SendKeys Alernative for Linux
lazarus / 1-Linux

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pixelink · 2025-10-28 23:40

I have am planning to move to Linux OS within a year or two.
So, as I prepare to do so I am beginning to remake some of my windows
apps (made in VS studio and Laz) to be Linux compatible
However, I do have an app that uses the Windows Sendkeys functionality
that performs "sendkeys" by sending text or OS commands to other
applications on Windows.

I am wondering.... is there an equivalent function in Laz (Free
Pascal) that I can do something similar to SendKeys on other external
programs?
If not, what about a 3rd party package or something similar?

Thanks for any suggestion!

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Handoko · 2025-10-29 03:41

I haven't tried, maybe MouseAndKeyInput unit is what you need. But it
is under GPL license, which means you can't use it for closed-sourced
projects.

https://wiki.freepascal.org/MouseAndKeyInput

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Thaddy · 2025-10-29 05:58

I found several examples:Code: Pascal  [Select][+][-]window.onload =
function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i unit inputsimulator;{$mode objfpc}{$linklib C}     {$linklib
X11}   // unit keysym contains the key codes, part of X11
package.interface uses  X, Xlib, Xutil, keysym;  procedure
Simulate_KeyPress(keySym: cardinal; shiftState: boolean =
false);procedure Simulate_Mouse_Click(x, y: integer; button: integer =
1);procedure Simulate_Mouse_move(x, y:
integer); implementation procedure Simulate_KeyPress(keySym: cardinal;
shiftState: boolean = false);var  display: PDisplay;  event:
TXKeyEvent;  keyCode: TKeyCode;begin  display := XOpenDisplay(nil); 
if display = nil then Exit;    keyCode := XKeysymToKeycode(display,
keySym);    event.display := display;  event.window :=
XDefaultRootWindow(display);  event.root :=
XDefaultRootWindow(display);  event.subwindow := None;  event.time :=
CurrentTime;  event.x := 1;  event.y := 1;  event.x_root := 1; 
event.y_root := 1;  event.same_screen := 1;  event.keycode :=
keyCode;  event.state := 0;    if shiftState then    event.state :=
event.state or ShiftMask;    // Key press  event._type := KeyPress; 
XSendEvent(display, XDefaultRootWindow(display), 1, KeyPressMask,
@event);    // Small delay (optional)  // Sleep(10);    // Key
release  event._type := KeyRelease;  XSendEvent(display,
XDefaultRootWindow(display), 1, KeyReleaseMask, @event);   
XFlush(display);  XCloseDisplay(display);end; procedure
Simulate_Mouse_Click(x, y: integer; button: integer = 1);var  display:
PDisplay;  event: TXButtonEvent;begin  display := XOpenDisplay(nil); 
if display = nil then Exit;    // Move mouse to position 
XWarpPointer(display, None, XDefaultRootWindow(display), 0, 0, 0, 0,
x, y);  XFlush(display);    // Set up event  event.display :=
display;  event.window := XDefaultRootWindow(display);  event.root :=
XDefaultRootWindow(display);  event.subwindow := None;  event.time :=
CurrentTime;  event.x := x;  event.y := y;  event.x_root := x; 
event.y_root := y;  event.same_screen := 1;  event.state := 0; 
event.button := button;    // Press  event._type := ButtonPress; 
XSendEvent(display, XDefaultRootWindow(display), 1, ButtonPressMask,
@event);  XFlush(display);    // Release  event._type :=
ButtonRelease;  XSendEvent(display, XDefaultRootWindow(display), 1,
ButtonReleaseMask, @event);  XFlush(display);   
XCloseDisplay(display);end; procedure Simulate_Mouse_move(x, y:
integer);var  display: PDisplay;begin  display := XOpenDisplay(nil); 
if display = nil then Exit;    XWarpPointer(display, None,
XDefaultRootWindow(display), 0, 0, 0, 0, x, y);  XFlush(display); 
XCloseDisplay(display);end; end. Depends on X, not tested for Wayland,
but XWayland works.

You can also use xdotool, which works like this:Code: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
SimulateWithXdotool(command: string);begin 
ExecuteProcess('/usr/bin/xdotool', command);end; // Usage examples://
SimulateWithXdotool('key a');           // Press 'a'//
SimulateWithXdotool('key Ctrl+c');      // Press Ctrl+C//
SimulateWithXdotool('mousemove 100 100'); // Move mouse//
SimulateWithXdotool('click 1');         // Left clickNeeds xdotool
installed: apt-get install xdotool

I have more examples, but these need root priviliges.

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Thaddy · 2025-10-29 07:25

Side note:
Does anybody know why I could not post my code without using
underscores: the original code did not use underscores, but I get
this:Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
Simula]"]>BlockeduseClick(x, y: integer; button: integer =
1);procedure Simula]"]>BlockeduseMove(x, y: integer);So I had to add
the underscores. Rather irritating...There should not be a security
risk, because the code is contained in the codeblock.
Anyway, the inputsimulator unit works, but note some key combinations
can be reserved. (also the case with sendkeys)

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MarkMLl · 2025-10-29 07:39

At a somewhat lower level there's the events API
https://www.kernel.org/doc/html/v4.18/input/event-codes.html and also
see the evtest program: note that this is specifically input device
codes, rather than "events" as in interrupts etc.

What I don't know is whether it's possible to send events to a
specific process (identified by PIC) or window (identified at the
widget set level).

MarkMLl

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Thaddy · 2025-10-29 07:43

That needs root privileges, so I left that out. If you are interested
I can post for that too..
Using /dev/uinput and fpioctrl. Not really recommended and I doubt if
it is very useful to OP.
(Or anybody sane for that matter, usually discussions unfold that are
not relevant to the question: a replacement for sendkeys)

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MarkMLl · 2025-10-29 10:49

Quote from: Thaddy on October 29, 2025, 08:43:08 amThat needs root
privileges, so I left that out.

No, user needs to be a member of the input group, or the program he's
running needs appropriate capabilities.

The sticking point is routing to a specific PID, window etc.

MarkMLl

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pixelink · 2025-10-29 15:54

Thanks for the info!

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LemonParty · 2025-11-22 12:40

Quote from: MarkMLl on October 29, 2025, 08:39:15 amAt a somewhat
lower level there's the events API
https://www.kernel.org/doc/html/v4.18/input/event-codes.html and also
see the evtest program: note that this is specifically input device
codes, rather than "events" as in interrupts etc.

What I don't know is whether it's possible to send events to a
specific process (identified by PIC) or window (identified at the
widget set level).

MarkMLl
I am intersting if someone successfully used this API.

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MarkMLl · 2025-11-22 18:16

Quote from: LemonParty on November 22, 2025, 01:40:50 pmI am
intersting if someone successfully used this API.

Not with my own code. I've got a slightly-modified version of mxk
originally from http://welz.org.za/projects/mxk (not sure whether that
site is still live **), but basically there should be plenty of
examples around although they'll probably be written in C.

However as I've said: the problem is that it's global, and oblivious
to what program's running etc. To decide whether that API is going to
be any use at all for you I suggest playing with evtest, noting that
you'll need to be a member of the input group.

MarkMLl

** https://web.archive.org/web/20150804022200/http://welz.org.za/proje
cts/mxk

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LemonParty · 2025-11-23 17:07

That is quite a lot of C code. But it well written C code. Will be
challenging to extract what needed from this sources.
Thank you.