JNA change windows 10 wallpaper

[winter ferry]

I have a problem when i try to change the wallpaper of my windows 10 desktop to a image in my project folder. When i execute my code my desktop gets just a black-screen instate of my image. Here is the code of the Main Class(Core): ```Java
public class Core {

public void setWallpaper(String path) {
    User32.INSTANCE.SystemParametersInfoA(0x0014, 0, path, 0x0001 | 0x0002);
}

public String getAbsolutePath(String relativePath){
    URL imageURL = getClass().getResource(relativePath);
    File imageFile = new File(imageURL.getPath());

    return imageFile.getAbsolutePath();
}

public Core(){
    setWallpaper(getAbsolutePath("wallpapers/BillCipher.jpg"));
}

public static void main(String[] args) throws Exception {
    new Core();
}

And here is the Interface with the JNA stuff to declare the action:Java
public interface User32 extends StdCallLibrary {
User32 INSTANCE = (User32) Native.loadLibrary("user32", User32.class, W32APIOptions.DEFAULT_OPTIONS);
boolean SystemParametersInfoA(int uiAction, int uiParam, String pvParam, int fWinIni);
}```

[timber geode]

<@&987246452180930620> please have a look, thanks.

[timber geode]

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[timber geode]

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[winter ferry]

This message is for reopening this Thread and hoping for help

[storm crag]

I'll play around with this later today and get back to you if nobody else does

[winter ferry]

This problem is prob some very deep sh*t because my code is right and i readed the whole windows assembly parameters how they work. I gave the right parameter to set the wallpaper and this boolean even return true that the call was successful but the wallpaper is just not set and my old wallpaper got to a blackscreen

And my .jpg format is windows supported as well

tryed with png too

The only reason i found is this: ```In Windows 10, WM_SETTINGCHANGE processes Windows Explorer notifications generated as a result of changes to a monitor's workspace by recalculating the workspace for all monitors connected to the system. This recalculation takes into account the size and position of the taskbar window on the monitor as well as any app bars on the monitor registered by applications calling the SHAppBarMessage function. Changes to the workspace made by applications calling the SystemParametersInfo function are not taken into account, and this is intentional behavior.

The recalculation of the workspace by Windows Explorer can override changes made by an application to a monitor workspace while Windows Explorer is running. Applications that rely on changing the workspace may not function properly in Windows 10.``` but if thats the reason i have tbh no clue how to fix that

So basicly its a Windows 10 limitation

and i need now a way around it which sucks

[storm crag]

what OS are you on?

[winter ferry]

Windows 10

[fluid plume]

@winter ferry did you try to move the wallpaper out of resources ?

[winter ferry]

wdym?

[fluid plume]

the wallpaper is in resources folder, move it out of here

[winter ferry]

It do no difference

And i mean why would it even do a difference

[fluid plume]

which path are you using after that ?

[winter ferry]

i always get a new absolute path out of the relative path

public String getAbsolutePath(String relativePath){
        URL imageURL = getClass().getResource(relativePath);
        File imageFile = new File(imageURL.getPath());

        return imageFile.getAbsolutePath();
    }

So its not the problem with the path or format or anything else

[fluid plume]

no

just get the path directly

[winter ferry]

its just because of this function limitation of windows 10, so i need to find a work around

[fluid plume]

this is not supposed to work

[winter ferry]

the path is right, i did system out printed the path and pasted it in my explorer and it worked, so not the path problem

[fluid plume]

still

[winter ferry]

if it would have a problem with the path then this windows function would return false, but it did return true

[fluid plume]

you are not supposed to do any path operation on anything located in resources

even if it works now

please change it

it's a coincidence if this return the correct path

[winter ferry]

Thanks for helping me with the "program design pattern" but even if i would do it now it would not fix my current problem

[fluid plume]

this is not a program design pattern, it's a java specific common mistake 👀

[winter ferry]

but its still not the current problem i have

[fluid plume]

also

what is the format of your image

[winter ferry]

Im sorry if it sounds rude what i said or some but i can directly paste the right absolute path inside of the windows function but it just not helps me with my problem

[fluid plume]

is it bmp ?

[winter ferry]

jpg

[fluid plume]

ah

convert it

[winter ferry]

Converted and bmp not work as well which is not a big surprize because windows supports: jpg, png, bmp and tiff. So as i said jpg is not the problem

Im currently just trying to build way around without using SystemParametersInfoA because that function windows 10 do not support anymore when called by a application

[storm crag]

Your params are correct for SystemParametersInfoA from what I can see

but the latest JNA doesn't have that function

Also, not sure if we need to pass the values like this:

UINT uiAction = new UINT(0x0014);
UINT uiParam = new UINT(0);

The hard coding of SPIF_UPDATEINIFILE | SPIF_SENDWININICHANGE is also fine

[winter ferry]

Well i not have in my JNA "UNIT" thats why i not use it

but its also still fine, i mean the function gets still called

[storm crag]

    implementation 'net.java.dev.jna:jna:5.13.0'
    implementation 'net.java.dev.jna:jna-jpms:5.13.0'
    implementation 'net.java.dev.jna:jna-platform:5.13.0'
    implementation 'net.java.dev.jna:jna-platform-jpms:5.13.0'

that's in my build.gradle

[winter ferry]

dependencies {
    implementation 'net.java.dev.jna:jna:5.13.0'
}``` thats my build

[storm crag]

How are you resolving your imports?

I tried that at first but a lot of the classes I needed were missing

u didn't show imports in your snippet 😦

[winter ferry]

ah 1 sec

import com.sun.jna.Native;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;

public interface User32 extends StdCallLibrary {
    User32 INSTANCE = (User32) Native.load("user32", User32.class, W32APIOptions.DEFAULT_OPTIONS);
    boolean SystemParametersInfoA(int uiAction, int uiParam, String pvParam, int fWinIni);
}```

[storm crag]

String filePath = "path/to/your/image.jpg";
BufferedImage image = ImageIO.read(new File(filePath));
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Rectangle screenRect = new Rectangle(screenSize);
Image scaledImage = image.getScaledInstance(screenRect.width, screenRect.height, Image.SCALE_SMOOTH);
BufferedImage wallpaper = new BufferedImage(screenRect.width, screenRect.height, BufferedImage.TYPE_INT_RGB);
Graphics g = wallpaper.getGraphics();
g.drawImage(scaledImage, 0, 0, null);
g.dispose();
ImageIO.write(wallpaper, "jpg", new File("wallpaper.bmp"));
UINT uiAction = new UINT(0x0014);
UINT uiParam = new UINT(0);
String lpvParam = "wallpaper.bmp";```

[winter ferry]

thats the only 3 imports i use

[storm crag]

this is what I'm currently working with, I think Ala is right, you need to convert to .bmp

[winter ferry]

already converted to .bmp

what imports do you use?

i mean in the class not the build gradle

[storm crag]

cool - I have repro'd ur issue

[winter ferry]

[storm crag]

on Win11 getting black wallpaper

[winter ferry]

same on windows 10

As i did read from the windows docs this function we currently used only worked on the lower versions of windows, in windows 10 there might be some issues with other processes when using this function

Im currently searching for other functions and i found one, trying to build it in my project but its way more complex and i will need some time

[storm crag]

Fixed itr

User32 INSTANCE = Native.loadLibrary("user32", User32.class, W32APIOptions.DEFAULT_OPTIONS);
boolean SystemParametersInfo(int one, int two, String s, int three);

boolean result = User32.INSTANCE.SystemParametersInfo(0x0014, 0, filePath, 1);

this worked

Give it ago @winter ferry

full code:

import com.sun.jna.Native;
import com.sun.jna.win32.StdCallLibrary;
import com.sun.jna.win32.W32APIOptions;

public class Main {
    public interface User32 extends StdCallLibrary {
        User32 INSTANCE = Native.loadLibrary("user32", User32.class, W32APIOptions.DEFAULT_OPTIONS);
        boolean SystemParametersInfo(int one, int two, String s, int three);
    }

    public Main() throws Exception {
        String filePath = "path-to-bmp";
        boolean result = User32.INSTANCE.SystemParametersInfo(0x0014, 0, filePath, 1);
        if (result) {
            System.out.println("Success");
        } else {
            System.out.println("Failure");
        }
    }

    public static void main(String[] args) throws Exception {
        new Main();
    }
}

[winter ferry]

what did you changed?

[storm crag]

0x0001 | 0x0002

and

SystemParametersInfo

not using SystemParametersInfoA

[winter ferry]

And i just did such a complex thing but the solution was so much easyer xd

[storm crag]

I ended up finding the solution from a C++ post on SO

[winter ferry]

Well its still not working for me, just tested

[storm crag]

Really?

[winter ferry]

yep

[storm crag]

Interesting, it worked for me on Windows 11

Is your image a .BMP?

[winter ferry]

yes

[storm crag]

And try using the absolute path, I had the image saved to my Desktop

So try hard coding the full path

e.g. "C:\\User\\Desktop\\image.bmp" or whatever

[winter ferry]

i did hard coded the path and its still not working

i think there are always small differences between windows versions

[storm crag]

I need a Windows 10 license to change my vm's wallpaper

But I don't think there should be a difference in the versions for this specific functionality since all the examples are win10 ones anyway

[winter ferry]

could you link the post?

[storm crag]

Sure but the "solution" was me copying the params he used lol

https://stackoverflow.com/questions/34710677/systemparametersinfo-sets-wallpaper-completly-black-using-spi-setdeskwallpaper

And he did say it worked fine 😂

Post from 7 years ago

[winter ferry]

Checked a C# solution and that one did not work as well, this is such a scam ngl

Thats the C# solution i found they used 0x2 as last argument, not worked for me too https://social.msdn.microsoft.com/Forums/sqlserver/en-US/ab83d0c3-0b82-4353-b447-38ad297dfece/how-to-change-the-wallpaper-programmatically?forum=csharpgeneral

[storm crag]

Are there any image constraints?

Like does it need to match your monitor etc?

In my other code, I resized the image

[winter ferry]

As i did read from Windows docs the function do it automatically if the size not match, but i still have my image on the monitor size just in case

[fallow jacinth]

What's your path value?

[winter ferry]

"C:\Users\Mr.Mystery%201.0\Desktop\WallpaperChanger\build\resources\main\wallpapers\BillCipher.bmp"

I just hard coded it for now

I fixed it just now i found the issue and this issue sucks that its really the issue

because my user name have a space it was confusing the path, so i removed the space from my user name and it works now

im so happy that it work now

A lot of thanks for everyone who helped!

[timber geode]

Closed the thread.

[fluid plume]

I managed to do it with FFMA 👀

[winter ferry]

weird flex

[storm crag]

Show?

[fluid plume]

Linker linker = Linker.nativeLinker();
try(MemorySession session = MemorySession.openConfined()){
    SymbolLookup user32 = SymbolLookup.libraryLookup("user32", session);
    MemorySegment sysParamAddress = user32.lookup("SystemParametersInfoA").orElseThrow();
    var funDes = FunctionDescriptor.of(ValueLayout.JAVA_BOOLEAN, ValueLayout.JAVA_INT, ValueLayout.JAVA_INT, ValueLayout.ADDRESS, ValueLayout.JAVA_INT);
    MethodHandle sysParam = linker.downcallHandle(sysParamAddress, funDes);
    MemorySegment cStringPath = session.allocateUtf8String("absolute_path");
    boolean result = (boolean) sysParam.invoke(0x0014, 0, cStringPath, 0x001 | 0x002);
    println(result);
}

@storm crag @winter ferry
If you ever want to do it with this new API which is currently available in preview in java 19, and you don't need any external lib.

[winter ferry]

Me using Java 8 for this one

[storm crag]

That is very interesting!

Thanks for the share ala

[fluid plume]

👍

now I have to turn my wallpaper back

[winter ferry]

[fluid plume]

You should update, java 8 is nearly 10 years old

And you wont guess what my wallpaper I set with this command

[fluid plume]

Also note that this new API is very interesting, because you see cStringPath ? It's a string allocated outside the jvm heap, in a memory that I manage myself, it's not managed by the gc

[winter ferry]

I wanted to do Java 17 for this project but then i did Java 8 because of one important thing but i forgot what was that important for me

[storm crag]

Is it cleaned up at all by java? Or at least when the try block exists?

[fluid plume]

then update 👀

[winter ferry]

yeah i prob should at least before i not remember that important thing

[fluid plume]

here I allocated it thanks to the session, so when the session exist the try-with-resources, it will be freed, this is so I don't forget to free it myself

[storm crag]

So if we don't call close, it'll be there forever?

[fluid plume]

yes

until the process stops

[winter ferry]

But tbh i think the solution with the external lib looks cleaner ngl

[fluid plume]

(like any C process)

[storm crag]

Ah okay

[winter ferry]

I mean with the lib its 3 lines of code the interface and 1 line to call it

[fluid plume]

The idea of this new lib is to replace JNI and many Unsafe methods basically (and so JNA)
The advantages are that it is safer, and it is fully controlled from java, like you directly use objects without any magic instead of the way jna works
Also note that libs may exist in the future allowing to simplify this, and there is already an existing tool that can generate such code automatically

[storm crag]

I would love a jna library that is just a wrapper over all those native api's

So you can call functions as you would any other way

Win32.systemBlah(param);

Or whatever

Followed by additional helper functions "changeWallpaper"

[fluid plume]

mhhhh

I'll make a question for jextract