XScreenSaver for iOS now available in the App Store!


I don't know which of you managed to change their minds, but to all of you who tried, thank you very much!

I hope you enjoy it. Let me know how it works.

Previously, previously, previously and most especially previously.

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78 Responses:

  1. Lun Esex says:

    Quickly mashing on the "Download" button, in case they change their minds...

    (Like I was one of the lucky few to get the VLC iOS port before it was pulled.)

  2. Edouard says:

    Sweet! Running through them now.

  3. Roger says:

    It works for me (iOS 5.1, iPod Touch 4g). I had to type the whole name in the seach box before it showed up.

    The web page linked to from inside the app doesn't mention iOS at all.

    As a feature request I would like to be able to sort on something other than name, including date and style/category.

    TronBit crashed on me. Hopefully you'll get some sort of report.

    Some are very low framerate on this device. For example Wormhole seems to be around 2fps. (The vast majority have good performance.)

    XAnalogTV asked to use my location - presumably it actually want to use my photos but never appeared to do so. It also runs around 1-2fps.

    It isn't apparent where the text for StarWars comes from.

    It all seems somewhat unstable. Often the app would exit back to the desktop on trying to run an item. If I started it back up the exact same one ran just fine.

    • David M.A. says:

      Interestingly, TronBit worked just fine for me, but Superquadrics crashed complaining of an invalid framebuffer. Rebooting the app fixed it. iPad 3 here, iOS 5.1.

      Finally, an app comes along that justifies how much I spent on this thing.

    • jwz says:

      I just updated the web page, I can only type so fast!

      It does not send crash reports to me, but if it crashed without an "oops" dialog popping up, the most likely reason is that it was out of memory. Unfortunately the savers are not good at cleaning up after themselves, because for most of their existence "cleanup" was "SIGTERM".

      Most of the X11 ones are pokey. Performance is better with the GL ones. Yes, this is ironic.

      When it asks for location, it's really asking for photos (which may have EXIF GPS data in them, which it doesn't use). XAnalogTV will show photos on some of the "channels" as they cycle through.

      Hit the disclosure arrow on StarWars (or any of them) to set the text source.

      • Roger says:

        I didn't realise the arrow did anything - just assumed it started the relevant saver rather than bringing up settings for that one (ie no different than clicking anywhere else on the line). If this is normal iOS UI then it is my fault for not knowing better, otherwise I'd suggest an icon more indicative of settings (eg cogs).

        I use analytics in my apps to get a good picture of what has been going on. However they won't be useful when you run out of memory since events are saved into a SQLite database for later network dispatch, and that requires (more) memory.

        A real hacker would solve the memory leak problem by stunts like saving the brk(2) value before starting a saver, and then restoring it afterwards :-) One of them hierarchical pool allocators would also work and be less brittle. Yes I am aware I'm suggesting more work for you.

        • jwz says:

          I'm told that the way I am using the so-called "disclosure arrow" is, in fact, the Party Line, though I also don't recall having seen them used that way before. I dunno. It's not the most obvious thing, but I can't think of a clearer way, since my first attempt -- select the line, then hit a "Run" or "Options" button up top -- is definitely not the Party Line. And it kinda sucked.

          I considered playing malloc games like that (thus my questions about heap tricks over here) but decided that it was probably going to just end up being destabilizing and more trouble than it was worth. If there was a true save/restore that would also smack global variables back to their default state, that would help, but there's not. Putting each of them into their own full process (not thread) is the level of separation they expect, but I think not practical on iOS.

          The other option is go through and run each and every hack under a profiler and make sure they actually free all their data at close, but does that sound like fun to you? Because to me it kinda sounds like the other thing.

          • James says:

            This method of getting a new process (with both answer comments from 'tc') is amusing, but it probably takes too long and is completely opposed to the Party Line -- calling exit(0) is grounds for rejection, even.

          • Frode M says:

            The disclosure arrow button is used in the built-in phone app to bring up contact details (instead of calling the person, which happens if you click anywhere else on the row). Not very intuitive.

            • Lun Esex says:

              In the Contacts list there are no blue arrows, and tapping on a row takes you to the contact details. Where blue arrows show up, in Favorites, Recents, and Voicemail, tapping a row initiates a call to that person/number.

              So XScreenSaver is fully consistent with this "tap the row to activate, tap the blue arrow to get more details" convention.

              A more ambitious UI on the iPad would for it to be more like the Settings app, with the list of savers on the left and then the settings for an individual saver showing up on the right--but then it'd need an "Activate" button because tapping a row would just show that saver's settings. There could be a preview view above the settings, though (like the screensavers have in Mac OS X System Preferences)--double-tapping the preview or hitting a "Full Screen" button below it would make it take over the screen... Up to Jaime whether he thinks it'd all be worth the effort, and I wouldn't be surprised if he didn't.

      • Colin says:

        Actually FWIW, when apps crash reports are sent to Apple and are accessible from your iTunes Connect account. I just forget exactly where to find them.

      • crowding says:

        >Most of the X11 ones are pokey. Performance is better with the GL ones. Yes, this is ironic.

        Especially since the GL ones are rendering at full resolution on an iPad 3 and the X11 ones seem to be rendering at half resolution and upsampling.

        CubicGrid and surfaces look stunning enough that I want to see what flame/ifs/moire/strange et al do at 260ppi.

        (thank you for all of the work you've done/bullshit you've put up with here.)

      • thielges says:

        I'm curious why location services need to be enabled in order to draw images from the photo library. Existence of GPS EXIF info (whether used or not) seems to be irrelevant. Is this requirement an Apple thang or specific to XScreensaver?

        Thanks for putting the effort to get this out. It is like carrying a little piece of the CHM around in the pocket. I can tell that it will be a lot of fun.

        • jwz says:

          Yeah, it's an Apple thing. That happens automatically when you request an image from the Photo Gallery, presumably on the off chance that one of them has EXIF location data inside it. I suppose they could avoid this warning by stripping the EXIF before returning the raw image to the caller, but they don't.

          • thielges says:

            OK I see, Apple is just being extra cautious about releasing location info even if via an inferred roundabout path:

            if (exif.camera == iPhone) and (exif.dateTime =~ currentDateTime()) and exif.location:
            location = exif.location

    • Edouard says:

      The shading on Superquadratics seems wrong - you can see it when the check pattern has both colours the same.

  4. Andreas says:

    Yay, amazing. I'm using it now, and it looks pretty great. Looks like an aged app, in fact. Must be the color on the top bar (-:

    Would love to filter out the GL/non-GL savers and fractal/non-fractal related ones, but I guess tagging them is a lot of work. Great stuff, at any rate.

  5. cpk says:


    now I can show my friends and they'll be all like, "great, that's neat, I'm busy"

  6. kvance says:

    TronBit also fails on my iPad (3rd generation) with "framebuffer unsupported".

    I got Pipes to segfault once, but haven't been able to do it again.

    TimeTunnel runs for like 10 seconds, black screen for 20 seconds, then restarts.

  7. Edouard says:

    Video Mirroring to an Apple TV works fine, without any loss of performance that I can see on the ones I've tried so far.

    • Ryan Finnie says:

      I have an iPhone 4 and an original iPad, neither of which are blessed by Apple to do full-environment mirroring, so AirPlay doesn't do anything.

      jwz, would it be hard to add explicit AirPlay video support? I know it's possible for third-party apps (Netflix, for example), but I suspect demons.

      • Tim says:

        AirPlay mirroring sends a H.264 stream to an AppleTV. Encoding H.264 in software is Hard. Probably more like "Impossible" with the relatively weak ARM CPUs in iOS devices.

        The A5 System-on-Chip used in the iPad 2 and iPhone 4S definitely has a suitable hardware encoder. I'd guess the A4 SoC in the original iPad and iPhone 4 does not. It's not about being blessed, it's about hardware capability. (I'm pretty doubtful about your statement that it's possible for 3rd party apps like Netflix to do it. Last I saw, Netflix simply streams Netflix video directly to your AppleTV, so there's never any point in making an iPhone or iPad play middleman.)

        So no, it's probably not possible for jwz to do that.

        • Ryan Finnie says:

          Sorry, I was mentally conflating AirPlay with the ability to connect the device via HDMI to a TV and stream Netflix that way.

          Apple's own video app has the ability to send video from the device to the AppleTV via AirPlay, but in light of what you said above, I assume it's only streaming the raw H.264, as opposed to transcoding.

  8. Edouard says:

    Tronbit works on my iPad 3, but most of the GL hacks crash after running about 8 in a row

  9. Greg Day says:

    It is a great day when I can AirPlay BouncingCow to my HDTV.

  10. Nate says:

    Did you consider making each screensaver a 99 cent in-app purchase? :)

  11. Eric TF Bat says:

    Wait - so you're saying my as-yet-unposted suggestion of producing a large bunch of separate apps translated into Java for Android and renamed "ZawinskiHack" won't be required after all? Damn! I was so sure you'd go for it!

  12. Andrew says:

    Congrats! I guess that TCook guy must have some pull there after all

  13. David M.A. says:

    Which ones are touch-interactive? I noticed Sonar was, and was rather surprised by it...

  14. Kevin says:

    XAnalogTV asked for my location, and then promptly crashed.

    Feature request: Random.

  15. yhvh says:

    "Before the Law"
    A man from the country seeks the law and wishes to gain entry to the law through a doorway. The doorkeeper tells the man that he cannot go through at the present time. The man asks if he can ever go through, and the doorkeeper says that it is possible. The man waits by the door for years, bribing the doorkeeper with everything he has. The doorkeeper accepts the bribes, but tells the man that he accepts them "so that you do not think you have failed to do anything." The man did not attempt to murder or hurt the doorkeeper to gain the law, but waits at the door until he is about to die. Right before his death, he asks the doorkeeper why even though everyone seeks the law, no one else has come in all the years. The doorkeeper answers "No one else could ever be admitted here, since this gate was made only for you. I am now going to shut it."

  16. Andrew Janke says:

    Works well for me on a retina iPad.

    Got Penetrate to crash. After going in to its settings and changing from "Start badly, but learn" to "Always play well", it crashes with message:
    smart = "True" but should have been a boolean

  17. Andrew Janke says:

    Retina iPad, iOS 5.1.1. SkyTentacles crashes when setting "Cartoony" to On, with error message "glPolygonMode: unimplemented mode".

    • relaxing says:

      Klein crashes out of the box with error message "glPolygonMode: unimplemented mode".

      • jwz says:

        Klein picks a random mode each time. Only some of them aren't implemented.

        "Unsupported polygon mode" and similar phrasing means "OpenGL things I couldn't figure out how to implement in OpenGLES". I'm aware of those, and they will likely go unfixed.

  18. Charlie says:

    Awesome! Stonerview on my iPhone!

  19. deathdrone says:

    I underestimated the power of your reputation and I apologize. Well done. May your guiding hand bring bouncing cow to the furthest reaches of the universe.

  20. Ben Brockert says:

    Top comment on the app page now:

    Apple should ban this
    by Rod Begbie
    It pretends to be a screensaver but it doesn't work. I think the author should be banned and his apps reviewed MUCH more carefully in the future since I enjoy his blog posts on the subject.

  21. Patrick says:

    I'm really surprised by how much I like watching it twiddle away on my iPhone in my dock. My only feature request would be to allow some way of letting it cycle through a preferred list, so it could be all demo-mode-y and potentially distract people who come to my desk with questions.

    Stupid Apple UI feature update request: Tapping the top of the screen usually jumps to the top of the list. It seems to be the Apple Way, 3rd party support is hit and miss. I don't know how much you want to go back into the tiger den, though. But if you ever find yourself considering releasing an update...

    • jwz says:

      Yeah, I'd like a random-mode too. I'm not sure what the UI for that would look like though. Also, it'd pretty much guarantee that the app would crash eventually, due to memory leaks. The savers aren't leaky while running, but most of them don't clean up when they exit, so if you left it running overnight it would probably have been shot down by morning.

      • Lun Esex says:

        Here's an example UI I could imagine for random mode:

        1. Add a "Random" button, either at the top or in a (new) toolbar at the bottom.
        2. Tapping the "Random" button makes checkboxes show up on the left side of the list, like in the Mail app after hitting "Edit."
        3. Tapping the "Random" button also makes a toolbar show up at the bottom, if it's not already there to hold the "Random" button itself.
        4. The bottom toolbar would have a "Check All" button on the left, and an "Activate" button.
        5. A "Cancel" button takes the place of the "Random" button.

        Usage should be self-evident.

        It'd also be nice if it remembered the list of savers that was checked between uses, but that's not as important. Plus there'd need to be a "Clear" or "Uncheck All" button as well, because canceling would no longer clear the list selection.

        • Patrick says:

          Yeah, something like that is about how I'd go about it as well. Another consideration: App-wide preferences to control stuff like pixel doubling (because holy hell the 1:1 retina pixels are tiny for certain savers like Squiral). Inside the preference pane you could have a disclosure line that would take you to the list of savers with checkboxes like Lun suggests.

          Moot point, of course, unless if it turns out there's an easy way to resource-cap the savers in a spawn/reap cycle like they would need.

          The more I play with it, the more I'm impressed with the retina display on my phone. Admittedly, half the time I have to take off my glasses so I can see the damn things, but that's just the slow march towards death I guess.

          • jwz says:

            So, the pixel-doubling thing was a hard call. It uses real pixels in GL mode since all of those were already resolution-independent, and it doesn't hurt performance. But for the X11 hacks, most of the savers look better when using real pixels (e.g. anything that loads pictures or uses images, like Distort or XMatrix) but some of them get hard to see (e.g. the particle systems like Julia or Hopalong). On the other hand, the particle systems look worse if you can see that the pixels are square. Maybe pixel-doubling wants to be a per-hack option.

            Sadly, X11 hacks use doubled pixels on Retina iPads because real pixels killed performance: that screen is larger than most desktop displays.

            • Patrick says:

              Yeah, I noticed that this morning when I loaded it on my iPad 3 and checked Squiral and was saddened to see the pixels were bigger than my phone. I figured you were doubling them across the board though because yeah - 2048x1536 is a _lot_ of pixels. But yeah, it's probably a per-hack decision. Although I could see a case being made for an app-wide configuration screen for stuff like pixel doubling and Show FPS and maybe some sort of list filtering options. I don't suppose there's any existing hack metadata that could be used to generate groups? i.e. "particle" "fractal" "openGL" "trippy" "math", etc. That could be a useful crowdsourced project if there isn't any.

              All that said, I forget which of the Moire-style ones I looked at this morning which was absolutely _beautiful_ once it finished rendering out the retina pixels, that would be a shame to force into a doubled mode.

  22. Jesper says:

    Congratulations. Let's hope it sticks.

  23. Ian Howson says:

    I enjoyed what must have been your third revision of the app description.

    Also, who posted this in the reviews?

    > It pretends to be a screensaver but it doesn't work. I think the author should be banned and his apps reviewed MUCH more carefully in the future since I enjoy his blog posts on the subject.

    As someone who is also enduring iOS-review-two-week-turnaround-fuckery, I must admit to also enjoying the blog posts.

    • jwz says:

      Actually I never revised the description at all! That was my first draft, before they made a fuss.

  24. Frankly, I am amazed you pulled this off based on my own interactions with the Apple Store. It's nice to have a genuinely pleasant surprise for change!

    Back a few years ago when they first opened the Store, you could get rejected and re-submit the exact same binary a few minutes later and get someone else to accept it. Not so much any more.

    I'd really, really like to know who pulled it off.

  25. NelC says:

    Congrats! I was wrong, I am a surrender-monkey. I shall wear the Cone of Shame for the rest of the day.

    Bugwatch: Time-tunnel blanks out after a few seconds and doesn't seem to want to do anything else. (iPad 1, whatever version of iOS is latest.)

  26. JP says:

    App Store shuts me down with the popup "This App Is Incompatible With This iPod Touch" when I hit "Install App." Curious: is that legit, or is it just sneering at iOS 4.0 and/or a 2nd-gen iPod Touch?

    • jwz says:

      Looks like my build options include "iOS Deployment Target: iOS 4.2", but I can't remember if that was just the default, or if it really wouldn't build when targeted at older versions.

      • JP says:

        Although I'm sure at least the 3Gs were available well before 4.2, it may be that Apple dropped support for mine at that release...I don't see much of iTunes since I live in linuxland.

        Anyway, build target seemed like the most likely reason - but I thought I'd ask since previously, if an app was visible to me in the store, the usual reasons for non-support were lack of a camera and/or built-in mic. I'm pretty confident I hadn't seen that Very Capitalized Message before.

        (This was a gift from a well-intentioned family member who knew I didn't have an mp3 player anymore, but didn't quite grok why. Not that I minded. In 2009 it was a much shinier toy than my Android.)

    • relaxing says:

      Under requirements it says iPod Touch 3G/4G only, so that's what it's sneering at.

  27. Scott says:

    To be honest, I'm actually impressed this ever got approved. At the very least, I would have expected them to keep finding screensavers that crashed or ran poorly, and forced you to remove them and resubmit.

  28. Joe says:

    Huzzah! Congrats, man. That was way more problematic than it ever should be.

    In addition to the feedback above, I've noticed that the app's UI handles being in landscape modes just fine, but triggers the screensavers in portrait mode. I use my iPad in portrait mode a lot and the sideways BSODs are kind of disconcerting. :-)

    Also Bouncing Cows and Flying Toasters occassionally crash with "buffer data not a pointer" but most other times work.

    I'm loving this, thanks for putting up with all the bull excrement to get it pushed through the system.

  29. Andres says:

    There is an extra "of" in the description:
    "The XScreenSaver application is a large collection of of historic and educational graphics demos."

  30. badc0ffee says:

    FlyingToasters crashed! The error message:

    buffer data not a pointer

    And then after that, it and FlipScreen3D (I didn't try any others) crashed with:

    glGenTexttures not allowed inside glNewList

    Until I exited and restarted the app.

    Also, FontGlide doesn't do much. The screen just goes black, and it takes a long time to respond to taps.

    • badc0ffee says:

      GLText also made the app just quit.

      Forgot to say, I love this! Maze, in particular, is making me very nostalgic.

    • jwz says:

      Several of them, especially the ones that operate on text from the network, take a little while to get going. Chill.

  31. Laco says:

    Hey, great stuff.

    I noticed Maze crashes with "ignorant = "True" but should have been a boolean" if that option is changed. Sounds like a type conversion thing, but I haven't looked into it at all.

  32. nooj says:

    JigglyPiff does a lot of it Jiggliness and Puffiness completely offscreen. Brand new iPhone 4s.

  33. pawliger says:

    Apple ][ got the "new iPad" to reboot, after I ran though a tasting menu of about 2/3rds of all the savers. Presumably Apple or you can see those crashes. My guess would be iOS not dealing well with GPU resource pressure. Or maybe it was judged "too meta" and kicked me out...

  34. matt says:

    Note that what's available at the app store is 5.18. But the current version, the one that claims to improve speed on the iPad 3, is 5.19.

    • jwz says:

      Because of all the delays, the numbers got slightly out of sync. The store-released version has those fixes in it.

  35. matt says:

    Okay; then I can test on iPad 3. So, in our previous exciting episode:

    * Julia: 1.7 FPS, near 100% load.

    * Attraction: 1.7 FPS, near 100% load.

    * Spotlight: 1.6 FPS, movement very jerky (big jumps), near 100% load.


    * Julia: 10.0 FPS, negligible load.

    * Attraction: 30 FPS, negligible load.

    * Spotlight: 6 FPS, 60% load.

    So many of the slow savers are fixed! Woo-hoo! But many of them are like Spotlight - still pretty slow, jerky appearance, load high though not 100% as before. Others in this category: Anemotaxis, Apple ][, Blaster, Blocktube, Bouboule...; hope that's enough to suggest some underlying commonality.

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