FreeDesktop.org Integration
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[edit] Current Status
We've all noticed that Psi checks for KDE on "make install". This happens because Psi installs a special .desktop file describing the application, only if it detects KDE.
The .desktop file has become a standard for describing applications, mime-types, menus described on freedesktop.org
This means Psi needs to install the .desktop file no matter if KDE is installed or not.
[edit] Prerequisites
There are 4 specs (until now) which need to concur to make a perfect desktop integration:
- desktop-entry spec - describes the contents of the .desktop file (the key-value entries)
- menu spec - lists the registered categories an application can be added to
- icon-theme spec - describes where the application icons should be placed
- startup-notification spec - describes interaction between the application and the desktop during startup
[edit] Implementation
[edit] Support detection
I am not sure yet wether to include freedesktop.org detection or not, for the Linux version. Detection would be useful though considering that there might be *nixes (as in distributions) not compatible with the FreeDesktop.org specifications. The major desktops (KDE, GNOME, XFCE - from what I'm aware) support the freedesktop.org specifications.
FreeDesktop.org provides a package with tools, desktop-file-utils, containing desktop-file-install, a program designed to help installing .desktop files into the system.
I believe that we could consider looking for desktop-file-install as a method for checking support for FreeDesktop.org support.
[edit] The XDG internals
Once FreeDesktop.org support is detected desktop-file-install would be used as following:
desktop-file-install --vendor=psi psi.desktop
This command will place psi.desktop in a directory, in our case $XDG_DATA_DIRS/applications (only the first dir in $XDG_DATA_DIRS will be used - I think).
According to the base-dir spec, $XDG_DATA_DIRS is a list of directories where data resides. If the variable is empty, "/usr/local/share:/usr/share" would be considered the default.
Therefore, it is safe to assume that the list in $XDG_DATA_DIRS would at least contain "$PREFIX/share". We use desktop-file-install to install psi.desktop but we don't have any program to install the icons, we only have specs. We will use this assumption when installing icons.
[edit] psi.desktop
An updated psi.desktop file follows
# This file complies to # http://standards.freedesktop.org/desktop-entry-spec ver, 0.9.4+ # http://www.freedesktop.org/Standards/menu-spec ver. 0.9+ [Desktop Entry] Type=Application Version=0.9.4 Encoding=UTF-8 Name=Psi GenericName=Jabber Client Comment=Psi Jabber Client Icon=psi.png TryExec=psi Exec=psi -caption "%c" %i %m Terminal=false Categories=Qt;Network;InstantMessaging; StartupNotify=true StartupWMClass=psi
- The key-value entries are listed as they are given in the desktop-file-spec.
- The categories are selected from the Registered Categories listing, in the menu-spec.
- StartupNotify/StartupWMClass is assumed to be working. We need to check wether Psi complies to the startup-notification-spec
A list of internationalized GenericName/Comment pairs for the psi.desktop file is maintained in Git source code repository.
[edit] Icons
The icons should be installed no matter if the FreeDeskop.org specs are met or not.
The latest icon-theme-spec says that there is a default icon theme which is used when the current theme does not have an icon suited for your application.
The default theme (named hicolor), available here, also installable via a package in the Linux distributions, contains the hierarchy in which application icons should keep their icons. The relevant directories for an application (Psi) are the following:
$PREFIX/share/icons/hicolor/128x128/apps/ $PREFIX/share/icons/hicolor/16x16/apps/ $PREFIX/share/icons/hicolor/192x192/apps/ $PREFIX/share/icons/hicolor/22x22/apps/ $PREFIX/share/icons/hicolor/24x24/apps/ $PREFIX/share/icons/hicolor/32x32/apps/ $PREFIX/share/icons/hicolor/36x36/apps/ $PREFIX/share/icons/hicolor/48x48/apps/ $PREFIX/share/icons/hicolor/64x64/apps/ $PREFIX/share/icons/hicolor/72x72/apps/ $PREFIX/share/icons/hicolor/96x96/apps/ $PREFIX/share/icons/hicolor/scalable/apps/
The spec also says that:
Minimally you should install a 48x48 icon in the hicolor theme. This means installing a PNG file in $prefix/share/icons/hicolor/48x48/apps.
To put it into $XDG_DATA_DIRS words, the application icons should put be their app icons into
$XDG_DATA_DIRS/icons/$theme_name/$size/apps
This means we could put in Psi icons for various sizes, including a SVG icon (see "scalable" dir) - although I have yet to see an application using that functionality.
