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Em 19-11-2012 19:46, Graeme Gill
escreveu:
drawoc wrote:If you simply open a jpeg, and then save it as a jpeg without modification, you will lose data. Jpeg is always lossy. More compression artifacts will be introduced in the saved image. There is no sane way to avoid this behavior.Technically that's true (but see below), but have you actually seen this ? Given a certain moderate compression ratio, how many open/slight edit/save cycles does it take before you can visually notice that the quality is worse than what you started with ? 2 ? 5 ? 10 ?If you allow the user to save back to jpeg, then you will not "honour the quality/file size trade-off" because the user will be slowly destroying their image every time they save and re-open.It turns out that (typically) open/save of a jpeg does not cause a steady decrease in quality, instead it asymptotes to a steady state. That's because once DCT coefficients have been quantised, they tend to get re-quantised to the same values. There is no question that a lossily compressed format is not what you want to use to create original artwork or do high quality editing or re-purposing, but I think I can be confident that the vast majority of image use is casual and non critical and in the jpeg format - all those billions of digital photo's taken every day by ordinary people.We're not saying that you can't slowly destroy your image - you still have the freedom to do that. We just want you to click a single button that says, "yes, I want to destroy my image", if you really do like destroying images.But you're saving to a lossy compressed file format - by doing that you have made that choice. Having a nag telling you all the time that "you do realise that jpeg is lossy, don't you?" seems fairly pointless. Graeme Gill. _______________________________________________ gimp-developer-list mailing list gimp-developer-list gnome org https://mail.gnome.org/mailman/listinfo/gimp-developer-list Well, I have a couple of opinions of my own for why I liked the new workflow. Supose you are using Blender. Blender is a 3d modeller. 3d files aren't image files, so the default save is for a 3d Blender file. While you have a lot of ways for exporting it - you can render and export an image, or even export to a 3d file format different than the native Blender one. Basically, this is the same for Gimp - XCF files are not regular image files, they're Gimp files. So, like in Blender, you save the program's data on a program's file, while the export generates files that are for viewing or interchanging. If you create a Blender file, export an image and try to close it, you will receive an alert message (ok, bad example. Blender by default don't ever asks if you really want to close the program before saving. But that feature is already implemented for windows and there's progress to another platforms too. I think that not asking is really really bad... the default behavior *should* be asking, even with the auto-save I think. You got the point, I guess :P). So I was already familiarized with this way of doing things when the change came. I guess Inkscape have this same behavior (and would be a very better example, because it do ask before closing :P). Also, I nearly always save a file that I edited, even if it's for small changes. I usually keep the .xcf and the export image in the same folder. It's like a posture, an attitude. I don't rely on myself on doing things right every time, because I am a human being. So I prefer to choose the caution way, and I think this is the most secure workflow. Of course, not everyone have to work the way I do, or plan things the same way I do... But if a software would have to choose for the default way of action, it should be the way with more caution. So, for advanced users, why wouldn't it be possible to just making Gimp stop asking if you want to save an exported image? Well, if you think about the Blender and Inkscape case, the answer would be obvious - if you exported an image, you didn't saved the blender/svg/xcf file. So having that option native in the software would be a conceptual mistake by the developers. It cannot be there while Gimp makes that file differentiation. So, if the message box is *really* getting in the way of your workflow, you can uncheck the "Confirm closing of unsaved images" box in the Environment preferences. When you change to an important .xcf file, you check it back again. It's a little confusing I guess, but at least it would let you export files without being annoyed - I am suposing that you and the users that like the 2.6 behavior do a lot of quick edits instead of spending reasonable amounts of time editing the images. I might be wrong. So, for closing my arguments, I think it would not be hard to do a script that checks and unchecks that save confirmation preference for you when you open a .xcf file and a common image file. That would solve the problem AND be conceptually correct, at least in my humble point of view (I might be wrong with the "easy to do script" part :P ). BUT it cannot be native to the software, that is conceptually incorrect - at least in my way of seeing things. Well, I made my attempt in providing a solution... Hope that helped in some way :) Regards to all, -- Thiago |