Python library for reading/displaying Eagle binary files
========================================================

Supported versions
------------------

This library has been written and tested for Eagle 5.11.
It *probably* works well with other 5.x versions, but
version 4.x support is not very good. Some very limited
testing with version 4.9 has been performed, and the files
mostly parse okay, but there are differences in the format,
so the 4.x format should be systematically reviewed instead
of randomly fixing just the differences that are encountered.

As an example, the value used for long pads in 5.11 means
offset pads in 4.9. Also, in 4.9, the schema section has no
attribute subsections, but the field used in 5.11 for
their count contains some other data in 4.9, which kind of
caused the parser to wonder why a child section overflows
the parent section.

Missing features
----------------

There are many unknown bits and bytes, for which I have no
idea what they are supposed to mean. You can get a colored
hexdump with eagledump.py to see visually which parts of
a file are not understood. Some things are very possibly
misunderstood. The parser tries to catch unexpected things,
but it certainly won't catch everything. String references
in the binary files are done in such a way, that missing
even one causes you to mess up all the strings after it.
Fortunately, at least the parser knows when it has messed
up. (When not all strings have been read)
I have no idea how the checksum calculation is done, so
files can't currently be written. (And even if this was
known, there is still some unknown data)

The renderer does not fill polygons or render text.
(Because filling polygons is pretty hard when you have to
take the isolation aspects into account. Add the fact that
you also have a minimum width to take into account, and
you don't want to do it anymore, at all. Text rendering
is very probably hard to do exactly like eagle, and if I
can't have it exactly right, I don't want it at all ;)
Items aren't rendered in the correct order or grouped in
any way. Thus items in bottom layer might be drawn on top
of items in the top layer, and items in the same layer
show through each other. Fill styles aren't used for lines,
arcs and some other things. Some items aren't rendered at
all, such as holes. Some properties aren't rendered correctly,
such as line styles and pin functions. (Lines are always
rendered continuous, pins without function, etc.)

Usage
-----

Dumping files: python eagledump.py FILE
- File can be a library, schematic or board (.lbr, .sch, .brd)
- Dumps files both in colored hexdump and human readable format
- Hexdump colors:
  * Red = unknown byte
  * Green = known byte
  * Blue = presumed to always be zero
  * Some combination of the above = contains bits from the
    respective categories

Viewing files: python eagleview.py FILE TYPE OBJECT
- File can be a library, schematic or board (.lbr, .sch, .brd)
- Type is one of: schematic, board, symbol, package, device
- Object selects the symbol/package/device to be displayed