Index: trunk/doc/developer/data.html =================================================================== --- trunk/doc/developer/data.html (revision 13989) +++ trunk/doc/developer/data.html (revision 13990) @@ -77,37 +77,36 @@
-The location of a layer group on of: +The location of a layer group on of (flags are in layer.h):
-In pcb-rnd only copper layers and the outline layer are fully explicit. -There are two hardwired silk layers, one for the top and one for the bottom side. -The silk layers are semi-explicit: they are existing layers in all structs -but: +In pcb-rnd most layer types are fully explicit:
-The outline layer is a hack: it's really an internal copper layer. If -the code detects the name of the layer is "outline" anywhere, it branches. +The layers of a composite layer group are combined + and -, depending +on the PCB_LYC_SUB in their comb field.
-There are a few virtual layers: +Assumptions: there are two silk layers, one for the top and one for the bottom +side and there are always a top and a bottom copper layer. (Long term +assumptions will be removed.) The outline layer has to be global. +
+The rest of the layers are virtual layers, often just GUI hacks, e.g.:
Global data affect all layers. The most trivial example is via: