Not sure if this will get closed as "not a real question" but I asked this on Superuser and it was closed for that very reason. We are thinking of implementing a QR code which will be sent to a number of users via a letter.
Now I'm aware that you can just Google 'QR codes' and there are a plethora of options that allow you to make a QR code. My question is thus; if we do go with this solution can we guarantee that it would work cross platform? I.e. on Android, iOS, Symbian etc? Once a QR code is generated will it work on ANY app on ANY platform?
Thanks and apologies if this is not really a 'programming question'
Thanks
Kiran
The only time I have had problems is when the resolution of the screen displaying/the printer that printed the QR code was too low. Ensure that your QR code is big enough for the data its holding and you should be ok.
I found if I padded out the data in my QRCode with spaces or zeros I could maintain a set size which helped me place it on a page and always know its size.
Kind of a suck it and see problem though
Edit
PS. Don't use QRCodes for the sake of using QRCodes - if you're sending the user the QRCode by email why not just send them a hyperlink?!
There are QR code readers for all platforms. It is a well-established ISO standard. Whether its content will be interpreted how you want is a bit more platform-dependent; the QR code spec says nothing about what to do with the content.
However, if you're just putting text or URLs in a QR code, it will certainly be handled as you expect on all known platforms. It might be more hit and miss if encoding stuff like vCard data.
See this guide to QR code contents.
Related
I've been looking at the SPIFFS file system project on https://github.com/pellepl/spiffs and it seems like it has a pretty large user community. I've been looking at the WIKI on the integration and configuration which seems to be well documented. I didn't see a user group forum? is there one?
My question pertains to the actual formatting of the flash device, within the examples shown in the WIKI pages I didn't example code on how to format the flash. There's a description, but it doesn't show an example of how to use the API.
I'm hoping someone might know of example of how to use the APIs. Any help is greatly appreciated.
I'm all set, I took another look at the API's and I figured out how to use them to mount and format the spi flash to initialize it. I ran thru the test example and it works. It went better than expected.
I am using Codename One to record the microphone input and play it back to the connected earphones.
First of all if I record audio from mic to a file, and play it back when the recording is over, it works as expected. That's why based on this 2014 question I implemented 2 periodic tasks (timer and timertask), as long as 2 files : one for recording, one for playing. I set the periodic tasks period to values between 100 ms and some seconds, but the result was awful on the Android device. Indeed there were random gaps, it was not smooth at all, nor understandable.
I assume the overhead of writing to a file every period is too high and consequently is causing that behaviour. So using proper high-level Codename One methods does not seem the way to go.
Then in the same question from 2014, the requester is suggesting to create an inputstream from the recording Media and use it as input for the playing Media. However the method MediaManager.createMediaRecorderStream() does not seem to be available anymore. I tried to use the file used to record audio as InputStream for the playing Media through fs.openInputStream(recFilepath) but it did not output any sound nor error on the device.
So my question is whether or not I can achieve my goal with bare Codename One or do I have to use the native interface ? Moreover Shai (in the 2014 above mentioned question) wrote that the second approach with MediaManager.createMediaRecorderStream() might work on some platforms : is the android platform among these, or only iOS platform was aimed at ?
Any help appreciated and sorry for not posting code since I cleared it as soon as an attempt did not appear to work. So I really messed up with my code which now is not doing anything I targetted initially.
Cheers,
As far as I recall Android back in the day didn't support input stream for media and later only allowed capturing input directly as uncompressed WAV which makes full duplex usage impractical. This might have changed since as I recall they did some overhaul of their media libraries.
I'm not sure if this is exposed in our higher level code. Besides using native interfaces you can also help us improve Codename One by forking and hacking it e.g. this is the relevant code in the Android project:
https://github.com/codenameone/CodenameOne/blob/master/Ports/Android/src/com/codename1/impl/android/AndroidImplementation.java#L2804-L2858
This is a contribution guide to Codename One, it covers running in the simulator but that's a good start: https://www.codenameone.com/blog/how-to-use-the-codename-one-sources.html
You can test your changes on an Android device with instructions here: https://www.codenameone.com/blog/debug-a-codename-one-app-on-an-android-device.html
I asked this question in the Raspberry PI section, so please forgive me for posting this here again. Its just there doesn't seem to be as active as this section of the forum. So, onto my question...
I have an idea and I'm working on it right now. I just wanted to see what the community's thought was on using a screensaver as digital signage. Every tutorial I've read shows someone using chromium in kiosk mode, and while that's fine and works well for some uses, it doesn't work for what I need. I have successfully completed a chromium kiosk, and it was cool. But the signage that I need to create now, has to work without internet. I've thought about installing LAMP locally on the PI, and still using chromium. I still may have to if this idea doesn't pan out. All I need from the signage is a Title Message in the top center, and a message body underneath it, with roughly 300-400 character limit. My idea is to write a screensaver module, in C, that will work with a screensaver such as xscreensaver. The module would need to be able to load messages from a directory on the pi. Then for my clients to update their signage text, I would write a simple client that sent commands as well as the text via SSH to the pi. I want to know what other people think about this. Is it a good idea? Bad idea? Should I "waste" my time doing something like this?
Thanks in advance.
I am already using a rPi as digital signage, just over a year. I am using two different setups:
version 1 uses Raspian loading xdesktop and qiv image viewer to cycle images stored on the Pi itself, synchronized with a remote server. The problem I found was power and SD stability, when the power fails, which it will do no matter what, just when... The Sd card can become corrupt due to all the writing that Raspian does all the time. Certainly does not really need to write to SD.
version 2 uses a RO-filesystem and a command line image tool. Uses the same process to show images from local, and sync with server. But power fail causes no ill effects.
I am not using screensaver to display images, that seemed redundant to me, and unnecessary to wait for the SS to start just to display the images.
Some of the images are created using imagemagik, which is nicely dynamic where needed.
I know people have asked this before, but i see no answer nor people even commenting about it.
So, i'm trying to make SHOUTcast streaming in WP7, anyone have done it? I know i have to use MediaStreamSource with my MediaElement, but how exactly can i skip that header from SHOUTcast and just get the stream and use it in a MediaStreamSource? Is there any app that has done it? Someone actually has some example working code?
There is a really good SHOUTcast Player called streamything (http://www.streamything.com/page/en/default.html) . Unfortunately it is not open source nor freeware but i shows that it is definitely a way to do that.
You need to setup a mechanism to get the stream of data to be passed to the application continuously. Here is a possible implementation. In order to be able to receive the stream directly (so that the application won't be treated as a web browser), you have to call the URL with a semicolon at the end. For example: http://00.00.00.00:8000/;
I want to make project for my final year in college.
So someone suggested me to make Remote Desktop in C.
Now I know basic socket functions for windows in C i.e. I know how to make
echo server in C.
But I don't know what to do next. I searched on internet but couldn't find
something informative.
Could someone suggest me how to approach from this point..any tutorial...or any source ?
I think this is do-able. For a college project, you don't need to have something as complex and as full-featured as VNC. Even demonstrating simple keyboard and mouse control and screen feedback would be enough, in my opinion, and that's well within reach.
If you're doing everything from scratch and using Win32, you can get the remote screen using the regular "printscreen" example all around the internet.
http://www.codeproject.com/KB/cpp/Screen_Capture__Win32_.aspx has it, for one. You can then compress the image with a third-party library, or just send it raw; this wouldn't be very efficient but it would still be a viable demonstration.
Apart from capturing the screen data remotely and showing it in the local window, you'll need to listen for local window messages for mouse and keyboard events, send them to the remote host, and then play them back. http://msdn.microsoft.com/en-us/library/ms646310%28VS.85%29.aspx will probably do that for you.
Check tightvnc TightVNC is a free remote control software package. The source code is also available.
For sending the image of the screen I would probably use rtp. The JRTPLIB is really handy for that.
And yes, as KevinDTimm says, an echo server is the very easiest part.
KevinDTimm may well be right, writing an RDP client would a fairly significant undertaking. To give you some idea, the current spec, available at the top of this page, is 419 pages long and includes references to several additional documents for specific aspects of RDP like Audio Redirection and Clipboards.