Skip to main content
`Ctrl`+`K`

# Source code for pyqtgraph.graphicsItems.AxisItem

    import weakref
    from math import ceil, floor, frexp, isfinite, log10, sqrt

    import numpy as np

    from .. import debug as debug
    from .. import functions as fn
    from .. import getConfigOption
    from ..Point import Point
    from ..Qt import QtCore, QtGui, QtWidgets
    from .GraphicsWidget import GraphicsWidget

    __all__ = ['AxisItem']

    class AxisItem(GraphicsWidget):
        """
        GraphicsItem showing a single plot axis with ticks, values, and label.

        Can be configured to fit on any side of a plot, automatically synchronize its
        displayed scale with ViewBox items. Ticks can be extended to draw a grid.

        If maxTickLength is negative, ticks point into the plot.

        Parameters
        ----------
        orientation : {'left', 'right', 'top', 'bottom'}
            The side of the plot the axis is attached to.
        pen : QPen or None
            Pen used when drawing axis and (by default) ticks.
        textPen : QPen or None
            Pen used when drawing tick labels.
        tickPen : QPen or None
            Pen used when drawing ticks.
        linkView : ViewBox or None
            Causes the range of values displayed in the axis to be linked to the visible
            range of a ViewBox.
        parent : QtWidgets.QGraphicsItem or None
            Parent Qt object to set to. End users are not expected to set, pyqtgraph should
            set correctly on its own.
        maxTickLength : int
            Maximum length of ticks to draw in pixels. Negative values draw into the
            plot, positive values draw outward.  Default -5.
        showValues : bool
            Whether to display values adjacent to ticks. Default true.
        **args
            All additional keyword arguments are passed to :func:`setLabel`.
        """

        def __init__(
                self,
                orientation: str,
                pen=None,
                textPen=None,
                tickPen = None,
                linkView=None,
                parent=None,
                maxTickLength=-5,
                showValues=True,
                **args,
        ):
            super().__init__(parent)
            self.label = QtWidgets.QGraphicsTextItem(self)
            self.picture = None
            self.orientation = orientation

            if orientation in {'left', 'right'}:
                self.label.setRotation(-90)
                # allow labels on vertical axis to extend above and below the length of the axis
                hide_overlapping_labels = False
            elif orientation in {'top', 'bottom'}:
                # stop labels on horizontal axis from overlapping so vertical axis labels have room
                hide_overlapping_labels = True
            else:
                raise ValueError(
                    "Orientation argument must be one of 'left', 'right', 'top', or 'bottom'."
                )
            self.style = {
                'tickTextOffset': [5, 2],  ## (horizontal, vertical) spacing between text and axis
                'tickTextWidth': 30,  ## space reserved for tick text
                'tickTextHeight': 18,
                'autoExpandTextSpace': True,  ## automatically expand text space if needed
                'autoReduceTextSpace': True,
                'hideOverlappingLabels': hide_overlapping_labels,
                'tickFont': None,
                'stopAxisAtTick': (False, False),  ## whether axis is drawn to edge of box or to last tick
                'textFillLimits': [  ## how much of the axis to fill up with tick text, maximally.
                    (0, 0.8),    ## never fill more than 80% of the axis
                    (2, 0.6),    ## If we already have 2 ticks with text, fill no more than 60% of the axis
                    (4, 0.4),    ## If we already have 4 ticks with text, fill no more than 40% of the axis
                    (6, 0.2),    ## If we already have 6 ticks with text, fill no more than 20% of the axis
                ],
                'showValues': showValues,
                'tickLength': maxTickLength,
                'maxTickLevel': 2,
                'maxTextLevel': 2,
                'tickAlpha': None,  ## If not none, use this alpha for all ticks.
            }

            self.textWidth = 30  ## Keeps track of maximum width / height of tick text
            self.textHeight = 18

            # If the user specifies a width / height, remember that setting
            # indefinitely.
            self.fixedWidth = None
            self.fixedHeight = None

            self.logMode = False

            self._tickDensity = 1.0   # used to adjust scale the number of automatically generated ticks
            self._tickLevels  = None  # used to override the automatic ticking system with explicit ticks
            self._tickSpacing = None  # used to override default tickSpacing method
            self.scale = 1.0
            self.autoSIPrefix = True
            self.autoSIPrefixScale = 1.0

            self.labelText = ""
            self.labelUnits = ""
            self.labelUnitPrefix = ""
            self.unitPower = 1
            self.labelStyle = {}
            self._siPrefixEnableRanges = None
            self.setRange(0, 1)
            self.setLabel(**args)
            self.showLabel(False)

            if pen is None:
                self.setPen()
            else:
                self.setPen(pen)

            if textPen is None:
                self.setTextPen()
            else:
                self.setTextPen(textPen)

            if tickPen is None:
                self.setTickPen()
            else:
                self.setTickPen(tickPen)

            self._linkedView = None
            if linkView is not None:
                self._linkToView_internal(linkView)

            self.grid = False

            #self.setCacheMode(self.DeviceCoordinateCache)

        def setStyle(self, **kwargs):
            """
            Set various style options.

            Parameters
            ----------
            **kwargs : dict, optional
                Here are a list of supported arguments.

                ===================== ======================================================
                Property              Description
                ===================== ======================================================
                tickLength            ``int``
                                      The maximum length of ticks in pixels. Positive values
                                      point toward the text; negative values point away.

                tickTextOffset        ``int``
                                      Reserved spacing between text and axis in pixels.

                tickTextWidth         ``int``
                                      Horizontal space reserved for tick text in pixels.

                tickTextHeight        ``int``
                                      Vertical space reserved for tick text in pixels.

                autoExpandTextSpace   ``bool``
                                      Automatically expand text space if the tick strings
                                      become too long.

                autoReduceTextSpace   ``bool``
                                      Automatically shrink the axis if necessary.

                hideOverlappingLabels ``bool`` or ``int``

                                      - ``True``  (default for horizontal axis): Hide tick
                                        labels which extend beyond the AxisItem's geometry
                                        rectangle.
                                      - ``False`` (default for vertical axis): Labels may be
                                        drawn extending beyond the extent of the axis.
                                      - ``int`` sets the tolerance limit for how many pixels
                                        a label is allowed to extend beyond the axis.
                                        Defaults to 15 for
                                        ``hideOverlappingLabels = False``.

                tickFont              :class:`QFont` or ``None``
                                      Determines the font used for tick values. Use None for
                                      the default font.

                stopAxisAtTick        tuple of ``bool, bool``
                                      The first element represents the horizontal axis, the
                                      second element represents the vertical axis.

                                      - ``True`` - The axis line is drawn only as far as the
                                        last tick.
                                      - ``False`` - The line is drawn to the edge of the
                                        :class:`~pyqtgraph.AxisItem` boundary.

                textFillLimits        list of ``(int, float)``
                                      This structure determines how the AxisItem decides how
                                      many ticks should have text appear next to them.
                                      The first value corresponds to the tick number.  The
                                      second value corresponds to the fill percentage. Each
                                      tuple in the list specifies what fraction of the axis
                                      length may be occupied by text, given the number of
                                      ticks that already have text displayed.

                                      For example ::

                                        [
                                            # Never fill more than 80% of the axis
                                            (0, 0.8),
                                            # If we already have 2 ticks with text, fill no
                                            # more than 60% of the axis
                                            (2, 0.6),
                                            # If we already have 4 ticks with text, fill no
                                            # more than 40% of the axis
                                            (4, 0.4),
                                            # If we already have 6 ticks with text, fill no
                                            # more than 20% of the axis
                                            (6, 0.2)
                                        ]

                showValues            ``bool``
                                      indicates whether text is displayed adjacent to ticks.

                tickAlpha             ``float``, ``int`` or ``None``
                                      If ``None``, pyqtgraph will draw the ticks with the
                                      alpha it deems appropriate. Otherwise, the alpha will
                                      be fixed at the value passed. With ``int``, accepted
                                      values are [0..255]. With value of type ``float``,
                                      accepted values are from [0..1].

                maxTickLevel          ``int``
                                      default: 2

                                      Tick (and grid line) density level.

                                      - 0: Show major ticks only
                                      - 1: Show major ticks and one level of minor ticks
                                      - 2: Show major ticks and two levels of minor ticks
                                        (higher CPU usage)
                ===================== ======================================================

            Raises
            ------
            NameError
                Raised when the name of a keyword argument is not recognized.
            TypeError
                Raised when a value for a keyword argument is of the wrong type.
            """
            for kwd, value in kwargs.items():
                if kwd not in self.style:
                    raise NameError(f"{kwd} is not a valid style argument.")

                if (
                    kwd in (
                        'tickLength',
                        'tickTextOffset',
                        'tickTextWidth',
                        'tickTextHeight'
                    ) and
                    not isinstance(value, int)
                ):
                    raise TypeError(f"Argument '{kwd}' must be int")

                if kwd == 'tickTextOffset':
                    if self.orientation in ('left', 'right'):
                        self.style['tickTextOffset'][0] = value
                    else:
                        self.style['tickTextOffset'][1] = value
                elif kwd == 'stopAxisAtTick':
                    if len(value) != 2 or not all(isinstance(val, bool) for val in value):
                        raise TypeError(
                            "Argument 'stopAxisAtTick' must have type (bool, bool)"
                        )
                    self.style[kwd] = value
                else:
                    self.style[kwd] = value

            self.picture = None
            self._adjustSize()
            self.update()

        def close(self):
            self.scene().removeItem(self.label)
            self.label = None
            self.scene().removeItem(self)

        def setGrid(self, grid: int | float | bool):
            """
            Set the alpha value for the grid, or ``False`` to disable.

            When grid lines are enabled, the axis tick lines are extended to cover the
            extent of the linked ViewBox, if any.

            Parameters
            ----------
            grid : bool or int or float
                Alpha value to apply to :class:`~pyqtgraph.GridItem`.

                - ``False`` - Disable the grid.
                - ``int`` - Values between [0, 255] to set the alpha of the grid to.
                - ``float`` - Values between [0..1] to set the alpha of the grid to.
            """
            if isinstance(grid, float):
                grid = int(grid * 255)
                grid = min(grid, 255)
                grid = max(grid, 0)
            self.grid = grid
            self.picture = None
            self.prepareGeometryChange()
            self.update()

        def setLogMode(
            self,
            *args: tuple[bool] | tuple[bool, bool] | None,
            **kwargs: dict[str, bool] | None
        ):
            """
            Set log scaling for x and / or y axes.

            If two positional arguments are provided, the first will set log scaling
            for the x axis and the second for the y axis. If a single positional
            argument is provided, it will set the log scaling along the direction of
            the AxisItem. Alternatively, x and y can be passed as keyword arguments.

            If an axis is set to log scale, ticks are displayed on a logarithmic scale and
            values are adjusted accordingly. The linked ViewBox will be informed of the
            change.

            Parameters
            ----------
            *args : tuple of bool
                If length 1, sets log mode regardless of orientation.  If length 2, the
                first element toggles log mode for x-axis, and the second element toggles
                log mode for the y-axis.
            **kwargs : dict
                Pass a dictionary with keys `x` and `y`, where the values are ``bool`` to
                set the log mode for the respective `x` or `y` axis.  Trying to set the `y`
                axis log mode while this axis item is horizontal (or vice versa) will be
                ignored.

            See Also
            --------
            :meth:`~pyqtgraph.PlotItem.setLogMode`
                The method called to shift the values of the data.
            """
            if len(args) == 1:
                self.logMode = args[0]
            else:
                if len(args) == 2:
                    x, y = args
                else:
                    x = kwargs.get('x')
                    y = kwargs.get('y')

                if x is not None and self.orientation in ('top', 'bottom'):
                    self.logMode = x
                if y is not None and self.orientation in ('left', 'right'):
                    self.logMode = y

            # inform the linked views of the change
            if self._linkedView is not None:
                if self.orientation in ('top', 'bottom'):
                    self._linkedView().setLogMode('x', self.logMode)
                elif self.orientation in ('left', 'right'):
                    self._linkedView().setLogMode('y', self.logMode)

            self.picture = None
            self.update()

        def setTickFont(self, font: QtGui.QFont | None):
            """
            Set the font used for tick values.

            Parameters
            ----------
            font : QtGui.QFont or None
                The font to use for the tick values. Set to ``None`` for the default font.
            """
            self.style['tickFont'] = font
            self.picture = None
            self.prepareGeometryChange()
            # Need to re-allocate space depending on font size?
            self.update()

        def resizeEvent(self, ev=None):
            # Set the position of the label
            nudge = 5
            # self.label is set to None on close, but resize events can still occur.
            if self.label is None:
                self.picture = None
                return

            br = self.label.boundingRect()
            p = QtCore.QPointF(0, 0)
            if self.orientation == 'left':
                p.setY(int(self.size().height()/2 + br.width()/2))
                p.setX(-nudge)
            elif self.orientation == 'right':
                p.setY(int(self.size().height()/2 + br.width()/2))
                p.setX(int(self.size().width()-br.height()+nudge))
            elif self.orientation == 'top':
                p.setY(-nudge)
                p.setX(int(self.size().width()/2. - br.width()/2.))
            elif self.orientation == 'bottom':
                p.setX(int(self.size().width()/2. - br.width()/2.))
                p.setY(int(self.size().height()-br.height()+nudge))
            self.label.setPos(p)
            self.picture = None

        def showLabel(self, show: bool=True):
            """
            Show or hide the label text for this axis.

            Parameters
            ----------
            show : bool, optional
                Show the label text, by default True.
            """
            self.label.setVisible(show)
            if self.orientation in ['left', 'right']:
                self._updateWidth()
            else:
                self._updateHeight()
            if self.autoSIPrefix:
                self.updateAutoSIPrefix()

        def setLabel(
            self,
            text: str | None=None,
            units: str | None=None,
            unitPrefix: str | None=None,
            siPrefixEnableRanges: tuple[tuple[float, float], ...] | None=None,
            unitPower: int | float=1,
            **kwargs
        ):
            """
            Set the text displayed adjacent to the axis.

            Parameters
            ----------
            text : str
                The text (excluding units) to display on the label for this axis.
            units : str
                The units for this axis. Units should generally be given without any scaling
                prefix (eg, 'V' instead of 'mV'). The scaling prefix will be automatically
                prepended based on the range of data displayed.
            unitPrefix : str
                An extra prefix to prepend to the units.
            siPrefixEnableRanges : tuple of tuple of float, float, Optional
                The ranges in which automatic SI prefix scaling is enabled. Defaults to
                everywhere, unless units is empty, in which case it defaults to
                ``((0., 1.), (1e9, inf))``.
            unitPower : int or float, optional
                The power to which the units are raised. For example, if units='m²', the
                unitPower should be 2. This ensures correct scaling when using SI prefixes.
                Supports positive, negative and non-integral powers.  Default is 1.
                Note: The power only affects the scaling, not the units themselves. For
                example, with units='m' and unitPower=2, the displayed units will still be 'm'.
            **kwargs
                All extra keyword arguments become CSS style options for the ``<span>`` tag
                which will surround the axis label and units. Note that CSS attributes are
                not always valid python arguments. Examples: ``color='#FFF'``,
                ``**{'font-size': '14pt'}``.

            Notes
            -----
            The final text generated for the label will usually take the form::

                <span style="...args...">{text} (prefix{units})</span>
            """
            self.labelText = text or ""
            self.labelUnits = units or ""
            self.labelUnitPrefix = unitPrefix or ""
            self.unitPower = unitPower
            if kwargs:
                self.labelStyle = kwargs
            self.setSIPrefixEnableRanges(siPrefixEnableRanges)
            # Account empty string and `None` for units and text
            visible = bool(text or units)
            self.showLabel(visible)
            self._updateLabel()

        def setSIPrefixEnableRanges(self, ranges=None):
            """
            Set the ranges in which automatic SI prefix scaling is enabled.

            This function allows you to define specific ranges where SI prefixes will be
            used. By default, SI prefix scaling is enabled everywhere, unless units are
            empty, in which case it defaults to ``((0., 1.), (1e9, inf))``.

            Parameters
            ----------
            ranges : tuple of tuple of float, float, optional
                A tuple of ranges where SI prefix scaling is enabled. Each range is a tuple
                containing two floats representing the start and end of the range.
            """
            self._siPrefixEnableRanges = ranges

        def getSIPrefixEnableRanges(self):
            """
            Get the ranges in which automatic SI prefix scaling is enabled.

            Returns
            -------
            tuple of tuple of float, float
                A tuple of ranges where SI prefix scaling is enabled. Each range is a tuple
                containing two floats representing the start and end of the range. If no
                custom ranges are set, then the default ranges are returned. The default
                ranges are ``((0., 1.), (1e9, inf))`` if units are empty, and
                ``((0., inf))`` otherwise.
            """
            if self._siPrefixEnableRanges is not None:
                return self._siPrefixEnableRanges
            elif self.labelUnits == '':
                return (0., 1.), (1e9, float('inf'))
            else:
                return ((0., float('inf')),)

        def _updateLabel(self):
            self.label.setHtml(self.labelString())
            self._adjustSize()
            self.picture = None
            self.update()

        def labelString(self) -> str:
            """
            Generate the label string based on current label, units, and prefix.

            Returns
            -------
            str
                The complete label string, including units and any prefixes.
            """
            if self.labelUnits == '':
                if not self.autoSIPrefix or self.autoSIPrefixScale == 1.0:
                    units = ''
                else:
                    units = f'(x{1.0 / self.autoSIPrefixScale:g})'
            else:
                units = f'({self.labelUnitPrefix}{self.labelUnits})'

            s = f'{self.labelText} {units}'

            style = ';'.join([f'{k}: {self.labelStyle[k]}' for k in self.labelStyle])

            return f"<span style='{style}'>{s}</span>"

        def _updateMaxTextSize(self, x: int):
            ## Informs that the maximum tick size orthogonal to the axis has
            ## changed; we use this to decide whether the item needs to be resized
            ## to accommodate.
            if self.orientation in ['left', 'right']:
                if self.style["autoReduceTextSpace"]:
                    if x > self.textWidth or x < self.textWidth - 10:
                        self.textWidth = x
                else:
                    mx = max(self.textWidth, x)
                    if mx > self.textWidth or mx < self.textWidth - 10:
                        self.textWidth = mx
                if self.style['autoExpandTextSpace']:
                    self._updateWidth()

            else:
                if self.style['autoReduceTextSpace']:
                    if x > self.textHeight or x < self.textHeight - 10:
                        self.textHeight = x
                else:
                    mx = max(self.textHeight, x)
                    if mx > self.textHeight or mx < self.textHeight - 10:
                        self.textHeight = mx
                if self.style['autoExpandTextSpace']:
                    self._updateHeight()

        def _adjustSize(self):
            if self.orientation in ['left', 'right']:
                self._updateWidth()
            else:
                self._updateHeight()

        def setHeight(self, h: int | None=None):
            """
            Set the height of this axis reserved for ticks and tick labels.

            The height of the axis label is automatically added.

            Parameters
            ----------
            h : int or None, optional
                If ``None``, then the value will be determined automatically based on the
                size of the tick text, by default None.
            """
            self.fixedHeight = h
            self._updateHeight()

        def _updateHeight(self):
            if not self.isVisible():
                h = 0
            elif self.fixedHeight is None:
                if not self.style['showValues']:
                    h = 0
                elif self.style['autoExpandTextSpace']:
                    h = self.textHeight
                else:
                    h = self.style['tickTextHeight']
                h += self.style['tickTextOffset'][1] if self.style['showValues'] else 0
                h += max(0, self.style['tickLength'])
                if self.label.isVisible():
                    h += self.label.boundingRect().height() * 0.8
            else:
                h = self.fixedHeight

            self.setMaximumHeight(h)
            self.setMinimumHeight(h)
            self.picture = None

        def setWidth(self, w: int | None=None):
            """
            Set the width of this axis reserved for ticks and tick labels.

            The width of the axis label is automatically added.

            Parameters
            ----------
            w : int or None, optional
                If ``None``, then the value will be determined automatically based on the
                size of the tick text, by default None.
            """
            self.fixedWidth = w
            self._updateWidth()

        def _updateWidth(self):
            if not self.isVisible():
                w = 0
            elif self.fixedWidth is None:
                if not self.style['showValues']:
                    w = 0
                elif self.style['autoExpandTextSpace']:
                    w = self.textWidth
                else:
                    w = self.style['tickTextWidth']
                w += self.style['tickTextOffset'][0] if self.style['showValues'] else 0
                w += max(0, self.style['tickLength'])
                if self.label.isVisible():
                    w += self.label.boundingRect().height() * 0.8  ## bounding rect is usually an overestimate
            else:
                w = self.fixedWidth

            self.setMaximumWidth(w)
            self.setMinimumWidth(w)
            self.picture = None

        def pen(self) -> QtGui.QPen:
            """
            Get the pen used for drawing text, axes, ticks, and grid lines.

            If no custom pen has been set, this method will return a pen with the
            default foreground color.

            Returns
            -------
            QPen
                The pen used to draw text, axes, ticks, and grid lines.
            """
            if self._pen is None:
                return fn.mkPen(getConfigOption('foreground'))
            return fn.mkPen(self._pen)

        def setPen(self, *args, **kwargs):
            """
            Set the pen used for drawing text, axes, ticks, and grid lines.

            If no arguments given, the default foreground color will be used.

            Parameters
            ----------
            *args : tuple
                Arguments relayed to :func:`~pyqtgraph.mkPen`.
            **kwargs : dict
                Arguments relayed to `:func:`~pyqtgraph.mkPen`.

            See Also
            --------
            :func:`setConfigOption <pyqtgraph.setConfigOption>`
                Option to change the default foreground color.
            """
            self.picture = None
            if args or kwargs:
                self._pen = fn.mkPen(*args, **kwargs)
            else:
                self._pen = fn.mkPen(getConfigOption('foreground'))
            self.labelStyle['color'] = self._pen.color().name() #   #RRGGBB
            self._updateLabel()

        def textPen(self) -> QtGui.QPen:
            """
            Get the pen used for drawing text.

            If no custom text pen has been set, this method will return a pen with the
            default foreground color.

            Returns
            -------
            QPen
                The pen used to draw text.
            """
            if self._textPen is None:
                return fn.mkPen(getConfigOption('foreground'))
            return fn.mkPen(self._textPen)

        def setTextPen(self, *args, **kwargs):
            """
            Set the pen used for drawing text.

            If no arguments given, the default foreground color will be used.

            Parameters
            ----------
            *args : tuple
                Arguments relayed to :func:`~pyqtgraph.mkPen`.
            **kwargs : dict
                Arguments relayed to `:func:`~pyqtgraph.mkPen`.

            See Also
            --------
            :func:`setConfigOption <pyqtgraph.setConfigOption>`
                Option to change the default foreground color.
            """
            self.picture = None
            if args or kwargs:
                self._textPen = fn.mkPen(*args, **kwargs)
            else:
                self._textPen = fn.mkPen(getConfigOption('foreground'))
            self.labelStyle['color'] = self._textPen.color().name() #   #RRGGBB
            self._updateLabel()

        def tickPen(self) -> QtGui.QPen:
            """
            Get the pen used for drawing ticks.

            If no custom tick pen has been set, this method will return the axis's
            main pen.

            Returns
            -------
            QPen
                The pen used to draw tick marks.
            """
            return self.pen() if self._tickPen is None else fn.mkPen(self._tickPen)

        def setTickPen(self, *args, **kwargs):
            """
            Set the pen used for drawing ticks.

            If no arguments given, the default foreground color will be used.

            Parameters
            ----------
            *args : tuple
                Arguments relayed to :func:`~pyqtgraph.mkPen`.
            **kwargs : dict
                Arguments relayed to `:func:`~pyqtgraph.mkPen`.

            See Also
            --------
            :func:`setConfigOption <pyqtgraph.setConfigOption>`
                Option to change the default foreground color.
            """
            self.picture = None
            self._tickPen = fn.mkPen(*args, **kwargs) if args or kwargs else None
            self._updateLabel()

        def setScale(self, scale=1.0):
            """
            Set the value scaling for this axis.

            Setting this value causes the axis to draw ticks and tick labels as if the view
            coordinate system were scaled.

            Parameters
            ----------
            scale : float, optional
                Value to scale the drawing of ticks and tick labels as if the view
                coordinate system was scaled, by default 1.0.
            """
            if scale != self.scale:
                self.scale = scale
                self._updateLabel()

        def enableAutoSIPrefix(self, enable=True):
            """
            Enable (or disable) automatic SI prefix scaling on this axis.

            When enabled, this feature automatically determines the best SI prefix
            to prepend to the label units, while ensuring that axis values are scaled
            accordingly.

            For example, if the axis spans values from -0.1 to 0.1 and has units set
            to 'V' then the axis would display values -100 to 100
            and the units would appear as 'mV'

            This feature is enabled by default, and is only available when a suffix
            (unit string) is provided to display on the label.

            Parameters
            ----------
            enable : bool, optional
                Enable Auto SI prefix, by default True.
            """

            self.autoSIPrefix = enable
            self.updateAutoSIPrefix()

        def updateAutoSIPrefix(self):
            scale = 1.0
            prefix = ''
            if self.label.isVisible():
                _range = 10**np.array(self.range) if self.logMode else self.range
                scaling_value = max(abs(_range[0]), abs(_range[1])) * self.scale
                if any(low <= scaling_value <= high for low, high in self.getSIPrefixEnableRanges()):
                    (scale, prefix) = fn.siScale(scaling_value, power=self.unitPower)

            self.autoSIPrefixScale = scale
            self.labelUnitPrefix = prefix
            self._updateLabel()

        def setRange(self, mn: float, mx: float):
            """
            Set the range of values displayed by the axis.

            Usually this is handled automatically by linking the axis to a ViewBox with
            :func:`linkToView <pyqtgraph.AxisItem.linkToView>`.

            Parameters
            ----------
            mn : float
                Bottom value to set the range to.
            mx : float
                Top value to set the range to.

            Raises
            ------
            ValueError
                When non-finite values are passed.
            """

            if not isfinite(mn) or not isfinite(mx):
                raise ValueError(f"Not setting range to [{mn}, {mx}]")
            self.range = [mn, mx]
            if self.autoSIPrefix:
                # XXX: Will already update once!
                self.updateAutoSIPrefix()
            else:
                self.picture = None
                self.update()

        def linkedView(self):
            """
            Return the ViewBox linked to this axis.

            Returns
            -------
            ViewBox
                The linked ViewBox, or ``None`` if there is no ViewBox linked.
            """
            return None if self._linkedView is None else self._linkedView()

        def _linkToView_internal(self, view):
            # We need this code to be available without override,
            # even though DateAxisItem overrides the user-side linkToView method
            self.unlinkFromView()

            self._linkedView = weakref.ref(view)
            if self.orientation in ['right', 'left']:
                view.sigYRangeChanged.connect(self.linkedViewChanged)
            else:
                view.sigXRangeChanged.connect(self.linkedViewChanged)
            view.sigResized.connect(self.linkedViewChanged)

        def linkToView(self, view):
            """
            Link to a ViewBox, causing its displayed range to match the view range.

            This is usually called automatically by the ViewBox.

            Parameters
            ----------
            view : ViewBox
                The view to link to.
            """
            self._linkToView_internal(view)

        def unlinkFromView(self):
            """
            Unlink this axis from its linked ViewBox.
            """
            oldView = self.linkedView()
            self._linkedView = None
            if oldView is not None:
                oldView.sigResized.disconnect(self.linkedViewChanged)
                if self.orientation in ['right', 'left']:
                    oldView.sigYRangeChanged.disconnect(self.linkedViewChanged)
                else:
                    oldView.sigXRangeChanged.disconnect(self.linkedViewChanged)

        @QtCore.Slot(object)
        @QtCore.Slot(object, object)
        def linkedViewChanged(self, view, newRange=None):
            """
            Call when the linked view range has changed.

            Parameters
            ----------
            view : ViewBox
                The view whose range has changed.
            newRange : tuple of float, float, optional
                The new range of the view, by default None.
            """
            if self.orientation in ['right', 'left']:
                if newRange is None:
                    newRange = view.viewRange()[1]
                if view.yInverted():
                    self.setRange(*newRange[::-1])
                else:
                    self.setRange(*newRange)
            else:
                if newRange is None:
                    newRange = view.viewRange()[0]
                if view.xInverted():
                    self.setRange(*newRange[::-1])
                else:
                    self.setRange(*newRange)

        def boundingRect(self):
            m = 0
            hide_overlapping_labels = self.style['hideOverlappingLabels']
            if hide_overlapping_labels is True:
                pass # skip further checks
            elif hide_overlapping_labels is False:
                m = 15
            else:
                try:
                    m = int( self.style['hideOverlappingLabels'] )
                except ValueError: pass # ignore any non-numeric value

            linkedView = self.linkedView()
            if linkedView is not None and self.grid is not False:
                return (
                    self.mapRectFromParent(self.geometry()) |
                    linkedView.mapRectToItem(self, linkedView.boundingRect())
                )
            rect = self.mapRectFromParent(self.geometry())
            ## extend rect if ticks go in negative direction
            ## also extend to account for text that flows past the edges
            tl = self.style['tickLength']
            if self.orientation == 'left':
                rect = rect.adjusted(0, -m, -min(0,tl), m)
            elif self.orientation == 'right':
                rect = rect.adjusted(min(0,tl), -m, 0, m)
            elif self.orientation == 'top':
                rect = rect.adjusted(-m, 0, m, -min(0,tl))
            elif self.orientation == 'bottom':
                rect = rect.adjusted(-m, min(0,tl), m, 0)
            return rect

        def shape(self):
            # override shape() to exclude grid lines from getting mouse events
            rect = self.mapRectFromParent(self.geometry())
            path = QtGui.QPainterPath()
            path.addRect(rect)
            return path

        def paint(self, p, opt, widget):
            profiler = debug.Profiler()
            if self.picture is None:
                try:
                    picture = QtGui.QPicture()
                    painter = QtGui.QPainter(picture)
                    if self.style["tickFont"]:
                        painter.setFont(self.style["tickFont"])
                    specs = self.generateDrawSpecs(painter)
                    profiler('generate specs')
                    if specs is not None:
                        self.drawPicture(painter, *specs)
                        profiler('draw picture')
                finally:
                    painter.end()
                self.picture = picture
            self.picture.play(p)

        def setTickDensity(self, density=1.0):
            """
            Set the density of ticks displayed on the axis.

            A higher density value means that more ticks will be displayed. The density
            value is used in conjunction with the tickSpacing method to determine the
            actual tick locations.

            Parameters
            ----------
            density : float, optional
                Density of ticks to display, by default 1.0.
            """
            self._tickDensity = density
            self.picture = None
            self.update()

        def setTicks(
            self,
            ticks: list[list[tuple[float, str]]] | None
        ):
            """
            Explicitly determine which ticks to display.

            This overrides the behavior specified by
            :meth:`~pyqtgraph.AxisItem.tickSpacing`, :meth:`~pyqtgraph.AxisItem.tickValues`,
            and :meth:`~pyqtgraph.AxisItem.tickStrings`.

            The format for *ticks* looks like::

                [
                    [
                        (majorTickValue1, majorTickString1),
                        (majorTickValue2, majorTickString2),
                        ...
                    ],
                    [
                        (minorTickValue1, minorTickString1),
                        (minorTickValue2, minorTickString2),
                        ...
                    ],
                    ...
                ]

            The two levels of major and minor ticks are expected. A third tier of additional
            ticks is optional. If *ticks* is ``None``, then the default tick system will be
            used.

            Parameters
            ----------
            ticks : list of list of float, str or None
                Explicitly set tick display information.

            See Also
            --------
            :meth:`~pyqtgraph.AxisItem.tickSpacing`
                How tick spacing is configured.
            :meth:`~pyqtgraph.AxisItem.tickValues`
                How tick values are set.
            :meth:`~pyqtgraph.AxisItem.tickStrings`
                How tick strings are specified.
            """

            self._tickLevels = ticks
            self.picture = None
            self.update()

        def setTickSpacing(
            self,
            major: float | None=None,
            minor: float | None=None,
            levels: list[tuple[float, float]] | None=None
        ):
            """
            Explicitly determine the spacing of major and minor ticks.

            This overrides the default behavior of the tickSpacing method, and disables
            the effect of setTicks(). Arguments may be either *major* and *minor*,
            or *levels* which is a list of ``(spacing, offset)`` tuples for each
            tick level desired. If no arguments are given, then the default
            behavior of tickSpacing is enabled.

            Parameters
            ----------
            major : float, optional
                Spacing for major ticks, by default None.
            minor : float, optional
                Spacing for minor ticks, by default None.
            levels : list of tuple of float, float, optional
                A list of (spacing, offset) tuples for each tick level, by default None.

            Examples
            --------
            .. code-block:: python

                # two levels, all offsets = 0
                axis.setTickSpacing(5., 1.)
                # three levels, all offsets = 0
                axis.setTickSpacing(levels=[(3., 0.), (1., 0.), (0.25, 0.)])
                # reset to default
                axis.setTickSpacing()
            """

            if levels is None:
                levels = None if major is None else [(major, 0.), (minor, 0.)]
            self._tickSpacing = levels
            self.picture = None
            self.update()

        def tickSpacing(self, minVal: float, maxVal: float, size: float):
            """
            Determine the spacing of ticks on the axis.

            This method is called whenever the axis needs to be redrawn and is a
            good method to override in subclasses that require control over tick locations.

            Parameters
            ----------
            minVal : float
                Minimum value being displayed on the axis.
            maxVal : float
                Maximum value being displayed on the axis.
            size : float
                Length of the axis in pixels.

            Returns
            -------
            list of tuple of float, float
                A list of tuples, one for each tick level.
                Each tuple contains two values: ``(spacing, offset)``.  The spacing value
                is the distance between ticks, and the offset is the first tick relative to
                *minVal*. For example, if ``result[0]`` is ``(10, 0)``, then major ticks
                will be displayed every 10 units and the first major tick will correspond to
                ``minVal``. If instead ``result[0]`` is ``(10, 5)``, then major ticks will
                be displayed every 10 units, but the first major tick will correspond to
                ``minVal + 5``.

                .. code-block:: python

                    [
                        (major_tick_spacing, offset),
                        (minor_tick_spacing, offset),
                        (sub_minor_tick_spacing, offset),
                        ...
                    ]
            """
            # First check for explicit tick spacing
            if self._tickSpacing is not None:
                return self._tickSpacing

            dif = abs(maxVal - minVal)
            if dif == 0:
                return []

            ref_size = 300. # axes longer than this display more than the minimum number of major ticks
            minNumberOfIntervals = max(
                2.25,       # 2.0 ensures two tick marks. Fudged increase to 2.25 allows room for tick labels.
                2.25 * self._tickDensity * sqrt(size/ref_size) # sub-linear growth of tick spacing with size
            )

            majorMaxSpacing = dif / minNumberOfIntervals

            # We want to calculate the power of 10 just below the maximum spacing.
            # Then divide by ten so that the scale factors for subdivision all become intergers.
            # p10unit = 10**( floor( log10(majorMaxSpacing) ) ) / 10

            # And we want to do it without a log operation:
            mantissa, exp2 = frexp(majorMaxSpacing) # IEEE 754 float already knows its exponent, no need to calculate
            p10unit = 10. ** ( # approximate a power of ten base factor just smaller than the given number
                floor(            # int would truncate towards zero to give wrong results for negative exponents
                    (exp2-1)      # IEEE 754 exponent is ceiling of true exponent --> estimate floor by subtracting 1
                    / 3.32192809488736 # division by log2(10)=3.32 converts base 2 exponent to base 10 exponent
                ) - 1             # subtract one extra power of ten so that we can work with integer scale factors >= 5
            )
            # neglecting the mantissa can underestimate by one power of 10 when the true value is JUST above the threshold.
            if 100. * p10unit <= majorMaxSpacing: # Cheaper to check this than to use a more complicated approximation.
                majorScaleFactor = 10
                p10unit *= 10.
            else:
                for majorScaleFactor in (50, 20, 10):
                    if majorScaleFactor * p10unit <= majorMaxSpacing:
                        break # find the first value that is smaller or equal
            majorInterval = majorScaleFactor * p10unit
            # manual sanity check: print(f"{majorMaxSpacing:.2e} > {majorInterval:.2e} = {majorScaleFactor:.2e} x {p10unit:.2e}")
            levels = [
                (majorInterval, 0),
            ]

            if self.style['maxTickLevel'] >= 1:
                minorMinSpacing = 2 * dif/size   # no more than one minor tick per two pixels
                trials = (5, 10) if majorScaleFactor == 10 else (10, 20, 50)
                for minorScaleFactor in trials:
                    minorInterval = minorScaleFactor * p10unit
                    if minorInterval >= minorMinSpacing:
                        break # find the first value that is larger or equal to allowed minimum of 1 per 2px
                levels.append((minorInterval, 0))

            # extra ticks at 10% of major interval are pretty, but eat up CPU
            if self.style['maxTickLevel'] >= 2: # consider only when enabled
                if majorScaleFactor == 10:
                    trials = (1, 2, 5, 10) # start at 10% of major interval, increase if needed
                elif majorScaleFactor == 20:
                    trials = (2, 5, 10, 20) # start at 10% of major interval, increase if needed
                elif majorScaleFactor == 50:
                    trials = (5, 10, 50) # start at 10% of major interval, increase if needed
                else: # invalid value
                    trials = () # skip extra interval
                    extraInterval = minorInterval
                for extraScaleFactor in trials:
                    extraInterval = extraScaleFactor * p10unit
                    if extraInterval >= minorMinSpacing or extraInterval == minorInterval:
                        break # find the first value that is larger or equal to allowed minimum of 1 per 2px
                if extraInterval < minorInterval: # add extra interval only if it is visible
                    levels.append((extraInterval, 0))
            return levels

        def tickValues(self, minVal:float, maxVal:float, size: float):
            """
            Return the values and spacing of ticks to draw.

            The values returned are essentially the same as those returned by
            :meth:`~pyqtgraph.AxisItem.tickSpacing`, but with the addition of
            explicit tick values for each tick level. This method is a good
            method to override in subclasses.

            Parameters
            ----------
            minVal : float
                Minimum value to generate tick values for.
            maxVal : float
                Maximum value to generate tick values for.
            size : float
                The length of the axis in pixels.

            Returns
            -------
            list of tuple of float, list of float
                A list of tuples, one for each tick level. Each tuple contains two
                values: ``(spacing, values)``, where *spacing* is the distance between
                ticks and *values* is a list of tick values.
            """
            minVal, maxVal = sorted((minVal, maxVal))

            minVal *= self.scale
            maxVal *= self.scale

            ticks = []
            tickLevels = self.tickSpacing(minVal, maxVal, size)
            allValues = np.array([])
            for i in range(len(tickLevels)):
                spacing, offset = tickLevels[i]

                ## determine starting tick
                start = (ceil((minVal-offset) / spacing) * spacing) + offset

                ## determine number of ticks
                num = int((maxVal-start) / spacing) + 1
                values = (np.arange(num) * spacing + start) / self.scale
                ## remove any ticks that were present in higher levels
                ## we assume here that if the difference between a tick value and a previously seen tick value
                ## is less than spacing/100, then they are 'equal' and we can ignore the new tick.
                close = np.any(
                    np.isclose(
                        allValues,
                        values[:, np.newaxis],
                        rtol=0,
                        atol=spacing/self.scale*0.01
                    ),
                    axis=-1
                )
                values = values[~close]
                allValues = np.concatenate([allValues, values])
                ticks.append((spacing/self.scale, values.tolist()))
            if self.logMode:
                return self.logTickValues(minVal, maxVal, size, ticks)
            return ticks

        def logTickValues(self, minVal, maxVal, size, stdTicks):
            """
            Return tick values for log-scale axes.

            This method is called by :meth:`~pyqtgraph.AxisItem.tickValues` when the axis
            is in logarithmic mode. It is a good method to override in subclasses.

            Parameters
            ----------
            minVal : float
                Minimum value to generate tick values for.
            maxVal : float
                Maximum value to generate tick values for.
            size : float
                The length of the axis in pixels.
            stdTicks : list of tuple of float, float
                The tick values generated by the standard
                :meth:`~pyqtgraph.AxisItem.tickValues` method.

            Returns
            -------
            list of tuple of float, float or list of tuple of None, float
                A list of tuples, one for each tick level. Each tuple contains two
                values: ``(spacing, values)``, where *spacing* is the distance between
                ticks and *values* is a list of tick values.
            """

            ## start with the tick spacing given by tickValues().
            ## Any level whose spacing is < 1 needs to be converted to log scale
            ticks = [(spacing, t) for spacing, t in stdTicks if spacing >= 1.0]
            if len(ticks) < 3:
                v1 = int(floor(minVal))
                v2 = int(ceil(maxVal))

                # minor = [v + np.log10(np.arange(1, 10)) for v in range(v1, v2)]
                minor = []
                for v in range(v1, v2):
                    minor.extend(v + np.log10(np.arange(1, 10)))
                minor = [x for x in minor if x > minVal and x < maxVal]
                ticks.append((None, minor))
            return ticks

        def tickStrings(self, values: list[float], scale: float, spacing: float):
            """
            Return the strings that should be displayed at each tick value.

            This method is used to generate tick strings, and is called automatically.

            Parameters
            ----------
            values : list of float
                List of tick values.
            scale : float
                The scaling factor for tick values.
            spacing : float
                The spacing between ticks.

            Returns
            -------
            list of str
                List of strings to display at each tick value.
            """

            if self.logMode:
                return self.logTickStrings(values, scale, spacing)

            places = max(0, ceil(-log10(spacing * scale)))
            strings = []
            for v in values:
                vs = v * scale
                if abs(vs) < .001 or abs(vs) >= 10000:
                    vstr = "%g" % vs
                else:
                    vstr = ("%%0.%df" % places) % vs
                strings.append(vstr)
            return strings

        def logTickStrings(self, values: list[float], scale: float, spacing: float):
            """
            Return the strings that should be displayed at each tick value in log mode.

            This method is called by :meth:`~pyqtgraph.AxisItem.tickStrings` when the axis
            is in logarithmic mode. It is a good method to override in subclasses.

            Parameters
            ----------
            values : list of float
                List of tick values.
            scale : float
                The scaling factor for tick values.
            spacing : float
                The spacing between ticks.

            Returns
            -------
            list of str
                List of strings to display at each tick value.
            """
            estrings = [
                "%0.1g"%x
                for x in 10 ** np.array(values).astype(float) * np.array(scale)
            ]
            convdict = {"0": "⁰",
                        "1": "¹",
                        "2": "²",
                        "3": "³",
                        "4": "⁴",
                        "5": "⁵",
                        "6": "⁶",
                        "7": "⁷",
                        "8": "⁸",
                        "9": "⁹",
                        }
            dstrings = []
            for e in estrings:
                if e.count("e"):
                    v, p = e.split("e")
                    sign = "⁻" if p[0] == "-" else ""
                    pot = "".join([convdict[pp] for pp in p[1:].lstrip("0")])
                    v = "" if v == "1" else f"{v}·"
                    dstrings.append(f"{v}10{sign}{pot}")
                else:
                    dstrings.append(e)
            return dstrings

        def generateDrawSpecs(self, p):
            """
            Generate the drawing specifications for the axis, ticks, and labels.

            This method determines all the coordinates and other information needed to draw
            the axis, including tick positions, tick labels, and axis label. It returns a
            tuple of values that are used to draw the axis. This is a good method to
            override in subclasses that need more control over the appearance of the axis.

            Parameters
            ----------
            p : QPainter
                The painter used to draw the axis.

            Returns
            -------
            tuple
                A tuple containing the drawing specifications for the axis, ticks, and
                labels. The tuple contains the following values:

                - ``axisSpec``: A tuple containing the pen, start point, and end point of
                  the axis line.
                - ``tickSpecs``: A list of tuples, one for each tick. Each tuple contains
                  the pen, start point, and end point of the tick line.
                - ``textSpecs``: A list of tuples, one for each tick label. Each tuple
                  contains the bounding rectangle, alignment flags, and text of the label.

            :meta private:
            """
            profiler = debug.Profiler()
            if self.style['tickFont'] is not None:
                p.setFont(self.style['tickFont'])
            bounds = self.mapRectFromParent(self.geometry())

            linkedView = self.linkedView()
            if linkedView is None or self.grid is False:
                tickBounds = bounds
            else:
                tickBounds = linkedView.mapRectToItem(self, linkedView.boundingRect())

            left_offset = -1.0
            right_offset = 1.0
            top_offset = -1.0
            bottom_offset = 1.0
            if self.orientation == 'left':
                span = (bounds.topRight() + Point(left_offset, top_offset),
                        bounds.bottomRight() + Point(left_offset, bottom_offset))
                tickStart = tickBounds.right()
                tickStop = bounds.right()
                tickDir = -1
                axis = 0
            elif self.orientation == 'right':
                span = (bounds.topLeft() + Point(right_offset, top_offset),
                        bounds.bottomLeft() + Point(right_offset, bottom_offset))
                tickStart = tickBounds.left()
                tickStop = bounds.left()
                tickDir = 1
                axis = 0
            elif self.orientation == 'top':
                span = (bounds.bottomLeft() + Point(left_offset, top_offset),
                        bounds.bottomRight() + Point(right_offset, top_offset))
                tickStart = tickBounds.bottom()
                tickStop = bounds.bottom()
                tickDir = -1
                axis = 1
            elif self.orientation == 'bottom':
                span = (bounds.topLeft() + Point(left_offset, bottom_offset),
                        bounds.topRight() + Point(right_offset, bottom_offset))
                tickStart = tickBounds.top()
                tickStop = bounds.top()
                tickDir = 1
                axis = 1
            else:
                raise ValueError(
                    "self.orientation must be in {'left', 'right', 'top', 'bottom'}"
                )
            ## determine size of this item in pixels
            points = list(map(self.mapToDevice, span))
            if None in points:
                return
            lengthInPixels = Point(points[1] - points[0]).length()
            if lengthInPixels == 0:
                return

            # Determine major / minor / subminor axis ticks
            if self._tickLevels is None:
                tickLevels = self.tickValues(self.range[0], self.range[1], lengthInPixels)
                tickStrings = None
            else:
                ## parse self.tickLevels into the formats returned by tickLevels() and tickStrings()
                tickLevels = []
                tickStrings = []
                for level in self._tickLevels:
                    values = []
                    strings = []
                    tickLevels.append((None, values))
                    tickStrings.append(strings)
                    for val, strn in level:
                        values.append(val)
                        strings.append(strn)

            ## determine mapping between tick values and local coordinates
            dif = self.range[1] - self.range[0]
            if dif == 0:
                xScale = 1
                offset = 0
            elif axis == 0:
                xScale = -bounds.height() / dif
                offset = self.range[0] * xScale - bounds.height()
            else:
                xScale = bounds.width() / dif
                offset = self.range[0] * xScale

            xRange = [x * xScale - offset for x in self.range]
            xMin = min(xRange)
            xMax = max(xRange)

            profiler('init')

            tickPositions = [] # remembers positions of previously drawn ticks

            ## compute coordinates to draw ticks
            ## draw three different intervals, long ticks first
            tickSpecs = []
            for i in range(len(tickLevels)):
                tickPositions.append([])
                ticks = tickLevels[i][1]

                ## length of tick
                tickLength = self.style['tickLength'] / ((i*0.5)+1.0)

                lineAlpha = self.style["tickAlpha"]
                if lineAlpha is None:
                    lineAlpha = 255 / (i+1)
                    if self.grid is not False:
                        lineAlpha *= self.grid/255. * fn.clip_scalar((0.05  * lengthInPixels / (len(ticks)+1)), 0., 1.)
                elif isinstance(lineAlpha, float):
                    lineAlpha *= 255
                    lineAlpha = max(0, int(round(lineAlpha)))
                    lineAlpha = min(255, int(round(lineAlpha)))
                elif isinstance(lineAlpha, int):
                    if (lineAlpha > 255) or (lineAlpha < 0):
                        raise ValueError("lineAlpha should be [0..255]")
                else:
                    raise TypeError("Line Alpha should be of type None, float or int")
                tickPen = self.tickPen()
                if tickPen.brush().style() == QtCore.Qt.BrushStyle.SolidPattern: # only adjust simple color pens
                    tickPen = QtGui.QPen(tickPen) # copy to a new QPen
                    color = QtGui.QColor(tickPen.color()) # copy to a new QColor
                    color.setAlpha(int(lineAlpha)) # adjust opacity
                    tickPen.setColor(color)

                for v in ticks:
                    ## determine actual position to draw this tick
                    x = (v * xScale) - offset
                    if x < xMin or x > xMax:  ## last check to make sure no out-of-bounds ticks are drawn
                        tickPositions[i].append(None)
                        continue
                    tickPositions[i].append(x)

                    p1 = [x, x]
                    p2 = [x, x]
                    p1[axis] = tickStart
                    p2[axis] = tickStop
                    if self.grid is False:
                        p2[axis] += tickLength*tickDir
                    tickSpecs.append((tickPen, Point(p1), Point(p2)))
            profiler('compute ticks')

            if self.style['stopAxisAtTick'][0] is True:
                minTickPosition = min(map(min, tickPositions))
                if axis == 0:
                    stop = max(span[0].y(), minTickPosition)
                    span[0].setY(stop)
                else:
                    stop = max(span[0].x(), minTickPosition)
                    span[0].setX(stop)
            if self.style['stopAxisAtTick'][1] is True:
                maxTickPosition = max(map(max, tickPositions))
                if axis == 0:
                    stop = min(span[1].y(), maxTickPosition)
                    span[1].setY(stop)
                else:
                    stop = min(span[1].x(), maxTickPosition)
                    span[1].setX(stop)
            axisSpec = (self.pen(), span[0], span[1])

            textOffset = self.style['tickTextOffset'][axis]  ## spacing between axis and text
            textSize2 = 0
            lastTextSize2 = 0
            textRects = []
            textSpecs = []  ## list of draw

            # If values are hidden, return early
            if not self.style['showValues']:
                return (axisSpec, tickSpecs, textSpecs)

            for i in range(min(len(tickLevels), self.style['maxTextLevel']+1)):
                ## Get the list of strings to display for this level
                if tickStrings is None:
                    spacing, values = tickLevels[i]
                    strings = self.tickStrings(values, self.autoSIPrefixScale * self.scale, spacing)
                else:
                    strings = tickStrings[i]

                if len(strings) == 0:
                    continue

                ## ignore strings belonging to ticks that were previously ignored
                for j in range(len(strings)):
                    if tickPositions[i][j] is None:
                        strings[j] = None

                ## Measure density of text; decide whether to draw this level
                rects = []
                for s in strings:
                    if s is None:
                        rects.append(None)
                    else:
                        br = p.boundingRect(QtCore.QRectF(0, 0, 100, 100), QtCore.Qt.AlignmentFlag.AlignCenter, s)
                        ## boundingRect is usually just a bit too large
                        ## (but this probably depends on per-font metrics?)
                        br.setHeight(br.height() * 0.8)

                        rects.append(br)
                        textRects.append(rects[-1])

                if textRects:
                    ## measure all text, make sure there's enough room
                    if axis == 0:
                        textSize = np.sum([r.height() for r in textRects])
                        textSize2 = np.max([r.width() for r in textRects])
                    else:
                        textSize = np.sum([r.width() for r in textRects])
                        textSize2 = np.max([r.height() for r in textRects])
                else:
                    textSize = 0
                    textSize2 = 0

                if i > 0:  ## always draw top level
                    ## If the strings are too crowded, stop drawing text now.
                    ## We use three different crowding limits based on the number
                    ## of texts drawn so far.
                    textFillRatio = float(textSize) / lengthInPixels
                    finished = False
                    for nTexts, limit in self.style['textFillLimits']:
                        if len(textSpecs) >= nTexts and textFillRatio >= limit:
                            finished = True
                            break
                    if finished:
                        break

                lastTextSize2 = textSize2

                # Determine exactly where tick text should be drawn
                for j in range(len(strings)):
                    vstr = strings[j]
                    if vstr is None: ## this tick was ignored because it is out of bounds
                        continue
                    x = tickPositions[i][j]
                    textRect = rects[j]
                    height = textRect.height()
                    width = textRect.width()
                    offset = max(0,self.style['tickLength']) + textOffset

                    rect = QtCore.QRectF()
                    if self.orientation == 'left':
                        alignFlags = QtCore.Qt.AlignmentFlag.AlignRight|QtCore.Qt.AlignmentFlag.AlignVCenter
                        rect = QtCore.QRectF(tickStop-offset-width, x-(height/2), width, height)
                    elif self.orientation == 'right':
                        alignFlags = QtCore.Qt.AlignmentFlag.AlignLeft|QtCore.Qt.AlignmentFlag.AlignVCenter
                        rect = QtCore.QRectF(tickStop+offset, x-(height/2), width, height)
                    elif self.orientation == 'top':
                        alignFlags = QtCore.Qt.AlignmentFlag.AlignHCenter|QtCore.Qt.AlignmentFlag.AlignBottom
                        rect = QtCore.QRectF(x-width/2., tickStop-offset-height, width, height)
                    elif self.orientation == 'bottom':
                        alignFlags = QtCore.Qt.AlignmentFlag.AlignHCenter|QtCore.Qt.AlignmentFlag.AlignTop
                        rect = QtCore.QRectF(x-width/2., tickStop+offset, width, height)

                    textFlags = alignFlags | QtCore.Qt.TextFlag.TextDontClip
                    br = self.boundingRect()

                    # br.contains(rect) suffers from floating point rounding errors
                    if br & rect != rect:
                        continue

                    textSpecs.append((rect, textFlags, vstr))
            profiler('compute text')

            ## update max text size if needed.
            self._updateMaxTextSize(lastTextSize2)

            return axisSpec, tickSpecs, textSpecs

        def drawPicture(self, p, axisSpec, tickSpecs, textSpecs):
            profiler = debug.Profiler()

            p.setRenderHint(p.RenderHint.Antialiasing, False)
            p.setRenderHint(p.RenderHint.TextAntialiasing, True)

            ## draw long line along axis
            pen, p1, p2 = axisSpec
            p.setPen(pen)
            p.drawLine(p1, p2)
            # p.translate(0.5,0)  ## resolves some damn pixel ambiguity

            ## draw ticks
            for pen, p1, p2 in tickSpecs:
                p.setPen(pen)
                p.drawLine(p1, p2)
            profiler('draw ticks')

            # Draw all text
            if self.style['tickFont'] is not None:
                p.setFont(self.style['tickFont'])
            p.setPen(self.textPen())
            bounding = self.boundingRect().toAlignedRect()
            p.setClipRect(bounding)
            for rect, flags, text in textSpecs:
                p.drawText(rect, int(flags), text)

            profiler('draw text')

        def show(self):
            super().show()
            if self.orientation in ['left', 'right']:
                self._updateWidth()
            else:
                self._updateHeight()

        def hide(self):
            super().hide()
            if self.orientation in ['left', 'right']:
                self._updateWidth()
            else:
                self._updateHeight()

        def wheelEvent(self, event):
            lv = self.linkedView()
            if lv is None:
                return
            # Did the event occur inside the linked ViewBox (and not over the axis iteself)?
            if lv.sceneBoundingRect().contains(event.scenePos()):
                event.ignore()
                return
            else:
                # pass event to linked viewbox with appropriate single axis zoom parameter
                if self.orientation in ['left', 'right']:
                    lv.wheelEvent(event, axis=1)
                else:
                    lv.wheelEvent(event, axis=0)
            event.accept()

        def mouseDragEvent(self, event):
            lv = self.linkedView()
            if lv is None:
                return
            # Did the mouse down event occur inside the linked ViewBox (and not the axis)?
            if lv.sceneBoundingRect().contains(event.buttonDownScenePos()):
                event.ignore()
                return
            # otherwise pass event to linked viewbox with appropriate single axis parameter
            if self.orientation in ['left', 'right']:
                return lv.mouseDragEvent(event, axis=1)
            else:
                return lv.mouseDragEvent(event, axis=0)

        def mouseClickEvent(self, event):
            lv = self.linkedView()
            if lv is None:
                return
            return lv.mouseClickEvent(event)