improve UX of Eeschema -> PcbNew net highlight

[Thomas Pointhuber]

# Current Behaviour

Highlighting of Components and of Net, works differently. This should be harmonized (and simplified)

Component: Click on it in Eeschema/PcbNew, it will be centered in the other window as well. Independent if in PcbNew the mouse cursor or the net-highlight tool is selected.

Net: Click on it in Eeschema. It will be selected in PcbNew only when Highlight Net is enabled there as well. Autofocus on Eeschema -> PcbNew, but not in the other direction (it should do this at least on the currently selected sheet if possible)

# Expected Behaviour

Marking nets in both tools should not depend on the currently activated tool in the other one. This is not an intuitive behavior.

# Version Information

Application: kicad
Version: (6.0.0-rc1-dev-1447-gdeae6d5bb), debug build
Libraries:
    wxWidgets 3.1.1
    libcurl/7.63.0 OpenSSL/1.1.1a zlib/1.2.11 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.4) libssh2/1.8.0 nghttp2/1.35.1
Platform: Linux 4.19.12-arch1-1-ARCH x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.1.1 (wchar_t,wx containers) GTK+ 3.24
    Boost: 1.68.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.62.0
    Compiler: Clang 7.0.1 with C++ ABI 1002

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON

[jean-pierre charras (jp-charras)]

The expected behavior is not good.

Highlighting a net in a large schematic can take a significant amount of time because the netlist calculation time.

Therefore highlighting a net cannot be made each time the user clicks on a pad/track in Pcbnew.

[Thomas Pointhuber (pointhi)]

this could be mitigated by adding a switch which enables/disables that behavior (but enabled by default). On the contrary side:

* highlight net/track has to be explicitly used. It does not happen all the time while the user wants to do different stuff
* I thought the new net-algorithm reduced the performance overhead to not noticeable in most cases?
* how often do you highlight a track (with this tool) and do not want to see it in Eeschema too?

[Tomasz Wlostowski (twlostow)]

@Jean-Pierre: JP, isn't it because the netlisting algorithm in eeschema is still a bit slow? In case of the P&S&PCB connectivity algorithms it takes fractions of a millisecond for a single net (and most of the time is taken anyway by point-to-polygon queries, which are not used in eeschema). Should we try optimizing this in V6?

Tom

[Wayne Stambaugh (stambaughw)]

@Tom and @JP, AFAIK, Jon already has the new schematic netlist code done which keeps the schematic netlist up to date on as the schematic is edited. He is just waiting for the v6 development window to open to get it merged. Once that is merged, this issue should go away unless I'm not understanding something.

[Jeff Young (jeyjey)]

I've made the highlighting consistent in both directions based on Jon's new connection code.

I'll await the "it's too slow" bug reports... ;)