I'm ready to outsource the screen capture functionality of our application, because it's not our core business and I've spent too much time trying to get our code to do all the things I need. Time for a specialist, I think. My requirements, in decreasing order of importance, are below. Does anyone have experience with any commercial or free libraries that meet most or all of these requirements?
Has to work in Windows XP and higher. (But not Win95/98/Me.)
Visual C++ 2005 compatible, where screenshot can be triggered from my code. Preferably a static library, but a DLL or COM object is OK. I'd prefer not to shell out to a standalone EXE because there are some users that will try to tamper with our application and I think having an obvious separate screenshot EXE makes that too easy.
Must be able to take full screenshots of multiple monitor systems. (Preferably the way the "Print Screen" key does in Windows, by making a bitmap of the displays stitched together, but if I have to take the pictures separately and combine them myself that's acceptable.)
Must be able to capture screen correctly when Remote Desktop Client (or any RDP client or VM) is in full screen mode. (Of course, it should also work when RDP is in windowed mode, but that shouldn't be a problem as long as it doesn't operate by simulating a key press that might get transmitted to the remote OS instead of being handled locally.)
Must be able to capture screen correctly when Windows Media Player (or any other media player) is in full screen mode.
Must be able to capture screen correctly when game (e.g. World of Warcraft) is in full screen mode.
Would be nice to be able to capture a few seconds of user activity as a video.
I don't know of a library that would do what you want.
If I had to code your requirements, I would probably use the source code of the TightVNC server as my starting point. I think it has the technology to do everything on your list EXCEPT....
I'm not sure that technically there's ANYTHING that can do a screen capture of somebody's Remote Desktop session. Think about it: There can be multiple remote desktop sessions (the csrss.exe process) occuring using the same physical remote desktop server. If you were sitting in front of the machine looking at the video monitor, you wouldn't see anything happening at all. So what woould you expect to capture. VNC is only going to capture what's happening with the "real" video (the non-remote csrss.exe).
I dont know if this really helps, but the best imaging libraries available are available from
www.accusoft.com and
www.leadtools.com
Both support creatting screenshots, though i don't know, if hey will properly capture movie player output that displays through graphics acceleration or the recording of movies from screen.
If I were you I would investigate WindowsClippings, a pretty mature and extensible application written in C++ that does precisely what you need. It has an API you can extend to your requirements and is pretty cheap at 18$
Some people in our office are using Magick++ (an ImageMagick library) to make screenshots. I don't know all the specs, but you could take a look at it and see if it matches your requirements.
Related
I need to access web camera using Java. This is what I want to do
Access web cam
Now the user can see web cam working because his face is visible on screen
(have heard some libs are there which doesn't show the video output of webcam)
when user click save button, take a snapshot and save it
I have tried number of ways to do this, from a long time.
JMF - Now it is dead
FMJ - Now it is dead too
VLCJ - too much because I am not creating a music/video player and it expect VLC to be installed
Xuggler - too much and hard work
JMyron - didn't work
JavaFX - I thought it could do it, but seems like it can't
I am even satisfied if the library is just ONLY doing the above mentioned, because that's enough for me. But I expect it to be simple too. Really great if it is not using DLLs, because it is not platform independent if it does. Really appreciate if it can DETECT the camera, without manually passing the camera name and other info as have do in VLCJ (because there might be thousands of camera brands, so I can't create a list of thousand elements in it). And, I am creating a desktop application, not web app.
If you know a library like this, please be kind enough to let me know. Other libraries (which might not suit to all of my requirements, but suits to the basic requirement) also welcome. Please help
I think the project you are looking for is: https://github.com/sarxos/webcam-capture (I'm the author)
There is an example working exactly as you've described - after it's run, the window appear where, after you press "Start" button, you can see live image from webcam device and save it to file after you click on "Snapshot" (source code available, please note that FPS counter in the corner can be disabled):
The project is portable (WinXP, Win7, Win8, Linux, Mac, Raspberry Pi) and does not require any additional software to be installed on the PC.
API is really nice and easy to learn. Example how to capture single image and save it to PNG file:
Webcam webcam = Webcam.getDefault();
webcam.open();
ImageIO.write(webcam.getImage(), "PNG", new File("test.png"));
I want my program to be able to launch any Windows game, and while the user is playing it, intermittently display some text or pictures in some part of the game window. The game may be in windowed or full-screen mode. From what I have been able to figure out from online resources, this could be done using a graphics library that supports overlays and using Windows Hooks to keep track of the target application's window. In this context I have some questions.
Will the overlays affect the game's performance?
How will hooking the application affect performance?
Is there any other way one could achieve this? For example, how do you think PIX, the DirectX debugging and analysis tool, work?
Fraps is the archetypal example of doing this sort of thing to a fullscreen DirectX application from a third-party app. It works by hooking some system calls and inserting itself into the call-chain between an app and DirectX. There is some performance hit, but in general its minimal.
This page seems to have some details and sample code on how to hook the app in this way.
If I recall correctly, from other forum discussions (can't find the link at the moment. search for things like "how does fraps work", it's a popular question), Fraps hooks a few things to force the app to load its DLL, then hooks Present() calls and executes a device->Clear() call before calling the real Present(), with a list of small rectangles to set to a different color, which can spell out the FPS number that it displays. This has a minimal performance impact and is widely compatible with whatever rendering the app is doing. Overlaying a bitmap would be more complicated since it wouldn't be as easy to do at Present-time. Perhaps if you could hook EndScene, then you could do more, but you would have to be careful to not change the device state.
PIX has privileged access to the DirectX driver, so I wouldn't expect to be able to use that as a model to emulate.
If an the target app is running in windowed mode, hooking DirectX still work, but you could also just use GDI instead.
Edit: I think this is the link I was originally thinking of.
Given that I only have one monitor, what's the best way to debug a program which uses the entire screen (such as a DirectX application)? Tools such as the step-by-step debugger seem useless in this context. Also, printing to the console isn't as effective, since you can only look at the console once the application has terminated.
Remote debugging is no option?
Else you can possibly borrow a second monitor (with video card).
And if all else fails you can go back to beep signals.
(Or find yourself an old matrix printer and write each line to the printer ;-) )
To just see some runtime information I would overlay debug text within fullscreen. If it were me, I would target the app to be able to run windowed as well- although the onscreen debug is good for play testing (if this is a game).
printf debugging is slow, painful and fool proof.
fill your code full of tracing lines like
fprint(logfile,"%s:%d\n",__FILE__,__LINE__);
or waterer you need for your language and run it. after your done, you can walk through what it did. Make sure you have lots of time and harddrive space first though. It has some advantage like that you can "run" things backwards and diff one run with the next.
I'll go with what BCS said and add that DebugView by SysInternals allows you to connect to it remotely from another machine.
You can test 99% of the code in windowed mode, then for the parts that need to be done in fullscreen you can have it jump to fullscreen, run some test, and jump back soon after (either programmatically or with alt-tab).
Basically I want to stress that most code will not be dependent on the fullscreenness and could be tested in a small window.
You might want to consider reading Joseph Newcombers essay on Graphical Developers Interfaces at http://www.flounder.com/gdi.htm
You may not be coding in MFC but you should be able to get some useful ideas. He's got lots of other interesting articles as well.
I am looking for a good, free (preferred) screen sharing program that works well for pair programming and code review sessions for Windows (Vista x64, Server 2008). It should allow either person take control of the screen and be fairly responsive for text editing over decent broadband connections. Additional features like the ability to draw/mark/annotate the other persons screen would be nice.
Edit: This will be used by developers in remote locations.
TeamViewer from http://www.teamviewer.com/ works very well. We use it for pair programming between London and Ukraine.
Notes:
We use Skype for voice.
TeamViewer uses extremely low bandwidth - 4kbyte/sec on average for programming in Visual Studio 2008 # 1024x768 resolution.
Can swap roles from hotseat to viewer with a button.
The remote view of the screen can be resized to fit in a smaller area with no loss in usability.
Windows Shared View works for me. It allows you to only share certain windows and even shows where your "attendees" mouse is. It would be best to use that in connection with some sort of voip connection so that you don't have to type questions/responses back and forth.
I have checked some hours now for a good one.
Best and the simplest thing i have found.
http://www.screenleap.com/
Free, no strings found so far.
No need to waste time installing or registering anything.
Works perfect with "share are only" if you have multimontor setup.
Most other software shares full screen default, and you cannot choose which monitor you share.
You need to be aware that it does not encrypt data. Check FAQ.
But if you have to run voice over Skype/Mymble/Whatever separate anyway..
What harm can a hacker do by simply getting 50% of the conference ?
Pff.. Oh you wished for screen sharing.. this one does not have it.
So try: http://www.mingleview.com/
It has that multimonitor "bug" and you need to install a simple pluginlike thing.
But "take control" is there and it's very simple also.
Most other software has bundled unneccesary functions like calendaring, document system, filesharing which i already have solutions for.
It's like developing games on excel macros..
unneccesary.. developers please learn that already !
I haven't actually tried it yet, but it looks promising. Check out DimDim. They have a free web service and a VMWare image on Sourceforge.
If you're using eclipse, you might wanna try ECF. There's a video presentation available here.
Try Mikogo at www.mikogo.com
very easy to setup. no problems with Firewalls etc etc
And my final suggestion, but this is not one I've tried. Go to Crossloop
On OSX, I've used vim and a multi-user GNU screen session - this gives much better responsiveness than VNC, screen-sharing, etc. I guess you could use these with Cygwin?
I like to use Screen Hero, which allows both users to use the mouse on the shared screen: http://screenhero.com/
or Zoom: http://zoom.us/
For a poor-man's solution, you can use the free edition of RealVNC. On the server, un-check all of these boxes:
(source: realvnc.com)
Would a VNC client not do the trick, combined with a one of those screen overlay apps people use for presentations (screenpen rings a bell)?
Another option is to use VNC, but use reverse connections. Have a look at this I use this in conjunction with No-IP to get a fixed address.
Do you need this to be remote?
You could just have two monitors set to mirror and 2 USB keyboards/mice
If it is remote then VNC is the way to go, I would use UltraVNC if you are looking for a free version, it has more features (chat, file transfer) than the free version of VNC - it also has a video driver hook that means it suffers less from any weird screen issues than regualr VNC.
If firewalls are a problem you can simply set up a VPN (which is probably a good idea anyway - although ultra can do encryption).
How about any of the services like Joel's https://www.copilot.com/?
Have you looked at the collaboration module that comes with netbeans? Its very useful for pair programming!
For multi-platform simplicity, I would suggest
https://join.me/ for screen share (you can even view a remote
screen using iOS!)
getting a phone headset, and using the phone for audio.
Has anyone noticed this odd behavior of application that utilize D3D or OpenGL when they go to full screen in Windows? It applies only when applications go to full screen and then switch back to window or terminate. They either shuffle window positions of other applications (when I am on single monitor machine), or move all the other applications windows to another screen when I am on multiple monitor machine.
I would take this for granted if there weren't for applications that didn't show this two anomalies. So, my question would be what exactly does one need to take care of when writing an application to alleviate these two problems? Also, I am not sure if this problem exists on other platforms besides Windows?
My primary setup concerning this is OpenGL/C++, but I presume this applies to whatever setup you have since it seems to be platform API thing that needs to be taken care of.
edit: OK, here is some more clarification on my observation. Problem persists even on same resolution as desktop one. So, it does not seem to be related to resolution switch, because I've seen application/games that even when they are not in the same resolution as desktop, when they switch back, windows on desktop are restored as they once were before the full screen application was run.
edit2: it looks like it is a resolution switch problem, Windows (at least XP) does not seem to remember positions and size (in case of multiple monitor setup) of applications windows. Looks like only solution is the one I provided in an answer to the question - even though it seems like something OS should provide, at least as an API call or two. I'm still not convinced this is the only solution, there must be an easy way of graceful, easy restoration, no?
Shouldn't you be using ChangedDisplaySettingsEx(..., CDS_FULLSCREEN, NULL)? That will tell the system the resolution swap is temporary.
I can't say that I'm 100% certain about the situation you're experiencing. However, my guess is it's because most D3D/OpenGL games will change the resolution of your machine when they startup/shutdown for performance reasons.
The ones you see that don't shuffle the windows around are likely not changing the resolution because they may be able to run at your current settings.
Hm, I've gone through some more research about this - it looks like there is no default fallback on restoring all running windows sizes and positions after changing resolution, so it must be done from within an application (at least in XP).
So, in order to gracefully return back from other resolution (full screen game for example), I would need to get all running applications hWnd's with EnumWindows and appropriate callback and store each of the windows RECT structure via GetWindowRect in a list.
When switching back to desktop resolution I would EnumWindows again, but with a different callback which sets each of the running application windows position and size with SetWindowPos, using the list of RECTs I've saved before switching to full screen.
There are gotcha's, ofcourse, like watching you get a window hwnd only through EnumWindows etc. It seems odd that OS doesn't provide a feature like that, even if only API. I wonder how other OS's out there handle this, if they handle it at all.