C#•11mo ago

❔ Overlay on other Windows from WPF

Hello 🙂 Is it possible from WPF to make a overlay over another window. I wanna show some information over another window on the computer from my WPF application, and was wondering if its possible, and if so how? Thanks

192 Replies

Jester•11mo ago

I know about Win32 but not everything about WPF capabilities. But yeah you could make your WPF window a top-most window. Then you could get the handle of the window you want to overlay and get its position on the screen to reposition your window above it. Some issues might be; getting WPF to be transparent and finding the right window. a way to get the window handle: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-findwindoww a way to find where it is: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getwindowrect a way to position and top-most your wpf app: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowpos hope this helps <:PES_ThumbsUp:513327253728264192>

Ossie•11mo ago

Will this also work for x64 ?

Jester•11mo ago

yes win32 is 64 bit on 64bit machines

Ossie•11mo ago

Jester•11mo ago

they updated it from 16 bit to 32 but didnt rename it from 32 to 64 <:PES_SadShrug:646092743378206760> WPF uses it under the hood too

Ossie•11mo ago

Okay 🙂 But, what if I don't know the class name of the window

Jester•11mo ago

you dont need it, its optional idk how familiar you are with interop?

Ossie•11mo ago

Can't I use like a process or smth I don't know anything about this topic I just wanna make a simple overlay for a game

Jester•11mo ago

the problem is overlays arent simple LULLLLLL

Ossie•11mo ago

Jester•11mo ago

while they shouldnt have to be <:PES_Think:639363477458255874>

Ossie•11mo ago

I found a nuget package, which is for .net, but it seems to be for cheats injected into a process, and then it draws on that window, but I just wanna find the window in the current processes

Jester•11mo ago

i think that nuget package then hooks into the swapchain of the game process to inject extra drawing yes your own window above the game should be simpler

Ossie•11mo ago

its called GameOverlay.NET, and I searched on some guides or smth for it, and got straight to unknown cheats, so yea im guessing

Jester•11mo ago

i think i have a project you might be able to build on what does your overlay need to have of functionality? just display text and shapes?

Ossie•11mo ago

idk, it would nice to deisng it a little but primary just text yea text and shapes should be fine

Jester•11mo ago

in this project i built upon a different one which allows you to easely draw text and shapes on a window. i made it so your own window is fully transparent https://github.com/QubitTooLate/Win2DSample/tree/main

GitHub

GitHub - QubitTooLate/Win2DSample: A simple and minimal Win2D sampl...

A simple and minimal Win2D sample in an unpackaged Win32 app - GitHub - QubitTooLate/Win2DSample: A simple and minimal Win2D sample in an unpackaged Win32 app

Jester•11mo ago

its not WPF but thats maybe an advantage you just have to add this functionality and then draw whatever it should already be top most bcuz this code is quite low-level compared to WPF not every method will be as easy to understand

Ossie•11mo ago

I'm just gonna try with the first things you send, with a WPF Window and see if I can maybe get it to work

Jester•11mo ago

i wish i could just change the render pipeline of WPF a little <:PES_Cry:493359762432327691>

Ossie•11mo ago

hehe what do I need to do to use the FindWindowW functions? do I need a DllImport or using something?

Jester•11mo ago

DllImport but in newer C# .NET it seems to recommend LibraryImport which is pretty much the same

Ossie•11mo ago

what dll do i need to import? winuser.dll?

Jester•11mo ago

user32

Ossie•11mo ago

idk I dont think i understand it says on the docs the return type is HWND, but when I try to make the type HWND it says it doesn't exist

Jester•11mo ago

yes, .NET doesnt know what HWND is but its an IntPtr

Ossie•11mo ago

ah ok

Jester•11mo ago

like this for example

[LibraryImport("user32.dll", EntryPoint = "FindWindowW", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
internal static partial IntPtr FindWindow(string lpClassName, string lpWindowName);

[LibraryImport("user32.dll", EntryPoint = "FindWindowW", SetLastError = true, StringMarshalling = StringMarshalling.Utf16)]
internal static partial IntPtr FindWindow(string lpClassName, string lpWindowName);

Ossie•11mo ago

but, do I then make the function called FindowW or okay i get their inaccessible due to their protection level...

Jester•11mo ago

if you give it an entrypoint it imports that function and then you can name it whatever you like make it public?

Ossie•11mo ago

its the LibraryImport not the function

Jester•11mo ago

put the functions in a class like this

public static partial class User32
{
...
}

public static partial class User32
{
...
}

Ossie•11mo ago

aight

Jester•11mo ago

which version of .NET are you on?

Ossie•11mo ago

6 .0 core

Jester•11mo ago

then i think you still have to use DllImport

[DllImport("user32.dll", EntryPoint = "FindWindowW", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

[DllImport("user32.dll", EntryPoint = "FindWindowW", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

like that then you dont need partial

Ossie•11mo ago

Okay And now I can call the User32.FindWindow to call the FindWindowW

Jester•11mo ago

yes

Ossie•11mo ago

what type is lpRect in .Net?

Jester•11mo ago

you would have to make a rect structure and have a pointer or reference to it in the method im asking bing chat to give me the code so i dont have to write it all myself but i know if the code is correct or not

Ossie•11mo ago

ah ok so i can make it a ref in the function def and then just pass a new Rect with a ref to it

Jester•11mo ago

you have to initialise the rect in advance and then ref it

Ossie•11mo ago

Yeye

Jester•11mo ago

bing chat is being annoying, why doesnt it just give me code

Ossie•11mo ago

Rect r = new Rect();
GetWindowRect(hwnd, ref r);

Rect r = new Rect();
GetWindowRect(hwnd, ref r);

Jester•11mo ago

[DllImport("user32")]
[return: MarshalAs(something.Bool)]
public static extern bool GetWindowRect(IntPtr handle, ref Rect rect);

[DllImport("user32")]
[return: MarshalAs(something.Bool)]
public static extern bool GetWindowRect(IntPtr handle, ref Rect rect);

Ossie•11mo ago

for this one

Ossie•11mo ago

https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowpos

SetWindowPos function (winuser.h) - Win32 apps

Changes the size, position, and Z order of a child, pop-up, or top-level window. These windows are ordered according to their appearance on the screen. The topmost window receives the highest rank and is the first window in the Z order.

Ossie•11mo ago

I would want it to be HWND_TOPMOST, but what do I pass in the function do I just pass -1?

Jester•11mo ago

[StructLayout(Sequential)]
public struct Rect {
public int Left; 
public int Top; 
public int Right; 
public int Bottom; }

[StructLayout(Sequential)]
public struct Rect {
public int Left; 
public int Top; 
public int Right; 
public int Bottom; }

yep

Ossie•11mo ago

Do I need that custom Struct Rect, or can I use the one from System.Windows

Jester•11mo ago

im writing the code myself bcuz the AI doesnt want to do it like this but add the accessability modifiers some methods are a hell to dll import, but there are generators to do it for you, but you dont need many so you dont really need them to be generated for you yet

Ossie•11mo ago

idk what is accessability modifiers

Jester•11mo ago

public, private, internal etc just make it all public

Ossie•11mo ago

It wants me to do LayoutKind.Sequential, is that ok?

Jester•11mo ago

yes

Ossie•11mo ago

ok Well I have a User32.cs now with the three functions and no errors, so thats a start atleast

Jester•11mo ago

otherwise the memory of the fields can be in a different order than you wrote it can you show it for me to check?

Ossie•11mo ago

Ossie•11mo ago

Since the FindWindowW, has the first parameter as optional, do I jsut pass a null value to it?

Jester•11mo ago

yes

Ossie•11mo ago

Jester•11mo ago

you have to change the return type of getwindowrect and setwindowpos it has to be like this

Ossie•11mo ago

oh yea, i changed it to bool now sorry for both?

Jester•11mo ago

add the publics like here yes like in the docs

Ossie•11mo ago

I dont understand

Jester•11mo ago

the return needs the marshalas bcuz a bool in C is 32bit and in c# only 8

Ossie•11mo ago

what is something.Bool

Jester•11mo ago

something is an enum i forgot the name of

Ossie•11mo ago

so what do I write instead of something

Jester•11mo ago

what does it tell you to write?

Ossie•11mo ago

nothing it just says error with something

Jester•11mo ago

UnmanagedType

Ossie•11mo ago

okay so this is

Ossie•11mo ago

Ossie•11mo ago

better ?

Jester•11mo ago

yes looks good hold on you made the second HWND an int instead of intptr in the last function

Ossie•11mo ago

yes because isnt -1 an int?

Jester•11mo ago

yes but it wants more bits than an int

Ossie•11mo ago

or it still needs to be a intpointer? Okay

Jester•11mo ago

intptr is 64 bit on 64 bit and int is always 32 sometimes it might work if you use the wrong types, until it doesnt or crashes everything

Ossie•11mo ago

ok lol good to know i dont understand it says on the docs that FindWindowW can return null, but when I check if the return of the function is null, it says it can never be null And if I try to make it nullable, then I can't use it for any of the other functions...

Jester•11mo ago

dont look at the return value of it, its not really useful

Ossie•11mo ago

wdym

Jester•11mo ago

oh wiat

Ossie•11mo ago

how would I know if I have found the window then

Jester•11mo ago

lmao my bad yes you do need the returned value

Ossie•11mo ago

I thought i had a way but now it says I cant use a unassigned variable...

Ossie•11mo ago

Jester•11mo ago

no dont make it nullable that changes the type null is just 0, so you have to check if the IntPtr is 0

Ossie•11mo ago

Okay How do I get around the Unassigned variable thing

Jester•11mo ago

IntPtr FoundWindow = default;

Ossie•11mo ago

oh, ok, didn't know that existed

Jester•11mo ago

bcuz IntPtr is a struct, and if you make a struct nullable, it actually becomes a different type. which we cant have bcuz then the bytes wont align anymore null is just a fancy 0

Ossie•11mo ago

I still dont quite understand If I run the code im doing rn, from a new WPF window, will that window then get drawed? or do I need to tell it somewhere which window to draw

Jester•11mo ago

i dont understand what you mean IntPtr? is actually Nullable<IntPtr> which is different than IntPtr you draw on your own WPF window but your WPF window is going to be above the game if everything goes right

Ossie•11mo ago

im not sure i understand im just gonna write the code and try it

Jester•11mo ago

you need to have the window title exactly right to find the window

Ossie•11mo ago

Okay, I have created the following now

Ossie•11mo ago

Ossie•11mo ago

So this code, if I understand, will draw the Window (OverLay) on top of the window title I input?

Jester•11mo ago

yes but why did you make your own window hidden? and you cant really have a while loop there bcuz its going to get stuck in it

Ossie•11mo ago

Because, I don't wanna draw the overlay imediatly on startup, only when the window to draw on is found

Jester•11mo ago

okay so when you have found it, break the loop and show the window

Ossie•11mo ago

Ossie•11mo ago

This better?

Jester•11mo ago

yes

Ossie•11mo ago

Im going thru Mainwindow.overlay since I instance the class from there Okay Im gonna try to build and run it

Jester•11mo ago

drawoverlay doesnt have to be static

Ossie•11mo ago

oh ok probably form before, when I tried to use DllImport it said it had to be static, just forgot to remove idk what is a good window to test on

Jester•11mo ago

notepad should be good but the problem is the title of notepad can not always be clear if you look in the taskbar and hover your mouse over an app icon of an open window you can see its title

Ossie•11mo ago

ye hm it doesn't draw it on top it just draws the overlay as a new window or well it draws it in the correct location but its drawn behind

Jester•11mo ago

its not top most?

Ossie•11mo ago

Jester•11mo ago

oh yeah you put notepad top most above your window instead of the opposite

Ossie•11mo ago

oh how do I do it the other way around lol I get the window for the overlay?

Jester•11mo ago

you can get that like this or simular IntPtr windowHandle = new WindowInteropHelper(Application.Current.MainWindow).Handle;

Ossie•11mo ago

but i dont want the mainwindow I need the Overlay Window

Jester•11mo ago

then use the overlay window as argument

Ossie•11mo ago

eh how its not showing with Intellisense

Jester•11mo ago

so for the setwindowposition you need your own handle im guessing this

Ossie•11mo ago

WindowInteropHandler(this)?

Jester•11mo ago

yes

Ossie•11mo ago

and just quick question, im not totally sure of the rect thing how would I turn that into the top left corner of the window i wanna do the overlay on is it just left; top;

Jester•11mo ago

Retrieves the dimensions of the bounding rectangle of the specified window. The dimensions are given in screen coordinates that are relative to the upper-left corner of the screen. it doesnt give you the size of the window it gives you the rectangle on screen where the window is

Ossie•11mo ago

okay and how would I turn that into coordinates for the overlay?

Jester•11mo ago

should be the same

Ossie•11mo ago

if I have the x,y and for cornerns isnt it just x,y for top corner rect.Left, rect.Top

Jester•11mo ago

width = right - left

Ossie•11mo ago

Okay, now it draws it on top but if I focus the application, it dissapears how do I make the overlay stay and follow

Jester•11mo ago

close and open notepad again and then re-run your app

Ossie•11mo ago

huh i dont understand

Jester•11mo ago

well i think before you made the notepad window top most as well on accident

Ossie•11mo ago

im not using notepad anymore im using Epic Games Launcher rn

Jester•11mo ago

oh ok

Ossie•11mo ago

it was just easier to type but let me check its fully closed

Jester•11mo ago

well if the window you are trying to get above isnt top most and yours doesnt stay above it then yours isnt top most either

Ossie•11mo ago

hm, idk I just always want to have the overlay on top of the window i dont care about other things getting in front, as long as its on top of the actual window i want

Jester•11mo ago

yes, im not sure why its not top most bcuz ur passing in -1

Ossie•11mo ago

but right now, when I jsut focus epic games launcher, it just hides behind it and if I focus something else, it hides behind that aswell

Jester•11mo ago

ooh i forgot about the flags read the docs about the flags of setwindowpos closely and the remarks maybe

Ossie•11mo ago

eh i dont understand it really there is many maybe this one SWP_SHOWWINDOW - Displays the window

Jester•11mo ago

well it was already showing so not really

Ossie•11mo ago

idk then

Jester•11mo ago

hmm maybe not a flag so your overlay window is not showing above the epic games launcher?

Ossie•11mo ago

right when I launch it, it shows but as soon as I focus the launcher, it just goes behind like any other application would like when you focus something behind someting else on windows, it just goes beheind i found this in the remarks

If neither the SWP_NOACTIVATE nor SWP_NOZORDER flag is specified (that is, when the application requests that a window be simultaneously activated and its position in the Z order changed), the value specified in hWndInsertAfter is used only in the following circumstances.

Neither the HWND_TOPMOST nor HWND_NOTOPMOST flag is specified in hWndInsertAfter.
The window identified by hWnd is not the active window.

If neither the SWP_NOACTIVATE nor SWP_NOZORDER flag is specified (that is, when the application requests that a window be simultaneously activated and its position in the Z order changed), the value specified in hWndInsertAfter is used only in the following circumstances.

Neither the HWND_TOPMOST nor HWND_NOTOPMOST flag is specified in hWndInsertAfter.
The window identified by hWnd is not the active window.

Jester•11mo ago

they couldve written that better

Ossie•11mo ago

i dont totally understand it

Jester•11mo ago

A window can be made a topmost window either by setting the hWndInsertAfter parameter to HWND_TOPMOST and ensuring that the SWP_NOZORDER flag is not set, or by setting a window's position in the Z order so that it is above any existing topmost windows. show me your code again

Ossie•11mo ago

Jester•11mo ago

ah you didnt pass in a width and height into to setwindowposition, maybe thats an issue?

Ossie•11mo ago

I did before, and it was the same issue

Jester•11mo ago

im clueless let me search my own code looks fine to Huh

Ossie•11mo ago

I also just tried to do it on the MainWindow of just the application it self, to check it wasnt something weird with epic games launcher but still it just hides behind when I focus the other window

Jester•11mo ago

you did change the int to an intptr right?

Ossie•11mo ago

Yes

Ossie•11mo ago

Jester•11mo ago

okay <:PES_Think:639363477458255874>

Ossie•11mo ago

it gets shown but as soon as I click anywhere on the window under, it just goes behind

Jester•11mo ago

ok so what if you look into the wpf window properties maybe there is a setting to set it as topmost probably. that should solve it

Ossie•11mo ago

eh how?

Ossie•11mo ago

Ossie•11mo ago

these?

Jester•11mo ago

like when you change properties of a label no in the editor

Ossie•11mo ago

ah I can do TopMost = true on the window

Jester•11mo ago

try that

Ossie•11mo ago

ok yes now it works ...

Jester•11mo ago

solved

Ossie•11mo ago

but, now it draws over eveything else lol is that meant to happen

Jester•11mo ago

yes, its all or nothing sadly

Ossie•11mo ago

:/ wish you could do something like WindowIWannaDrawOverZ+1

Jester•11mo ago

yeah that would be nice but unfortunatly not

Ossie•11mo ago

okay well still also How would I make it follow the window its drawed on around? I can make like a tick or smth, i havent tried that before

Jester•11mo ago

you need a timer to have something happen repeatedly i think thats also a wpf thing in the editor? im going to sleep soon, you will probably also have to make your window click-trough if its not yet

Ossie•11mo ago

Im just gonna try something, but thanks so fucking much I would have never figured this out without you

Jester•11mo ago

took me a while to figure it all out myself a while ago

Ossie•11mo ago

just a quick final question

Jester•11mo ago

getting to know internals and modifying linux? howieno

mastering and customizing windows? howieyes

Ossie•11mo ago

how can I make the Handle to the overlaywindow outside of the DrawOverlay()? I can't use this outside of the method

Jester•11mo ago

make it a field in your overlay class also your drawoverlay method is doing too much right now, to make the code more readable you should divide it in multiple functions which each do only one thing add some DRY (dont repeat yourself) and SRP (single responsability principle) to your code

Ossie•11mo ago

okay is it a bad idea to get the WindowSize of the window under a lot of times

Jester•11mo ago

30 times a second should be enough for sure and fine only as much as nescessary

Ossie•11mo ago

I will look into it tommorow, sleep well, and thanks for the help

Jester•11mo ago

good night

sibber•11mo ago

this is gonna be harder a simple topmost window probably wont work on fullscreen games one way i know that is used to to hook into the graphics api and draw that means you need to implement that for every graphics api that a game may use or find an implementation/lib or you can try a topmost window and see if it works

Ossie•11mo ago

i just really dont wanna fiddle with injection, as the game has an anti cheat, and I don’t wanna get banned… So I've tried to create a timer, but it doesn't update the WindowPos for some odd reason. I have the following as a Timer.Elapsed event:

        private void UpdateWindowPos(object sender, EventArgs e)
        {
            if (Found)
            {
                this.Dispatcher.Invoke((Action)(() =>
                {
                    Classes.User32.Rect rect = GetRect();
                    DrawText.Text = rect.Left.ToString() + " " + rect.Top.ToString();
                    Classes.User32.SetWindowPosition(OverlayWindowHandle, (IntPtr)(-1), rect.Left, rect.Top, 10, 10, 0);
                }));
            }
        }

        private void UpdateWindowPos(object sender, EventArgs e)
        {
            if (Found)
            {
                this.Dispatcher.Invoke((Action)(() =>
                {
                    Classes.User32.Rect rect = GetRect();
                    DrawText.Text = rect.Left.ToString() + " " + rect.Top.ToString();
                    Classes.User32.SetWindowPosition(OverlayWindowHandle, (IntPtr)(-1), rect.Left, rect.Top, 10, 10, 0);
                }));
            }
        }

But, this doesn't update the position of the overlay for some reason, however the text get changed to the right thing, it updates like it should to the new rect coordinates. but the windowposition of the overlay never changes

Ossie•11mo ago

sibber•11mo ago

this wont trigger it you wouldnt be modifying any of the games files fraps is open source iirc you can check at how they did it if their implementation still works

Jester•11mo ago

Ossie•11mo ago

I fixed it with this.Left and this.Top

Accord•11mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

Gaming

Programming

❔ Overlay on other Windows from WPF