Bitmap/Flood fill: Difference between revisions
→{{header|J}}: add alternative findcontig
(→{{header|J}}: Add usage) |
(→{{header|J}}: add alternative findcontig) |
||
Line 524:
<lang j>
NB. finds and labels contiguous areas with the same numbers
NB. ref: http://www.jsoftware.com/pipermail/general/2005-August/023886.html
findcontig=: (|."1@|:@:>. (* * 1&(|.!.0)))^:4^:_@(* >:@i.@$)
NB.*getFloodpoints v Returns points to fill given starting point (x) and image (y)
getFloodpoints=: [: 4&$.@$. [ (] = getPixels) [: findcontig ] -:"1 getPixels
NB.*floodFill v Floods area
NB. x is: 2-item list of (y x) ; (color)
floodFill=: (1&({::)@[ ;~ 0&({::)@[ getFloodpoints ]) setPixels ]
Line 546:
myimg=: (5 36;red) floodFill myimg
viewRGB myimg</lang>
'''Alternative findcontig:'''<br>
The following alternative version of <code>findcontig</code> is less concise but is leaner, faster, works for n-dimensions and is not restricted to numerical arrays.
<lang>NB. ref: http://www.jsoftware.com/pipermail/general/2005-August/024174.html
eq=:[:}:"1 [:($$[:([:+/\1:,}:~:}.),) ,&_"1 NB. equal numbers for atoms of y connected in first direction
eq_nd=: i.@#@$(<"0@[([:, |:^:_1"0 _)&> [:EQ&.> <@|:"0 _)] NB. n-dimensional eq, gives an #@$,*/@$ shaped matrix
repl=: (i.~{.){ {:@] NB. replaces x by applying replace table y
cnnct=: [: |:@({."1<.//.]) [: ; <@(,.<./)/.~
findcontig_nd=: 3 : '($y)${. ([:({.,~}:) ([ repl cnnct)/\.)^:([:+./@(~:/)2&{.)^:_ (,{.) eq_nd (i.~ ~.@,) y'</lang>
=={{header|Perl}}==
| |||