img)
            self.lblTitle.setText("")

            self.fx_wdg_inst = None

        # destruct old fixpoint widget instance
        _disable_fx_wdg(self)

        # instantiate new fixpoint widget class as self.fx_wdg_inst
        cmb_wdg_fx_cur = qget_cmb_box(self.cmb_wdg_fixp, data=False)
        if cmb_wdg_fx_cur:  # at least one valid fixpoint widget found
            self.fx_wdg_found = True
            # get list [module name and path, class name]
            fx_mod_class_name = qget_cmb_box(self.cmb_wdg_fixp,
                                             data=True).rsplit('.', 1)
            fx_mod = importlib.import_module(
                fx_mod_class_name[0])  # get module
            fx_wdg_class = getattr(fx_mod, fx_mod_class_name[1])  # get class
            #++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            self.fx_wdg_inst = fx_wdg_class(
                self)  # instantiate the fixpoint widget
            #++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
            self.layH_fx_wdg.addWidget(self.fx_wdg_inst,
                                       stretch=1)  # and add it to layout
            self.fx_wdg_inst.setVisible(True)
            # Doesn't work at the moment, combo box becomes inaccessible
            #            try:
            #                self.fx_wdg_inst = fx_wdg_class(self) # instantiate the widget
            #                self.layH_fx_wdg.addWidget(self.fx_wdg_inst, stretch=1) # and add it to layout
            #            except KeyError as e:
            #                logger.warning('Key Error {0} in fixpoint filter \n{1}'\
            #                               .format(e, fx_mod_name + "." + cmb_wdg_fx_cur))
            #                _disable_fx_wdg(self)
            #                return

            self.wdg_dict2ui(
            )  # initialize the fixpoint subwidgets from the fxqc_dict

            #---- connect signals to fx_wdg_inst ----
            if hasattr(self.fx_wdg_inst, "sig_rx"):
                self.sig_rx.connect(self.fx_wdg_inst.sig_rx)
            if hasattr(self.fx_wdg_inst, "sig_tx"):
                self.fx_wdg_inst.sig_tx.connect(self.sig_rx)

            #---- get name of new fixpoint filter image ----
            if not (hasattr(self.fx_wdg_inst, "img_name") and
                    self.fx_wdg_inst.img_name):  # is an image name defined?
                img_file = self.default_fx_img
            else:
                file_path = os.path.dirname(
                    fx_mod.__file__
                )  # get path of imported fixpoint widget and
                img_file = os.path.join(file_path, self.fx_wdg_inst.img_name
                                        )  # construct full image name from it

        #---- instantiate and scale graphic of filter topology ----
            self.embed_fixp_img(img_file)

            #---- set title and description for filter
            self.lblTitle.setText(self.fx_wdg_inst.title)

            #--- try to reference Python fixpoint filter instance -----
            #            if hasattr(self.fx_wdg_inst,'fxpy_filter'):
            #                self.fxpy_filter_inst = self.fx_wdg_inst.fxpy_filter
            #                self.butSimFxPy.setEnabled(True)
            #            else:
            #                self.butSimFxPy.setVisible(False)

            #--- Check whether fixpoint widget contains HDL filters -----
            if hasattr(self.fx_wdg_inst, 'fixp_filter'):
                self.butExportHDL.setEnabled(
                    hasattr(self.fx_wdg_inst, "to_verilog"))
                self.butSimHDL.setEnabled(hasattr(self.fx_wdg_inst, "run_sim"))
                self.update_fxqc_dict()
                self.sig_tx.emit({
                    'sender': __name__,
                    'fx_sim': 'specs_changed'
                })
            else:
                self.butSimHDL.setEnabled(False)
                self.butExportHDL.setEnabled(False)

        else:
            _disable_fx_wdg(self)

#------------------------------------------------------------------------------

    def wdg_dict2ui(self):
        """
        Trigger an update of the fixpoint widget UI when view (i.e. fixpoint 
        coefficient format) or data have been changed outside this class. Additionally,
        pass the fixpoint quantization widget to update / restore other subwidget
        settings.
        
        Set the RUN button to "changed".
        """
        #        fb.fil[0]['fxqc']['QCB'].update({'scale':(1 << fb.fil[0]['fxqc']['QCB']['W'])})
        self.wdg_q_input.dict2ui(fb.fil[0]['fxqc']['QI'])
        self.wdg_q_output.dict2ui(fb.fil[0]['fxqc']['QO'])
        self.wdg_w_input.dict2ui(fb.fil[0]['fxqc']['QI'])
        self.wdg_w_output.dict2ui(fb.fil[0]['fxqc']['QO'])
        if self.fx_wdg_found and hasattr(self.fx_wdg_inst, "dict2ui"):
            self.fx_wdg_inst.dict2ui()
#            dict_sig = {'sender':__name__, 'fx_sim':'specs_changed'}
#            self.sig_tx.emit(dict_sig)

        qstyle_widget(self.butSimHDL, "changed")
#------------------------------------------------------------------------------

    def update_fxqc_dict(self):
        """
        Update the fxqc dictionary before simulation / HDL generation starts.
        """
        if self.fx_wdg_found:
            # get a dict with the coefficients and fixpoint settings from fixpoint widget
            if hasattr(self.fx_wdg_inst, "ui2dict"):
                fb.fil[0]['fxqc'].update(self.fx_wdg_inst.ui2dict())
                logger.debug("update fxqc: \n{0}".format(
                    pprint_log(fb.fil[0]['fxqc'])))
        else:
            logger.error("No fixpoint widget found!")
#------------------------------------------------------------------------------

    def exportHDL(self):
        """
        Synthesize HDL description of filter
        """
        if not hasattr(self.fx_wdg_inst, 'construct_fixp_filter'):
            logger.warning(
                'Fixpoint widget has no method "construct_fixp_filter", aborting.'
            )
            return

        dlg = QFD(self)  # instantiate file dialog object

        file_types = "Verilog (*.v)"
        dlg.setDefaultSuffix(
            'v'
        )  # needed for overwrite confirmation when name is entered without suffix
        dlg.setWindowTitle('Export Vlog')
        dlg.setNameFilter(file_types)
        dlg.setDirectory(dirs.save_dir)
        dlg.setAcceptMode(
            QFD.AcceptSave)  # set mode "save file" instead "open file"
        dlg.setOption(QFD.DontConfirmOverwrite, False)
        if dlg.exec_() == QFD.Accepted:
            hdl_file = qstr(dlg.selectedFiles()[0])
            # hdl_type = extract_file_ext(qstr(dlg.selectedNameFilter()))[0]

            # =============================================================================
            #       # static method getSaveFileName_() is simple but unflexible
            #         hdl_file, hdl_filter = dlg.getSaveFileName_(
            #                 caption="Save Verilog netlist as (this also defines the module name)",
            #                 directory=dirs.save_dir, filter=file_types)
            #         hdl_file = qstr(hdl_file)
            #         if hdl_file != "": # "operation cancelled" returns an empty string
            #             # return '.v' or '.vhd' depending on filetype selection:
            #             # hdl_type = extract_file_ext(qstr(hdl_filter))[0]
            #             # sanitized dir + filename + suffix. The filename suffix is replaced
            #             # by `v` later.
            #             hdl_file = os.path.normpath(hdl_file) # complete path + file name
            # =============================================================================
            hdl_dir_name = os.path.dirname(
                hdl_file)  # extract the directory path
            if not os.path.isdir(
                    hdl_dir_name):  # create directory if it doesn't exist
                os.mkdir(hdl_dir_name)
            dirs.save_dir = hdl_dir_name  # make this directory the new default / base dir
            hdl_file_name = os.path.splitext(os.path.basename(hdl_file))[0]
            hdl_full_name = os.path.join(hdl_dir_name, hdl_file_name + ".v")
            vlog_mod_name = re.sub(
                r'\W+', '',
                hdl_file_name).lower()  # remove all non-alphanumeric chars

            logger.info(
                'Creating hdl_file "{0}"\n\twith top level module "{1}"'.
                format(hdl_full_name, vlog_mod_name))
            try:
                self.update_fxqc_dict()
                self.fx_wdg_inst.construct_fixp_filter()
                code = self.fx_wdg_inst.to_verilog(name=vlog_mod_name)
                #logger.info(str(code)) # print verilog code to console
                with io.open(hdl_full_name, 'w', encoding="utf8") as f:
                    f.write(str(code))

                logger.info("HDL conversion finished!")
            except (IOError, TypeError) as e:
                logger.warning(e)

##------------------------------------------------------------------------------
#    def fx_sim_py(self):
#        """
#        Start fix-point simulation: Send the ``fxqc_dict``
#        containing all quantization information and request a stimulus signal
#        Not implemented yet
#        """
#        try:
#            logger.info("Started python fixpoint simulation")
#            self.update_fxqc_dict()
#            self.fxpyfilter.setup(fb.fil[0]['fxqc'])   # setup filter instance
#            dict_sig = {'sender':__name__, 'fx_sim':'get_stimulus'}
#            self.sig_tx.emit(dict_sig)
#
#        except AttributeError as e:
#            logger.warning("Fixpoint stimulus generation failed:\n{0}".format(e))
#        return

#------------------------------------------------------------------------------

    def fx_sim_init(self):
        """
        Initialize fix-point simulation: 
            
        - Update the `fxqc_dict` containing all quantization information
        
        - Setup a filter instance for migen simulation
        
        - Request a stimulus signal
        """
        if not hasattr(self.fx_wdg_inst, 'construct_fixp_filter'):
            logger.error(
                'Fixpoint widget has no method "construct_fixp_filter", aborting.'
            )
            self.sig_tx.emit({'sender': __name__, 'fx_sim': 'error'})
            return

        try:
            logger.info("Fixpoint simulation started")
            self.t_start = time.process_time()
            self.update_fxqc_dict()
            self.fx_wdg_inst.construct_fixp_filter()  # setup filter instance

            dict_sig = {'sender': __name__, 'fx_sim': 'get_stimulus'}
            self.sig_tx.emit(dict_sig)

        except ValueError as e:  # exception
            logger.error(
                'Fixpoint stimulus generation failed during "init" for dict\n{0}'
                '\nwith "{1} "'.format(pprint_log(dict_sig), e))
        return

#------------------------------------------------------------------------------

    def fx_sim_set_stimulus(self, dict_sig):
        """
        - Get fixpoint stimulus from `dict_sig` in integer format
          
        - Pass it to the fixpoint filter and calculate the fixpoint response
        
        - Send the reponse to the plotting widget
        """
        try:
            logger.debug(
                'Starting fixpoint simulation with stimulus from "{0}":\n\tfx_stimulus:{1}'
                '\n\tStimuli: Shape {2} of type "{3}"'.format(
                    dict_sig['sender'],
                    pprint_log(dict_sig['fx_stimulus'], tab=" "),
                    np.shape(dict_sig['fx_stimulus']),
                    dict_sig['fx_stimulus'].dtype,
                ))
            self.t_stim = time.process_time()
            logger.info("Fixpoint simulation [{0:5.3g} ms]: Stimuli generated"\
                        .format((self.t_stim-self.t_start)*1000))

            # Run fixpoint simulation and return the results as integer values:
            self.fx_results = self.fx_wdg_inst.run_sim(
                dict_sig['fx_stimulus'])  # Run the simulation
            self.t_resp = time.process_time()

            if len(self.fx_results) == 0:
                logger.warning("Fixpoint simulation returned empty results!")
            else:
                #logger.debug("fx_results: {0}"\
                #            .format(pprint_log(self.fx_results, tab= " ")))
                logger.debug('Fixpoint simulation successful for dict\n{0}'
                         '\tStimuli: Shape {1} of type "{2}"'
                         '\n\tResponse: Shape {3} of type "{4}"'\
                           .format(pprint_log(dict_sig),
                                   np.shape(dict_sig['fx_stimulus']),
                                   dict_sig['fx_stimulus'].dtype,
                                   np.shape(self.fx_results),
                                   type(self.fx_results)
                                    ))
                logger.info('Fixpoint simulation [{0:5.3g} ms]: Response calculated'\
                            .format((self.t_resp - self.t_stim)*1000))

            #TODO: fixed point / integer to float conversion?
            #TODO: color push-button to show state of simulation
            #TODO: add QTimer single shot
#            self.timer_id = QtCore.QTimer()
#            self.timer_id.setSingleShot(True)
#            # kill simulation after some idle time, also add a button for this
#            self.timer_id.timeout.connect(self.kill_sim)

        except ValueError as e:
            logger.error("Simulator error {0}".format(e))
            self.fx_results = None
            qstyle_widget(self.butSimHDL, "error")
            self.sig_tx.emit({'sender': __name__, 'fx_sim': 'error'})
            return
        except AssertionError as e:
            logger.error('Fixpoint simulation failed for dict\n{0}'
                         '\twith msg. "{1}"\n\tStimuli: Shape {2} of type "{3}"'
                         '\n\tResponse: Shape {4} of type "{5}"'\
                           .format(pprint_log(dict_sig), e,
                                   np.shape(dict_sig['fx_stimulus']),
                                   dict_sig['fx_stimulus'].dtype,
                                   np.shape(self.fx_results),
                                   type(self.fx_results)
                                    ))

            self.fx_results = None
            qstyle_widget(self.butSimHDL, "error")
            self.sig_tx.emit({'sender': __name__, 'fx_sim': 'error'})
            return

        logger.debug("Sending fixpoint results")
        dict_sig = {
            'sender': __name__,
            'fx_sim': 'set_results',
            'fx_results': self.fx_results
        }
        self.sig_tx.emit(dict_sig)
        qstyle_widget(self.butSimHDL, "normal")
        return