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How to create file global property of OASIS

MasakiMasaki
edited January 2015 in File Formats
Hello, Matthias,

At first, let me say Thank you for your decision to support python script!
Klayout was a wonderful tool.
With integrated python script engine, Klayout become much better for me.

I have a question about scripting or File Format.
What I want is to create an oasis file with file global property.
I setup Klayout includes python, then from the assistant window, I searched 'set_property'
and found 3 methods

Cell#set_property
Shape#set_property
Instance#set_proprety

But I cannot find a method to set a property which is associated globally with the entire OASIS file. Could you tell me the way to create such property?

Best Regards,
Masaki

Comments

  • MatthiasMatthias
    edited November -1

    Hi Masaki,

    thank you for this feedback :-)

    Right now, global properties are not supported, but that is something that may make sense to add.

    I wonder what is the understanding of "global properties". Are you interested in the special properties too? Like top cell, bounding box or similar? Or are you interested in arbitrary properties outside the special property domain?

    I employ global properties already to store PCell context information, so I have to be careful not to create a name clash.

    Matthias

  • MasakiMasaki
    edited January 2015

    Dear Matthias,

    Thank you for your positive answer to support such property.
    My understanding of “global property” is not associate to geometries, instances nor cells.
    According to semi P39 (31.8), PROPERTY placed just after START record are associated globally with the entire OASIS file.
    Semi p44 is a subset of P39, but it requires such property as a mandatory records.
    http://en.wikipedia.org/wiki/OASIS.MASK

  • MatthiasMatthias
    edited January 2015

    Hi Masaki,

    I see the point. But if you want to implement OASIS.MASK, I'd except you to face other, and more severe issues:

    • The file structure appears to be tightly specified, specifically the order of properties and how they relate to the cell records and placements. In normal OASIS, the order is not specified, hence KLayout is free to chose any order.
    • Properties with the same name can be present multiple times (like "P44_LOCALIZATION_AREA"). In KLayout's database, a property name is a unique key and there is only one value per name.
    • There are concepts like the figure operations which are not mapped to anything inside KLayout's database.
    • Some of the property values refer to file locations that you don't know when writing a file.

    I think that even though OASIS.MASK is a subset of OASIS, a writer for OASIS.MASK is a different piece of software. Compatibility mainly refers to reading: if you're not interested in the additional information from an OASIS.MASK file, you can load OASIS.MASK with a normal OASIS reader.

    Regards,

    Matthias

  • MasakiMasaki
    edited November -1

    Hi, Matthias,

    Thank you for your reply, my goal is not make exact OASIS.MASK but make a oasis include information not associated to any cells. So, I can avoid 2,3 and 4th issues you listed,if there is file global properties :)

    Your answer clarify my another issue, thank you very much! So, I have a question about the first issue of your list. Although I only check a very small number of cells made by python script, I think the order seems to be controllable by order of calling insert method of sub cells. My understanding is wrong? The order of cells are not guaranteed when increase the number of cells just like a hash table?

    Even in case of the order of the cell is not controllable by script, I do not make a request about the cell order control because I understand assuming controlled cell order is illegal usage within P39.

    Best Regards,
    Masaki

  • MatthiasMatthias
    edited November -1

    Hi Masaki,

    To be frank, I can't give a simple answer to the cell order question, but I think in a simple application like yours the order of the cells written will be the order the cells are created.

    I'll note your request about the global properties. But that's not a simple change so that will be something for a major release.

    Matthias

  • MasakiMasaki
    edited November -1

    Hi, Matthias,

    Thank you for your commnet,
    I asume order of cells by my own risk (or change my plan)
    Also, thank you for appending my request to your stack!

    Best Regards,
    Masaki

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