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QImage linux integration is lacking

  • I get the impression that QImage exists in a linux vacuum.

    Please excuse me, I'm new here, driven along by frustration. Maybe my skillset is lacking, but I see nothing as yet on the forum here that echoes my concerns. I find that disturbing.

    I do see tags here related to (some) "linux", but nothing tagging major pertinent linux apps.

    For a start, consider the most basic of standards evident to the very beginner.

    QImage files arrive at my browser and are downloaded with names something like "main-qimg-salad".

    Everyone else (everyone else?) seems to designate file-types as a dot-suffix.
    I can't imagine this idiosyncratic iconoclastic new standard not causing problems.

    The .filetype thing is somewhat conventional (a convention no-where near as bad as time-wasting as "http://").

    I suspect that having a standard layout where the suffix indicates type, makes processing easier in some respects - both to define how one treats the format, but also because the main designation on the left of the item-name can be usefully sorted, sequenced. It's something users and system developers are familiar with and which fits in with their customary way of working. something QImage breaks.

    Here, Qt/QImage is different, eccentric.
    I shouldn't say barmy; it may be simply be something that hasn't been explained to me, or certainly that I haven't looked into sufficiently. Or it may be something limiting.

    Is Qt intent on changing the world for the sake of it, or just indulging in self-regarding disruption? I'm mildly curious.

    To move on to my immediate concern: I have problems seeing QImages in linux. in the GNU/linux world, there are some widely used file-managers and image viewers, image editors, image handlers. I use them.

    Frustratingly, whilst QImages arrive at my browser(s) and display graciously in the browser environment, if I download them, there the politeness stops. (What was it about minding "p"s and "q"s? - Pease play nicely with the others, thankyou.)

    My file-manager (which happens to be nautilus) displays any main-qimg-salad file as an uncommunicative icon of a green music sheet. Piece of useless sheet, to be frank. With MIME-type "audio/xriff", for some reason that eludes me, whereas other images have MIME-type "image". Perhaps it's just that they're a little difficult to recognise, not having a proper suffix. The reason may be obvious to a developer immersed in coding, though I doubt intuitive in the wider sense. (At this stage I no longer do systems QA and such, I'm a mere user.)

    For .jpg and .png files, and so on - all the other image files I generally see - there's a practicable thumbnail image by default.
    Does QImage have thumbnails? They are very useful. Especially if integrated with the user interface.

    You know, it would be so much better if the world were perfect and linux file-managers (of which there are several) could cope with qimg in a similar way to all the other images they manage so well.

    To me, this seems to indicate that the Qt community is perhaps not properly engaging with others in a pro-active manner. Am I being too harsh? I don't see these failings as a purely linux matter, but that's just my opinion.

    I see a need for progenitors of QImage to go out and help, if only so that my life can be a little more comfortable.

    Or, the least you could do is to make things really really ridiculously easy for linux app devs. I'm sure that GNU/linux application developers already have enough to do. Whatever, something is failing along the way, and the qimg files I see don't play nicely with linux.

    Linux also has a number of image viewers and editors and so on (some of which can do format conversion). A most popular viewer is EOG (Eye of Gnome).
    EOG does not recognise the qimg format, which is a bit of a pain. Ditto GIMP.

    I cannot view downloaded qimg images except with a web browser. I have to work around. I am unhappy.

    It would be splendid if everything "just worked" between .qimg elements (sic) and the majority of linux applications, through foresight and liaison with all concerned.


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    What is that .qimg file you have ?

    QImage is a class for manipulating pixels of an image loaded. The formats supported varies but you can find a list here Other formats can be added later.

  • Moderators

    Hi @I-d-na,

    To clarify @SGaist's point:

    • QImage is not an image format. It is a C++ class that lets C++ programmers manipulate images.
    • A QImage cannot be downloaded over the internet. A QImage can only exist in a program that's written with Qt.
    • File names like "main-qimg-salad" are not related to QImage. (Yes, I know the both start with a 'Q' and end with "image/"img", but really: they are not related at all.)

    Now that we've cleared that up, let's get to the root of your problem. If you download a file and it's called "main-qimg-salad", it simply means that the server gave it a filename that starts with "main-qimg", but the server neglected to include the .filetype extension at the end. Therefore, we can't tell what type of image it is. See https://www.quora.com/Why-do-we-get-main-qimg-e7b0b4951d663c737e5bbf2722d23612-jpg-types-of-saving-titles-when-we-download-images-from-the-Internet for a discussion of this naming system.

    If you search https://www.google.com/search?q="main-qimg" you will find that most of these images are actually JPEG files. So, try renaming your file from "main-qimg-salad" to "main-qimg-salad.jpg" and see what happens.

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