frontend/scripts/fonts-subset.sh
Dominik Pschenitschni b6a89a0cde feat: use variable fonts with subsetting (#2817)
Co-authored-by: Dominik Pschenitschni <mail@celement.de>
Reviewed-on: vikunja/frontend#2817
Co-authored-by: Dominik Pschenitschni <dpschen@noreply.kolaente.de>
Co-committed-by: Dominik Pschenitschni <dpschen@noreply.kolaente.de>
2022-12-15 21:37:02 +00:00

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#!/bin/sh
set -e
#
# This script subsets our variable fonts,
# converts them to woff2 files and puts them in the
# fonts folder.
#
# We do have to update the font paths in the @font-face
# definitions manually since we use a checksum to make
#
# We use fonttools to create a partial instance of the
# variable font where we keep only our needed features.
# See more at:
# https://fonttools.readthedocs.io/en/latest/varLib/instancer.html
#
# fonttools requires python > 3.7. For up-to-date
# instructions see https://github.com/fonttools/fonttools#installation
#
# Lot's of info was gathered from:
# https://markoskon.com/creating-font-subsets/
# https://barrd.dev/article/create-a-variable-font-subset-for-smaller-file-size/
#
ORIGINAL_FONTS="./originalMedia/fonts"
TEMP_FOLDER="./.subset-fonts-temp"
FONT_FOLDER="./src/assets/fonts"
err_report() {
echo "Error on line $(caller)" >&2
}
trap err_report ERR
mkdir -p $TEMP_FOLDER
# the latin subset that google uses on GoogleFonts
# this is the same as the latin subset range that google uses on GoogleFonts
# see for examle the unicode-range definition here:
# https://fonts.googleapis.com/css2?family=Open+Sans
UNICODE_LATIN_SUBSET="U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,\
U+02C6,U+02DA,U+02DC,U+2000-206F,U+2074,U+20AC,\
U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD"
get_filename_without_type() {
filename=$1
dirname=$(dirname $filename)
# Extract the file type using parameter expansion
filetype=${filename##*.}
basename=$(basename $filename .$filetype)
echo $basename
}
# This function takes a font file and creates a subset of it using a specified set of unicode characters.
instance_and_subset () {
# Define default arguments for the subsetter.
DEFAULT_SUBSETTER_ARGS="--layout-features=* --unicodes=${UNICODE_LATIN_SUBSET}"
# Assign function arguments to variables with more descriptive names.
INPUT_FONT_FILE=$1
INSTANCER_ARGS=$2
OUTPUT_FONT_BASENAME=$3
OUTPUT_FOLDER=$FONT_FOLDER
# If the output font basename is not provided, use the input font file's basename as the output font basename.
if [ -z "$OUTPUT_FONT_BASENAME" ]; then
INPUT_FONT_BASENAME=$(get_filename_without_type $INPUT_FONT_FILE)
OUTPUT_FONT_BASENAME=$INPUT_FONT_BASENAME
fi
# Use the default subsetter arguments if no custom arguments are provided.
SUBSETTER_ARGS="${4:-$DEFAULT_SUBSETTER_ARGS}"
CHECKSUM=$(
# Concatenate the contents of the input font file, the instancer arguments, and the subsetter arguments
printf "%s%s" "$(cat $INPUT_FONT_FILE)" "$INSTANCER_ARGS" "$SUBSETTER_ARGS" |
# Calculate the Blake2b checksum of the concatenated string
b2sum |
# Extract the checksum from the output of b2sum (it's the first field)
awk '{print $1}'
)
# Limit the checksum to 8 characters.
CHECKSUM=$(echo "${CHECKSUM:0:8}")
# Construct the output font's filename
OUTPUT_FONT_BASENAME="${OUTPUT_FONT_BASENAME}_${CHECKSUM}"
OUTPUT_FONT_FILE="${OUTPUT_FOLDER}/${OUTPUT_FONT_BASENAME}.woff2"
# Check if the output font file already exists
if test -f $OUTPUT_FONT_FILE; then
echo "${OUTPUT_FONT_FILE} exists"
return 0
fi
FONT_INSTANCE="${TEMP_FOLDER}/${OUTPUT_FONT_BASENAME}.ttf"
if [ -n "$INSTANCER_ARGS" ]; then
# If the INSTANCER_ARGS variable is set, use fonttools to create a font instance
fonttools varLib.instancer --output $FONT_INSTANCE $INPUT_FONT_FILE $INSTANCER_ARGS
else
# Otherwise, just copy the input font file to the font instance file
cp $INPUT_FONT_FILE $FONT_INSTANCE
fi
# Use pyftsubset to create a subset of the font instance and save it to the output font file
pyftsubset $FONT_INSTANCE --output-file=$OUTPUT_FONT_FILE --flavor=woff2 $SUBSETTER_ARGS
echo "${OUTPUT_FONT_BASENAME} subsetted."
}
echo ""
echo "###################################################"
echo "# Install required libs"
echo "###################################################"
echo ""
pip install fonttools brotli
echo ""
echo "###################################################"
echo "# Create a partial instance of the variable font"
echo "# where we keep only our needed features and then"
echo "# subset fonts with latin unicode range and export"
echo "# as woff2 file"
echo "###################################################"
echo ""
mkdir -p $TEMP_FOLDER
echo "\nOpen Sans"
# we drop the wdth axis for all
instance_and_subset "${ORIGINAL_FONTS}/OpenSans[wdth,wght].ttf" "wdth=drop wght=400:700" "OpenSans[wght]"
# we restrict the wght range
instance_and_subset "${ORIGINAL_FONTS}/OpenSans[wdth,wght].ttf" "wdth=drop wght=400" "OpenSans-Regular"
instance_and_subset "${ORIGINAL_FONTS}/OpenSans[wdth,wght].ttf" "wdth=drop wght=700" "OpenSans-Bold"
echo "\nOpen Sans Italic"
# we drop the wdth axis for all
instance_and_subset "${ORIGINAL_FONTS}/OpenSans-Italic[wdth,wght].ttf" "wdth=drop wght=400:700" "OpenSans-Italic[wght]"
# we restrict the wght range
instance_and_subset "${ORIGINAL_FONTS}/OpenSans-Italic[wdth,wght].ttf" "wdth=drop wght=400" "OpenSans-RegularItalic"
instance_and_subset "${ORIGINAL_FONTS}/OpenSans-Italic[wdth,wght].ttf" "wdth=drop wght=700" "OpenSans-BoldItalic"
echo "\nQuicksand"
instance_and_subset "${ORIGINAL_FONTS}/Quicksand[wght].ttf" "wght=400:700"
# we restrict the wght range
instance_and_subset "${ORIGINAL_FONTS}/Quicksand[wght].ttf" "wght=400" "Quicksand-Regular"
instance_and_subset "${ORIGINAL_FONTS}/Quicksand[wght].ttf" "wght=600" "Quicksand-SemiBold"
instance_and_subset "${ORIGINAL_FONTS}/Quicksand[wght].ttf" "wght=700" "Quicksand-Bold"
echo "\nSubsetting files complete"
# remove temp folder
rm -r $TEMP_FOLDER