Free Software Foundation advice on use of the GPL for Art

Contribute art for mainline Wesnoth.

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xtifr
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Post by xtifr »

I think you'll find that few if any projects which are both GPL'd and include art go to such elaborate lengths. I think that in general, a piece of artwork or an icon is considered eminently editable on its own. Much as one might have a script generated automatically by some tool -- the input provided to the tool is often, but not always, provided. If it's not, well, the script is editable; it's not really an issue.

The point really is to make sure that the users have the ability to modify, fix, and enhance the program as they need. Compiled, binary code is not readily editable by any but a handful of extreme experts. Digital images, however, are editable by anyone with a paint program. The GPL speaks of the "preferred format for editing", but in the case of images, this is quite vague. Jetryl's Photoshop files would be almost useless to me, since I don't have (and do not want) Photoshop. But his completed images I can readily edit with any of the many graphical tools at my disposal. In this case, I would say that the PNGs are the preferred format! :)

I think the wisest advice here is, don't borrow trouble. The artwork is readily editable, and nobody is complaining about their format. And you don't normally recompile the images from multilayered Photoshop or Gimp input files when you build Wesnoth binaries. The PNGs are, effectively, part of the source, and thus, all that's necessary to meet a reasonable reading of the GPL.

As for separate licenses, there's no reason that individual pieces of artwork can't be under any license that's compatible with the GPL (including, if necessary, dual-licenses, like Mozilla). It's only the work as a whole (and, for now, add-ons hosted on official Wesnoth servers) that have to be licensed under the GPL.

And always remember: if it's your art, you own the copyrights, and aren't bound by any license terms. You can even release the same artwork under different licenses at different times, i.e. creative commons for a standalone release, and GPL for the version included in Wesnoth. It's not a problem. Let's please don't make it one. :)
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Post by yobbo »

I hate to butt in on an intelligent discussion about licensing, but I feel that a public repository for the files used to make terrain art at least would be useful. All of the swamp terrain I've done so far (approximately 40 .png files) is derived from a single .xcf file (currently weighing in at under 200kb), and if someone was to tweak or update it it would be much easier if this file was available.

I've looked at the castle tiles a few times with thoughts of adding shading and shadows, but the sheer volume of individual tiles to update (around 400 including keeps, ruins and sunken ruins) would involve a herculean amount of effort. If these images were derived from a few base files, some repitition of work could probably be avoided.

These are in the minority, but in these cases my preferred method of editing the images is definitely not editing the individual .png files.

As a sort of aside, I recently suffered a major hard drive failure. Although I managed to recover most of my personal files, I don't think I can be trusted to keep the gimp files intact for 3 years :?.
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Post by wayfarer »

Who cares I don't use layers and Neorice uses paint!!!
I quess we can't give something out that we don't have.
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Post by scott »

irrevenant wrote:This definition is pretty clear, but the email from the FSF guy confirms that, eg. for GIMP art, this would be the .xcf file.
There's nothing wrong with your reasoning and conclusions. I think the FSF guy is wrong. That might require some gall to say, but it's possible he hasn't thought it through enough since he failed to include a discussion of the relationship of the source code to the binary code for the case of digital images. The FAQ's answer is equally silent. Music might be a completely different story... I'm just surprised that this has not come up before. It definitely has, but if it has then why is there no prepackaged FAQ-like discussion available of image/music "source code"?
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irrevenant
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Post by irrevenant »

wayfarer wrote:Who cares I don't use layers and Neorice uses paint!!!
I quess we can't give something out that we don't have.
Yup! You have to make it available in the preferred working format that you used. For you and Neorice, the distributed .PNG already meets that requirement. The same applies for WML documents.
scott wrote:There's nothing wrong with your reasoning and conclusions. I think the FSF guy is wrong. That might require some gall to say, but it's possible he hasn't thought it through enough since he failed to include a discussion of the relationship of the source code to the binary code for the case of digital images. The FAQ's answer is equally silent. Music might be a completely different story... I'm just surprised that this has not come up before. It definitely has, but if it has then why is there no prepackaged FAQ-like discussion available of image/music "source code"?
It's entirely possible it hasn't come up before because noone else is licencing their art under the GPL. The GPL is not designed to be used with art. It's designed to be used with software and its language is clearly software-oriented.

I actually think "the relationship of the source code to the binary code" is a furphy (and embarassingly, one that I introduced). The relationship between the two is irrelevant. All that really matters for our purposes is "when this licence says 'source code' what does that mean for artworks?". The GPL and FAQ state that it's "the preferred form for making modifications".

To me and the FSF guy, that's clearly the .xcf or equivalent. But neither of us are lawyers. If you can find something that runs counter to that interpretation, that would be very helpful.
xtifr wrote:I think the wisest advice here is, don't borrow trouble. The artwork is readily editable, and nobody is complaining about their format.
As for separate licenses, there's no reason that individual pieces of artwork can't be under any license that's compatible with the GPL
Actually, individual artwork licences don't even have to be GPL-compatible. They're not linked into the program so they don't have to be the same licence as the software.

Yes, I am feeling a bit like Chicken Little, at the moment. But even if there's not a problem now, it's a legal issue that could bite Wesnoth badly in the posterior later down the track.

I would be ecstatic if it turned out I was wrong about this being a problem. I hate messing with something that's working so well (not least 'cos it makes me the bad guy).

But as far as I can tell, I'm not wrong.
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Post by scott »

irrevenant wrote:I actually think "the relationship of the source code to the binary code" is a furphy (and embarassingly, one that I introduced). The relationship between the two is irrelevant. All that really matters for our purposes is "when this licence says 'source code' what does that mean for artworks?". The GPL and FAQ state that it's "the preferred form for making modifications".

To me and the FSF guy, that's clearly the .xcf or equivalent. But neither of us are lawyers. If you can find something that runs counter to that interpretation, that would be very helpful.
By relationship, I was referring to the concept that the source and binary are equivalent. If true, there is no requirement to provide anything else, even if it is used to render the image. There is no basis for you to declare that the xcf is the preferred form for modification other than intuition. Since the image contains internally everything you need to modify it, then there may be no requirement to include outside data. The contention is that the other pixels in the xcf are not part of the image and they are not part of the source any more than extra unused code lying around in your software repository is source code for a particular software product. Since the working form is pixels, and the final form is pixels, having those pixels separated into layers in a different image format is not substantially different than the final form. What's the originator's preferred form for making modifications when it comes to digital photography? If I am required to provide a 3D model file as the source for digital renderings, then equivalently I should be required to provide the source scene for the photo, especially if I go back to it when shooting with new angles or lighting. Same thing for scanned pencil drawings. The license requires source to be in machine readable format. Thus, if there are times when the GPL requirement leads to absurd situations like that then it may be possible that it is completely illegal to use the GPL in those instances... if deciding when this occurs is subjective, inconsistent, or vague, then the license becomes completely unusable. There is a clarity requirement for legal standards, or else they are unenforceable. I guess a summary of my position is that it's all or nothing when the technicalities are fully explored, and that making the source analogy with working files is a natural thing to do but ultimately not correct. Regardless, switching licenses like you advocate could be a great remedy. I will continue to search for instances when other people attempted to answer this question.
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lwa
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Post by lwa »

According the GPL,

Code: Select all

The source code for a work means the preferred form of the work for
making modifications to it.  For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable.  However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.
Now, the questions:

Is photoshop the preferred form of the work for making modifications of the game images ? If it is, as photoshop is not a major operating system component, it must be shared with the source code for any OS where the executable runs. Please, send me photoshop for FreeBSD.

Are photoshop drafts required to control compilation and installation of the executable, and then missing from the complete source code ?
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Post by zookeeper »

What "art" in the game is this about?

If it's about unit graphics, then I'd say that it'd be pretty darn daft to argue whether the final .png is good enough as the "preferred form for making modifications". The graphics are 72x72. If you edit them, it's pushing of pixels anyway, so the layered versions are more of a convenience, and even if the author edits his graphics in such formats, the final flat images are just as good for general modification-making.

For portraits, I agree that I'd prefer to modify them in some sort of layered format, but they're still (usually?) 200x200, which I think is perfectly well modifiable in the final flat form.

Besides, does everyone store their artwork in GIMP/Photoshop/Corel/whatever formats anyway? I have a bunch of unit graphics I've just flattened, stored only the .png's and deleted the layered versions. Might do the same with my portrait edits when I consider them finished.
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Post by Darth Fool »

yobbo wrote: I've looked at the castle tiles a few times with thoughts of adding shading and shadows, but the sheer volume of individual tiles to update (around 400 including keeps, ruins and sunken ruins) would involve a herculean amount of effort. If these images were derived from a few base files, some repitition of work could probably be avoided.
I am not sure about the original castle tiles which were made with the aid of the imploder/exploder scripts along with some image editor (presumably gimp), but the current castle and ruin tiles were done using gimp on the individual pngs. It was quite painful, but since the goal was to have the individual ruin images each unique to avoid repetition destroying the ruined look, it was really quite necessay. Layers would not be of much use.
These are in the minority, but in these cases my preferred method of editing the images is definitely not editing the individual .png files.
I generally agree, but that is a personal preference. I would argue that in the case of Wesnoth, that .png is the preferred file for editing, for the simple fact that we do not all have photoshop, we do not all have gimp, and we do not all have MSPaint. The .png format is one that can be edited by many different editors, where as a .xcf file would not be, nor would a photoshop file.
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Post by Jastiv »

I think we mostly agree that .png is sufficient for editing artwork. .png contains all the important visible information of the artwork in a form that can be read by humans and computers. The problem might come when trying to edit something like a .jpg. .jpgs lose quality every time you save them again. I remember saving stuff as .jpg, editing it, then saving again and being disgusted with the continuing degradation of quality.


This might be a problem with music and .ogg. I think for music we might need .wav format. Also, why are proprietary instrument samples a problem? Someone must have instruments at home and can record the sounds they make, putting the new sounds in the public domain. In fact, someone has probably already done that.
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Post by lwa »

Jastiv wrote: This might be a problem with music and .ogg. I think for music we might need .wav format. Also, why are proprietary instrument samples a problem? Someone must have instruments at home and can record the sounds they make, putting the new sounds in the public domain. In fact, someone has probably already done that.
Sources are computer readable. If I record some animal noises to make an ambient scenario sound, I don't have to supply any beast when asked for.

The main difference between the sources and the work (executable) is that sources are read-write and executables read only. You pass from one to the other form using compiler and scripts. In reality, you can't script the musician play, every band has its own style. It's probably the same for graphic artists with the photoshop layers (sorry if I mistake about that, I've just a rough idea what it could be), two different artists with the same layers set will not produce the same final art.
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Post by xtifr »

irrevenant wrote:Yup! You have to make it available in the preferred working format that you used. For you and Neorice, the distributed .PNG already meets that requirement. The same applies for WML documents.
It doesn't say "the format you used"! It merely says, "the preferred form of the work for making modifications to it". This, in the case of artwork, is ambiguous. If I collaborate with someone on C code, we're both going to be working in C, but if Neo and Jetryl collaborate on a piece of art, which format would be "preferred"?

And again, I'd like to point out that creators/copyright-holders are not bound by the terms of the license! If Jetryl releases a PNG under the GPL, he is effectively suggesting that PNG is the preferred format, even if that's not what he actually used himself!

For that matter, someone might prefer to edit C code using a word processor, with keywords rendered in a different font. But this would not make the word processor's format the preferred format for making modifications, even for code that person wrote!

Once again, I strongly suggest that the Wesnoth project not borrow trouble here. There are thousands of GPL'd projects that use art, and, as far as I know, basically none of them provide their art in any special format. Since none of us are lawyers (I assume), and therefore none of us are qualified to give legal advice to anyone, I think the best bet is to follow precedent in this matter. It's not an issue at present, let's not make it into one, and possibly cause trouble for all those thousands of existing projects!

p.s. I also wrote code using the Apple II ROM monitor in my day. I also wrote my own assember for several systems, and was, at one time, fluent enough in both 6502 and 8088 machine language to be able to more-or-less sight-read hex dumps. But I'm mostly thankful I don't have to do that kind of junk any more. :)
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Post by irrevenant »

lwa wrote:According the GPL,

Code: Select all

The source code for a work means the preferred form of the work for making modifications to it.  For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable.  However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
Now, the questions:

Is photoshop the preferred form of the work for making modifications of the game images ? If it is, as photoshop is not a major operating system component, it must be shared with the source code for any OS where the executable runs. Please, send me photoshop for FreeBSD.

Are photoshop drafts required to control compilation and installation of the executable, and then missing from the complete source code ?
The third sentence is a continuation of the second sentence, which is talking about executables. As art is not executable, the first sentence is the only one of the above that's relevant to our purposes. Also, you've confused two different meanings of 'photoshop' - it's the photoshop format that is required, not the photoshop software.
zookeeper wrote:For portraits, I agree that I'd prefer to modify them in some sort of layered format, but they're still (usually?) 200x200, which I think is perfectly well modifiable in the final flat form.
You've put your finger precisely on the point of contention: It's modifiable in that form, but is it the 'preferred' form for modification (which is what is legally required).
zookeeper wrote:Besides, does everyone store their artwork in GIMP/Photoshop/Corel/whatever formats anyway? I have a bunch of unit graphics I've just flattened, stored only the .png's and deleted the layered versions. Might do the same with my portrait edits when I consider them finished.
By releasing the art under the GPL, you've agreed to provide the 'preferred form' on request. Destroying the preferred form would be a violation of that agreement - the equivalent of Dave going "oops, I accidentally destroyed the Wesnoth source code - you can only have the binaries after all".

Of course, this is only an issue if I & the FSF guy have interpretted 'preferred form' correctly. If the artwork itself is the preferred form, there's no problem.
Jastiv wrote:Also, why are proprietary instrument samples a problem?
Honestly, I don't follow what the FSF guy is saying re: proprietary samples so I wrote to clarify.

The music licencing issue really is the same as the art licencing issue with a few additional wrinkles, so it makes sense to get the art issue ('preferred form') sorted out first.

(Although if I & FSF guy are right about preferred form, there may be an analogous issue re: use of non-GPL textures in GPLed art).

I don't suppose anyone knows a lawyer who could clear this all up?
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Post by lwa »

irrevenant wrote:The third sentence is a continuation of the second sentence, which is talking about executables. As art is not executable, the first sentence is the only one of the above that's relevant to our purposes.
I didn't talked about executables but GPL work, like the licence.
irrevenant wrote: Also, you've confused two different meanings of 'photoshop' - it's the photoshop format that is required, not the photoshop software.
Both. photoshop is required to use photoshop format. A script or a tool has to be released to compile from source on any supported OS.
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Post by turin »

lwa wrote:
irrevenant wrote: Also, you've confused two different meanings of 'photoshop' - it's the photoshop format that is required, not the photoshop software.
Both. photoshop is required to use photoshop format. A script or a tool has to be released to compile from source on any supported OS.
First of all, that's not true. I'm pretty sure the GIMP can read .psd files. But, in any case, it shouldn't matter. If there are no compilers other than proprietary ones than can compile code written in Whatsome*, does that mean it is impossible to release programs written in Whatsome under the GPL? I don't think so!


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