pcb-rnd modularization

Why bother...

I believe good software should be modular. This is especially important in the context of large software, such as CAD applications. There should be a thin core that can model the world and provide the basic operations defined on it but anything else should go in separate modules.

Fortunately PCB already had a strong infrastructure supporting this idea. It has dynamic loadable plugins and the GUI and exporters are in separate HID modules. While working on pcb-gpmi and later pcb-rnd, I added the gpmi module as a separate plugin.

In version 1.0.8 to 1.1.0 a considerable chunk of core code has been moved into core plugins. A core plugin is just a plugin that is maintained together with the core, in the same repository, still the code is somewhat detached from the core. More importantly, the user can choose, for each plugin, separately:

I believe such modularization has benefits on multiple levels:

Progress in charts


All numbers are in SLOC and are acquired running sloccount on the given directory. While lines of code alone is not a true measure of complexity, it's a good estimation. The slices of pie charts are the major components of the pcb-rnd executable.
Before modularization: pcb-rnd version 1.0.7
Note: gpmi was already a plugin
After modularization: current pcb-rnd
Note: gpmi is part of the "plugins" slice

Zooming on to the plugins

total size per class
IO plugins
feature plugins
export plugins
HID plugins
import plugins
library plugins
footprint plugins

(Red means the plugin doesn't really work).

Progress in numbers

Below is a table with the summary of core plugins.
module size [sloc] status configure
class description
acompnet75 WIP disable feature Auto-complete the current network. A very limited autorouter/assistant.
autocrop52 works buildin feature Reduce the board dimensions to just enclose the objects on the board.
autoplace672 works buildin feature Automatically place subcircuits.
autoroute4358 works buildin feature Automatically route selected or all rats. This is the original autorouter.
(doesn't update rtrees)
buildin feature All objects on the board are up-down flipped.
diag613 works disable feature Actions for pcb-rnd core diagnostics, intended for developers. These are not in core because end users normally don't need these. As a plugin, due to dynamic loading, it can be dropped on an existing pcb-rnd installation with minimal risk of scaring away a reproducible bug.
dialogs1138 works disable feature Interactive core functionality: HID-independent GUI dialogs (enabled by GUI HIDs)
distalign433 works buildin feature Introducing Align() and Distribute(), which work much like the similarly named functions in Visio. Given that PCB does not have the concept of "first selected object" to draw on, the reference points can be selected by arguments.
distaligntext469 works buildin feature Same as distalign, operates on text objects.
djopt2255 works buildin feature Various board optimization algorithms.
draw_csect741 works disable feature Draw cross section and layer map.
draw_fab282 works buildin feature Draw the fab layer (for various exporters).
draw_fontsel188 works disable feature Draw the font selector GUI
export_bboard439 WIP disable-all export Export breadboard
export_bom235 works buildin export Export bom (Bill of Materials)
export_dsn451 works buildin export Export specctra .dsn files
export_dxf595 works buildin export Export dxf
export_fidocadj279 WIP buildin export Export to FidoCadJ format (.fcd)
export_gcode2478 works buildin export Export to gcode
export_gerber1070 works buildin export Export to gerber
export_ipcd356371 works buildin export IPC-D-356 Netlist export.
export_lpr104 works buildin export Export to lpr (using export_ps to generate postscript)
export_nelma678 deprecated disable export Export to nelma (Numerical capacitance calculator) - the 3rd party software, Nelma is not maintained any more.
export_openems1372 WIP disable export Export copper to OpenEMS simulation
export_openscad725 WIP buildin export Export openscad
export_png1382 works buildin export Export to png, gif and jpeg
export_ps1576 works buildin export Export postscript or embedded postscript.
export_stat295 works buildin export Export various board statistics in lihata format
export_svg654 works buildin export Scalable Vector Graphics (SVG) exporter
export_test94 WIP disable export A thin layer of code to dump exporter calls for testing the HID exporter API.
export_xy718 works buildin export Template based export of XY centroid subcircuit data e.g. for pick & place.
extedit305 works buildin feature invoke external program to edit parts of the current board
fontmode262 works buildin feature Font editing actions.
fp_board131 WIP buildin fp Footprint: load a board and expose all the unique subcircuits on that board as a footprint library
fp_fs424 works buildin fp Footprint: file system based implementation. Used to be called Newlib: load footprints from directories. Run external processes for the parametric footprints.
fp_wget628 works buildin fp Footprint: get static (file) footprints from the web, e.g. from http://gedasymbols.org
gpmi2799 works buildin feature Scriptable plugin system with about 10 scripting languages supported and dynamic load/unload of scripts that can manipulate the GUI, the board, can implement exporters, etc.
hid_batch324 works buildin hid HID without GUI: read actions from stdin.
hid_gtk2_gdk1227 works buildin hid GUI: GTK2 HID with GDK software rendering.
hid_gtk2_gl924 works buildin hid GUI: GTK2 with opengl rendering
hid_gtk3_cairo1131 WIP disable-all hid GUI: the GTK3 HID, using cairo for rendering
hid_gtk3_gl52 WIP disable-all hid GUI: the GTK3 HID, using gl for rendering
hid_lesstif6595 works buildin hid GUI: the lesstif HID.
hid_remote1185 WIP disable-all hid Remote access HID: implement a protocol and use it to relay between a core and a remote HID implementation.
import_dsn269 works buildin import Import specctra .dsn files
import_edif3628 works buildin import Import plugin for netlists in the EDIF format.
import_hpgl133 works buildin import Emulate a plotter and import the plot as lines, arcs and polygons.
import_ipcd356378 works buildin import IPC-D-356 Netlist and pad centroid import
import_ltspice244 works buildin import Import the netlist and footprints from an ltspice .asc and .net pair of files
import_mentor_sch495 works buildin import Import Mentor Graphics Design Capture from flattened .edf netlist, using a parts conversion table.
import_mucs119 works buildin import Import lines and vias from MUCS unixplot .pl files
import_netlist141 works buildin import Import plugin for netlists in the classic pcb netlist format.
import_sch310 works buildin import Imports footprints and netlist data from the schematics (or some other source).
import_tinycad151 works buildin import Import the netlist and footprints from a tinycad netlist.
io_autotrax1578 works buildin io Import and export autotrax layouts and footprints.
io_eagle3902 works buildin io Load the design from eagle's xml and binary formats.
io_hyp4065 works buildin io Import plugin for hyperlynx geometry (no polygons yet).
io_kicad3478 works buildin io Load and save the design and footprints in Kicad's s-expression format - this is the new, currently preferred format in Kicad.
io_kicad_legacy878 works buildin io Export the design and footprints in Kicad's legacy format.
io_lihata3784 works buildin io Load and save the design and footprints in the lihata board format.
io_mentor_cell400 WIP disable io Load Mentor Graphics cell footprint library and make footprints available (e.g. for fp_board)
io_pcb2723 works buildin io Load and save the design and footprints in the original gEDA/PCB text format.
io_tedax831 works buildin import Import and export tEDAx netlists and footprints.
jostle432 works buildin feature Pushes lines out of the way.
lib_compat_help1155 works buildin lib a library of functions providing a simplified API compatibility layer, mainly for I/O plugins
lib_gensexpr13 works disable-all lib S-expression parser lib
lib_gtk_common10952 works disable-all lib hid_gtk* common code (regardless of gtk version or drawing mechanism: for both gtk2 and gtk3 and for both sw rendering and gl)
lib_gtk_config2395 works disable-all lib hid_gtk* preferences dialog common code (regardless of gtk version)
lib_gtk_hid1471 works disable-all lib Generic gtk HID implementation, independent of GTK version (2 vs. 3) and rendering engine. Mostly a dispatcher that fills in all the glue to connect the parts. An actual gtk HID implementation may use this lib or replace parts of it or the whole with local implementation.
lib_hid_common292 works disable-all lib hid_* common helper functions
lib_hid_gl1127 works disable-all lib generic openGL renderer shared among GUI HIDs
lib_legacy_func91 works buildin lib Random collection of old/obsolete (legacy) functions. 3rd party plugins may depend on them. This module implements C functions and variables and does not register actions or flags.
lib_netmap149 works disable-all lib create disposable cross-reference maps between all objects and all nets
lib_polyhelp703 works buildin lib functions to help plugins processing polygons and PolyHatch() action
loghid314 WIP disable feature Sits between a HID (or exporter) and the core and logs all core->plugin calls made through the HID structure.
millpath230 WIP disable feature Calculate and simulate toolpath for milling away opper
mincut886 works buildin feature Use the minimal cut algorithm to indicate shorts: instead of highlighting two random pins/pads, try to highlight the least number of objects that connect the two networks.
oldactions174 works disable feature Random collection of old/obsolete actions. Bell(): audible feedback, DumpLibrary(): print footprint library on stdout, a set of debug actions useful for writing pcb scripts: Debug(), DebugXY(), Return(). Old plugin actions to toggle or set settings that are now accessible via the unified config system (vendordrill, djopt)
polycombine209 works buildin feature The selected polygons are combined together according to the ordering of their points.
polystitch96 works buildin feature The polygon under the cursor (based on closest-corner) is stitched together with the polygon surrounding it on the same layer. Use with pstoedit conversions where there's a "hole" in the shape - select the hole.
propedit955 works buildin feature List and edit properties of a group of objects.
puller1731 works buildin feature Pull traces to minimize their length.
query1898 works buildin feature pcb-rnd query language: execute expressions on objects and rules for the programmed drc.
renumber331 works buildin feature Renumber subcircuits (renaming them) and generate a text file for back annotation.
report854 works buildin feature Report() and ReportObject() actions - print a report about design objects.
rubberband_orig1190 works buildin feature The original rubberband code.
shand_cmd214 works buildin feature vi-like command shorthands (1..3 character long commands)
shape686 works buildin feature Generate objects of regular shape (regular polygons, circle, round rect)
sketch_route28 WIP disable feature TODO
smartdisperse172 works buildin feature Improve the initial dispersion of subcircuits by choosing an order based on the netlist, rather than the arbitrary subcircuit order. This isn't the same as a global autoplace, it's more of a linear autoplace. It might make some useful local groupings. For example, you should not have to chase all over the board to find the resistor that goes with a given LED.
stroke121 works buildin feature Configurable gesture recognition with libstroke.
teardrops210 works buildin feature Draw teardrops on pins.
vendordrill517 works buildin feature Vendor drill mapping.


Each plugin implements a class (rarely a set of classes). Classes are:
name description
feature random features directly accessible for the user, usually actions
lib support code library for other plugins (core doesn't depend on these); functionality not directly accessible for the user but other plugins may depend on it
hid Human Interface Device: interactive user interface, usually GUI
import load alien formats into the design space
export save (parts of) the design space in alien formats
fp footprint (element) library implementation
io native file format (save & load) implementation


Common status column values mean:
name description
works production quality code - configures, compiles, tested
WIP work in progress: the plugin may be avaialble for testing but is not yet production quality
abandoned unmaintained plugin; may be in working condition but there is no developer supporting it
deprecated legacy plugin scheduled for removal; may still work but will soon be removed; if your workflow depends on it, please report ASAP

Plugin dependency map

pcb-rnd plugin dependency graph