[PythonCAD] layers

Art Haas ahaas at airmail.net
Tue Jul 27 17:17:30 CEST 2004

On Tue, Jul 27, 2004 at 12:44:06AM -0500, Eric Wilhelm wrote:
> Continuing with my review, I'll move on to the interface.  I'm being
> critical, because that's how things get critiqued.  Please don't take
> any of this as scathing, scalding, or flaming.

This is good stuff. Keep it coming.

> Layers nested under layers seems awkward, and there doesn't appear to
> be a way to create more than one top-level layer.  Maybe your analogy
> for top-level layers is the same as the one that autocad uses for
> model/layout tabs.  If I could have multiple top-level layers, would
> I be able to see them simultaneously?

A-la Highlander, there can be only one ... top layer. I think of layers
in a manner similar to directories on the unix file system, and the top
layer is the root directory. You can have as many sublayers as you like,
and each sublayer can have sublayers, and so on, but there is just one
topmost directory. This approach was how ME-10 worked as well. My
AutoCAD experiences from way back when are that a drawing had lots of
layers, but that layers could not be nested. Nesting layers may be
possible, but I don't recall doing that, nor seeing drawings made by
others that did that.

> Also, the differentiation in color of the active layer could get
> unsettling at higher drawing densities.  If I had just drawn a yellow
> line on layer '300' and then changed to layer 'concrete' and wanted to
> snap to that yellow line, it is not yellow anymore.  That could get
> confusing if it is between 10 other lines.

That is true.

> Possibly, the inactive layer coloring should be done with some sort of mask 
> using the background color (if the background is black, whites turn grey, etc 
> (object color minus background color?))  But, even at that, there should be a 
> way to toggle it on and off.  It is good to be able to highlight the active 
> layer, or individual inactive layers, but I mostly don't care what layer 
> things are on while drawing (there's some mental record-keeping and sometimes 
> it just plain doesn't matter.)  That said, turning off layers to find what is 
> what can be a real pain too.

In another mail I mentioned that the color change when activating or
deactivating a layer came from my use of ME-10, and ME-10 had the
ability to disable the color change. I always found it very confusing
when working in that mode, as I had a hard time telling what entities
were in the layer (in ME-10 speak the layer is a "part") I was currently
editing and which entities weren't. Adding the ability to switch on or
off the use of the INACTIVE_LAYER_COLOR sounds like something that could
be done with relatively little coding, so I'll take a look at doing
that. If someone sends along a patch to do this I'd look at that
also ... :-)

Man once surrendering his reason, has no remaining guard against absurdities
the most monstrous, and like a ship without rudder, is the sport of every wind.

-Thomas Jefferson to James Smith, 1822

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