[Artwork] / [QisMLib] / [Programmer's Corner]

Overview of the QisMLib system

QisMLib is a collection of C++ APIs to work with CAD designs in form of GDSII/OASIS files. It allows an application to do the following:

• Create one or more database objects from GDSII/OASIS files on disk

• Get structural information about the design such as cells, layers, cell hierarchy etc.

• Run one or more (multi-threaded) spatial queries (explosions) over a view of the design (cell, layers, window, nesting level) and collect data vectors (boundaries, paths, texts, single and array cell references) crossing that view

• Perform advanced multi-threaded post-processing with the design such as :

  • Polygonal operations (union, difference, intersection, xor, clipping, sizing, convexing etc.)
  • Create new layers from an expression of boolean operations between existing layers
  • Tracing nets of connected polygons on METAL and VIA layers
  • Generate high resolution monochrome bitmaps
  • Extract portions of the design as GDSII/OASIS with various clipping and filtering options
  • Apply homogeneous and bi-linear transformations (corrections)
  • Boolean operations between two or more designs
  • Colored graphical rendering to GIF, XPM files or directly to client windows (Window/MFC, Linux/Motif)
  • Custom post-processing functions as per the needs of the client application

System Architecture

• QisMLib works as a collection of DLLs (.SO on Linux)
• At the center of the system, qismlib64.dll (libqis64.so) provides all the core APIs for creating and interfacing with GDSII/OASIS database(s) as well as access to other modules also known as extensions
• Extensions are plug-ins that provide APIs for specialized data processing such as rasterization, layer synthesis, boolean operations, net tracing, bilinear transformations, extraction etc.
• Extensions can be made available to the application on demand by installing them alongside qismlib64.dll and specifying the intent to load them via a Configuration file
• This way, a client application links/loads only one DLL -- qismlib64.dll. The loading and management of all other DLLs is done behind the scenes, outside the purview of the client application
• All the binaries as well as supporting files required to run the qismlib system can be found in the artwork directory of a qismlib distribution (installation)
• As shown in the diagram above, a client application uses qismlib64.dll in conjunction with four other extensions to achieve it's GDSII/OASIS processing needs

• To the application developer, QisMLib is a collection of well-defined C++ APIs, each defined in it's own header (.H) file
• All the relevant header files required by the application can be found in the include directory of the corresponding qismlib distribution (installation)
• Each header file provides a detailed description of the API in line with the code (in form of C++ comments)
• The QisMLib API serves as the gateway to the system. It allows an application to create one or more databases from a GDSII/OASIS file and provides access to other (extended) APIs in the system
• Once a database has been created, the QisMFile API provides an interface to work with that database
• The QisMExploder API allows an application to run spatial queries on a view of the database (cell, layers, window, nesting level) to collect data vectors (boundaries, paths, texts, cell references) crossing that view
• The QisMBool API provides functions to perform multi-threaded boolean operations (union, difference, intersection, xor) as well as other operations (clipping, sizing, convexing) on large sets of polygons
• Each extension provides it's own API for specialized data processing
• Some APIs are free to use while others require one or more product licenses during execution. Learn more about QisMLib licensing here
• A comprehensive list of available APIs can be found here

Configuration File

• The configuration file is a text file that lists the extensions to be loaded during initialization of the QisMLib system (QisMLib_initialize_once)
• On each line, an extension is listed using the syntax EXTENSION={extension_dll_path} where the path MUST be the absolute path of the corresponding DLL/SO
• The extensions are guaranteed to be loaded in the order in which they appear in the file
• Any line beginning with a # is treated as a comment and ignored
• The default configuration file is qismlib.cfg and is expected to be found in the same directory as qismlib64.dll
• An application can specify it's own configuration file using the QISM_ARG_USECFG initialization argument to QisMLib_initialize_once. See qismlib.h for details
• The Get_extension_report method of QisMLib provides a report of the extensions loaded as well as any errors/warnings that may have occurred during the loading process