Zhang-Suen thinning algorithm: Difference between revisions
Added Wren
SqrtNegInf (talk | contribs) m (→{{header|Perl}}: Fix link: Perl 6 --> Raku) |
(Added Wren) |
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................................</pre>
=={{header|Wren}}==
{{trans|Kotlin}}
<lang ecmascript>class Point {
construct new(x, y) {
_x = x
_y = y
}
x { _x }
y { _y }
}
var image = [
" ",
" ################# ############# ",
" ################## ################ ",
" ################### ################## ",
" ######## ####### ################### ",
" ###### ####### ####### ###### ",
" ###### ####### ####### ",
" ################# ####### ",
" ################ ####### ",
" ################# ####### ",
" ###### ####### ####### ",
" ###### ####### ####### ",
" ###### ####### ####### ###### ",
" ######## ####### ################### ",
" ######## ####### ###### ################## ###### ",
" ######## ####### ###### ################ ###### ",
" ######## ####### ###### ############# ###### ",
" "
]
var nbrs = [
[ 0, -1], [ 1, -1], [ 1, 0],
[ 1, 1], [ 0, 1], [-1, 1],
[-1, 0], [-1, -1], [ 0, -1]
]
var nbrGroups = [
[ [0, 2, 4], [2, 4, 6] ],
[ [0, 2, 6], [0, 4, 6] ]
]
var toWhite = []
var grid = List.filled(image.count, null)
for (i in 0...grid.count) grid[i] = image[i].toList
var numNeighbors = Fn.new { |r, c|
var count = 0
for (i in 0...nbrs.count - 1) {
if (grid[r + nbrs[i][1]][c + nbrs[i][0]] == "#") count = count + 1
}
return count
}
var numTransitions = Fn.new { |r, c|
var count = 0
for (i in 0...nbrs.count - 1) {
if (grid[r + nbrs[i][1]][c + nbrs[i][0]] == " ") {
if (grid[r + nbrs[i + 1][1]][c + nbrs[i + 1][0]] == "#") count = count + 1
}
}
return count
}
var atLeastOneIsWhite = Fn.new { |r, c, step|
var count = 0
var group = nbrGroups[step]
for (i in 0..1) {
for (j in 0...group[i].count) {
var nbr = nbrs[group[i][j]]
if (grid[r + nbr[1]][c + nbr[0]] == " ") {
count = count + 1
break
}
}
}
return count > 1
}
var thinImage = Fn.new {
var firstStep = false
var hasChanged
while (true) {
hasChanged = false
firstStep = !firstStep
for (r in 1...grid.count - 1) {
for (c in 1...grid[0].count - 1) {
if (grid[r][c] == "#") {
var nn = numNeighbors.call(r, c)
if ((2..6).contains(nn)) {
if (numTransitions.call(r, c) == 1) {
var step = firstStep ? 0 : 1
if (atLeastOneIsWhite.call(r, c, step)) {
toWhite.add(Point.new(c, r))
hasChanged = true
}
}
}
}
}
}
for (p in toWhite) grid[p.y][p.x] = " "
toWhite.clear()
if (!firstStep && !hasChanged) break
}
for (row in grid) System.print(row.join())
}
thinImage.call()</lang>
{{out}}
<pre>
# ########## #######
## # #### #
# # ##
# # #
# # #
# # #
############ #
# # #
# # #
# # #
# # #
# ##
# ############
### ###
</pre>
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