feat: console: various improvements, auto-adapt rows to widget size, Qt Designer plugin

bec_widgets/widgets/console/console.py

@@ -1,24 +1,24 @@
 """
-BECConsole is a Qt widget that runs a Bash shell. The widget can be used and
-embedded like any other Qt widget.
+BECConsole is a Qt widget that runs a Bash shell. 
 
-BECConsole is powered by Pyte, a Python based terminal emulator
+BECConsole VT100 emulation is powered by Pyte,
 (https://github.com/selectel/pyte).
 """
 
+import collections
 import fcntl
 import html
 import os
 import pty
-import subprocess
 import sys
-import threading
 
 import pyte
+from pyte.screens import History
 from qtpy import QtCore, QtGui, QtWidgets
-from qtpy.QtCore import QSize, QSocketNotifier, Qt
+from qtpy.QtCore import Property as pyqtProperty
+from qtpy.QtCore import QSize, QSocketNotifier, Qt, QTimer
 from qtpy.QtCore import Signal as pyqtSignal
-from qtpy.QtGui import QClipboard, QTextCursor
+from qtpy.QtGui import QClipboard, QColor, QPalette, QTextCursor
 from qtpy.QtWidgets import QApplication, QHBoxLayout, QScrollBar, QSizePolicy
 
 from bec_widgets.qt_utils.error_popups import SafeSlot as Slot
@@ -137,13 +137,52 @@ def QtKeyToAscii(event):
 
 
 class Screen(pyte.HistoryScreen):
-    def __init__(self, stdin_fd, numColumns, numLines, historyLength):
-        super().__init__(numColumns, numLines, historyLength, ratio=1 / numLines)
+    def __init__(self, stdin_fd, cols, rows, historyLength):
+        super().__init__(cols, rows, historyLength, ratio=1 / rows)
         self._fd = stdin_fd
 
     def write_process_input(self, data):
-        """Response to CPR request for example"""
-        os.write(self._fd, data.encode("utf-8"))
+        """Response to CPR request (for example),
+        this can be for other requests
+        """
+        try:
+            os.write(self._fd, data.encode("utf-8"))
+        except (IOError, OSError):
+            pass
+
+    def resize(self, lines, columns):
+        lines = lines or self.lines
+        columns = columns or self.columns
+
+        if lines == self.lines and columns == self.columns:
+            return  # No changes.
+
+        self.dirty.clear()
+        self.dirty.update(range(lines))
+
+        self.save_cursor()
+        if lines < self.lines:
+            if lines <= self.cursor.y:
+                nlines_to_move_up = self.lines - lines
+                for i in range(nlines_to_move_up):
+                    line = self.buffer[i]  # .pop(0)
+                    self.history.top.append(line)
+                self.cursor_position(0, 0)
+                self.delete_lines(nlines_to_move_up)
+                self.restore_cursor()
+                self.cursor.y -= nlines_to_move_up
+        else:
+            self.restore_cursor()
+
+        self.lines, self.columns = lines, columns
+        self.history = History(
+            self.history.top,
+            self.history.bottom,
+            1 / self.lines,
+            self.history.size,
+            self.history.position,
+        )
+        self.set_margins()
 
 
 class Backend(QtCore.QObject):
@@ -155,17 +194,17 @@ class Backend(QtCore.QObject):
     """
 
     # Signals to communicate with ``_TerminalWidget``.
-    startWork = pyqtSignal()
     dataReady = pyqtSignal(object)
+    processExited = pyqtSignal()
 
-    def __init__(self, fd, numColumns, numLines):
+    def __init__(self, fd, cols, rows):
         super().__init__()
 
         # File descriptor that connects to Bash process.
         self.fd = fd
 
         # Setup Pyte (hard coded display size for now).
-        self.screen = Screen(self.fd, numColumns, numLines, 10000)
+        self.screen = Screen(self.fd, cols, rows, 10000)
         self.stream = pyte.ByteStream()
         self.stream.attach(self.screen)
 
@@ -174,12 +213,14 @@ class Backend(QtCore.QObject):
 
     def _fd_readable(self):
         """
-        Poll the Bash output, run it through Pyte, and notify the main applet.
+        Poll the Bash output, run it through Pyte, and notify
         """
         # Read the shell output until the file descriptor is closed.
         try:
             out = os.read(self.fd, 2**16)
         except OSError:
+            self.processExited.emit()
+            self.notifier.setEnabled(False)
             return
 
         # Feed output into Pyte's state machine and send the new screen
@@ -188,93 +229,256 @@ class Backend(QtCore.QObject):
         self.dataReady.emit(self.screen)
 
 
-class BECConsole(QtWidgets.QScrollArea):
+class BECConsole(QtWidgets.QWidget):
     """Container widget for the terminal text area"""
 
-    def __init__(self, parent=None, numLines=50, numColumns=125):
+    ICON_NAME = "terminal"
+
+    def __init__(self, parent=None, cols=132):
         super().__init__(parent)
 
-        self.innerWidget = QtWidgets.QWidget(self)
-        QHBoxLayout(self.innerWidget)
-        self.innerWidget.layout().setContentsMargins(0, 0, 0, 0)
+        self.term = _TerminalWidget(self, cols, rows=43)
+        self.scroll_bar = QScrollBar(Qt.Vertical, self)
+        # self.scroll_bar.hide()
+        layout = QHBoxLayout(self)
+        layout.addWidget(self.term)
+        layout.addWidget(self.scroll_bar)
+        layout.setAlignment(Qt.AlignLeft | Qt.AlignTop)
+        layout.setContentsMargins(0, 0, 0, 0)
+        self.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Expanding)
 
-        self.term = _TerminalWidget(self.innerWidget, numLines, numColumns)
-        self.term.setSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed)
-        self.innerWidget.layout().addWidget(self.term)
+        pal = QPalette()
+        self.set_bgcolor(pal.window().color())
+        self.set_fgcolor(pal.windowText().color())
+        self.term.set_scroll_bar(self.scroll_bar)
+        self.set_cmd("bec --nogui")
 
-        self.scroll_bar = QScrollBar(Qt.Vertical, self.term)
-        self.innerWidget.layout().addWidget(self.scroll_bar)
+        self._check_designer_timer = QTimer()
+        self._check_designer_timer.timeout.connect(self.check_designer)
+        self._check_designer_timer.start(1000)
 
-        self.term.set_scroll(self.scroll_bar)
+    def minimumSizeHint(self):
+        size = self.term.sizeHint()
+        size.setWidth(size.width() + self.scroll_bar.width())
+        return size
 
-        self.setWidget(self.innerWidget)
+    def sizeHint(self):
+        return self.minimumSizeHint()
 
-    def start(self, cmd=["bec", "--nogui"], deactivate_ctrl_d=True):
+    def check_designer(self, calls={"n": 0}):
+        calls["n"] += 1
+        if self.term.fd is not None:
+            # already started
+            self._check_designer_timer.stop()
+        elif self.window().windowTitle().endswith("[Preview]"):
+            # assuming Designer preview -> start
+            self._check_designer_timer.stop()
+            self.term.start()
+        elif calls["n"] >= 3:
+            # assuming not in Designer -> stop checking
+            self._check_designer_timer.stop()
+
+    def get_rows(self):
+        return self.term.rows
+
+    def set_rows(self, rows):
+        self.term.rows = rows
+        self.adjustSize()
+        self.updateGeometry()
+
+    def get_cols(self):
+        return self.term.cols
+
+    def set_cols(self, cols):
+        self.term.cols = cols
+        self.adjustSize()
+        self.updateGeometry()
+
+    def get_bgcolor(self):
+        return QColor.fromString(self.term.bg_color)
+
+    def set_bgcolor(self, color):
+        self.term.bg_color = color.name(QColor.HexRgb)
+
+    def get_fgcolor(self):
+        return QColor.fromString(self.term.fg_color)
+
+    def set_fgcolor(self, color):
+        self.term.fg_color = color.name(QColor.HexRgb)
+
+    def get_cmd(self):
+        return self.term._cmd
+
+    def set_cmd(self, cmd):
         self.term._cmd = cmd
+        if self.term.fd is None:
+            # not started yet
+            self.term.clear()
+            self.term.appendHtml(f"<h2>BEC Console - {repr(cmd)}</h2>")
+
+    def start(self, deactivate_ctrl_d=True):
         self.term.start(deactivate_ctrl_d=deactivate_ctrl_d)
 
     def push(self, text):
         """Push some text to the terminal"""
         return self.term.push(text)
 
+    cols = pyqtProperty(int, get_cols, set_cols)
+    rows = pyqtProperty(int, get_rows, set_rows)
+    bgcolor = pyqtProperty(QColor, get_bgcolor, set_bgcolor)
+    fgcolor = pyqtProperty(QColor, get_fgcolor, set_fgcolor)
+    cmd = pyqtProperty(str, get_cmd, set_cmd)
+
 
 class _TerminalWidget(QtWidgets.QPlainTextEdit):
     """
     Start ``Backend`` process and render Pyte output as text.
     """
 
-    def __init__(self, parent, numColumns=125, numLines=50, **kwargs):
-        super().__init__(parent)
-
+    def __init__(self, parent, cols=125, rows=50, **kwargs):
         # file descriptor to communicate with the subprocess
         self.fd = None
         self.backend = None
-        self.lock = threading.Lock()
         # command to execute
-        self._cmd = None
+        self._cmd = ""
         # should ctrl-d be deactivated ? (prevent Python exit)
         self._deactivate_ctrl_d = False
 
+        # Default colors
+        pal = QPalette()
+        self._fg_color = pal.text().color().name()
+        self._bg_color = pal.base().color().name()
+
         # Specify the terminal size in terms of lines and columns.
-        self.numLines = numLines
-        self.numColumns = numColumns
-        self.output = [""] * numLines
+        self._rows = rows
+        self._cols = cols
+        self.output = collections.deque()
+
+        super().__init__(parent)
+
+        self.setSizePolicy(QSizePolicy.MinimumExpanding, QSizePolicy.Expanding)
+
+        # Disable default scrollbars (we use our own, to be set via .set_scroll_bar())
+        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
+        self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
+        self.scroll_bar = None
 
         # Use Monospace fonts and disable line wrapping.
         self.setFont(QtGui.QFont("Courier", 9))
         self.setFont(QtGui.QFont("Monospace"))
         self.setLineWrapMode(QtWidgets.QPlainTextEdit.NoWrap)
-
-        # Disable vertical scrollbar (we use our own, to be set via .set_scroll())
-        self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
-
         fmt = QtGui.QFontMetrics(self.font())
-        self._char_width = fmt.width("w")
-        self._char_height = fmt.height()
-        self.setCursorWidth(self._char_width)
-        # self.setStyleSheet("QPlainTextEdit { color: #ffff00; background-color: #303030; } ");
+        char_width = fmt.width("w")
+        self.setCursorWidth(char_width)
 
-    def start(self, deactivate_ctrl_d=False):
+        self.adjustSize()
+        self.updateGeometry()
+        self.update_stylesheet()
+
+    @property
+    def bg_color(self):
+        return self._bg_color
+
+    @bg_color.setter
+    def bg_color(self, hexcolor):
+        self._bg_color = hexcolor
+        self.update_stylesheet()
+
+    @property
+    def fg_color(self):
+        return self._fg_color
+
+    @fg_color.setter
+    def fg_color(self, hexcolor):
+        self._fg_color = hexcolor
+        self.update_stylesheet()
+
+    def update_stylesheet(self):
+        self.setStyleSheet(
+            f"QPlainTextEdit {{ border: 0; color: {self._fg_color}; background-color: {self._bg_color}; }} "
+        )
+
+    @property
+    def rows(self):
+        return self._rows
+
+    @rows.setter
+    def rows(self, rows: int):
+        if self.backend is None:
+            # not initialized yet, ok to change
+            self._rows = rows
+            self.adjustSize()
+            self.updateGeometry()
+        else:
+            raise RuntimeError("Cannot change rows after console is started.")
+
+    @property
+    def cols(self):
+        return self._cols
+
+    @cols.setter
+    def cols(self, cols: int):
+        if self.fd is None:
+            # not initialized yet, ok to change
+            self._cols = cols
+            self.adjustSize()
+            self.updateGeometry()
+        else:
+            raise RuntimeError("Cannot change cols after console is started.")
+
+    def start(self, deactivate_ctrl_d: bool = False):
         self._deactivate_ctrl_d = deactivate_ctrl_d
 
-        # Start the Bash process
-        self.fd = self.forkShell()
+        self.update_term_size()
 
-        # Create the ``Backend`` object
-        self.backend = Backend(self.fd, self.numColumns, self.numLines)
-        self.backend.dataReady.connect(self.dataReady)
+        # Start the Bash process
+        self.fd = self.fork_shell()
+
+        if self.fd:
+            # Create the ``Backend`` object
+            self.backend = Backend(self.fd, self.cols, self.rows)
+            self.backend.dataReady.connect(self.data_ready)
+            self.backend.processExited.connect(self.process_exited)
+        else:
+            self.process_exited()
+
+    def process_exited(self):
+        self.fd = None
+        self.clear()
+        self.appendHtml(f"<br><h2>{repr(self._cmd)} - Process exited.</h2>")
+        self.setReadOnly(True)
+
+    def data_ready(self, screen):
+        """Handle new screen: redraw, set scroll bar max and slider, move cursor to its position
+
+        This method is triggered via a signal from ``Backend``.
+        """
+        self.redraw_screen()
+        self.adjust_scroll_bar()
+        self.move_cursor()
 
     def minimumSizeHint(self):
-        width = self._char_width * self.numColumns
-        height = self._char_height * self.numLines
-        return QSize(width, height + 20)
+        """Return minimum size for current cols and rows"""
+        fmt = QtGui.QFontMetrics(self.font())
+        char_width = fmt.width("w")
+        char_height = fmt.height()
+        width = char_width * self.cols
+        height = char_height * self.rows
+        return QSize(width, height)
 
-    def set_scroll(self, scroll):
-        self.scroll = scroll
-        self.scroll.setMinimum(0)
-        self.scroll.valueChanged.connect(self.scroll_value_change)
+    def sizeHint(self):
+        return self.minimumSizeHint()
 
-    def scroll_value_change(self, value, old={"value": 0}):
+    def set_scroll_bar(self, scroll_bar):
+        self.scroll_bar = scroll_bar
+        self.scroll_bar.setMinimum(0)
+        self.scroll_bar.valueChanged.connect(self.scroll_value_change)
+
+    def scroll_value_change(self, value, old={"value": -1}):
+        if self.backend is None:
+            return
+        if old["value"] == -1:
+            old["value"] = self.scroll_bar.maximum()
         if value <= old["value"]:
             # scroll up
             # value is number of lines from the start
@@ -288,13 +492,35 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
             for i in range(nlines):
                 self.backend.screen.next_page()
         old["value"] = value
-        self.dataReady(self.backend.screen, reset_scroll=False)
+        self.redraw_screen()
+
+    def adjust_scroll_bar(self):
+        sb = self.scroll_bar
+        sb.valueChanged.disconnect(self.scroll_value_change)
+        tmp = len(self.backend.screen.history.top) + len(self.backend.screen.history.bottom)
+        sb.setMaximum(tmp if tmp > 0 else 0)
+        sb.setSliderPosition(tmp if tmp > 0 else 0)
+        # if tmp > 0:
+        #    # show scrollbar, but delayed - prevent recursion with widget size change
+        #    QTimer.singleShot(0, scrollbar.show)
+        # else:
+        #    QTimer.singleShot(0, scrollbar.hide)
+        sb.valueChanged.connect(self.scroll_value_change)
+
+    def write(self, data):
+        try:
+            os.write(self.fd, data)
+        except (IOError, OSError):
+            self.process_exited()
 
     @Slot(object)
     def keyPressEvent(self, event):
         """
         Redirect all keystrokes to the terminal process.
         """
+        if self.fd is None:
+            # not started
+            return
         # Convert the Qt key to the correct ASCII code.
         if (
             self._deactivate_ctrl_d
@@ -311,15 +537,17 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
             # MacOS only: CMD-V handling
             self._push_clipboard()
         elif code is not None:
-            os.write(self.fd, code)
+            self.write(code)
 
     def push(self, text):
         """
         Write 'text' to terminal
         """
-        os.write(self.fd, text.encode("utf-8"))
+        self.write(text.encode("utf-8"))
 
     def contextMenuEvent(self, event):
+        if self.fd is None:
+            return
         menu = self.createStandardContextMenu()
         for action in menu.actions():
             # remove all actions except copy and paste
@@ -341,7 +569,20 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
         clipboard = QApplication.instance().clipboard()
         self.push(clipboard.text())
 
+    def move_cursor(self):
+        textCursor = self.textCursor()
+        textCursor.setPosition(0)
+        textCursor.movePosition(
+            QTextCursor.Down, QTextCursor.MoveAnchor, self.backend.screen.cursor.y
+        )
+        textCursor.movePosition(
+            QTextCursor.Right, QTextCursor.MoveAnchor, self.backend.screen.cursor.x
+        )
+        self.setTextCursor(textCursor)
+
     def mouseReleaseEvent(self, event):
+        if self.fd is None:
+            return
         if event.button() == Qt.MiddleButton:
             # push primary selection buffer ("mouse clipboard") to terminal
             clipboard = QApplication.instance().clipboard()
@@ -355,34 +596,34 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
                 # mouse was used to select text -> nothing to do
                 pass
             else:
-                # a simple 'click', make cursor going to end
-                textCursor.setPosition(0)
-                textCursor.movePosition(
-                    QTextCursor.Down, QTextCursor.MoveAnchor, self.backend.screen.cursor.y
-                )
-                textCursor.movePosition(
-                    QTextCursor.Right, QTextCursor.MoveAnchor, self.backend.screen.cursor.x
-                )
-                self.setTextCursor(textCursor)
-                self.ensureCursorVisible()
+                # a simple 'click', move scrollbar to end
+                self.scroll_bar.setSliderPosition(self.scroll_bar.maximum())
+                self.move_cursor()
                 return None
         return super().mouseReleaseEvent(event)
 
-    def dataReady(self, screenData, reset_scroll=True):
+    def redraw_screen(self):
         """
-        Render the new screen as text into the widget.
+        Render the screen as formatted text into the widget.
+        """
+        screen = self.backend.screen
 
-        This method is triggered via a signal from ``Backend``.
-        """
-        with self.lock:
-            # Clear the widget
+        # Clear the widget
+        if screen.dirty:
             self.clear()
+            while len(self.output) < (max(screen.dirty) + 1):
+                self.output.append("")
+            while len(self.output) > (max(screen.dirty) + 1):
+                self.output.pop()
 
             # Prepare the HTML output
-            for line_no in screenData.dirty:
+            for line_no in screen.dirty:
                 line = text = ""
                 style = old_style = ""
-                for ch in screenData.buffer[line_no].values():
+                old_idx = 0
+                for idx, ch in screen.buffer[line_no].items():
+                    text += " " * (idx - old_idx - 1)
+                    old_idx = idx
                     style = f"{'background-color:%s;' % ansi_colors.get(ch.bg, ansi_colors['black']) if ch.bg!='default' else ''}{'color:%s;' % ansi_colors.get(ch.fg, ansi_colors['white']) if ch.fg!='default' else ''}{'font-weight:bold;' if ch.bold else ''}{'font-style:italic;' if ch.italics else ''}"
                     if style != old_style:
                         if old_style:
@@ -396,45 +637,47 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
                     line += f"<span style={repr(style)}>{html.escape(text, quote=True)}</span>"
                 else:
                     line += html.escape(text, quote=True)
+                # do a check at the cursor position:
+                # it is possible x pos > output line length,
+                # for example if last escape codes are "cursor forward" past end of text,
+                # like IPython does for "..." prompt (in a block, like "for" loop or "while" for example)
+                # In this case, cursor is at 12 but last text output is at 8 -> insert spaces
+                if line_no == screen.cursor.y:
+                    llen = len(screen.buffer[line_no])
+                    if llen < screen.cursor.x:
+                        line += " " * (screen.cursor.x - llen)
                 self.output[line_no] = line
             # fill the text area with HTML contents in one go
             self.appendHtml(f"<pre>{chr(10).join(self.output)}</pre>")
-            # done updates, all clean
-            screenData.dirty.clear()
+            # did updates, all clean
+            screen.dirty.clear()
 
-            # Activate cursor
-            textCursor = self.textCursor()
-            textCursor.setPosition(0)
-            textCursor.movePosition(QTextCursor.Down, QTextCursor.MoveAnchor, screenData.cursor.y)
-            textCursor.movePosition(QTextCursor.Right, QTextCursor.MoveAnchor, screenData.cursor.x)
-            self.setTextCursor(textCursor)
-            self.ensureCursorVisible()
+    def update_term_size(self):
+        fmt = QtGui.QFontMetrics(self.font())
+        char_width = fmt.width("w")
+        char_height = fmt.height()
+        self._cols = int(self.width() / char_width)
+        self._rows = int(self.height() / char_height)
 
-            # manage scroll
-            if reset_scroll:
-                self.scroll.valueChanged.disconnect(self.scroll_value_change)
-                tmp = len(self.backend.screen.history.top) + len(self.backend.screen.history.bottom)
-                self.scroll.setMaximum(tmp if tmp > 0 else 0)
-                self.scroll.setSliderPosition(len(self.backend.screen.history.top))
-                self.scroll.valueChanged.connect(self.scroll_value_change)
-
-    # def resizeEvent(self, event):
-    #    with self.lock:
-    #        self.numColumns = int(self.width() / self._char_width)
-    #        self.numLines = int(self.height() / self._char_height)
-    #        self.output = [""] * self.numLines
-    #        print("RESIZING TO", self.numColumns, "x", self.numLines)
-    #        self.backend.screen.resize(self.numLines, self.numColumns)
+    def resizeEvent(self, event):
+        self.update_term_size()
+        if self.fd:
+            self.backend.screen.resize(self._rows, self._cols)
+            self.redraw_screen()
+            self.adjust_scroll_bar()
+            self.move_cursor()
 
     def wheelEvent(self, event):
+        if not self.fd:
+            return
         y = event.angleDelta().y()
         if y > 0:
             self.backend.screen.prev_page()
         else:
             self.backend.screen.next_page()
-        self.dataReady(self.backend.screen, reset_scroll=False)
+        self.redraw_screen()
 
-    def forkShell(self):
+    def fork_shell(self):
         """
         Fork the current process and execute bec in shell.
         """
@@ -443,32 +686,30 @@ class _TerminalWidget(QtWidgets.QPlainTextEdit):
         except (IOError, OSError):
             return False
         if pid == 0:
-            # Safe way to make it work under BSD and Linux
             try:
                 ls = os.environ["LANG"].split(".")
             except KeyError:
                 ls = []
             if len(ls) < 2:
                 ls = ["en_US", "UTF-8"]
+            os.putenv("COLUMNS", str(self.cols))
+            os.putenv("LINES", str(self.rows))
+            os.putenv("TERM", "linux")
+            os.putenv("LANG", ls[0] + ".UTF-8")
+            if not self._cmd:
+                self._cmd = os.environ["SHELL"]
+            cmd = self._cmd
+            if isinstance(cmd, str):
+                cmd = cmd.split()
             try:
-                os.putenv("COLUMNS", str(self.numColumns))
-                os.putenv("LINES", str(self.numLines))
-                os.putenv("TERM", "linux")
-                os.putenv("LANG", ls[0] + ".UTF-8")
-                if isinstance(self._cmd, str):
-                    os.execvp(self._cmd, self._cmd)
-                else:
-                    os.execvp(self._cmd[0], self._cmd)
-                # print "child_pid", child_pid, sts
+                os.execvp(cmd[0], cmd)
             except (IOError, OSError):
                 pass
-            # self.proc_finish(sid)
             os._exit(0)
         else:
             # We are in the parent process.
             # Set file control
             fcntl.fcntl(fd, fcntl.F_SETFL, os.O_NONBLOCK)
-            print("Spawned Bash shell (PID {})".format(pid))
             return fd
 
 
@@ -478,17 +719,13 @@ if __name__ == "__main__":
 
     from qtpy import QtGui, QtWidgets
 
-    # Terminal size in characters.
-    numLines = 25
-    numColumns = 100
-
-    # Create the Qt application and QBash instance.
+    # Create the Qt application and console.
     app = QtWidgets.QApplication([])
     mainwin = QtWidgets.QMainWindow()
-    title = "BECConsole ({}x{})".format(numColumns, numLines)
+    title = "BECConsole"
     mainwin.setWindowTitle(title)
 
-    console = BECConsole(mainwin, numColumns, numLines)
+    console = BECConsole(mainwin)
     mainwin.setCentralWidget(console)
     console.start()
 

bec_widgets/widgets/console/console.pyproject

@@ -0,0 +1 @@
+{'files': ['console.py']}

bec_widgets/widgets/console/console_plugin.py

@@ -0,0 +1,58 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+import os
+
+from qtpy.QtDesigner import QDesignerCustomWidgetInterface
+
+import bec_widgets
+from bec_widgets.utils.bec_designer import designer_material_icon
+from bec_widgets.widgets.console.console import BECConsole
+
+DOM_XML = """
+<ui language='c++'>
+    <widget class='BECConsole' name='bec_console'>
+    </widget>
+</ui>
+"""
+
+MODULE_PATH = os.path.dirname(bec_widgets.__file__)
+
+
+class BECConsolePlugin(QDesignerCustomWidgetInterface):  # pragma: no cover
+    def __init__(self):
+        super().__init__()
+        self._form_editor = None
+
+    def createWidget(self, parent):
+        t = BECConsole(parent)
+        return t
+
+    def domXml(self):
+        return DOM_XML
+
+    def group(self):
+        return "BEC Console"
+
+    def icon(self):
+        return designer_material_icon(BECConsole.ICON_NAME)
+
+    def includeFile(self):
+        return "bec_console"
+
+    def initialize(self, form_editor):
+        self._form_editor = form_editor
+
+    def isContainer(self):
+        return False
+
+    def isInitialized(self):
+        return self._form_editor is not None
+
+    def name(self):
+        return "BECConsole"
+
+    def toolTip(self):
+        return "A terminal-like vt100 widget."
+
+    def whatsThis(self):
+        return self.toolTip()

bec_widgets/widgets/console/register_console.py

@@ -0,0 +1,15 @@
+def main():  # pragma: no cover
+    from qtpy import PYSIDE6
+
+    if not PYSIDE6:
+        print("PYSIDE6 is not available in the environment. Cannot patch designer.")
+        return
+    from PySide6.QtDesigner import QPyDesignerCustomWidgetCollection
+
+    from bec_widgets.widgets.console.console_plugin import BECConsolePlugin
+
+    QPyDesignerCustomWidgetCollection.addCustomWidget(BECConsolePlugin())
+
+
+if __name__ == "__main__":  # pragma: no cover
+    main()