Which libraries are these? Perhaps you need to first use [declare -lib libname] before trying to create one of its objects. This concerns single binary file libraries like zexy or Gem.

Since you're using the else library you can use [else/envgen~] combined with the function object. Check its help patch and the [pd function] subpatch that's in there.

@gentleclockdivider your approach is totally against netiquette, if you ever read any etiquette rules. Posting the same question to multiple channels just because you need an answer fast is just bad practice for a community member. @porres might sound a bit aggressive, but I do agree with him, and I guess you don't agree with me, still, basic netiquette is necessary in community fora. Also, @porres did not imply he is in any position of authority. He's just recommending a better community behaviour in Pd's channels.

@oid you're write about making all ramps go from 0 to 1, apply curvature, and then scale and offset to bring them to the desired range. I've done that too in a project of mine, but it's quite some more work. As you write, the approach above is probably good for most applications. I did this as a reply to @ddw_music's post.

@porres the Bela has only libPd and not an actual Pd installation. I agree that it's very outdated and an easier way to update Pd in the Bela is needed, but for now that's what we get.

@ddw_music I thought about it and it turns out that just squaring is not enough, even if you store the square root of the sustaing value. If you just square, the curve of the attack will be inversed (it will be exponential instead of logarithmic). You need some more logic to inverse the power you raise the amplitude to, depending on the direction of your signal. Here's a snapshot of my take.

[adsr] is an abstraction I have built. It stores the square root of the sustain value. What's important here is the logic underneath [vline~]. Here I'm using zexy's [z~ 1] to get the previous sample and compare it to the current one. If the current sample is smaller or equal to the previous one (the decay, sustain and release parts), then the envelope is raised to the 2nd power, otherwise, it is raised to 0.5.
This way, you can get the correct curvatures.

@ddw_music unless, you do square it, but set the sustain value through a [sqrt] first, so when squared, it gets to the correct value!

Check out this https://github.com/alexdrymonitis/filter_abstractions
both [omniFilter_abs~] and [multiFilter_abs~] can create a resonant lowpass filter. Getting note on and note off messages in Pd can be done with the [notein] object. Just create one and right-click on it, then click on help in the pop-up menu.
As for [mtof~], you're right, you need that to convert MIDI notes to frequencies. There's also a control-rate version, [mtof], without the tilde.

@ddw_music you can't really square the value in case it's a volume envelope, because that will square the sustain value as well, and that will reduce the actual value. I understand that squaring will create curves, but you need a more complex logic to get the curves but maintain the sustain value.

You need [text get]. Check [text]'s help patch, everything you need is there.

Gem is a one binary file library. You hane to import the lib before trying to create an object from it.
Try putting a [declare -path /path/to/Gem -lib Gem] object in your patch.

Do you have any suggestions I could try out? I think Ofelia is a great project, and I'd really like to help with its development/maintenance if needed. There are plenty of stuff about the compiling process that I don't know though.

I can't find any of the equivalent files of the .dll files anywhere. I guess these are the ones you are talking about?

These are the contents of the .zip file you mention:

abs/                  CHANGES.txt                    examples/     LICENSE.txt  ofelia-object-help.lua  ofelia_textwindow.tcl   opencv_core4100.dll  opencv_features2d4100.dll  opencv_imgproc4100.dll    README.md
assimp-vc142-mt.dll  classesAndGlobalFunctions.txt  libxml2.dll  ofelia.dll   ofelia-object-help.pd   opencv_calib3d4100.dll  opencv_dnn4100.dll   opencv_flann4100.dll       opencv_objdetect4100.dll  stable-diffusion.dll

Are these supposed to be located in the ofeliaExtendedLib directory? Because, all there is in there, is already in the directory of the ofelia.pd_linux Pd external directory too.

Oh, I followed the instructions, (which are probably forked from ofxOfelia?) where it writes that the directory needs to be named ofxOfelia. I renamed it to ofxOfeliaExtended and make now worked. I copied ofelia.pd_linux to my externals folder, but Pd can't create the object. Trying to load the library with [declare -lib ofelia], I get the following errors:

load_object: Symbol "ofelia_setup" not found in "/home/alex/Documents/Pd/externals/ofelia/ofelia.pd_linux"
load_object: Symbol "ofelia_setup" not found in "/home/alex/Documents/Pd/externals/ofelia/ofelia.pd_linux"
load_object: Symbol "ofelia_setup" not found in "/home/alex/Documents/Pd/externals/ofelia/ofelia.pd_linux"

It turns out that the build instructions are there. For some reason, I thought that the instructions had only to do with the OF addon and not the Pd object. I tried to compile the Pd object, and got this error:

../../../addons/ofxOfelia/src//../libs/ofxImGui/src/BaseTheme.h:3:10: fatal error: imgui.h: No such file or directory
    3 | #include "imgui.h"

I looke for ofxImGui and found this, which I downloaded and put in the addons directory, but I'm still getting the same error.
I'm on Debian 12, with OF 0.12.0.

If you want to do shell stuff, just install the command external. It's up on deken (Help -> Find externals), just look for "command".

@FFW not really, the [sel 0] has to connect to [f ], like @porres did it. But [mousefilter] is indeed the object for this job. Didn't have that in mind.

@FFW I think you got it wrong, unless [mousestate] has changed with a new release. The left-most outlet of [mousestate] outputs the click state, and the second from left outlet is the X position. If you feed that to [f ], then the latter will output the X position of the mouse, not the slider value. @porres solution is correct, though if we want to take into account the "when I move the slider" part of the OP, then a [change] after [f ] is necessary, like @FFW did.

Try [command], which is an actively maintained replacement of [shell]. [shell] is no longer maintained, and that could be the issue.