Use OpenSans as default font and ship the font file inside the 'resources' directory.

plotid/resources/OpenSans/OFL.txt

+Copyright 2020 The Open Sans Project Authors (https://github.com/googlefonts/opensans)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

plotid/resources/__init__.py

+ 

plotid/tagplot_image.py

@@ -7,6 +7,7 @@ Functions:
 """
 import os
 import warnings
+from importlib.resources import files
 from PIL import Image, ImageDraw, ImageFont, ImageOps
 from plotid.create_id import create_id, create_qrcode
 from plotid.plotoptions import PlotOptions, PlotIDTransfer
@@ -42,7 +43,9 @@ def tagplot_image(plotid_object: PlotOptions) -> PlotIDTransfer:
             # Check if figs is a valid file is done by pillow internally
 
     color = tuple(rgb_value * 255 for rgb_value in plotid_object.fontcolor)
-    font = ImageFont.load_default()
+    # font = ImageFont.load_default()
+    font_path = files("plotid.resources").joinpath("OpenSans", "OpenSans-Regular.ttf")
+    font = ImageFont.truetype(str(font_path), plotid_object.fontsize)
 
     if plotid_object.font:
         try:

plotid/tagplot_matplotlib.py

 # -*- coding: utf-8 -*-
 """Tag your matplotlib plot with an ID."""
 
+from importlib.resources import files
 import matplotlib
 import matplotlib.pyplot as plt
 from PIL import Image
@@ -35,6 +36,15 @@ def tagplot_matplotlib(plotid_object: PlotOptions) -> PlotIDTransfer:
         if not isinstance(figure, matplotlib.figure.Figure):
             raise TypeError("Figure is not a valid matplotlib-figure.")
 
+    if plotid_object.font:
+        # Load custom font into matplotlib
+        matplotlib.font_manager.fontManager.addfont(plotid_object.font)
+        font = matplotlib.font_manager.FontProperties(fname=plotid_object.font)
+    else:
+        font = files("plotid.resources").joinpath("OpenSans", "OpenSans-Regular.ttf")
+        matplotlib.font_manager.fontManager.addfont(font)
+        font = matplotlib.font_manager.FontProperties(fname=font)
+
     # Loop to create and position the IDs
     for fig in plotid_object.figs:
         fig_id: str = create_id(plotid_object.id_method)
@@ -43,11 +53,6 @@ def tagplot_matplotlib(plotid_object: PlotOptions) -> PlotIDTransfer:
         plt.figure(fig)
 
         if plotid_object.id_on_plot:
-            font = "DejaVu Sans"
-            if plotid_object.font:
-                # Load custom font into matplotlib
-                matplotlib.font_manager.fontManager.addfont(plotid_object.font)
-                font = matplotlib.font_manager.FontProperties(fname=plotid_object.font)
 
             plt.figtext(
                 x=plotid_object.position[0],

tests/test_tagplot_image.py

@@ -47,7 +47,7 @@ class TestTagplotImage(unittest.TestCase):
             id_method=METHOD,
             qrcode=True,
             fontsize=10,
-            font="fonts/xolonium-fonts-4.1/ttf/Xolonium-Bold.ttf",
+            font="plotid/resources/OpenSans/OpenSans-Bold.ttf",
             fontcolor=(0, 1, 0),
         )
         options.validate_input()

tests/test_tagplot_matplotlib.py

@@ -5,6 +5,7 @@ Unittests for tagplot_matplotlib
 """
 
 import unittest
+from importlib.resources import files
 import matplotlib.pyplot as plt
 from matplotlib.figure import Figure
 from plotid.tagplot_matplotlib import tagplot_matplotlib
@@ -37,7 +38,7 @@ class TestTagplotMatplotlib(unittest.TestCase):
             id_method=METHOD,
             qrcode=True,
             fontsize=10,
-            font="tests/fonts/xolonium-fonts-4.1/otf/Xolonium-Regular.otf",
+            font="plotid/resources/OpenSans/OpenSans-Bold.ttf",
             fontcolor=(0, 0, 1),
         )
         options.validate_input()