Panel optimize

[set-soft]

When processing a panel with tabs and similar stuff the PCB contour is complex.
PcbDraw time needed to process these cases increases exponentially.
This patch solves a couple of issues related to extracting the PCB contour:

1. The algorithm used to find the closest element to a point.
2. Compute the contour just once (not twice)

[yaqwsx]

What's the point of commenting out this function? At the moment, it is not used. However, it makes sense to have it ready to complement pseudo_distance. And if we want to get rid of it, we should delete it.

[set-soft]

I commented it because it isn't used, you can uncomment it when needed. Or just as a reference of what a real distance is.

I usually uncomment unused functions to avoid confusion (people might think this is used), misleading coverage results (code not covered just because is dead), avoid wasting resources, etc.

[yaqwsx]

Hi! Thanks for the optimization. I have a suggestion not to use commented out code.

Nevertheless, the true cost is in the following routine:

PcbDraw/pcbdraw/plot.py

Lines 429 to 469 in d2af9d4

	while len(elements) > 0:
	# Initiate seed for the outline
	outline = [elements[0]]
	elements = elements[1:]
	size = 0
	# Append new segments to the ends of outline until there is none to append.
	while size != len(outline) and len(elements) > 0:
	size = len(outline)
	i = get_closest(outline[0].start, [x.end for x in elements])
	if SvgPathItem.is_same(outline[0].start, elements[i].end):
	outline.insert(0, elements[i])
	del elements[i]
	continue
	i = get_closest(outline[0].start, [x.start for x in elements])
	if SvgPathItem.is_same(outline[0].start, elements[i].start):
	e = elements[i]
	e.flip()
	outline.insert(0, e)
	del elements[i]
	continue
	i = get_closest(outline[-1].end, [x.start for x in elements])
	if SvgPathItem.is_same(outline[-1].end, elements[i].start):
	outline.insert(0, elements[i])
	del elements[i]
	continue
	i = get_closest(outline[-1].end, [x.end for x in elements])
	if SvgPathItem.is_same(outline[-1].end, elements[i].end):
	e = elements[i]
	e.flip()
	outline.insert(0, e)
	del elements[i]
	continue
	# ...then, append it to path.
	first = True
	for x in outline:
	path += x.format(first)
	first = False

It is cubic to the number of input segments. It could be done in n log(n). However, that would require the use of some space segmentation trees. I wanted to preserve the simplicity of the code, and I was counting on the outline being quite simple. This is, however, not the case with panels without reconstructed arcs.

[set-soft]

Nevertheless, the true cost is in the following routine:

Yes, this is exactly why this patch optimizes get_closest, the bottle neck of the code you mention.

[yaqwsx]

This should be addressed by afb3b8b. The commit still needs further testing to ensure there are no edge cases breaking it.