The problem is that the definition of an arc in the legacy file format is ambiguous. A center point and two additional points (or angles) define two possible arcs - one smaller than 180 degrees and one larger (or two equal, 180 degree arcs). In order to distinguish between the two, additional constraint is required. If I understand correctly, the constraint here is that the arc is strictly smaller than 180 degrees. In the new file format, a midpoint is specified, solving this ambiguity.
Avishay בתאריך יום ג׳, 12 בנוב׳ 2019 ב-23:28 מאת Evan Shultz < [email protected]>: > I've also found > https://www.compuphase.com/electronics/LibraryFileFormats.pdf to be > useful. > > On Mon, Nov 11, 2019 at 4:14 AM Wayne Stambaugh <[email protected]> > wrote: > >> Take a look at the legacy footprint library file format documentation[1] >> for help. You really should be supporting the new s-expression file >> format. The legacy file format is deprecated and is read only. >> >> [1]: >> http://bazaar.launchpad.net/~stambaughw/kicad/doc-read-only/download/head:/1115%4016bec504-3128-0410-b3e8-8e38c2123bca:trunk%252Fkicad-doc%252Fdoc%252Fhelp%252Ffile_formats%252Ffile_formats.pdf/file_formats.pdf >> >> On 11/11/2019 4:42 AM, Avishay Orpaz wrote: >> > I'm writing a program the reads schematic library symbols, and I'm >> > having hard time understanding how arcs are drawn. >> > Taking, for example, the Antenna_Shield symbol from device.lib. This >> > symbol contains two arcs: >> > >> > A -1 -73 32 -882 1242 0 1 0 N 0 -105 -20 -45 >> > A 1 -73 32 -918 558 0 1 0 N 0 -105 20 -45 >> > >> > Both arcs start at approximately the same angle (-90 = 270 degrees) and >> > end at two different angles - the first at 124 degrees, the second at 56 >> > degrees. When the symbol is drawn, the first arc is drone clockwise >> > while the latter is drawn anti-clockwise. So, how is it possible to >> > determine the direction of the arc? >> > >> > Avishay. >> > >> > >> > _______________________________________________ >> > Mailing list: https://launchpad.net/~kicad-developers >> > Post to : [email protected] >> > Unsubscribe : https://launchpad.net/~kicad-developers >> > More help : https://help.launchpad.net/ListHelp >> > >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~kicad-developers >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~kicad-developers >> More help : https://help.launchpad.net/ListHelp >> > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : [email protected] > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp >
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