diff --git a/docs/conf_common.py b/docs/conf_common.py
index cd1d3768e5..1820e0c352 100644
--- a/docs/conf_common.py
+++ b/docs/conf_common.py
@@ -26,6 +26,7 @@ from idf_extensions.util import download_file_if_missing
 # build_docs on the CI server sometimes fails under Python3. This is a workaround:
 sys.setrecursionlimit(3500)
 
+config_dir = os.path.abspath(os.path.dirname(__file__))
 
 # http://stackoverflow.com/questions/12772927/specifying-an-online-image-in-sphinx-restructuredtext-format
 #
@@ -367,3 +368,31 @@ def setup(app):
     # note: we generate into xml_in and then copy_if_modified to xml dir
     app.config.breathe_projects = {"esp32-idf": os.path.join(app.config.build_dir, "xml_in/")}
     app.config.breathe_default_project = "esp32-idf"
+
+
+    setup_diag_font(app)
+
+def setup_diag_font(app):
+    # blockdiag and other tools require a font which supports their character set
+    # the font file is stored on the download server to save repo size
+
+    font_name = {
+        'en': 'DejaVuSans.ttf',
+        'zh_CN': 'NotoSansSC-Regular.otf',
+    }[app.config.language]
+
+    font_dir = os.path.join(config_dir, '_static')
+    assert os.path.exists(font_dir)
+
+    print("Downloading font file %s for %s" % (font_name, app.config.language))
+    download_file_if_missing('https://dl.espressif.com/dl/esp-idf/docs/_static/{}'.format(font_name), font_dir)
+
+    font_path = os.path.abspath(os.path.join(font_dir, font_name))
+    assert os.path.exists(font_path)
+
+    app.config.blockdiag_fontpath = font_path
+    app.config.seqdiag_fontpath = font_path
+    app.config.actdiag_fontpath = font_path
+    app.config.nwdiag_fontpath = font_path
+    app.config.rackdiag_fontpath = font_path
+    app.config.packetdiag_fontpath = font_path
diff --git a/docs/en/conf.py b/docs/en/conf.py
index ec996f62f2..1bd7f8812f 100644
--- a/docs/en/conf.py
+++ b/docs/en/conf.py
@@ -10,7 +10,6 @@ import sys
 import os
 sys.path.insert(0, os.path.abspath('..'))
 from conf_common import *  # noqa: F401, F403 - need to make available everything from common
-from idf_extensions.util import download_file_if_missing  # noqa: E402 - need to import from common folder
 
 # General information about the project.
 project = u'ESP-IDF Programming Guide'
@@ -20,16 +19,4 @@ copyright = u'2016 - 2019, Espressif Systems (Shanghai) CO., LTD'
 # for a list of supported languages.
 language = 'en'
 
-# Download font file that is stored on a separate server to save on esp-idf repository size.
-print("Downloading font file")
-download_file_if_missing('https://dl.espressif.com/dl/esp-idf/docs/_static/DejaVuSans.ttf', '../_static')
-
-# Set up font for blockdiag, nwdiag, rackdiag and packetdiag
-blockdiag_fontpath = '../_static/DejaVuSans.ttf'
-seqdiag_fontpath = '../_static/DejaVuSans.ttf'
-actdiag_fontpath = '../_static/DejaVuSans.ttf'
-nwdiag_fontpath = '../_static/DejaVuSans.ttf'
-rackdiag_fontpath = '../_static/DejaVuSans.ttf'
-packetdiag_fontpath = '../_static/DejaVuSans.ttf'
-
 update_exclude_patterns(tags)  # noqa: F405, need to import * from conf_common
diff --git a/docs/zh_CN/conf.py b/docs/zh_CN/conf.py
index b857bc0d75..70e377de10 100644
--- a/docs/zh_CN/conf.py
+++ b/docs/zh_CN/conf.py
@@ -20,16 +20,4 @@ copyright = u'2016 - 2019 乐鑫信息科技（上海）股份有限公司'
 # for a list of supported languages.
 language = 'zh_CN'
 
-# Download font file that is stored on a separate server to save on esp-idf repository size.
-print("Downloading font file")
-download_file_if_missing('https://dl.espressif.com/dl/esp-idf/docs/_static/NotoSansSC-Regular.otf', '../_static')
-
-# Set up font for blockdiag, nwdiag, rackdiag and packetdiag
-blockdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-seqdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-actdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-nwdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-rackdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-packetdiag_fontpath = '../_static/NotoSansSC-Regular.otf'
-
 update_exclude_patterns(tags)  # noqa: F405, need to import * from conf_common