better desktop entries of konsole for HiDPI mode

generate-konsole-entries.bash

#!/bin/bash

# key=src, value=dst
declare -A entries=(
    # desktop file, used when you launch konsole from most of the launchers
    ["/usr/share/applications/org.kde.konsole.desktop"]="$HOME/.local/share/applications/org.kde.konsole.desktop"
    ["/usr/share/applications/org.kde.konsole.desktop"]="$HOME/.local/share/applications/org.kde.konsole.desktop"
    # KDE only, used when you launch a shell script with konsole from dolphin
    ["/usr/share/kservices5/ServiceMenus/konsolerun.desktop"]="$HOME/.local/share/kservices5/ServiceMenus/konsolerun.desktop"
    # KDE only, used when you click "Open konsole here" from dolphin's context menu
    ["/usr/share/kservices5/ServiceMenus/konsolehere.desktop"]="$HOME/.local/share/kservices5/ServiceMenus/konsolehere.desktop"
)

declare -A apps=(
    # some applications launched in terminal mode
    ["/usr/share/applications/vim.desktop"]="$HOME/.local/share/applications/vim.desktop"
    ["/usr/share/applications/htop.desktop"]="$HOME/.local/share/applications/htop.desktop"
)

get_current_scaling_factor() {
    # this function only works on KDE
    config_file="$HOME/.config/kdeglobals"
    section_name="KScreen"
    key_name="ScaleFactor"

    # XXX: section name is ignored for now
    factor="$(grep "^${key_name}=" "$config_file" | cut -d'=' -f2)"
    echo ${factor}
}

fill_and_install() {
    src="$1"
    dst="$2"
    patterns="$3"

    if [ -f "$dst" ]; then
        echo $dst already present, backing it up...
        mv "$dst" "$dst.backup"
    fi

    echo Generating $dst based on $src...
    sed "${patterns[@]}" "$src" > "$dst"
}


main() {
    factor="$(get_current_scaling_factor)"
    reversed_factor="$(bc <<< "scale=10; 1 / ${factor}")"
    echo Current scaling factor is $factor, will set QT_SCALE_FACTOR to $reversed_factor

    for src in "${!entries[@]}"; do
        dst="${entries[$src]}"
        # pattern used in sed
        patterns=("-e" "s/^Exec=konsole/Exec=QT_SCALE_FACTOR=$reversed_factor konsole/")
        fill_and_install "$src" "$dst" "$patterns"
    done

    for src in "${!apps[@]}"; do
        dst="${apps[$src]}"
        patterns=("-e" "s/^Exec=\(.*\)/Exec=QT_SCALE_FACTOR=$reversed_factor konsole -e \1/" "-e" "s/^Terminal=true$/Terminal=false/")
        fill_and_install "$src" "$dst" "$patterns"
    done
}


main