Icon for linux application

atom_352

Hello, how could i add icon for my app? I need the icon to be displayed in the system tray when launched, I am writing the application for Ubuntu and other Linux systems, my build system is cmake, and the language is C++ (I don’t know if this is important)

Pl45m4

@atom_352

This also works

{
    ui->setupUi(this);
    QMainWindow::setWindowIcon(QIcon("qrc:/new/icons/img/information.png"));
}

Because at startup the taskbar still displays the standard icon

If you want to have your icon as "shortcut" / desktop icon on Linux you need to follow @JonB 's solution in the topic linked by @jsulm above.

jsulm

@atom_352 See https://forum.qt.io/topic/102167/how-to-add-qt-application-icon-in-ubuntu

atom_352

@jsulm , i tried somthing from that, but probably did something wrong, I think I didn’t really understand where to write this and how to point to an image if it is in .qrc resources

jsulm

@atom_352 Did you try QMainWindow::setWindowIcon(), I think this is what you need and you can use an icon embedded in a rosource file.

atom_352

@jsulm , Yes, I tried to use exactly this, but where can I write this, and is it necessary to use the qicon class?

Pl45m4

@atom_352 said in Icon for linux application:

but where can I write this

Anywhere ;-)
But I don't think your neighbors will like you if you paint that on their door.

However, to set your MainWindow icon you need to write it in a function that is called when creating your QMainWindow :)

is it necessary to use the qicon class

You can construct a QIcon from file, either QRC or directly from file string.

atom_352

@Pl45m4 Thanks!! But should it look like this?

mainwindow.cpp

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    icon();
}

void MainWindow::icon()
{
     QMainWindow::setWindowIcon(QIcon("qrc:/new/icons/img/information.png"));
}

Because at startup the taskbar still displays the standard icon

Pl45m4

@atom_352

This also works

{
    ui->setupUi(this);
    QMainWindow::setWindowIcon(QIcon("qrc:/new/icons/img/information.png"));
}

Because at startup the taskbar still displays the standard icon

If you want to have your icon as "shortcut" / desktop icon on Linux you need to follow @JonB 's solution in the topic linked by @jsulm above.

atom_352

@Pl45m4 Ok! Finally, i understand, thank you so much

SimonSchroeder

I am using AppImages (created with linuxdeploy and linuxdeployqt) to have portable applications. These rely on a .desktop file which is supposed to be portable between KDE and Gnome (and hopefully other desktop environments). The .desktop file plays together with the xdg-utils. You can install these with xdg-desktop-menu or xdg-desktop-icon. I'd expect that through this they would also immediately show the icon in the taskbar when launched this way. (You can even register file extensions with xdg-mime and than open file with the associated program with xdg-open–much like macOS's open command.)

If I am not mistaken, this is the official link for .desktop files: https://specifications.freedesktop.org/desktop-entry-spec/latest/index.html

eman086

To add a system tray icon in a C++ app on Ubuntu/Linux using CMake, you can use libappindicator or Qt (if using Qt framework). Here's a short summary:

Use libappindicator for GTK-based apps:

Install: sudo apt install libappindicator3-dev

Link in CMake: target_link_libraries(your_app appindicator3-0.1)

Set icon: app_indicator_set_icon_full(indicator, "icon-name", "description");

Or use Qt:

Use QSystemTrayIcon and set icon with setIcon(QIcon(":/icon.png"));

Make sure the icon file is included in your build and accessible at runtime.

Joe von Habsburg

@Pl45m4 said in Icon for linux application:

QMainWindow::setWindowIcon(QIcon("qrc:/new/icons/img/information.png"));

Hello I have same issue.

When I in windows, I use like that

//Cmake

set(APP_ICON_RESOURCE_WINDOWS "${CMAKE_CURRENT_SOURCE_DIR}/icon.rc")

qt_add_executable(MyApp
    MANUAL_FINALIZATION
    ${PROJECT_SOURCES}
    ${APP_ICON_RESOURCE_WINDOWS}
)

//Icon.rc
IDI_ICON1               ICON    "Resources/icon/icon.ico"

But I can see only that :

I added also on ui,

and extra add with code

QMainWindow::setWindowIcon(QIcon("qrc:/new/icons/img/information.png"));

Any opinion or advice ?

Christian Ehrlicher

This should work the way you did it. Do you see that rc.exe is executed during compilation? It should create a .res file which then gets linked into the resulting executable

Joe von Habsburg

@Christian-Ehrlicher said in Icon for linux application:

This should work the way you did it.

I did something wrong probably.

@Christian-Ehrlicher said in Icon for linux application:

Do you see that rc.exe is executed during compilation?

I see only that icon :

I didn't quite understand what you meant. Are you referring to my application as rx.exe? If so, and by compilation you mean build and run, I don't see it.

@Christian-Ehrlicher said in Icon for linux application:

It should create a .res file which then gets linked into the resulting executable

When I look in the build folder, I don't see any files with a .res extension. Do I need to build it differently?

Christian Ehrlicher

@Joe-von-Habsburg said in Icon for linux application:

I didn't quite understand what you meant

When you compile the application in QtCreator you see what/how the compiler is invoked. There you see a lot of output and one of them should be the invocation of rc.exe. You need to clean the build dir before or at least modify the rc file so it gets recompiled.

Joe von Habsburg

I looked at the "Compile Output" window and, it is finished succesfully. I could not see about icon or rc.exe.

[15/15 10.2/sec] Linking CXX executable MyApp
16:28:18: The command "/home/x/Qt/Tools/CMake/bin/cmake --build /home/x/Desktop/MyApp/build --target all" finished successfully.

I want to ask again, is rc.exe my app or different thing ? If different thing how can I add to my app, and why should I add ?
I clear cmake configuration, I run cmake, I clean and rebuild. Still icon does not exist.

I've worked this hard on Qt in Ubuntu before. I apologize if I did anything wrong.

Christian Ehrlicher

@Joe-von-Habsburg said in Icon for linux application:

I've worked this hard on Qt in Ubuntu before

You're aware that the rc application icon is for windows??? Please read the full thread.

Joe von Habsburg

Ok, I am sorry, I read : https://forum.qt.io/topic/102167/how-to-add-qt-application-icon-in-ubuntu
I need both of them also, .destop file and QMainWindow::setWindowIcon().

I create icon.destop file and add resouces.qrc and add also to build folder.
My file :

[Desktop Entry]
Version=1.0
Type=Application
Name=MyApp
Icon=Resources/icon/icon.png
Exec=MyApp
Comment=MyApp Application
Categories=Application
Terminal=false

I could not see any thing.
And QMainWindow::setWindowIcon(). not work.

I checked, is icon null, it is return false. icon is not null.

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QIcon ic(":/Resources/icon/icon.png");
    qDebug() << "ic.isNull" << ic.isNull(); // return false
    QMainWindow::setWindowIcon(QIcon(":/Resources/icon/icon.png"));
}

Did I create .destop file correct location ?

JonB

@Joe-von-Habsburg said in Icon for linux application:

Icon=Resources/icon/icon.png

QIcon ic(":/Resources/icon/icon.png");

The first looks in the filing system for Resources/icon/icon.png, which doesn't exist. I do not think you can tell desktop to use a resource in a Qt executable, or I don't know how if you can (unless :/Resources/icon/icon.png works which I doubt). For the desktop shortcut I imagine you have to extract or copy the png file so you can point to that.

Joe von Habsburg

@JonB said in Icon for linux application:

Icon=Resources/icon/icon.png

thay are in same directory.

icon.destop
Resources/

I added on project location and build location. So it exists.

@JonB said in Icon for linux application:

I do not think you can tell desktop to use a resource in a Qt executable,

I know what you mean. You think I'm using a file in resources.qrc, but I copied Resources/icon/icon.png to the build folder myself. So I know you can't use it from the .qrc file, it's inside the icon.desktop file.

@JonB said in Icon for linux application:

QIcon ic(":/Resources/icon/icon.png");

That was for mainwindow icon. I tested for access to icon.png file or it is null, app can access to file because it returns as false for ask is it null.