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: pcb-rnd version 1.1.3
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.
autocrop158 works buildin feature Reduce the board dimensions to just enclose the elements.
autoplace618 works buildin feature Automatically place elements.
autoroute4361 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.
dbus487 WIP
(needs to install the xml?)
disable feature Remote control PCB using DBUS.
diag211 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.
distalign428 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.
distaligntext467 works buildin feature Same as distalign, operates on text objects.
djopt2334 works buildin feature Various board optimization algorithms.
draw_csect537 WIP disable feature Draw cross section and layer map.
draw_fab258 works buildin feature Draw the fab layer (for various exporters).
draw_fontsel188 WIP disable feature Draw the font selector GUI
export_bboard422 WIP disable-all export Export breadboard
export_bom234 works buildin export Export bom (Bill of Materials)
export_dsn455 works buildin export Export specctra .dsn files
export_dxf3985 WIP disable-all export Export dxf
export_fidocadj257 WIP disable-all export Export to FidoCadJ format (.fcd)
export_gcode2476 works buildin export Export to gcode
export_gerber1000 works buildin export Export to gerber
export_ipcd356472 Work-in-progress disable-all export IPC-D-356 Netlist export.
export_lpr108 works buildin export Export to lpr (using export_ps to generate postscript)
export_nelma674 works buildin export Export to nelma (Numerical capacitance calculator)
export_openscad1385 WIP disable-all export Export openscad
export_png1118 works buildin export Export to png, gif and jpeg
export_ps1645 works buildin export Export postscript or embedded postscript.
export_stat269 works buildin export Export various board statistics in lihata format
export_svg571 works buildin export Scalable Vector Graphics (SVG) exporter
export_test261 WIP disable export A thin layer of code to dump exporter calls for testing the HID exporter API.
export_xy276 works buildin export Export XY centroid element data for pick & place.
fontmode266 works buildin feature Font editing actions.
fp_fs389 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_wget570 works buildin fp Footprint: get static (file) footprints from the web, e.g. from http://gedasymbols.org
gpmi3218 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_batch319 works buildin hid HID without GUI: read actions from stdin.
hid_gtk2_gdk1203 works buildin hid GUI: GTK2 HID with GDK software rendering.
hid_gtk2_gl1638 works buildin hid GUI: GTK2 with opengl rendering
hid_gtk3_cairo1005 WIP disable-all hid GUI: the GTK3 HID, using cairo for rendering
hid_lesstif6994 works buildin hid GUI: the lesstif HID.
hid_remote1174 WIP disable-all hid Remote access HID: implement a protocol and use it to relay between a core and a remote HID implementation.
hid_srv_ws15 WIP disable-all hid HID server: websockets using hid_remote.
import_dsn238 works buildin import Import specctra .dsn files
import_edif3625 works buildin import Import plugin for netlists in the EDIF format.
import_ltspice505 works buildin import Import the netlist and footprints from an ltspice .asc and .net pair of files
import_mentor_sch493 works buildin import Import Mentor Graphics Design Capture from flattened .edf netlist, using a parts conversion table.
import_mucs114 works buildin import Import lines and vias from MUCS unixplot .pl files
import_netlist137 works buildin import Import plugin for netlists in the classic pcb netlist format.
import_sch306 works buildin import Imports element and netlist data from the schematics (or some other source).
import_tinycad148 works buildin import Import the netlist and footprints from a tinycad netlist.
io_eagle940 WIP disable-all io Load the design from eagle's xml format.
io_hyp3278 works buildin import Import plugin for hyperlynx geometry (no polygons yet).
io_kicad3179 works buildin io Load and save the design and elements in Kicad's s-expression format - this is the new, currently preferred format in Kicad.
io_kicad_legacy945 works buildin io Export the design and elements in Kicad's legacy format.
io_lihata2268 works buildin io Load and save the design and elements in the lihata board format.
io_pcb2349 works buildin io Load and save the design and elements in the original pcb text format.
io_tedax686 works buildin import Import and export tEDAx netlists and footprints.
jostle446 works buildin feature Pushes lines out of the way.
lib_gensexpr10 works disable-all lib S-expression parser lib
lib_gtk_common11405 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_config2679 works disable-all lib hid_gtk* preferences dialog common code (regardless of gtk version)
lib_gtk_hid1380 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_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.
loghid273 WIP disable feature Sits between a HID (or exporter) and the core and logs all core->plugin calls made through the HID structure.
mincut905 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.
oldactions155 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)
polycombine208 works buildin feature The selected polygons are combined together according to the ordering of their points.
polystitch185 segfaults disable-all 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.
propedit773 works buildin feature List and edit properties of a group of objects.
puller1889 works buildin feature Pull traces to minimize their length.
query1835 works buildin feature pcb-rnd query language: execute expressions on objects and rules for the programmed drc.
renumber309 works buildin feature Renumber elements (renaming them) and generate a text file for back annotation.
report1021 works buildin feature Report() and ReportObject() actions - print a report about design objects.
rubberband_orig904 works buildin feature The original rubberband code.
shand_cmd212 works buildin feature vi-like command shorthands (1..3 character long commands)
smartdisperse173 works buildin feature Improve the initial dispersion of elements by choosing an order based on the netlist, rather than the arbitrary element 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.
stroke139 partially works (doesn't work with lesstif, works with the gtk hid, but there's no zoom bindings) disable feature Gesture recognition with libstroke.
teardrops233 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

Plugin dependency map

pcb-rnd plugin dependency graph