HELP: Cloning live parts of a screen

Discussion in 'Mac Programming' started by looneygeorge, Feb 15, 2011.

  1. looneygeorge macrumors newbie

    Feb 15, 2011
    Hi fellow :apple: addicts.

    This thought came to me when a forum member over at DJ Techtools started a project on a homemade DIY DJ controller with a little screen built in. He got a friend to program a simple application to duplicate a part of the screen (Where the application is visible) like the waveforms of a DJ software, he could then move the duplicates around to rearrange them in new ways on another screen (and resizing).
    Basically duplicating the GUI in small video windows that provided a live feed of what is going on another part of a screen.

    Here you can see the program in use:


    The original thread:

    I have searched everywhere for a similar application for the OSX platform, but haven't found anything. Ideally I would use this program on my macbook pro in conjunction with my iPad for Djing live (iDisplay for iPad over bluetooth). having my Effect section and bigger waveform displays on the screen to make my life easier.

    So, how would I go about this? or have my google magic failed and such an application already exists? I would like to replicate the windows program in the simplest and easiest way due to the fact that my programming skills are quite lacking.

    Thanks for any help you guys provide!


  2. kainjow Moderator emeritus


    Jun 15, 2000
    FYI, the image in your post is broken since it's being linked to a forum that requires you to be logged in to view. I suggest either uploading here or put it on an image hosting site.
  3. looneygeorge thread starter macrumors newbie

    Feb 15, 2011
    sorry about that, I didn't notice since I'm able to view it perfectly fine :)

    I've added the image as an attachment.

    Attached Files:

    • test.JPG
      File size:
      151.1 KB
  4. chown33 macrumors 604

    Aug 9, 2009
    That part sounds like VNC, also called "Screen Sharing".

    There are any number of VNC clients that run on various platforms, including Mac and iOS. Some are even open source.

    If all you're doing is defining a section of another host's active screen, I don't see why you couldn't modify a VNC client to only provide access to that part. Maybe that's what the other project did.

    I doubt that you'd find anything that would do this for a non-programmer, so exactly how lacking are your programming skills?
  5. looneygeorge thread starter macrumors newbie

    Feb 15, 2011
    Very lacking, but I have a strong willpower to do this. I looked at VNC but it has a terrible latency, and you duplicate the whole screen which will be pointless when im using an iPad as the second screen.
  6. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England
    That's why chown33 was suggesting modified VNC software that would only work on a section of the screen or window. The way VNC work with the hextiles taking only a portion of the screen should help reduce bandwidth requirements a lot.

    Skype and other screen sharing software like GoToMeeting already have the ability to share only a window. This would be something similar to that. EDIT: Seems like some of that has already been implemented Google "VNC share a single window".

    On Windows, RDP is a lighter weight screen sharing protocol, but I don't believe there is a similar pathway for OS X (Macs use VNC as their Remote Desktop solution).

  7. chown33 macrumors 604

    Aug 9, 2009
    If you don't already know how to program, then learning to program will be the first thing to do. If you do know how to program, then learning the language that the VNC client is written in is the first thing to do.

    You should also set a realistic time goal on writing this program. If you're a new programmer, then you'll have to write a lot of simpler programs before getting the final one right.

    VNC latency can be quite good. It's the client where much of the blame will lie.

    For example, I get very low latency using screen sharing with the builtin Mac client, and with Jolly's Fast VNC. Chicken of the VNC, however, is pretty awful, using the same computers and networks.

    Without knowing what you actually looked at when you decided VNC had terrible latency, it's possible you simply need a different program.
  8. balamw Moderator


    Staff Member

    Aug 16, 2005
    New England

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