RSTdocument-bug? 'Opposite' effect of base_font_size in Android and Ubuntu?

There is a big difference between how

RstDocument: base_font_size: sp(15)

is rendered on my Android phone and in PyCharm on Ubuntu 18.04.3 LTS with GNOME 3.28.2.

On Ubuntu, the letters on that RST-document are much smaller than on the other, where I do NOT specify any base_font_size. But on Android the letters on that RST-document are much bigger than on the other, where I do NOT specify any base_font_size.

In the RST-document where I do NOT specify any base_font_size the font size seems to be 15sp on both Android and Ubuntu.

I have created a small demo, attached, that shows the bug in RST on a TabbedPanel: I run/deploy it on my Android in Terminal with: $ buildozer android debug deploy run (Having the folder with the attached files as current of course.) And I ran it in PyCharm under Ubuntu as mentioned earlier.

Versions

Python: 3.6
OS: Ubuntu 18.04.3 LTS with GNOME 3.28.2.
Kivy: 1.11.1
Kivy installation method: (I don't remember.)

Description

See above.

Code and Logs:

First the Python/Kivy test file:

import kivy

kivy.require('1.11.1')
# Developed in Python 3.6

from kivy.app import App
from kivy.uix.tabbedpanel import TabbedPanel
from kivy.lang import Builder

Builder.load_string('''
#:kivy 1.11.1
#  Useless?  #:import kivy kivy

<MyTabbedPanel>:
    size_hint: 1, 1  # Is this really necessary?
    do_default_tab: False
    # tab_width: self.width / 4  # Only good if there are 4 tabs

    TabbedPanelItem:
        text: 'Intro 1'
        font_size: '15sp'
        RstDocument:
            base_font_size: sp(15)
            bar_color: [.3, .3, .3, .9]
            bar_inactive_color: [.3, .3, .3, .9]
            bar_width: 16
            source: 'README.rst'

    TabbedPanelItem:
        text: 'Intro 2'
        # font_size: '15sp'
        RstDocument:
            # base_font_size: sp(15)
            bar_color: [.3, .3, .3, .9]
            bar_inactive_color: [.3, .3, .3, .9]
            bar_width: 16
            source: 'README.rst'

''')

class MyTabbedPanel(TabbedPanel):
    pass

class MyAppWithTabs(App):
    def build(self):
        return MyTabbedPanel()

if __name__ == '__main__':
    MyAppWithTabs().run()

Here comes the Buildozer.spec:

[app]

# (str) Title of your application
title = My Application

# (str) Package name
package.name = myapp

# (str) Package domain (needed for android/ios packaging)
package.domain = org.test

# (str) Source code where the main.py live
source.dir = .

# (list) Source files to include (let empty to include all the files)
#source.include_exts = py,png,jpg,kv,atlas
source.include_exts = 

# (list) List of inclusions using pattern matching
#source.include_patterns = assets/*,images/*.png

# (list) Source files to exclude (let empty to not exclude anything)
#source.exclude_exts = spec

# (list) List of directory to exclude (let empty to not exclude anything)
#source.exclude_dirs = tests, bin

# (list) List of exclusions using pattern matching
#source.exclude_patterns = license,images/*/*.jpg

# (str) Application versioning (method 1)
version = 0.1

# (str) Application versioning (method 2)
# version.regex = __version__ = ['"](.*)['"]
# version.filename = %(source.dir)s/main.py

# (list) Application requirements
# comma separated e.g. requirements = sqlite3,kivy
# requirements = python3,kivy
# requirements = kivy,pil,sqlite3,pygments,docutils
requirements = python3,kivy,pil,sqlite3,pygments,docutils

# (str) Custom source folders for requirements
# Sets custom source for any requirements with recipes
# requirements.source.kivy = ../../kivy

# (list) Garden requirements
#garden_requirements =

# (str) Presplash of the application
#presplash.filename = %(source.dir)s/data/presplash.png

# (str) Icon of the application
#icon.filename = %(source.dir)s/data/icon.png

# (str) Supported orientation (one of landscape, sensorLandscape, portrait or all)
orientation = all

# (list) List of service to declare
#services = NAME:ENTRYPOINT_TO_PY,NAME2:ENTRYPOINT2_TO_PY

#
# OSX Specific
#

#
# author = © Copyright Info

# change the major version of python used by the app
osx.python_version = 3

# Kivy version to use
osx.kivy_version = 1.11.1

#
# Android specific
#

# (bool) Indicate if the application should be fullscreen or not
fullscreen = 0

# (string) Presplash background color (for new android toolchain)
# Supported formats are: #RRGGBB #AARRGGBB or one of the following names:
# red, blue, green, black, white, gray, cyan, magenta, yellow, lightgray,
# darkgray, grey, lightgrey, darkgrey, aqua, fuchsia, lime, maroon, navy,
# olive, purple, silver, teal.
#android.presplash_color = #FFFFFF

# (list) Permissions
#android.permissions = INTERNET

# (int) Target Android API, should be as high as possible.
#android.api = 27

# (int) Minimum API your APK will support.
#android.minapi = 21

# (int) Android SDK version to use
#android.sdk = 20

# (str) Android NDK version to use
#android.ndk = 17c

# (int) Android NDK API to use. This is the minimum API your app will support, it should usually match android.minapi.
#android.ndk_api = 21

# (bool) Use --private data storage (True) or --dir public storage (False)
#android.private_storage = True

# (str) Android NDK directory (if empty, it will be automatically downloaded.)
#android.ndk_path =

# (str) Android SDK directory (if empty, it will be automatically downloaded.)
#android.sdk_path =

# (str) ANT directory (if empty, it will be automatically downloaded.)
#android.ant_path =

# (bool) If True, then skip trying to update the Android sdk
# This can be useful to avoid excess Internet downloads or save time
# when an update is due and you just want to test/build your package
# android.skip_update = False

# (bool) If True, then automatically accept SDK license
# agreements. This is intended for automation only. If set to False,
# the default, you will be shown the license when first running
# buildozer.
# android.accept_sdk_license = False

# (str) Android entry point, default is ok for Kivy-based app
#android.entrypoint = org.renpy.android.PythonActivity

# (list) Pattern to whitelist for the whole project
android.whitelist = '*.rst'

# (str) Path to a custom whitelist file
#android.whitelist_src =

# (str) Path to a custom blacklist file
#android.blacklist_src =

# (list) List of Java .jar files to add to the libs so that pyjnius can access
# their classes. Don't add jars that you do not need, since extra jars can slow
# down the build process. Allows wildcards matching, for example:
# OUYA-ODK/libs/*.jar
#android.add_jars = foo.jar,bar.jar,path/to/more/*.jar

# (list) List of Java files to add to the android project (can be java or a
# directory containing the files)
#android.add_src =

# (list) Android AAR archives to add (currently works only with sdl2_gradle
# bootstrap)
#android.add_aars =

# (list) Gradle dependencies to add (currently works only with sdl2_gradle
# bootstrap)
#android.gradle_dependencies =

# (list) Java classes to add as activities to the manifest.
#android.add_activites = com.example.ExampleActivity

# (str) OUYA Console category. Should be one of GAME or APP
# If you leave this blank, OUYA support will not be enabled
#android.ouya.category = GAME

# (str) Filename of OUYA Console icon. It must be a 732x412 png image.
#android.ouya.icon.filename = %(source.dir)s/data/ouya_icon.png

# (str) XML file to include as an intent filters in <activity> tag
#android.manifest.intent_filters =

# (str) launchMode to set for the main activity
#android.manifest.launch_mode = standard

# (list) Android additional libraries to copy into libs/armeabi
#android.add_libs_armeabi = libs/android/*.so
#android.add_libs_armeabi_v7a = libs/android-v7/*.so
#android.add_libs_arm64_v8a = libs/android-v8/*.so
#android.add_libs_x86 = libs/android-x86/*.so
#android.add_libs_mips = libs/android-mips/*.so

# (bool) Indicate whether the screen should stay on
# Don't forget to add the WAKE_LOCK permission if you set this to True
#android.wakelock = False

# (list) Android application meta-data to set (key=value format)
#android.meta_data =

# (list) Android library project to add (will be added in the
# project.properties automatically.)
#android.library_references =

# (list) Android shared libraries which will be added to AndroidManifest.xml using <uses-library> tag
#android.uses_library =

# (str) Android logcat filters to use
#android.logcat_filters = *:S python:D

# (bool) Copy library instead of making a libpymodules.so
#android.copy_libs = 1

# (str) The Android arch to build for, choices: armeabi-v7a, arm64-v8a, x86, x86_64
android.arch = armeabi-v7a

#
# Python for android (p4a) specific
#

# (str) python-for-android fork to use, defaults to upstream (kivy)
#p4a.fork = kivy

# (str) python-for-android branch to use, defaults to master
#p4a.branch = master

# (str) python-for-android git clone directory (if empty, it will be automatically cloned from github)
#p4a.source_dir =

# (str) The directory in which python-for-android should look for your own build recipes (if any)
#p4a.local_recipes =

# (str) Filename to the hook for p4a
#p4a.hook =

# (str) Bootstrap to use for android builds
# p4a.bootstrap = sdl2

# (int) port number to specify an explicit --port= p4a argument (eg for bootstrap flask)
#p4a.port =

#
# iOS specific
#

# (str) Path to a custom kivy-ios folder
#ios.kivy_ios_dir = ../kivy-ios
# Alternately, specify the URL and branch of a git checkout:
ios.kivy_ios_url = https://github.com/kivy/kivy-ios
ios.kivy_ios_branch = master

# Another platform dependency: ios-deploy
# Uncomment to use a custom checkout
#ios.ios_deploy_dir = ../ios_deploy
# Or specify URL and branch
ios.ios_deploy_url = https://github.com/phonegap/ios-deploy
ios.ios_deploy_branch = 1.7.0

# (str) Name of the certificate to use for signing the debug version
# Get a list of available identities: buildozer ios list_identities
#ios.codesign.debug = "iPhone Developer: <lastname> <firstname> (<hexstring>)"

# (str) Name of the certificate to use for signing the release version
#ios.codesign.release = %(ios.codesign.debug)s

[buildozer]

# (int) Log level (0 = error only, 1 = info, 2 = debug (with command output))
log_level = 1

# (int) Display warning if buildozer is run as root (0 = False, 1 = True)
warn_on_root = 1

# (str) Path to build artifact storage, absolute or relative to spec file
# build_dir = ./.buildozer

# (str) Path to build output (i.e. .apk, .ipa) storage
# bin_dir = ./bin

#    -----------------------------------------------------------------------------
#    List as sections
#
#    You can define all the "list" as [section:key].
#    Each line will be considered as a option to the list.
#    Let's take [app] / source.exclude_patterns.
#    Instead of doing:
#
#[app]
#source.exclude_patterns = license,data/audio/*.wav,data/images/original/*
#
#    This can be translated into:
#
#[app:source.exclude_patterns]
#license
#data/audio/*.wav
#data/images/original/*
#

#    -----------------------------------------------------------------------------
#    Profiles
#
#    You can extend section / key with a profile
#    For example, you want to deploy a demo version of your application without
#    HD content. You could first change the title to add "(demo)" in the name
#    and extend the excluded directories to remove the HD content.
#
#[app@demo]
#title = My Application (demo)
#
#[app:source.exclude_patterns@demo]
#images/hd/*
#
#    Then, invoke the command line with the "demo" profile:
#
#buildozer --profile demo android debug

And finally 'README.rst':

This is the 'Intro-1' RSTdocument
=================================

NOTE: PyInstaller does not extend PYTHONPATH (sys.path) with this directory
that contains bundled 3rd party libraries.

Some users complained that PyInstaller failed because their apps were using
too old versions of some libraries that PyInstaller uses too and that's why
extending sys.path was dropped.

All libraries are tweaked to be importable as::

    from PyInstaller.lib.LIB_NAME import xyz

In libraries replace imports like::

    from altgraph import y
    from modulegraph import z

with relative prefix::

    from ..altgraph import y
    from ..modulegraph import z

altgraph
----------

- add fixed version string to ./altgraph/__init__.py::

    # For PyInstaller/lib/ define the version here, since there is no
    # package-resource.
    __version__ = '0.13'

modulegraph
-----------

https://bitbucket.org/ronaldoussoren/modulegraph/downloads

- TODO Use official modulegraph version when following issue is resolved and pull request merged
  https://bitbucket.org/ronaldoussoren/modulegraph/issues/28/__main__-module-being-analyzed-for-wheel

- add fixed version string to ./modulegraph/__init__.py::

    # For PyInstaller/lib/ define the version here, since there is no
    # package-resource.
    __version__ = '0.13'

kivy / kivy