Alex,
Thank you. As I just posted, I think I am seeing that *most* people
think of the distance between 2 rects as the distance between nearest
edges or vertices which is the same as the smallest distance between any
two points.
On 2/15/2021 7:53 PM, Alex Tweedly via use-livecode wrote:
On 15/02/2021 23:21, Sean Cole (Pi) via use-livecode wrote:
Hi,
No point reinventing the wheel..
But most of those links actually did not have this particular wheel,
or anything like it.
The exception was the last one (programmerssought.com) which had an
ugly, inefficient and lengthy (45 lines in Python) solution. [OK, that
45 includs blank and comments :-) !!
For me, a more precise problem specification is:
Given two rectangles (in regular Livecode format), the distance
between them is :
- if they touch or overlap, distance is zero.
- otherwise, it's the smallest distance from any point in R1 to any
point in R2.
Which leads to a simple solution
function rdist R1, R2
local DX, DY
put max( item 1 of R1 - item 3 of R2, item 1 of R2 - item 3 of R1,
0) into DX
put max( item 2 of R1 - item 4 of R2, item 2 of R2 - item 4 of R1,
0) into DY
return sqrt( DX*DX + DY * DY)
end rdist
Alex.
Lots of other way. Distance between two near or far edges. distance
between
corners, distance to centers, or area median, area of space between,
overal usage area minus the area used by the two rectangles. Math is
fun.
Keeps us in business.
Google (distance between two rectangles):
https://stackoverflow.com/questions/4978323/how-to-calculate-distance-between-two-rectangles-context-a-game-in-lua
https://math.stackexchange.com/questions/2724537/finding-the-clear-spacing-distance-between-two-rectangles
https://www.wyzant.com/resources/answers/583373/finding-the-distance-between-two-rectangles
https://www.programmersought.com/article/44554760896/
etc
On Mon, 15 Feb 2021 at 22:53, Paul Dupuis via use-livecode <
use-livecode@lists.runrev.com> wrote:
This is an Off Topic informal poll of sorts, but related to LiveCode as
I am writing a LiveCode expression to determine if 2 arbitrary
rectangles (r1,r2) are with some distance d (in px) of one another. In
considering this problem, the questions comes up: What is meant by
rectangles being within a distance d of one another. What is the 'd'
measured from?
center to center? Easiest is many ways, but I don't think this is what
most people would think of.
adjacent edge to adjacent edge? This is harder (I think), but I think
this is what more people intuitively think of. To me, implicit in the
visual concept of 2 rects being within some distance of one another is
that they are NOT overlapping, but that some gap exists between the
nearest adjacent edges?
Something else? What does 2 rects being 'within' d pixels of one
another mean to you, if not one of the two above options?
Maybe there is a exact mathematical definition of what 2 rectangles
being within distance d of one another is, but, if there is, I am
unfamiliar with it.
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