Fix doc strings.

kivymd/uix/scrollview.py

@@ -4,7 +4,8 @@
 
 .. versionadded:: 1.0.0
 
-:class:`~kivy.uix.scrollview.ScrollView` class equivalent. It implements Material Design's overscorll effect and
+:class:`~kivy.uix.scrollview.ScrollView` class equivalent.
+It implements Material Design's overscorll effect and
 simplifies working with some widget properties. For example:
 
 ScrollView
@@ -28,6 +29,119 @@
 
     MDScrollView:
         md_bg_color: app.theme_cls.primaryColor
+
+The stretching effect
+---------------------
+
+.. code-block:: python
+
+    import os
+    import sys
+
+    from kivy.core.window import Window
+    from kivy import __version__ as kv__version__
+    from kivy.lang import Builder
+    from kivy.metrics import dp
+
+    from kivymd.app import MDApp
+    from kivymd import __version__
+    from kivymd.uix.list import (
+        MDListItem,
+        MDListItemHeadlineText,
+        MDListItemSupportingText,
+        MDListItemLeadingIcon,
+    )
+
+    from materialyoucolor import __version__ as mc__version__
+
+    from examples.common_app import CommonApp
+
+    MAIN_KV = '''
+    MDScreen:
+        md_bg_color: app.theme_cls.backgroundColor
+
+        MDScrollView:
+            do_scroll_x: False
+
+            MDBoxLayout:
+                id: main_scroll
+                orientation: "vertical"
+                adaptive_height: True
+
+                MDBoxLayout:
+                    adaptive_height: True
+
+                    MDLabel:
+                        theme_font_size: "Custom"
+                        text: "OS Info"
+                        font_size: "55sp"
+                        adaptive_height: True
+                        padding: "10dp", "20dp", 0, 0
+
+                    MDIconButton:
+                        icon: "menu"
+                        on_release: app.open_menu(self)
+                        pos_hint: {"center_y": .5}
+    '''
+
+
+    class Example(MDApp, CommonApp):
+        def build(self):
+            self.theme_cls.theme_style = "Dark"
+            return Builder.load_string(MAIN_KV)
+
+        def on_start(self):
+            info = {
+                "Name": [
+                    os.name,
+                    (
+                        "microsoft"
+                        if os.name == "nt"
+                        else ("linux" if os.uname()[0] != "Darwin" else "apple")
+                    ),
+                ],
+                "Architecture": [os.uname().machine, "memory"],
+                "Hostname": [os.uname().nodename, "account"],
+                "Python Version": ["v" + sys.version, "language-python"],
+                "Kivy Version": ["v" + kv__version__, "alpha-k-circle-outline"],
+                "KivyMD Version": ["v" + __version__, "material-design"],
+                "MaterialYouColor Version": ["v" + mc__version__, "invert-colors"],
+                "Pillow Version": ["Unknown", "image"],
+                "Working Directory": [os.getcwd(), "folder"],
+                "Home Directory": [os.path.expanduser("~"), "folder-account"],
+                "Environment Variables": [os.environ, "code-json"],
+            }
+
+            try:
+                from PIL import __version__ as pil__version_
+
+                info["Pillow Version"] = ["v" + pil__version_, "image"]
+            except Exception:
+                pass
+
+            for info_item in info:
+                self.root.ids.main_scroll.add_widget(
+                    MDListItem(
+                        MDListItemLeadingIcon(
+                            icon=info[info_item][1],
+                        ),
+                        MDListItemHeadlineText(
+                            text=info_item,
+                        ),
+                        MDListItemSupportingText(
+                            text=str(info[info_item][0]),
+                        ),
+                        pos_hint={"center_x": .5, "center_y": .5},
+                    )
+                )
+
+            Window.size = [dp(350), dp(600)]
+
+
+    Example().run()
+
+.. image:: https://github.com/HeaTTheatR/KivyMD-data/raw/master/gallery/kivymddoc/stretch_over_scroll_stencil.gif
+    :align: center
 """
 
 from __future__ import annotations
@@ -48,25 +162,27 @@ class StretchOverScrollStencil(ScrollEffect):
     """
     Stretches the view on overscroll and absorbs
     velocity at start and end to convert to stretch.
-    .. note:: This effect only works with :class:`kivymd.uix.scrollview.MDScrollView`.
+
+    .. note:: This effect only works with
+        :class:`kivymd.uix.scrollview.MDScrollView`.
+
     If you need any documentation please look at
     :class:`~kivy.effects.dampedscrolleffect`.
     """
 
-    # Android constants
+    # Android constants.
     minimum_absorbed_velocity = 0
     maximum_velocity = 10000
     stretch_intensity = 0.016
     exponential_scalar = math.e / (1 / 3)
     scroll_friction = 0.015
-    # Used in `absorb_impact` but for now
-    # it's not compatible with kivy so we using
-    # are approx value.
+    # Used in `absorb_impact` but for now it's not compatible with kivy so we
+    # using are approx value.
     # fling_friction = 1.01
     approx_normailzer = 2e5
 
     # Duration to normalize scale
-    # when touch up is recieved and view is stretched
+    # when touch up is received and view is stretched.
     duration_normailzer = 10
 
     scroll_view = None  # scroll view instance
@@ -97,7 +213,8 @@ def on_value(self, stencil, scroll_distance):
             if self.is_top_or_bottom():
                 if (
                     abs(self.velocity) > self.minimum_absorbed_velocity
-                    and self._should_absorb  # only first time when reaches top or bottom
+                    and self._should_absorb  # only first time when reaches
+                    # top or bottom
                 ):
                     self.absorb_impact()
                 self._should_absorb = False
@@ -109,7 +226,7 @@ def get_hw(self):
 
     def set_scale_origin(self):
         # Check if target size is small than scrollview
-        # if yes don't stretch scroll view
+        # if yes don't stretch scroll view.
         if getattr(self.target_widget, self.get_hw()) < getattr(
             self.scroll_view, self.get_hw()
         ):
@@ -150,17 +267,17 @@ def convert_overscroll(self, touch):
             and self.velocity == 0
             and self.set_scale_origin()  # sets stretch direction
         ):
-            # Distance travelled by touch divided by size of scrollview
+            # Distance travelled by touch divided by size of scrollview.
             distance = (
                 abs(
                     self.get_component(touch.pos)
                     - self.get_component(self.last_touch_pos)
                 )
                 / self.scroll_view.height
             )
-            # constant scale due to distance
+            # Constant scale due to distance.
             linear_intensity = self.stretch_intensity * distance
-            # Far the touch -> less it stretches
+            # Far the touch -> less it stretches.
             exponential_intensity = self.stretch_intensity * (
                 1 - math.exp(-distance * self.exponential_scalar)
             )