Difference between revisions of "How to use a TrayIcon"

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(Added info about Linux issues and how to work around)
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=== Problems with newer Gnome based Linux ===
+
=== Linux may not display the Icon ===
  
There are at least two reasons why a Linux system may fail to display the System Tray Icon, a clash between libappindicator1 and libappindicator3 and, secondly, a distribution's adherence to the Gnome hard line about not displaying System Tray Icons. See next section for the second case.
+
Some Linux systems will have trouble displaying the GTK TrayIcon, in general this relates to a move away from the System Tray model that Lazarus TrayIcon is based on. This problem is a particular issue with Gnome but some other Desktops may also suffer. There are workarounds that involve using another library, and in some cases other extra packages and specific configuration steps. Its important to note, and to advise your end users, that the problem is with the Linux Distribution and its Desktop. You, as the application's programmer cannot directly solve the problem. Sadly, your app cannot tell if the TrayIcon is visible or not on an uncooperative Desktops !
  
June 2019
+
At the time of writing, October 2019, Gnome desktop versions of Fedora, Red Hat, Suse and Mageia and Debian all require a AppIndicator library be installed and the Gnome Shell Extension, gnome-shell-extension-appindicator be installed and enabled, see below.  
I intend to (shortly) submit a patch related to https://bugs.freepascal.org/view.php?id=33778 but goes a little further. 33778 took a conservative approach and only used the (Unity inspired) libappindicator3 if libappindicator1 was not present. However, several distributions now exist that cannot use libappindicator1 but do work with libappindicator3. Not usually a problem as libappindicator1 is not installed automatically if it not usable. But an OS that has been upgraded from, say U18.04 to U19.04 will have both versions of the appindicator library. LCL will choose the older one and it will not display the System Tray Icon.
 
  
patch (TBA) fixes that.
+
Mageia Enlightenment also requires an AppIndicator library and enabling System Tray in Settings->Modules and the adding that System Tray to a Shelf (all terms familiar to Enlightenment users). Unfortunately, even that gets 'an' icon, not the one you carefully select for your application.
  
=== Gnome 3.28 and later won't display Icon ===
+
As of Lazarus 2.0.6, LCL will attempt to 'guess' the correct model to display a Tray Icon. However as distributions change over time, or with more obscure distributions you may need to override these guesses. For GTK2 apps, by setting an environment variable, LAZUSEAPPIND you can force an app to try to use LibAppIndicator3, prevent it from trying or just tell us which way it has guessed using YES, NO or INFO.  eg
  
The Gnome Developers have determined that Gnome should not support the System Tray Icon model at all, apparently to avoid screen clutter. If your end users are willing to risk a little screen clutter to achieve a usable desktop, keep reading.
+
<syntaxhighlight lang="bash">LAZUSEAPPIND=YES project1 <enter></syntaxhighlight>
  
Distributions such as RedHat and openSUSE will not, out of the box, display the LCL System Tray Icon. Sadly, it fails silently, giving a user no indication of whats happening. Fortunatly, there are a number of Gnome Extensions that can restore normal operation but be aware that each new release of Gnome appears (and maybe only 'appears') to take steps to stop even those extension from working. At the time of writing this, June 2019, a model that does work for Fedora 30 and openSUSE 15 is to install the Gnome Extension TopIcons-plus and a version 3 appindicator library. Note, both steps are required, doing one or the other alone will not be enough !
+
Will force project1 to try to use an Appindicator library (instead of the traditional System Tray) on GTK2. Obviously, it may not be available or it may not be suitable for the desktop in use but it will try. A line or two of text will be printed on stdout if the var is defined and not blank. Many systems will display the TrayIcon without using this environment variable.  If the desktop you are running does require an AppIndicator library, then you must accept all it can ever do is trigger a menu, no OnClick event.
  
To install a Gnome Extension, you have to install, into (eg) Firefox an extension that allows you to control your collection of Gnome Extensions. Awkard process but OK if you want to play with the wide range of extensions available. An alternative approach that works at present is to download the extension from github and install it, maybe not a good long term suggestion (?) -
+
GTK3 can support only the AppIndicator model. Its use of the Ayatana version (in trunk only) is determined by https://bugs.freepascal.org/view.php?id=38909
  
As root -
+
==== Why two models ? ====
<syntaxhighlight lang="bash">dnf install make libappindicator-gtk3 gnome-tweak-tool</syntaxhighlight>
+
The AppIndicator model does not do as much as the older System Tray model. Both libraries are derived from Unity's definition of a 'simpler' interface, it will display only a menu, it does not pass an event, OnClick, back to your app. Indeed, if you have not assigned a popup menu to your TrayIcon will not show up at all. So, applications that depend on getting a OnClick event will not work with LibAppIndicator3.
  
As yourself -
+
''Developers of new applications may well be advised to design their program around TrayIcon using only a popUpMenu !''
<syntaxhighlight lang="bash">git clone https://github.com/phocean/TopIcons-plus.git
 
cd TopIcons-plus
 
make install</syntaxhighlight>
 
  
Logout and back in again.
+
==== AppIndicator Libraries ====
<syntaxhighlight lang="bash">gnome-tweaks</syntaxhighlight>
 
In the app thats runs, click Extensions, turn TopIcons-plus ON and click close
 
  
Note that for OpenSUSE the appindicator library is called libappindicator3-1, its likely other distributions may call it the same thing. Distributions based on Ubuntu will have it installed already.
+
There are currently two possible AppIndicator libraries, Canonical's LibAppIndicator3-1 or libayatana-appindicator3-1, some systems have both, Bullseye has only the Ayatana one. Lazarus trunk supports Ayatana after 22 May 2021, r65122.
  
=== Issue On the Mac, OSX ===
+
One or the other library can generally be installed from your distribution's normal package library. However, it is packaged with a number of different names. Sigh ...
In October, 2017 it was noted that on the Mac, Sierra, Carbon, Lazarus 1.8rc4 a small problem existed. Attempts to updates to the caption of a menu item in a popup  menu associated with a TrayIcon do not happen as expected. Its not uncommon to want to update the menu text at run time, for example, to display a list of recently opened files. This problem has been logged, https://bugs.freepascal.org/view.php?id=32516 . A workaround that appears reliable is to call TrayIcon1.InternalUpdate; after making changes to the captions.  
+
* libappindicator3 - Slackware, NetBSD
 +
* libappindicator3-1 - openSUSE and Debian [-based]
 +
* libappindicator-gtk3 - Arch, ALT, CentOS and Fedora, RedHat
 +
* libappindicator3_1 - all Mandrake/Mandriva derivatives -- Mageia,  OpenMandriva, PCLinuxOS, Rosa
 +
* libayatana-appindicator3-1 - Debian Bullseye and most other Linuxs that offer Ayatana.
 +
 +
 
 +
==== gnome-shell-extension-appindicator ====
 +
This seems to be a viable solution mid 2021 for Gnome based systems. This plugin for Gnome Shell (the desktop) is made by Ubuntu to work like its old Unity AppIndicator model. So, in addition the the gnome plugin, you also need to install an AppIndicator3 library (AppIndicator3-1 on Fedora, Ayanata on Bullseye). It is KNSI inspired so no fancy right clicks allowed, just assign it a menu.
 +
 
 +
On Fedora, you can do this (note you don't need gnome-tweaks on Fedora 34) -
 +
<syntaxhighlight lang="bash">sudo dnf install libappindicator-gtk3  gnome-shell-extension-appindicator gnome-tweaks [enter]</syntaxhighlight>
 +
Once installed, you need to restart the Desktop, just logout and back in. Then you must 'enable' the new plugin. On Fedora 33 thats easy, use the gnome-tweaks command, Extensions, enable "Kstatusnotifieritem/appindicator support". On Fedora 34, they have made it a bit harder by removing the Extensions section from Gnome Tweaks (too many happy users I expect). So, with Fedora 34, use the gnome-extensions command, it does not have a gui so issue the following command -
 +
<syntaxhighlight lang="bash"> gnome-extensions enable appindicatorsupport@rgcjonas.gmail.com [enter]</syntaxhighlight>
 +
Replace 'enable' with 'info' to get some diagnostic information.
 +
 
 +
Note, three steps, install, restart desktop, enable plugin !
 +
 
 +
'''Debian Bullseye''' appears to arrive with the Ayatana library pre installed but the Gnome version still requires gnome-shell-extension-appindicator, install as above.
 +
 
 +
Your application can enable the extension (after a desktop restart), if you are feeling brave see https://github.com/tomboy-notes/tomboy-ng/blob/master/source/mainunit.pas
 +
 
 +
==== TopIconsPlus ====
 +
 
 +
Sadly, the coming of Wayland seems to have killed TopIconsPlus. This section may be removed before long.
 +
 
 +
 
 +
==== Checking before invoking TrayIcon ====
 +
Because you app may show the user only its TrayIcon and if that's not visible the user cannot interact, you may like to test to see if its going to work. Firstly, you can, sort of determine if LCL will use the old System Tray (in which case it will probably be OK), look at code in lcl/interfaces/gtk2/UnityWSCtrl.pas.  If LCL is going to use an AppIndicator library, you need to see if the library is available and, on a Gnome system, if gnome-shell-extension-appindicator is enabled. The library is easy, try and load it, an error says its not there. To see if TopIcons is going to be available, the command "dconf read /org/gnome/shell/enabled-extensions" returns a few strings that may include "TopIcons". I expect there may also be an API ....
 +
 
 +
==== On GTK3 ====
 +
Trunk from October 2019 has a working GTK3 TrayIcon based, again, on LibAppIndicator3. The advice above relation to installing LibAppindicator3 and, where necessary TopIconsPlus applies to GTK3 as well. As the only way you can get a TrayIcon under GTK3 is the LibAppIndicator3, you can only use it to display a popup menu, don't expect to get a working OnClick event.
  
This problem does not exist on Linux, Windows or OSX using Cocoa Widget Set.
+
====QT5 on Linux====
 +
Some linux systems that won't display the GTK Tray Icon will display the Qt5 version, but only if they use XOrg. Any system using wayland apparently has other has issues with Qt5. Fedora and OpenSuse use wayland by default but users can choose to use XOrg instead at logon time.
  
Note that TrayIcon on the Mac, Carbon (ie 32bit) has a memory leak.
+
=== Issue On the macOS 32 bit Carbon ===
 +
In October 2017 it was noted that a small problem existed on Sierra 10.12 when using the [[Carbon Interface|Carbon]] widget set. Attempts to update the caption of a menu item in a popup menu associated with a TrayIcon do not happen as expected. It is not uncommon to want to update the menu text at run time, for example, to display a list of recently opened files. This problem has been logged,  https://bugs.freepascal.org/view.php?id=32516 . A workaround that appears reliable is to call <syntaxhighlight inline lang="pascal">TrayIcon1.InternalUpdate;</syntaxhighlight> after making changes to the captions.
 +
 
 +
This problem does not exist on Linux, Windows or on macOS when using the 64 bit [[Cocoa Interface|Cocoa]] widget set.
 +
 
 +
{{Warning|TrayIcon on macOS, using the 32 bit [[Carbon Interface|Carbon]] widget set has a memory leak.}}
  
 
=== Documentation ===
 
=== Documentation ===
Line 93: Line 124:
  
 
{{Note| Does not work on win32.}}
 
{{Note| Does not work on win32.}}
 +
 +
{{Note| Following events not available on Linux if using the LibAppIndicator3 model, its menu only.}}
  
 
<span style="color: teal">'''OnClick'''</span>
 
<span style="color: teal">'''OnClick'''</span>
Line 129: Line 162:
 
Can be located at Lazarus 0.9.22 or inferior at the directory: lazarus/components/trayicon
 
Can be located at Lazarus 0.9.22 or inferior at the directory: lazarus/components/trayicon
  
And on Lazaurs 0.9.23 or superior it is automatically installed with LCL
+
And on Lazarus 0.9.23 or superior it is automatically installed with LCL
  
 
=== Example 1 - Using TIcon ===
 
=== Example 1 - Using TIcon ===
 
As of Lazarus 0.9.26 TIcon has been fully implemented and it is no longer necessary to load the icon from a resource file on Windows. The icon can be loaded in the IDE or with usual code.
 
As of Lazarus 0.9.26 TIcon has been fully implemented and it is no longer necessary to load the icon from a resource file on Windows. The icon can be loaded in the IDE or with usual code.
  
Go to the Additional tab of components, and add a TTrayIcon to your form. Then change it's '''Name''' property to SystrayIcon
+
Go to the Additional tab of components, and add a TTrayIcon to your form. Then change its '''Name''' property to SystrayIcon
  
 
Next add a button to the form. Double click the button and add this code to it:
 
Next add a button to the form. Double click the button and add this code to it:
  
<syntaxhighlight>procedure MyForm.Button1Click(Sender: TObject);
+
<syntaxhighlight lang="pascal">
 +
procedure MyForm.Button1Click(Sender: TObject);
 
begin
 
begin
 
   SystrayIcon.Icon.LoadFromFile('/path_to_icon/icon.ico');
 
   SystrayIcon.Icon.LoadFromFile('/path_to_icon/icon.ico');
Line 147: Line 181:
  
 
   SystrayIcon.Show;
 
   SystrayIcon.Show;
end;</syntaxhighlight>
+
end;
 +
</syntaxhighlight>
  
 
=== Example 2 - Creating the icon with TLazIntfImage ===
 
=== Example 2 - Creating the icon with TLazIntfImage ===
You can use TLazIntfImage to draw quickly your icon, as in the example code below:
+
You can use TLazIntfImage to draw your icon quickly, as in the example code below:
  
<syntaxhighlight>procedure TForm1.DrawIcon;
+
<syntaxhighlight lang="pascal">
 +
procedure TForm1.DrawIcon;
 
var
 
var
 
   TempIntfImg: TLazIntfImage;
 
   TempIntfImg: TLazIntfImage;
Line 192: Line 228:
 
Please, post Bug Reports and Feature Requests on the [http://bugs.freepascal.org/main_page.php Lazarus Bugtracker].
 
Please, post Bug Reports and Feature Requests on the [http://bugs.freepascal.org/main_page.php Lazarus Bugtracker].
  
Help requests can be posted on the Lazarus mailling list or on the Lazarus [http://www.lazarus.freepascal.org/modules.php?op=modload&name=PNphpBB2&file=index Forum].
+
Help requests can be posted on the Lazarus mailing list or on the Lazarus [http://www.lazarus.freepascal.org/modules.php?op=modload&name=PNphpBB2&file=index Forum].
  
 
=== Change Log ===
 
=== Change Log ===
Line 198: Line 234:
 
# 24/01/2006 - Stable under win32, gnome and gtk1, but still waiting for gtk2 support. Lazarus 0.9.12 was release with this version.
 
# 24/01/2006 - Stable under win32, gnome and gtk1, but still waiting for gtk2 support. Lazarus 0.9.12 was release with this version.
 
# 17/02/2006 - Added support for gtk2 on subversion.
 
# 17/02/2006 - Added support for gtk2 on subversion.
# July 2008 - Implments support for Qt 4
+
# July 2008 - Implements support for Qt 4
 
# July 2008 - Implements support for Carbon through [[PasCocoa]]
 
# July 2008 - Implements support for Carbon through [[PasCocoa]]
  
Line 212: Line 248:
 
'''Linux (WindowMaker, Openbox, etc)''' - Does not support system tray icons out-of-the-box. However, There are at least two softwares that provides support for it: [http://icculus.org/openbox/2/docker/ Docker] and [http://freshmeat.net/projects/wmsystray/ WMSystray]
 
'''Linux (WindowMaker, Openbox, etc)''' - Does not support system tray icons out-of-the-box. However, There are at least two softwares that provides support for it: [http://icculus.org/openbox/2/docker/ Docker] and [http://freshmeat.net/projects/wmsystray/ WMSystray]
  
'''Mac OS X''' - TTrayIcon support is implemented using the menu bar extras. Unfortunatelly the API to use menu bar extras is only available in Cocoa and not in Carbon, so we use the stable PasCocoa bindings in the Carbon interface to support menu bar extras even in older FPC compilers and in the Cocoa interface we will use the more modern Objective Pascal syntax.
+
'''macOS''' - TTrayIcon support is implemented using the menu bar extras. Unfortunately the API to use menu bar extras is only available in Cocoa and not in Carbon, so we use the stable PasCocoa bindings in the Carbon interface to support menu bar extras even in older FPC compilers and in the Cocoa interface we will use the more modern Objective Pascal syntax.
  
 
[[Image:Mn_menubaritems.jpg]]
 
[[Image:Mn_menubaritems.jpg]]
  
 
To read more about menu bar extras:
 
To read more about menu bar extras:
# http://developer.apple.com/documentation/UserExperience/Conceptual/OSXHIGuidelines/XHIGMenus/chapter_16_section_6.html
+
 
# http://developer.apple.com/mac/library/documentation/UserExperience/Conceptual/AppleHIGuidelines/XHIGMenus/XHIGMenus.html
+
# https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/StatusBar/StatusBar.html
 +
# https://developer.apple.com/design/human-interface-guidelines/macos/extensions/menu-bar-extras/
 +
# https://developer.apple.com/design/human-interface-guidelines/macos/menus/dock-menus/
 +
# https://developer.apple.com/design/human-interface-guidelines/macos/system-capabilities/dock/
 +
# https://developer.apple.com/design/human-interface-guidelines/macos/menus/menu-anatomy/
 
# http://en.wikipedia.org/wiki/Menu_extra
 
# http://en.wikipedia.org/wiki/Menu_extra
 +
 
With this in mind an approach which supports all Platforms was created:
 
With this in mind an approach which supports all Platforms was created:
 +
 
* Painting is done via a TIcon object. (Required by Windows)
 
* Painting is done via a TIcon object. (Required by Windows)
 +
 
The following extra features are already available or will be, but they won´t work on all platforms.
 
The following extra features are already available or will be, but they won´t work on all platforms.
 
* OnPaint event and Canvas property to draw the icon freely. Won´t work on Windows.
 
* OnPaint event and Canvas property to draw the icon freely. Won´t work on Windows.
 
  
 
=== External Links ===
 
=== External Links ===

Revision as of 03:52, 28 May 2021

English (en)

About

TTrayIcon is a multiplatform System Tray component. You can find TrayIcon on the Additional tab of the Component Palette (0.9.23+).

TrayIcon used to be an optional component, but is part of LCL since Lazarus 0.9.23

To start quickly, please read the demonstration program.


Linux may not display the Icon

Some Linux systems will have trouble displaying the GTK TrayIcon, in general this relates to a move away from the System Tray model that Lazarus TrayIcon is based on. This problem is a particular issue with Gnome but some other Desktops may also suffer. There are workarounds that involve using another library, and in some cases other extra packages and specific configuration steps. Its important to note, and to advise your end users, that the problem is with the Linux Distribution and its Desktop. You, as the application's programmer cannot directly solve the problem. Sadly, your app cannot tell if the TrayIcon is visible or not on an uncooperative Desktops !

At the time of writing, October 2019, Gnome desktop versions of Fedora, Red Hat, Suse and Mageia and Debian all require a AppIndicator library be installed and the Gnome Shell Extension, gnome-shell-extension-appindicator be installed and enabled, see below.

Mageia Enlightenment also requires an AppIndicator library and enabling System Tray in Settings->Modules and the adding that System Tray to a Shelf (all terms familiar to Enlightenment users). Unfortunately, even that gets 'an' icon, not the one you carefully select for your application.

As of Lazarus 2.0.6, LCL will attempt to 'guess' the correct model to display a Tray Icon. However as distributions change over time, or with more obscure distributions you may need to override these guesses. For GTK2 apps, by setting an environment variable, LAZUSEAPPIND you can force an app to try to use LibAppIndicator3, prevent it from trying or just tell us which way it has guessed using YES, NO or INFO. eg

LAZUSEAPPIND=YES project1 <enter>

Will force project1 to try to use an Appindicator library (instead of the traditional System Tray) on GTK2. Obviously, it may not be available or it may not be suitable for the desktop in use but it will try. A line or two of text will be printed on stdout if the var is defined and not blank. Many systems will display the TrayIcon without using this environment variable. If the desktop you are running does require an AppIndicator library, then you must accept all it can ever do is trigger a menu, no OnClick event.

GTK3 can support only the AppIndicator model. Its use of the Ayatana version (in trunk only) is determined by https://bugs.freepascal.org/view.php?id=38909

Why two models ?

The AppIndicator model does not do as much as the older System Tray model. Both libraries are derived from Unity's definition of a 'simpler' interface, it will display only a menu, it does not pass an event, OnClick, back to your app. Indeed, if you have not assigned a popup menu to your TrayIcon will not show up at all. So, applications that depend on getting a OnClick event will not work with LibAppIndicator3.

Developers of new applications may well be advised to design their program around TrayIcon using only a popUpMenu !

AppIndicator Libraries

There are currently two possible AppIndicator libraries, Canonical's LibAppIndicator3-1 or libayatana-appindicator3-1, some systems have both, Bullseye has only the Ayatana one. Lazarus trunk supports Ayatana after 22 May 2021, r65122.

One or the other library can generally be installed from your distribution's normal package library. However, it is packaged with a number of different names. Sigh ...

  • libappindicator3 - Slackware, NetBSD
  • libappindicator3-1 - openSUSE and Debian [-based]
  • libappindicator-gtk3 - Arch, ALT, CentOS and Fedora, RedHat
  • libappindicator3_1 - all Mandrake/Mandriva derivatives -- Mageia, OpenMandriva, PCLinuxOS, Rosa
  • libayatana-appindicator3-1 - Debian Bullseye and most other Linuxs that offer Ayatana.


gnome-shell-extension-appindicator

This seems to be a viable solution mid 2021 for Gnome based systems. This plugin for Gnome Shell (the desktop) is made by Ubuntu to work like its old Unity AppIndicator model. So, in addition the the gnome plugin, you also need to install an AppIndicator3 library (AppIndicator3-1 on Fedora, Ayanata on Bullseye). It is KNSI inspired so no fancy right clicks allowed, just assign it a menu.

On Fedora, you can do this (note you don't need gnome-tweaks on Fedora 34) -

sudo dnf install libappindicator-gtk3  gnome-shell-extension-appindicator gnome-tweaks [enter]

Once installed, you need to restart the Desktop, just logout and back in. Then you must 'enable' the new plugin. On Fedora 33 thats easy, use the gnome-tweaks command, Extensions, enable "Kstatusnotifieritem/appindicator support". On Fedora 34, they have made it a bit harder by removing the Extensions section from Gnome Tweaks (too many happy users I expect). So, with Fedora 34, use the gnome-extensions command, it does not have a gui so issue the following command -

 gnome-extensions enable appindicatorsupport@rgcjonas.gmail.com [enter]

Replace 'enable' with 'info' to get some diagnostic information.

Note, three steps, install, restart desktop, enable plugin !

Debian Bullseye appears to arrive with the Ayatana library pre installed but the Gnome version still requires gnome-shell-extension-appindicator, install as above.

Your application can enable the extension (after a desktop restart), if you are feeling brave see https://github.com/tomboy-notes/tomboy-ng/blob/master/source/mainunit.pas

TopIconsPlus

Sadly, the coming of Wayland seems to have killed TopIconsPlus. This section may be removed before long.


Checking before invoking TrayIcon

Because you app may show the user only its TrayIcon and if that's not visible the user cannot interact, you may like to test to see if its going to work. Firstly, you can, sort of determine if LCL will use the old System Tray (in which case it will probably be OK), look at code in lcl/interfaces/gtk2/UnityWSCtrl.pas. If LCL is going to use an AppIndicator library, you need to see if the library is available and, on a Gnome system, if gnome-shell-extension-appindicator is enabled. The library is easy, try and load it, an error says its not there. To see if TopIcons is going to be available, the command "dconf read /org/gnome/shell/enabled-extensions" returns a few strings that may include "TopIcons". I expect there may also be an API ....

On GTK3

Trunk from October 2019 has a working GTK3 TrayIcon based, again, on LibAppIndicator3. The advice above relation to installing LibAppindicator3 and, where necessary TopIconsPlus applies to GTK3 as well. As the only way you can get a TrayIcon under GTK3 is the LibAppIndicator3, you can only use it to display a popup menu, don't expect to get a working OnClick event.

QT5 on Linux

Some linux systems that won't display the GTK Tray Icon will display the Qt5 version, but only if they use XOrg. Any system using wayland apparently has other has issues with Qt5. Fedora and OpenSuse use wayland by default but users can choose to use XOrg instead at logon time.

Issue On the macOS 32 bit Carbon

In October 2017 it was noted that a small problem existed on Sierra 10.12 when using the Carbon widget set. Attempts to update the caption of a menu item in a popup menu associated with a TrayIcon do not happen as expected. It is not uncommon to want to update the menu text at run time, for example, to display a list of recently opened files. This problem has been logged, https://bugs.freepascal.org/view.php?id=32516 . A workaround that appears reliable is to call TrayIcon1.InternalUpdate; after making changes to the captions.

This problem does not exist on Linux, Windows or on macOS when using the 64 bit Cocoa widget set.

Warning-icon.png

Warning: TrayIcon on macOS, using the 32 bit Carbon widget set has a memory leak.

Documentation

Below is a list of all methods, properties and events of the component. They have the same names and work the same way on the visual component and on the non-visual object.

A function works on all target platforms unless written otherwise.

Methods

Show

procedure Show;

Shows the icon on the system tray.

Hide

procedure Hide;

Removes the icon from the system tray.

GetPosition

function GetPosition: TPoint;

Returns the position of the tray icon on the display. This function is utilized to show message boxes near the icon. Currently it´s only a stub, no implementations are available and TPoint(0, 0) is returned.

Properties

Hint

property Hint: string;

A Hint will be shown the string isn't empty

PopUpMenu

property PopUpMenu: TPopUpMenu;

A PopUp menu that appears when the user right-clicks the tray icon.

Events

OnPaint

property OnPaint: TNotifyEvent;

Use this to implement custom drawing to the icon. Draw using the canvas property of the icon.

Light bulb  Note: Does not work on win32.
Light bulb  Note: Following events not available on Linux if using the LibAppIndicator3 model, its menu only.

OnClick

property OnClick: TNotifyEvent;

OnDblClick

property OnDblClick: TNotifyEvent;

OnMouseDown

property OnMouseDown: TMouseEvent;


OnMouseUp

property OnMouseUp: TMouseEvent;

OnMouseMove

property OnMouseMove: TMouseMoveEvent;

Authors

Light bulb  Note: Windows: Ozz Nixon

License

Modified LGPL.

Download

Status: Stable

Can be located at Lazarus 0.9.22 or inferior at the directory: lazarus/components/trayicon

And on Lazarus 0.9.23 or superior it is automatically installed with LCL

Example 1 - Using TIcon

As of Lazarus 0.9.26 TIcon has been fully implemented and it is no longer necessary to load the icon from a resource file on Windows. The icon can be loaded in the IDE or with usual code.

Go to the Additional tab of components, and add a TTrayIcon to your form. Then change its Name property to SystrayIcon

Next add a button to the form. Double click the button and add this code to it:

procedure MyForm.Button1Click(Sender: TObject);
begin
  SystrayIcon.Icon.LoadFromFile('/path_to_icon/icon.ico');
  SystrayIcon.ShowHint := True;
  SystrayIcon.Hint := 'my tool tip';

  SystrayIcon.PopUpMenu := MyPopUpMenu;

  SystrayIcon.Show;
end;

Example 2 - Creating the icon with TLazIntfImage

You can use TLazIntfImage to draw your icon quickly, as in the example code below:

procedure TForm1.DrawIcon;
var
  TempIntfImg: TLazIntfImage;
  ImgHandle, ImgMaskHandle: HBitmap;
  px, py: Integer;
  TempBitmap: TBitmap;
begin
  try
    TempIntfImg := TLazIntfImage.Create(16, 16);
    TempBitmap := TBitmap.Create;
    TempBitmap.Width := 16;
    TempBitmap.Height := 16;
    TempIntfImg.LoadFromBitmap(TempBitmap.Handle, TempBitmap.MaskHandle);

    // Set the pixels red
    for py := 0 to TempIntfImg.Height - 1 do
      for px := 0 to TempIntfImg.Width - 1 do
        TempIntfImg.Colors[px, py] := colRed;

    // Copy it to a TBitmap
    TempIntfImg.CreateBitmaps(ImgHandle,ImgMaskHandle, False);
    TempBitmap.Handle := ImgHandle;
    TempBitmap.MaskHandle := ImgMaskHandle;

    // And copy the TBitmap to your Icon
    SystrayIcon.Icon.Assign(TempBitmap);
    SystrayIcon.Show;
 
  finally
    TempIntfImg.Free;
    TempBitmap.Free;
  end;
end;

Subversion

Located under components/trayicon/ on the latest subversion Lazarus.

Help, Bug Reporting and Feature Request

Please, post Bug Reports and Feature Requests on the Lazarus Bugtracker.

Help requests can be posted on the Lazarus mailing list or on the Lazarus Forum.

Change Log

  1. 17/01/2006 - Available as a preview on the Lazarus subversion. Still under heavy construction, however.
  2. 24/01/2006 - Stable under win32, gnome and gtk1, but still waiting for gtk2 support. Lazarus 0.9.12 was release with this version.
  3. 17/02/2006 - Added support for gtk2 on subversion.
  4. July 2008 - Implements support for Qt 4
  5. July 2008 - Implements support for Carbon through PasCocoa

Technical Details

A difficulty on the development of this component was the many differences on the system tray implementation on various OSes and even Window Managers on Linux. To solve this, the component tries to implement the minimal set of features common to all target platforms. Below is a list of the features implemented on each platform:

Windows - Multiple system tray icons per application are supported. The image of the icon can be altered using a HICON handle. Events to the icon are sent via a special message on the user reserved space of messages (>= WM_USER) to the Window which owns the Icon. No paint events are sent to the Window.

Light bulb  Note: for some odd reason the environment by default does not support WM_USER+ messages, you will need to add "-dPassWin32MessagesToLCL" (without quotations) to support the messaging code. The steps are, click Tools -> Configure "Build Lazarus"..., and add that compiler option to "Options". If you have any existing options, they are "space" delimited.

Linux (Gnome, KDE, IceWM, etc) - Multiple system tray icons per application are supported. The image of the icon is actually a very small Window, and can be painted and receive events just like any other TForm descendant.

Linux (WindowMaker, Openbox, etc) - Does not support system tray icons out-of-the-box. However, There are at least two softwares that provides support for it: Docker and WMSystray

macOS - TTrayIcon support is implemented using the menu bar extras. Unfortunately the API to use menu bar extras is only available in Cocoa and not in Carbon, so we use the stable PasCocoa bindings in the Carbon interface to support menu bar extras even in older FPC compilers and in the Cocoa interface we will use the more modern Objective Pascal syntax.

Mn menubaritems.jpg

To read more about menu bar extras:

  1. https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/StatusBar/StatusBar.html
  2. https://developer.apple.com/design/human-interface-guidelines/macos/extensions/menu-bar-extras/
  3. https://developer.apple.com/design/human-interface-guidelines/macos/menus/dock-menus/
  4. https://developer.apple.com/design/human-interface-guidelines/macos/system-capabilities/dock/
  5. https://developer.apple.com/design/human-interface-guidelines/macos/menus/menu-anatomy/
  6. http://en.wikipedia.org/wiki/Menu_extra

With this in mind an approach which supports all Platforms was created:

  • Painting is done via a TIcon object. (Required by Windows)

The following extra features are already available or will be, but they won´t work on all platforms.

  • OnPaint event and Canvas property to draw the icon freely. Won´t work on Windows.

External Links