GDSII是版图数据的格式
GDSII文件:
GDSII Stream format is the standard file format for transfering/archiving 2D g
raphical design data. It contains a hiearchy of structures, each structure con
taining elements (boundary/polygon, path/polyline, text,box, structure referen
ces, structure array references). The elements are situated on layers. It is a
binary format that is platform independent, because it uses internally define
d formats for its data types. While reading GDSII files, the GDSII internal da
ta types (like reals, integers etc.) need to be converted to the platform/CAE
package datatypes that are used.The GDSII format is a sequential list of recor
ds, each record contains a header to tell what information is in the record.Th
e order of the record needs to be according to the GDSII BNF, because of this
strict organization it is relativly easy to parse. The maximum number of verti
xes is officially only 200 x,y pairs, but many packages can read up to the abs
olute maximum of 64k/2=32k, simple because this is the maximum record lenght tha
t can be specified (two bytes).The format is hard to read, since it is binary,
for that viewers are available to view (boolean) the contents as ASCII. Also
an ASCII format has been developed (KEY format) which is more than just a text
representation. It is possible to convert GDSIIformat to KEYformat and back.
KEYformat has extended the basic primitives to contain cicrles, arcs,
polygons/polylines with arc segments.
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