Development/Tutorials/Icons
Parts to be reviewed:
Port to KF5When you create your own KDE application you will probably want icons in it like this:
These icons are called KIcons. This article shows you how to do this using the software krep as an example. In case of a CMake-based project you will need to
How to use icons in QMake-based projects is discussed elsewhere.
Your KDE project
If you have a KDE project and want to use icons within it, and want these icons installed seamlessly, you will have to name the icons after the project. In the following we look at a project named krep. The important lines in CMakeLists.txt are the ones printed bold below:
PROJECT( krep )
FIND_PACKAGE( KDE4 REQUIRED )
INCLUDE_DIRECTORIES( ${KDE4_INCLUDES} . )
SET( krepSources main.cpp krep.cpp krep.h )
qt4_add_dbus_adaptor( krepSources
org.kde.krep.xml
krep.h
krep
mainadaptor
MainAdaptor )
kde4_add_ui_files( krepSources krepui.ui )
kde4_add_app_icon( krepSources "hi*-app-krep.png" )
KDE4_ADD_EXECUTABLE( krep ${krepSources} )
TARGET_LINK_LIBRARIES( krep ${KDE4_KPARTS_LIBS} )
install( TARGETS krep ${INSTALL_TARGETS_DEFAULT_ARGS} )
kde4_install_icons( ${ICON_INSTALL_DIR} )
Weitere Informationen:
How to test it
The easy way is to define a custom cmake install prefix where you can simply insall the project without touching your system. Use following commands to setup this:
cd build
cmake -DCMAKE_INSTALL_PREFIX=$HOME/playground ../
make && make install
now the files should be deployed under
$HOME/playground/bin/krep
$HOME/playground/share/apps/krep
$HOME/playground/share/icons/hicolor/22x22/apps/krep.png
With this method you can easy see what you will get.
Normaly kde support a user defined space under $HOME/.kde.
Find out if this is supported with the command
kde4-config -path icon
finally you have to extend the search path for kde
export KDEDIRS=$KDEDIRS:$HOME/playground
The icon naming scheme
Example for icon names:
- hisc-apps-bla.svgz will be installed e.g. to /usr/local/share/icons/hicolor/scalable/apps/bla.svgz. hi stands for "hicolor", sc for "scalable", apps for "applications", bla for the application's name and .svgz is the suffix for gzipped scalable vector graphic files.
- hi128-apps-ktimetracker.png will be installed e.g. to /usr/share/icons/hicolor/128x128/apps/ktimetracker.png. hi stands for "hicolor", 128 for a resolution of 128x128 pixels, apps for "applications", ktimetracker for the application's name and .png is the suffix for portable network graphic files.
example application
In this chapter we will build - on top of the KAction example - an example application kicons that looks like this:
You can obtain its source code as part of kdeexamples by calling
git clone git://anongit.kde.org/kdeexamples
files
The example application consists of
- just taken from the KAction example
- Note the command that sets the icon
clearAction->setIcon(KIcon("tutorial-kicon"));
- just taken from the KAction example
- This is a file that defines our icon in (almost natural) english language. It is a scalable vector graphic file. Before being used, it must be converted into a zipped scalable vector graphic named hisc-apps-tutorial-kicon.svgz, see below.
- just taken from the KAction example
- sorry for the name, but there are naming conventions. Create this file with the convert command from the ImageMagick package
convert world.svg hisc-apps-tutorial-kicon.svgz
- Note the commands and
kde4_install_icons(${ICON_INSTALL_DIR})
which integrate the icons.kde4_update_iconcache()
build it
To compile, link and install the example application, do a
mkdir build && cd build
cmake ../ && make && make install
To run it, call
tutorial-kicon
Analyzing the KApplications
Maybe you have already searched for yourself how a KDE application finds its icons. You will not be successful like this:
# [http://www.linuxintro.org/wiki/Strace#Search_for_a_syscall strace -e open] ktimetracker 2>&1 | grep icon
open("/usr/lib64/libkemoticons.so.4", O_RDONLY) = 3
#
You see, a KDE application (in this case ktimetracker) does not open icon files or even look for them. However, it spawns a process to look for these icons:
linux-qgla:~/repos/kdepim/ktimetracker # strace -ffe open ktimetracker 2>&1 | grep icon
open("/usr/lib64/libkemoticons.so.4", O_RDONLY) = 3
[pid 3457] open("/root/.icons/DMZ/cursors/left_ptr", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 3457] open("/root/.icons/DMZ/index.theme", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 3457] open("/usr/share/icons/DMZ/cursors/left_ptr", O_RDONLY) = 10
[pid 3457] open("/var/tmp/kdecache-root/icon-cache.kcache", O_RDWR|O_CREAT|O_CLOEXEC, 0666) = 10
[pid 3457] open("/var/tmp/kdecache-root/kpc/kde-icon-cache.data", O_RDONLY|O_CLOEXEC) = 10
[pid 3457] open("/var/tmp/kdecache-root/kpc/kde-icon-cache.index", O_RDONLY|O_CLOEXEC) = 10
[...]
Moving On
Now you can move on to how to place your application in the K-Menu using .desktop files.