How to build a printer

(nishantjosh.dev)

385 points | by cat-whisperer 15 hours ago

19 comments

  • ValdikSS 11 hours ago
    >penguin would shrink the result to fit its screen. >I declared A5 and Letter paper, media type stationery, and an output bin called face-up.

    You can (and should!) define exact dimensions of your screen in `media-size-supported`. It will probably be a non-standard IPP name, that's why you should define that in `media-supported` as `om_NNNmmxYYYmm` or `oe_NNNinxYYYin`

    That way you don't need to scale the incoming data, the PC will format it exactly to the dimensions of the screen.

    Both PWG Raster and Apple Raster support 1-bit-per-pixel mode (instead of 8-bit-per-pixel you use), that's why the input could be 8 times less in size. Use `print-color-mode-{supported,default}=bi-level` instead of `monochrome` for that. And also tune `urf-supported`'s `W` option, use `W1` for this case.

    The screen/dithering could be ass in 1-bit mode, see https://github.com/OpenPrinting/libcupsfilters/pull/160 where I added more dithering options (Linux-only though, Apple seems to abandon their CUPS).

    • Neywiny 11 hours ago
      This is why I like it here. Somebody does irrefutably incredible work outside of their comfort zone, and somebody else goes "yeah actually I was born in that zone. Moulded by it. Here's how to improve it" (in a positive way)
      • ValdikSS 10 hours ago
        Oh no, I wasn't, and that's definitely not my comfort zone. I mess with the printers and printing stack due to anger, not because I like it.

        It's bugs on bugs, with bugs chasing bugs! So little developers, so complex stack with 25 years of technical debt, and little community around because it's not a sexy technology to be involved in.

        That's why I have to dive deep and fix my bugs myself if I want to make it work properly as I would like it to. I also ended up making my own print server device, because China did not make a proper one for some reason for all these years.

        • lopis 6 hours ago
          Anger is the only valid emotion when dealing with printers.
          • TheMiller 22 minutes ago
            This thread made me laugh. I worked on network printing software in Banyan VINES a century or two ago, and my wife always wondered why I hated printing software so much. Everything about the printing software stack, especially in Windows, is terrible.
          • actionfromafar 2 hours ago
            PC Load Letter?
        • Neywiny 2 hours ago
          Hey sadly this stuff doesn't ask for consent when it makes you an expert. Everybody hates printers, only a few make their own print server device
        • edoceo 8 hours ago
          That's even cooler
          • quijoteuniv 6 hours ago
            Same feeling when family or friends ask me for help with Micros word about formatting, tables or inserting pictures in the last 25 years….
    • cat-whisperer 11 hours ago
      lovely, this would save me a bunch of memory during transformation and dithering. Will do!
    • darkvision77 5 hours ago
      > Use `print-color-mode-{supported,default}=bi-level` instead of `monochrome` for that

      The last time I checked (a year ago), 1bpp was suddenly supported only by Windows. IIRC, monochrome is REQUIRED, while bi-level is OPTIONAL in RFC.

      Not sure how things stand now, though. Ever since then, I've just been carrying Floyd–Steinberg dithering around.

  • alternativeworl 11 hours ago
    Very cool. I was expecting to learn about the ins and outs of ink, printheads etc but instead learned "How to build a paper that acts like a printer" which turned out much more entertaining.
    • a3w 3 hours ago
      Wanted ideas on how to build an ink printer that is untraceable. For privacy reasons.
      • NooneAtAll3 1 hour ago
        I wonder why we don't see slow-but-actually-works approaches that reuse 3d-printer hardware

        just put a pen or sharpie on the same mechanism, no?

        • amoshebb 1 hour ago
          This is called a 'plotter', there's a whole community of axi-draw enthusiasts making cool art, for 200 bones you can probably have one on your doorstep tomorrow
    • cat-whisperer 10 hours ago
      glad you liked it!
  • pimterry 4 hours ago
    This would be a neat API for a digital photo frame - just print photos to it and they appear on the screen.
    • spwa4 1 hour ago
      And then maybe different pages become a slideshow.
    • cat-whisperer 4 hours ago
      yes!!
  • tapia 7 hours ago
    In Linux it's pretty easy to create such things with cups. A while ago I did a cups backend for my Fujitsu Quaderno A4 [1]. It is super useful to be able to just open any document, in any program that supports printing, and then just "print" it to my device.

    [1] https://github.com/cristobaltapia/dpt-rp1-cups

    • IdiotSavage 7 hours ago
      > any program that supports printing

      Unfortunately printing support seems to go out of fashion, at least in macOS land.

      Lately I needed a quick printout of a markdown document. I could have used TextEdit for the raw text, but I wanted the styling too. Learned that neither VSCode, Xcode nor Obsidian can print. (There is a community plugin for Obsidian.)

      • rrr_oh_man 6 hours ago
        LOL. TIL you can’t print from VSCode.
        • maybewhenthesun 5 hours ago
          printing has never really been a thing from text editors I think.

          Used to be that printing a text file was just `cat myfile.txt > /dev/lp0` .

          It has been a while since I printed a plain text file, but I guess there's still a similar command available with some research.

          • geocar 52 minutes ago
            > printing has never really been a thing from text editors I think.

            It's always been a thing: We programmed on paper before we had screen editors, and so early screen editors have always had a way to murder trees on demand:

            In vi it's :ha

            In emacs it's M-x print-buffer

            > It has been a while since I printed a plain text file, but I guess there's still a similar command available with some research.

            `lp myfile.txt`

            I still prefer using hardcopy for reading/debugging.

          • namibj 2 hours ago
            I think back in the days before office workers that happened to do their work on a computer had access to the ancient relatives of "Microsoft Word"/"Libreoffice Writer", it was pretty normal for printers to take care of plain text files, with about as much fidelity as manual operation of a classic purely mechanical Typewriter.

            Since then printers progressively forgot how to cope with such "documents", though IIRC good-old HP "PCL" should only require about a bare minimum of framing/job control to get a modern printer to handle ASCII plain text.

          • NooneAtAll3 38 minutes ago
            > printing has never really been a thing from text editors I think.

            there's literally ctrl+p shortcut for printing

          • IdiotSavage 3 hours ago
            TextEdit.app supports printing, so does Notepad.exe (unless they removed that recently).
          • voidUpdate 4 hours ago
            I've done the same from a raspberry pi to a receipt printer, just piping to lp0
          • ptman 3 hours ago
            vim/nvim at least have :print
        • simonjgreen 6 hours ago
          Or Obsidian
  • kitd 5 hours ago
    Good article.

    One of the great things about having an open platform like the Xteink is that it should uncover loads of novel and unsatisfied use cases. Eg, this could be paired with a mobile phone to act as a secondary display much better suited to outdoor applications in bright sunlight.

    • utopiah 2 hours ago
      working on an daily life ePub generator (because I want to stick to CrossPoint) with the opposite goal, namely use the phone as little as possible, but I admit I would also like to tinker with an additional temporary display, at least for typing
  • yeasin-arafat 5 hours ago
    Emulating a network printer to send pages to an e-ink screen is such a clever hack. Every OS already has the print dialog built in.
    • conorcleary 2 hours ago
      Just like print-to-pdf is (one of many) peeves of adobe's
  • ks2048 12 hours ago
    Good job, but I’m left wanting to know how to build a printer.
    • tdeck 9 hours ago
      If a DIY plotter would do, this site has a long list of different projects

      https://mattwidmann.net/notes/pen-plotters/

      • voxelghost 6 hours ago
        What if I want a cabinet sized rotating head printer that can print carbonpaper triplets, sounds a machinegun, and has LP0 ON FIRE error message
    • jfsebastian 2 hours ago
      As far as I can remember, framework has this still on their schedule. So sooner or later you maybe can at least have a well maintainable one.
    • cat-whisperer 12 hours ago
      I'd say it's an eco-friendly printer
    • d--b 8 hours ago
      There is an open source one https://www.opentools.studio
      • zxexz 6 hours ago
        How is that open source? There’s not a single line of code. No CAD. Nothing. Sure, there’s a “coming soon” CrowdSupply link, which I guess is more than a KickStarter. But open source?
        • utopiah 2 hours ago
          Fair enough but I trust CrowdSupply to keep them in check. I bought quite a few projects via CS and never been disappointed. They have too much trust from the community not to follow up, it's their most important differentiator versus KickStarter and other crowdfunding platforms.
        • d--b 4 hours ago
          Ah sorry, I thought they were already open source. They say they will open source it once they finalize the design, but yeah, not there yet.
  • jiehong 7 hours ago
    Pretty cool work! And it’s nice to see printer discovery works through the standard mDNS!

    Regarding the size of the page being sent to the printer, I remember reading that printers used to be postscript interpreters and the result of that program would be the page.

    Perhaps that would trade ram for compute, but might be more complex in the end.

  • e12e 8 hours ago
    Nice. I keep wondering if these devices would play nicer with DjVu rather than pdfs and raster formats?

    https://djvu.sourceforge.net/

    • namibj 1 hour ago
      For fast updates / high frame rate, especially also smooth fade from previous to next page, those displays only do black/white. They can typically modulate about 14 levels of gray in-between but reliably (without really bad ghosting, due to strong temperature sensitivity of the pixel's transition response and the display being static so all gray has to be done by carefully interrupting a transition part way through) only from a nice flash-to-black -> flash-to-white -> fade-to-target-greyscale (sometimes one or two alternating full contrast flashes prepended to more intensely equalize the pixels/erase ghosting, but should only be needed every couple dozen page flips in grayscale mode).

      I think the nice b/w no-flicker fade transitions chop the transitioning of all changing pixels into small burst/chunks and interleave/alternate the chunks of white-to-black with the chunks of black-to-white, so it's perceptually simultaneous. Or it's actually pulling off some kind of tri-state driving leaving unchanging pixels alone and pulling those that change to either plus or minus polarity depending on what transition direction they are supposed to go in... Sadly IIRC all quite proprietary-gated :(

      What that means for djvu is that at least for text-only content on those readers that manage the 300 dpi "threshold" you'd just rasterize to pure 300dpi black/white (1 bit per pixel) comparable to a 300dpi "don't skimp on toner but don't you dare take half a second longer than you must in order to make the text crisp enough for $reader to have no good reason to whine about it being not crisp enough" laser printer job.

      Djvu is particularly for displays with more than about 5bits of grayscale as well as for lossy compression of grayscale/color scans. And maybe also some efficiency gains on 1-bit-per-pixel quantized scans, but those aren't usually the target content for these readers, IMO. Might want to try for them, though!

      • e12e 1 hour ago
        Hm.. I just tried on my Google pixel 7 Pro (obviously very different display - OLED) - and certainly seems like the result of a test conversion pdf2djvu should be at home on an eink screen. Not sure if there's a simple way to test on the only eink I have to hand; a Remarkable.

        Fwiw google Gemini cane up with the following to convert pdfs on device in termux after some prodding (koreader can display DjVu):

        You'll need access to storage:

        termux-setup-storage

        Then pipe/paste this to a script: (Sorry for the verbose slop)

        Ed: moved to sibling comment

        • e12e 1 hour ago
          [flagged]
  • jarboot 13 hours ago
    This is amazing!!! It just makes sense. And its just how you would want to use a e reader.
  • joshmarinacci 12 hours ago
    I love the concept, but I wonder why he wasn’t printing to PDF. Can this device not render PDFs?
    • ValdikSS 11 hours ago
      PDF is very, very complicated standard which can't be handled properly on tiny MCUs with reasonable performance and spec conformance:

          - 4 font formats
          - 9 image formats
          - blending with transparency
          - different colorspaces, each image could use its own on the page
          - different dithering algorithms, each image with its own
          - the page can have elements from another pages (global elements)
      
      This is only a small part from the top of my head.

      Common simple home printers absolutely should not accept regular PDF as an input: thanks to Apple and IETF we now have Apple Raster and PWG Raster for printers, as a part of AirPrint and IPP Everywhere/Mopria driverless printing standards, which are very similar but have slightly different options and headers. It's a simple raster input for printers specifically.

      Some companies, such as HP, invented a "raster PDF": PCLm / PCLms. Don't be confused by the name, it's a regular standard-conforming PDF which contain nothing but a full-page JPEG on each page, and don't use any other features. It's created only to be able to open "printed page" (driver output) in a standard PDF viewer on a PC for debugging or business logging needs, but otherwise it's like a regular JPEG with additional per-page metadata.

    • cat-whisperer 12 hours ago
      I was thinking of this, but rendering PDF takes a lot out of a 400KB RAM'd device. It also needs a ton of things to actually work which the ROM can't hold.

      Kindles have a ton of RAM, this one didn't.

      • conorcleary 2 hours ago
        I'm sure there's a super trimmed down linux pdf reader that could be ported over
    • utopiah 2 hours ago
      CrossPoint at least only support ePub and BMP so they could have printed to a directory of BMPs.
    • bluGill 12 hours ago
      Probably not. It doesn't appear to have enough ram. I'm not sure the CPU is up to that either.
  • greazy 12 hours ago
    I don't understand the purpose. What am I missing?

    The author "prints" to the eink display. Why not load say the pdf directly?

    • sowbug 8 hours ago
      I've wanted something like this for a long time to print recipes that I'm about to cook. I don't want my phone in the kitchen getting gunk on it, so I'll usually print on paper, get the gunk on the paper, and then throw it out.

      I'm not going to create a recipe PDF and load it on an e-reader. That's too much work. But I will happily press control-P on a recipe web page and select the eink display as the target.

      • greazy 4 hours ago
        Right! I like this usecase very much. For uses existing software infra to perform the required task.

        I wonder now what else we've reinvented when it comes to sending data...

      • cat-whisperer 8 hours ago
        I am no cook, but you my friend are cooking something here
    • stdatomic 12 hours ago
      From the 4th line in the article:

      > But getting stuff onto it was tedious. I had to join its hotspot and open a little upload website in my browser. Yuck.

      Anyway, very creative, I like the idea a lot.

    • cat-whisperer 12 hours ago
      > I was thinking of this, but rendering PDF takes a lot out of a 400KB RAM'd device. It also needs a ton of things to actually work which the ROM can't hold.

      > Kindles have a ton of RAM, this one didn't.

      • ghostly_s 11 hours ago
        It's an e-reader. According to the specs it has native support for PDF.
        • mrheosuper 10 hours ago
          It's an esp32 MCU, even if it can somehow run the PDF render pipeline, it won't be more ideal than just accept the raw byte stream and display.
    • maybewhenthesun 5 hours ago
      I'd like my e-reader to show up as a printer, and when I print something on it it actually gets saved as a pdf on the reader. Like in the article, but multi-page pdf.

      I often do 'print to A5 pdf => copy pdf to e-reader'. Would be nice to do that in one step from any program that can print.

  • stavros 13 hours ago
    I've been seeing the Xteink a lot lately. Should I get an X3 or an X4? I don't really know why I want it, but I have an eInk addiction, so I just need it.
    • a2dam 13 hours ago
      I've owned all of them and the answer is the X4 Pro IMO. It has a backlight, which is the only thing I really missed on the others.
    • cat-whisperer 13 hours ago
      It's funny that X3 is a successor of X4. Only downside is that X4 has a USB-C port and X3 doesn't
      • stavros 12 hours ago
        What about the back light? Are they otherwise identical?
        • cat-whisperer 12 hours ago
          X3 isn't backlit, but the battery lasts 7 days. So, it's pretty good for me
    • hamaluik 12 hours ago
      I bought an x4 a month or so ago, zero regrets. It sounds hyperbolic but it’s finally been the thing to actually decouple me from my phone. Whenever I’m out and about, bored, I just slide it out and pick up where I left off reading last. It’s a nicer reading experience on my kobo but the portability and.. frankly charm just can’t be beat.
  • sho_hn 13 hours ago
    This is a fantastic idea!
  • Wilson2000 3 hours ago
    Love this!
  • NDlurker 12 hours ago
    Very cool. I'll be updating to this fork
    • cat-whisperer 12 hours ago
      Thanks. It's rough around the edges, so PRs are open, and there's a recipe in the repo if you want to build your own apps.
  • andyfilms1 13 hours ago
    We finally have PADDs from Star Trek!
  • Brian_K_White 14 hours ago
    Outstanding! This is so...correct.
  • phoenixtao 9 hours ago
    [dead]