nixpkgs/pkgs/build-support/setup-hooks/desktop-to-darwin-bundle.sh
Marco Rebhan f78175ad35 desktopToDarwinBundle: Fix icon selection algorithm
Now, the fallback icon is only used after considering all possible icons
instead of only the first one.
2023-03-29 16:42:57 +02:00

246 lines
8.9 KiB
Bash

# shellcheck shell=bash
fixupOutputHooks+=('convertDesktopFiles $prefix')
# Get a param out of a desktop file. First parameter is the file and the second
# is the key who's value we should fetch.
getDesktopParam() {
local file="$1"
local key="$2"
local line k v
while read -r line; do
if [[ "$line" = *=* ]]; then
k="${line%%=*}"
v="${line#*=}"
if [[ "$k" = "$key" ]]; then
echo "$v"
return
fi
fi
done < "$file"
return 1
}
# Convert a freedesktop.org icon theme for a given app to a .icns file. When possible, missing
# icons are synthesized from SVG or rescaled from existing ones (when within the size threshold).
convertIconTheme() {
local -r out=$1
local -r sharePath=$2
local -r iconName=$3
local -r theme=${4:-hicolor}
# Sizes based on archived Apple documentation:
# https://developer.apple.com/design/human-interface-guidelines/macos/icons-and-images/app-icon#app-icon-sizes
local -ra iconSizes=(16 32 128 256 512)
local -ra scales=([1]="" [2]="@2")
# Based loosely on the algorithm at:
# https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html#icon_lookup
# Assumes threshold = 2 for ease of implementation.
function findIcon() {
local -r iconSize=$1
local -r scale=$2
local scaleSuffix=${scales[$scale]}
local exactSize=${iconSize}x${iconSize}${scaleSuffix}
local -a validSizes=(
${exactSize}
$((iconSize + 1))x$((iconSize + 1))${scaleSuffix}
$((iconSize + 2))x$((iconSize + 2))${scaleSuffix}
$((iconSize - 1))x$((iconSize - 1))${scaleSuffix}
$((iconSize - 2))x$((iconSize - 2))${scaleSuffix}
)
local fallbackIcon=
for iconIndex in "${!candidateIcons[@]}"; do
for maybeSize in "${validSizes[@]}"; do
icon=${candidateIcons[$iconIndex]}
if [[ $icon = */$maybeSize/* ]]; then
if [[ $maybeSize = $exactSize ]]; then
echo "fixed $icon"
return 0
else
echo "threshold $icon"
return 0
fi
elif [[ -a $icon && -z "$fallbackIcon" ]]; then
fallbackIcon="$icon"
fi
done
done
if [[ -n "$fallbackIcon" ]]; then
echo "fallback $fallbackIcon"
return 0
fi
echo "scalable"
}
function resizeIcon() {
local -r in=$1
local -r out=$2
local -r iconSize=$3
local -r scale=$4
local density=$((72 * scale))x$((72 * scale))
local dim=$((iconSize * scale))
echo "desktopToDarwinBundle: resizing icon $in to $out, size $dim" >&2
magick convert -scale "${dim}x${dim}" -density "$density" -units PixelsPerInch "$in" "$out"
}
function synthesizeIcon() {
local -r in=$1
local -r out=$2
local -r iconSize=$3
local -r scale=$4
if [[ $in != '-' ]]; then
local density=$((72 * scale))x$((72 * scale))
local dim=$((iconSize * scale))
echo "desktopToDarwinBundle: rasterizing svg $in to $out, size $dim" >&2
rsvg-convert --keep-aspect-ratio --width "$dim" --height "$dim" "$in" --output "$out"
magick convert -density "$density" -units PixelsPerInch "$out" "$out"
else
return 1
fi
}
function getIcons() {
local -r sharePath=$1
local -r iconname=$2
local -r theme=$3
local -r resultdir=$(mktemp -d)
local -ar candidateIcons=(
"${sharePath}/icons/${theme}/"*"/${iconname}.png"
"${sharePath}/icons/${theme}/"*"/${iconname}.xpm"
)
local -a scalableIcon=("${sharePath}/icons/${theme}/scalable/${iconname}.svg"*)
if [[ ${#scalableIcon[@]} = 0 ]]; then
scalableIcon=('-')
fi
# Tri-state variable, NONE means no icons have been found, an empty
# icns file will be generated, not sure that's necessary because macOS
# will default to a generic icon if no icon can be found.
#
# OTHER means an appropriate icon was found.
#
# Any other value is a path to an icon file that isn't scalable or
# within the threshold. This is used as a fallback in case no better
# icon can be found and will be scaled as much as
# necessary to result in appropriate icon sizes.
local foundIcon=NONE
for iconSize in "${iconSizes[@]}"; do
for scale in "${!scales[@]}"; do
local iconResult=$(findIcon $iconSize $scale)
local type=${iconResult%% *}
local icon=${iconResult#* }
local scaleSuffix=${scales[$scale]}
local result=${resultdir}/${iconSize}x${iconSize}${scales[$scale]}${scaleSuffix:+x}.png
echo "desktopToDarwinBundle: using $type icon $icon for size $iconSize$scaleSuffix" >&2
case $type in
fixed)
local density=$((72 * scale))x$((72 * scale))
magick convert -density "$density" -units PixelsPerInch "$icon" "$result"
foundIcon=OTHER
;;
threshold)
# Synthesize an icon of the exact size if a scalable icon is available
# instead of scaling one and ending up with a fuzzy icon.
if ! synthesizeIcon "${scalableIcon[0]}" "$result" "$iconSize" "$scale"; then
resizeIcon "$icon" "$result" "$iconSize" "$scale"
fi
foundIcon=OTHER
;;
scalable)
synthesizeIcon "${scalableIcon[0]}" "$result" "$iconSize" "$scale" || true
foundIcon=OTHER
;;
fallback)
# Use the largest size available to scale to
# appropriate sizes.
if [[ $foundIcon != OTHER ]]; then
foundIcon=$icon
fi
;;
*)
;;
esac
done
done
if [[ $foundIcon != NONE && $foundIcon != OTHER ]]; then
# Ideally we'd only resize to whatever the closest sizes are,
# starting from whatever icon sizes are available.
for iconSize in 16 32 128 256 512; do
local result=${resultdir}/${iconSize}x${iconSize}.png
resizeIcon "$foundIcon" "$result" "$iconSize" 1
done
fi
echo "$resultdir"
}
iconsdir=$(getIcons "$sharePath" "apps/${iconName}" "$theme")
if [[ -n "$(ls -A1 "$iconsdir")" ]]; then
icnsutil compose --toc "$out/${iconName}.icns" "$iconsdir/"*
else
echo "Warning: no icons were found. Creating an empty icon for ${iconName}.icns."
touch "$out/${iconName}.icns"
fi
}
processExecFieldCodes() {
local -r file=$1
local -r execRaw=$(getDesktopParam "${file}" "Exec")
local -r execNoK="${execRaw/\%k/${file}}"
local -r execNoKC="${execNoK/\%c/$(getDesktopParam "${file}" "Name")}"
local -r icon=$(getDesktopParam "${file}" "Icon")
local -r execNoKCI="${execNoKC/\%i/${icon:+--icon }${icon}}"
local -r execNoKCIfu="${execNoKCI/\%[fu]/\$1}"
local -r exec="${execNoKCIfu/\%[FU]/\$@}"
if [[ "$exec" != "$execRaw" ]]; then
echo 1>&2 "desktopToDarwinBundle: Application bundles do not understand desktop entry field codes. Changed '$execRaw' to '$exec'."
fi
echo "$exec"
}
# For a given .desktop file, generate a darwin '.app' bundle for it.
convertDesktopFile() {
local -r file=$1
local -r sharePath=$(dirname "$(dirname "$file")")
local -r name=$(getDesktopParam "${file}" "Name")
local -r macOSExec=$(getDesktopParam "${file}" "X-macOS-Exec")
if [[ "$macOSExec" ]]; then
local -r exec="$macOSExec"
else
local -r exec=$(processExecFieldCodes "${file}")
fi
local -r iconName=$(getDesktopParam "${file}" "Icon")
local -r squircle=$(getDesktopParam "${file}" "X-macOS-SquircleIcon")
mkdir -p "${!outputBin}/Applications/${name}.app/Contents/MacOS"
mkdir -p "${!outputBin}/Applications/${name}.app/Contents/Resources"
convertIconTheme "${!outputBin}/Applications/${name}.app/Contents/Resources" "$sharePath" "$iconName"
write-darwin-bundle "${!outputBin}" "$name" "$exec" "$iconName" "$squircle"
}
convertDesktopFiles() {
local dir="$1/share/applications/"
if [ -d "${dir}" ]; then
for desktopFile in $(find "$dir" -iname "*.desktop"); do
convertDesktopFile "$desktopFile";
done
fi
}