diff --git a/src/silx/gui/_glutils/font.py b/src/silx/gui/_glutils/font.py
index bee9745642..2fd5653072 100644
--- a/src/silx/gui/_glutils/font.py
+++ b/src/silx/gui/_glutils/font.py
@@ -1,6 +1,6 @@
 # /*##########################################################################
 #
-# Copyright (c) 2016-2022 European Synchrotron Radiation Facility
+# Copyright (c) 2016-2023 European Synchrotron Radiation Facility
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -23,6 +23,8 @@
 # ###########################################################################*/
 """Text rasterisation feature leveraging Qt font and text layout support."""
 
+from __future__ import annotations
+
 __authors__ = ["T. Vincent"]
 __license__ = "MIT"
 __date__ = "13/10/2016"
@@ -42,7 +44,7 @@
 _logger = logging.getLogger(__name__)
 
 
-def getDefaultFontFamily():
+def getDefaultFontFamily() -> str:
     """Returns the default font family of the application"""
     return qt.QApplication.instance().font().family()
 
@@ -70,24 +72,30 @@ def getDefaultFontFamily():
 """Thickest characters: Maximum font weight"""
 
 
-def rasterTextQt(text, font, size=-1, weight=-1, italic=False, devicePixelRatio=1.0):
+def rasterTextQt(
+    text: str,
+    font: str | qt.QFont,
+    size: int = -1,
+    weight: int = -1,
+    italic: bool = False,
+    devicePixelRatio: float = 1.0,
+) -> tuple[numpy.ndarray, int]:
     """Raster text using Qt.
 
     It supports multiple lines.
 
-    :param str text: The text to raster
+    :param text: The text to raster
     :param font: Font name or QFont to use
-    :type font: str or :class:`QFont`
-    :param int size:
+    :param size:
         Font size in points
         Used only if font is given as name.
-    :param int weight:
+    :param weight:
         Font weight in [0, 99], see QFont.Weight.
         Used only if font is given as name.
-    :param bool italic:
+    :param italic:
         True for italic font (default: False).
         Used only if font is given as name.
-    :param float devicePixelRatio:
+    :param devicePixelRatio:
         The current ratio between device and device-independent pixel
         (default: 1.0)
     :return: Corresponding image in gray scale and baseline offset from top
@@ -160,24 +168,30 @@ def rasterTextQt(text, font, size=-1, weight=-1, italic=False, devicePixelRatio=
     return array, metrics.ascent() - min_row
 
 
-def rasterText(text, font, size=-1, weight=-1, italic=False, devicePixelRatio=1.0):
+def rasterText(
+    text: str,
+    font: str | qt.QFont,
+    size: int = -1,
+    weight = -1,
+    italic: bool = False,
+    devicePixelRatio=1.0,
+) -> tuple[numpy.ndarray, int]:
     """Raster text using Qt or matplotlib if there may be math syntax.
 
     It supports multiple lines.
 
-    :param str text: The text to raster
+    :param text: The text to raster
     :param font: Font name or QFont to use
-    :type font: str or :class:`QFont`
-    :param int size:
+    :param size:
         Font size in points
         Used only if font is given as name.
-    :param int weight:
+    :param weight:
         Font weight in [0, 99], see QFont.Weight.
         Used only if font is given as name.
-    :param bool italic:
+    :param italic:
         True for italic font (default: False).
         Used only if font is given as name.
-    :param float devicePixelRatio:
+    :param devicePixelRatio:
         The current ratio between device and device-independent pixel
         (default: 1.0)
     :return: Corresponding image in gray scale and baseline offset from top
diff --git a/src/silx/gui/plot/backends/BackendBase.py b/src/silx/gui/plot/backends/BackendBase.py
index abe6dbf518..333140fea4 100755
--- a/src/silx/gui/plot/backends/BackendBase.py
+++ b/src/silx/gui/plot/backends/BackendBase.py
@@ -28,12 +28,18 @@
 This API is a simplified version of PyMca PlotBackend API.
 """
 
+from __future__ import annotations
+
+
 __authors__ = ["V.A. Sole", "T. Vincent"]
 __license__ = "MIT"
 __date__ = "21/12/2018"
 
+from collections.abc import Callable
 import weakref
 
+from ... import qt
+
 
 # Names for setCursor
 CURSOR_DEFAULT = 'default'
@@ -188,17 +194,28 @@ def addShape(self, x, y, shape, color, fill, overlay,
         """
         return object()
 
-    def addMarker(self, x, y, text, color,
-                  symbol, linestyle, linewidth, constraint, yaxis, font):
+    def addMarker(
+        self,
+        x: float | None,
+        y: float | None,
+        text: str | None,
+        color: str,
+        symbol: str | None,
+        linestyle: str,
+        linewidth: float,
+        constraint: Callable[[float, float], tuple[float, float]] | None,
+        yaxis: str,
+        font: qt.QFont,
+    ) -> object:
         """Add a point, vertical line or horizontal line marker to the plot.
 
-        :param float x: Horizontal position of the marker in graph coordinates.
-                        If None, the marker is a horizontal line.
-        :param float y: Vertical position of the marker in graph coordinates.
-                        If None, the marker is a vertical line.
-        :param str text: Text associated to the marker (or None for no text)
-        :param str color: Color to be used for instance 'blue', 'b', '#FF0000'
-        :param str symbol: Symbol representing the marker.
+        :param x: Horizontal position of the marker in graph coordinates.
+            If None, the marker is a horizontal line.
+        :param y: Vertical position of the marker in graph coordinates.
+            If None, the marker is a vertical line.
+        :param text: Text associated to the marker (or None for no text)
+        :param color: Color to be used for instance 'blue', 'b', '#FF0000'
+        :param symbol: Symbol representing the marker.
             Only relevant for point markers where X and Y are not None.
             Value in:
 
@@ -209,7 +226,7 @@ def addMarker(self, x, y, text, color,
             - 'x' x-cross
             - 'd' diamond
             - 's' square
-        :param str linestyle: Style of the line.
+        :param linestyle: Style of the line.
             Only relevant for line markers where X or Y is None.
             Value in:
 
@@ -218,16 +235,14 @@ def addMarker(self, x, y, text, color,
             - '--' dashed line
             - '-.' dash-dot line
             - ':'  dotted line
-        :param float linewidth: Width of the line.
+        :param linewidth: Width of the line.
             Only relevant for line markers where X or Y is None.
         :param constraint: A function filtering marker displacement by
-                           dragging operations or None for no filter.
-                           This function is called each time a marker is
-                           moved.
-        :type constraint: None or a callable that takes the coordinates of
-                          the current cursor position in the plot as input
-                          and that returns the filtered coordinates.
-        :param str yaxis: The Y axis this marker belongs to in: 'left', 'right'
+            dragging operations or None for no filter.
+            This function is called each time a marker is moved.
+            It takes the coordinates of the current cursor position in the plot
+            as input and that returns the filtered coordinates.
+        :param yaxis: The Y axis this marker belongs to in: 'left', 'right'
         :param font: QFont to use to render text
         :return: Handle used by the backend to univocally access the marker
         """
diff --git a/src/silx/gui/plot/backends/glutils/GLText.py b/src/silx/gui/plot/backends/glutils/GLText.py
index 36ee07e05d..e3ed86b0ff 100644
--- a/src/silx/gui/plot/backends/glutils/GLText.py
+++ b/src/silx/gui/plot/backends/glutils/GLText.py
@@ -43,10 +43,7 @@
 from .GLSupport import mat4Translate
 
 
-# TODO: Font should be configurable by the main program: using mpl.rcParams?
-
-
-class _Cache(object):
+class _Cache:
     """LRU (Least Recent Used) cache.
 
     :param int maxsize: Maximum number of (key, value) pairs in the cache
@@ -92,7 +89,7 @@ def __setitem__(self, key, value):
 ROTATE_90, ROTATE_180, ROTATE_270 = 90, 180, 270
 
 
-class Text2D(object):
+class Text2D:
 
     _SHADERS = {
         'vertex': """
@@ -138,12 +135,19 @@ class Text2D(object):
     _sizes = _Cache()
     """Cache already computed sizes"""
 
-    def __init__(self, text, font, x=0, y=0,
-                 color=(0., 0., 0., 1.),
-                 bgColor=None,
-                 align=LEFT, valign=BASELINE,
-                 rotate=0,
-                 devicePixelRatio= 1.):
+    def __init__(
+        self,
+        text: str,
+        font: qt.QFont,
+        x: float = 0.,
+        y: float = 0.,
+        color: tuple[float, float, float, float] = (0., 0., 0., 1.),
+        bgColor: tuple[float, float, float, float] | None = None,
+        align: str = LEFT,
+        valign: str = BASELINE,
+        rotate: float = 0.,
+        devicePixelRatio: float = 1.,
+    ):
         self.devicePixelRatio = devicePixelRatio
         self.font = font
         self._vertices = None
@@ -169,7 +173,7 @@ def _textureKey(self) -> tuple[str, str, float]:
         """Returns the current texture key"""
         return self.text, self.font.key(), self.devicePixelRatio
 
-    def _getTexture(self):
+    def _getTexture(self) -> tuple[Texture, int]:
         # Retrieve/initialize texture cache for current context
         textureKey = self._textureKey()
 
@@ -200,11 +204,11 @@ def _getTexture(self):
         return textures[textureKey]
 
     @property
-    def text(self):
+    def text(self) -> str:
         return self._text
 
     @property
-    def size(self):
+    def size(self) -> tuple[int, int]:
         textureKey = self._textureKey()
         if textureKey not in self._sizes:
             image, offset = font.rasterText(
@@ -214,7 +218,7 @@ def size(self):
             self._sizes[textureKey] = image.shape[1], image.shape[0]
         return self._sizes[textureKey]
 
-    def getVertices(self, offset, shape):
+    def getVertices(self, offset: int, shape: tuple[int, int]) -> numpy.ndarray:
         height, width = shape
 
         if self._align == LEFT:
@@ -247,7 +251,7 @@ def getVertices(self, offset, shape):
 
         return vertices
 
-    def render(self, matrix):
+    def render(self, matrix: numpy.ndarray):
         if not self.text.strip():
             return
 
diff --git a/src/silx/gui/plot/items/marker.py b/src/silx/gui/plot/items/marker.py
index 4c988874a9..6907d047e7 100755
--- a/src/silx/gui/plot/items/marker.py
+++ b/src/silx/gui/plot/items/marker.py
@@ -23,6 +23,7 @@
 # ###########################################################################*/
 """This module provides markers item of the :class:`Plot`.
 """
+from __future__ import annotations
 
 __authors__ = ["T. Vincent"]
 __license__ = "MIT"
@@ -30,7 +31,6 @@
 
 
 import logging
-from typing import Tuple, Optional
 
 from ....utils.proxy import docstring
 from .core import (Item, DraggableMixIn, ColorMixIn, LineMixIn, SymbolMixIn,
@@ -119,14 +119,14 @@ def setText(self, text):
             self._text = text
             self._updated(ItemChangedType.TEXT)
 
-    def getFont(self) -> Optional[qt.QFont]:
+    def getFont(self) -> qt.QFont | None:
         """Returns a copy of the QFont used to render text.
 
         To modify the text font, use :meth:`setFont`.
         """
         return None if self._font is None else qt.QFont(self._font)
 
-    def setFont(self, font: Optional[qt.QFont]):
+    def setFont(self, font: qt.QFont | None):
         """Set the QFont used to render text, use None for default.
 
         A copy is stored, so further modification of the provided font are not taken into account.
@@ -149,7 +149,7 @@ def getYPosition(self):
         """
         return self._y
 
-    def getPosition(self) -> Tuple[Optional[float], Optional[float]]:
+    def getPosition(self) -> tuple[float | None, float | None]:
         """Returns the (x, y) position of the marker in data coordinates
 
         :rtype: 2-tuple of float or None
diff --git a/src/silx/gui/utils/image.py b/src/silx/gui/utils/image.py
index cebe2ed393..3dbb949254 100644
--- a/src/silx/gui/utils/image.py
+++ b/src/silx/gui/utils/image.py
@@ -1,6 +1,6 @@
 # /*##########################################################################
 #
-# Copyright (c) 2017-2022 European Synchrotron Radiation Facility
+# Copyright (c) 2017-2023 European Synchrotron Radiation Facility
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -39,7 +39,7 @@
 from .. import qt
 
 
-def convertArrayToQImage(array):
+def convertArrayToQImage(array: numpy.ndarray) -> qt.QImage:
     """Convert an array-like image to a QImage.
 
     The created QImage is using a copy of the array data.
@@ -50,7 +50,6 @@ def convertArrayToQImage(array):
        Channels are expected to be either RGB or RGBA.
     :type array: numpy.ndarray of uint8
     :return: Corresponding Qt image with RGB888 or ARGB32 format.
-    :rtype: QImage
     """
     array = numpy.array(array, copy=False, order='C', dtype=numpy.uint8)
 
@@ -82,7 +81,7 @@ def convertArrayToQImage(array):
     return qimage.copy()  # Making a copy of the image and its data
 
 
-def convertQImageToArray(image):
+def convertQImageToArray(image: qt.QImage) -> numpy.ndarray:
     """Convert a QImage to a numpy array.
 
     If QImage format is not Format_RGB888, Format_RGBA8888 or Format_ARGB32,
@@ -94,7 +93,6 @@ def convertQImageToArray(image):
     :param QImage image: The QImage to convert.
     :return: The image array of RGB or RGBA channels of shape
         (height, width, channels (3 or 4))
-    :rtype: numpy.ndarray of uint8
     """
     rgba8888 = getattr(qt.QImage, 'Format_RGBA8888', None)  # Only in Qt5
 
diff --git a/src/silx/gui/utils/matplotlib.py b/src/silx/gui/utils/matplotlib.py
index 8843cf9f55..56049cd15c 100644
--- a/src/silx/gui/utils/matplotlib.py
+++ b/src/silx/gui/utils/matplotlib.py
@@ -29,6 +29,8 @@
 It provides the matplotlib :class:`FigureCanvasQTAgg` class corresponding
 to the used backend.
 """
+from __future__ import annotations
+
 
 __authors__ = ["T. Vincent"]
 __license__ = "MIT"
@@ -72,24 +74,30 @@ def qFontToFontProperties(font: qt.QFont):
     )
 
 
-def rasterMathText(text, font, size=-1, weight=-1, italic=False, devicePixelRatio=1.0):
+def rasterMathText(
+    text: str,
+    font: str | qt.QFont,
+    size: int = -1,
+    weight: int = -1,
+    italic: bool = False,
+    devicePixelRatio: float = 1.0,
+) -> tuple[numpy.ndarray, int]:
     """Raster text using matplotlib supporting latex-like math syntax.
 
     It supports multiple lines.
 
-    :param str text: The text to raster
+    :param text: The text to raster
     :param font: Font name or QFont to use
-    :type font: str or :class:`QFont`
-    :param int size:
+    :param size:
         Font size in points
         Used only if font is given as name.
-    :param int weight:
+    :param weight:
         Font weight in [0, 99], see QFont.Weight.
         Used only if font is given as name.
-    :param bool italic:
+    :param italic:
         True for italic font (default: False).
         Used only if font is given as name.
-    :param float devicePixelRatio:
+    :param devicePixelRatio:
         The current ratio between device and device-independent pixel
         (default: 1.0)
     :return: Corresponding image in gray scale and baseline offset from top