Le 24/12/2019 à 21:43, Jon Evans a écrit : > OK, so both the JSON format itself and the Ucamco gerber format (which > is not necessarily the same as the job file format, but hey) specify > storing doubles. > But, the examples in the Ucamco doc, and KiCad itself, do not store doubles. > > I have to imagine that the gerber job file format is so new that it > isn't entrenched in anyone's workflow yet, and if it is, they are not > relying on this quirk of KiCad's implementation (but anything is possible). > The only way to get KiCad's behavior is through manual formatting of > JSON, so anyone who writes software that parses job files through a JSON > parsing library is going to have those values "upcasted" anyway. > > My personal opinion is that we should bite the bullet and change the > behavior to comply with the standard (i.e. store doubles), and also > suggest to Ucamco that they revise the job file spec to be more explicit > about this. > > Perhaps JP should weigh in on this as well. > > -Jon
Sorry for the delay. I am unsure to understand the meaning of "KiCad itself do not store doubles" (in gerber job files) A line like: "BoardThickness": 1.600, stores a double: AFAIK, "1.600" is of course a floating number, and also a double, not an integer. In job files, most of values (board sizes, layers thickness, clearances) are "mechanical" values. A reasonable precision is the micron for this kind of parameters. No need to use nanometers. So values are written using 3 digits for the mantissa. Using the notation: "BoardThickness": 1600e-3, is perfectly valid, but useless and less readable. FYI, using 6 digits (1 nanometer) in other Gerber files is needed to avoid coordinates truncation. 3 digits is certainly enough to fabricate a board. Unfortunately, truncation slightly modify polygon coordinates, and this truncation can (and frequently does) create self intersecting polygons. (self intersecting polygons are illegal). -- Jean-Pierre CHARRAS _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : kicad-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
