1 | srecord noeq G22RegionThinner_v2<Img extends WidthAndHeight>(IImageRegion<Img> originalRegion) is Steppable { |
2 | Rect bounds; |
3 | IImageRegion<Img> region; |
4 | bool phase1done; |
5 | |
6 | settable bool debug; |
7 | settable bool doFinalStep = true; |
8 | settable int lastPhaseThreshold1 = 2; |
9 | settable int lastPhaseThreshold = 5; |
10 | |
11 | settable byte[] lookupTable; |
12 | |
13 | // 0 = outside of region |
14 | // 1 = inner pixel |
15 | // 2 = border pixel |
16 | // index is in bounds coordinates |
17 | byte[] pixels; |
18 | |
19 | int idx(int x, int y) { |
20 | ret (y-bounds.y)*bounds.w+x-bounds.x; |
21 | } |
22 | int idx(Pt p) { ret idx(p.x, p.y); } |
23 | |
24 | Pt idxToPt(int idx) { |
25 | ret pt(bounds.x+(idx % bounds.w), bounds.y+idx/bounds.w); |
26 | } |
27 | |
28 | byte getPixel(long p) { |
29 | ret getPixel(firstIntFromLong(p), secondIntFromLong(p)); |
30 | } |
31 | |
32 | byte getPixel(Pt p) { |
33 | ret !containsPt(bounds, p) ? 0 : pixels[idx(p)]; |
34 | } |
35 | |
36 | byte getPixel(int x, int y) { |
37 | ret !containsPt(bounds, x, y) ? 0 : pixels[idx(x, y)]; |
38 | } |
39 | |
40 | bool contains(int x, int y) { |
41 | ret getPixel(x, y) != 0; |
42 | } |
43 | |
44 | bool clearPixel(int x, int y) { |
45 | if (!region.contains(x, y)) false; |
46 | pixels[idx(x, y)] = 0; |
47 | true; |
48 | } |
49 | |
50 | void init { |
51 | if (bounds != null) ret; |
52 | bounds = originalRegion.bounds(); |
53 | pixels = new byte[area(bounds)]; |
54 | for (Pt p : originalRegion.pixelIterator()) |
55 | pixels[idx(p.x, p.y)] = 1; |
56 | |
57 | region = new ThinnedRegion; |
58 | } |
59 | |
60 | class ThinnedRegion is IImageRegion<Img> { |
61 | public Img image() { ret originalRegion.image(); } |
62 | public Rect bounds() { ret bounds; } |
63 | |
64 | public bool contains(int x, int y) { |
65 | ret containsPt(bounds, x, y) && pixels[idx(x, y)] > 0; |
66 | } |
67 | |
68 | public ItIt<Pt> pixelIterator() { |
69 | ret iff_null(new IF0<Pt> { |
70 | int idx = 0; |
71 | |
72 | public Pt get() { |
73 | for (; idx < pixels.length; idx++) |
74 | if (pixels[idx] > 0) |
75 | ret idxToPt(idx++); |
76 | null; |
77 | } |
78 | }); |
79 | } |
80 | } |
81 | |
82 | public bool step() { |
83 | init(); |
84 | |
85 | if (phase1done) |
86 | ret finalStep(); |
87 | |
88 | L<PtBuffer> traces = g22_allBorderTraces_withDiagonals(region); |
89 | for (points : traces) |
90 | for (p : points) |
91 | pixels[idx(p)] = 2; |
92 | |
93 | new PtBuffer toDelete; |
94 | |
95 | for (points : traces) { |
96 | int nPoints = l(points); |
97 | BitSet deletable = emptyBitSet(nPoints); |
98 | for i to nPoints: { |
99 | bool del = deletableBorderPoint(points, i); |
100 | /*bool del2 = deletableBorderPoint_old(points, i); |
101 | if (del != del2) |
102 | failWithVars("deletableBorderPoint", +i, +nPoints, +del);*/ |
103 | if (del) |
104 | deletable.set(i); |
105 | } |
106 | |
107 | // handle special cases |
108 | for i to nPoints: |
109 | if (cyclicGet(deletable, nPoints, i-1) |
110 | && !deletable.get(i) |
111 | && cyclicGet(deletable, nPoints, i+1)) { |
112 | Pt p = points.get(i); |
113 | Pt prev = ptMinus(cyclicGet(points, i-1), p); |
114 | Pt next = ptMinus(cyclicGet(points, i+1), p); |
115 | int dir1 = onePathLookupDirection(prev); |
116 | int dir2 = onePathLookupDirection(next); |
117 | int diff = mod(dir2-dir1, 8); |
118 | if (debug) printVars("special case", +p, +prev, +next, +dir1, +dir2, +diff); |
119 | if (diff == 1 || diff == 7) |
120 | deletable.set(i); |
121 | } |
122 | |
123 | for i to nPoints: |
124 | if (deletable.get(i)) |
125 | toDelete.add(points.get(i)); |
126 | } |
127 | |
128 | for (p : toDelete) |
129 | pixels[idx(p)] = 0; |
130 | |
131 | if (empty(toDelete)) |
132 | set phase1done; |
133 | true; |
134 | } |
135 | |
136 | bool deletableBorderPoint(PtBuffer points, int i) { |
137 | //L<Pt> range = cyclicSubList_incl(points, i-3, i+3); |
138 | LongBuffer pointsBuf = points.buf; |
139 | long p_long = pointsBuf.get(i); |
140 | |
141 | // special case |
142 | |
143 | if (p_long == cyclicGet(pointsBuf, i-2) |
144 | || p_long == cyclicGet(pointsBuf, i+2)) { |
145 | printVars ifdef G22RegionThinner_debug("special case", p := ptFromLong(p_long)); |
146 | false; |
147 | } |
148 | |
149 | int surroundingBorderPixels = 0, surroundingInnerPixels = 0; |
150 | for (int dir = 1; dir <= 8; dir++) { |
151 | long p2_long = onePathDirection_long(p_long, dir); |
152 | byte value = getPixel(p2_long); |
153 | if (value == 2 && !rangeContains(pointsBuf, i, p2_long)) { |
154 | printVars ifdef G22RegionThinner_debug("surroundingBorderPixel", p2 := ptFromLong(p2_long)); |
155 | //surroundingBorderPixels++; |
156 | false; |
157 | } else if (value == 1) { |
158 | printVars ifdef G22RegionThinner_debug("surroundingInnerPixel", p2 := ptFromLong(p2_long)); |
159 | surroundingInnerPixels++; |
160 | } |
161 | } |
162 | |
163 | ret surroundingInnerPixels > 0; |
164 | |
165 | //bool deletable = surroundingInnerPixels > 0 && surroundingBorderPixels == 0; |
166 | //printVars ifdef G22RegionThinner_debug(+p, +surroundingInnerPixels, +surroundingBorderPixels, +deletable, +range); |
167 | //ret deletable; |
168 | } |
169 | |
170 | bool rangeContains(LongBuffer pointsBuf, int i, long p2_long) { |
171 | for (int j = i-3; j <= i+3; j++) |
172 | if (cyclicGet(pointsBuf, j) == p2_long) |
173 | true; |
174 | false; |
175 | } |
176 | |
177 | bool deletableBorderPoint_old(PtBuffer points, int i) { |
178 | L<Pt> range = cyclicSubList_incl(points, i-3, i+3); |
179 | Pt p = points.get(i); |
180 | |
181 | // special case |
182 | if (eq(range.get(1), p) || eq(range.get(5), p)) false; |
183 | |
184 | int surroundingBorderPixels = 0, surroundingInnerPixels = 0; |
185 | for (int dir = 1; dir <= 8; dir++) { |
186 | Pt p2 = ptPlus(p, onePathDirection(dir)); |
187 | byte value = getPixel(p2); |
188 | if (value == 2 && !range.contains(p2)) |
189 | surroundingBorderPixels++; |
190 | else if (value == 1) |
191 | surroundingInnerPixels++; |
192 | } |
193 | |
194 | bool deletable = surroundingInnerPixels > 0 && surroundingBorderPixels == 0; |
195 | |
196 | printVars ifdef G22RegionThinner_debug(+p, +surroundingInnerPixels, +surroundingBorderPixels, +deletable, +range); |
197 | ret deletable; |
198 | } |
199 | |
200 | IImageRegion region aka get() { ret or(region, originalRegion); } |
201 | |
202 | // go from 2 pixels wide to 1 pixel wide (TODO) |
203 | bool finalStep() { |
204 | if (!doFinalStep) false; |
205 | |
206 | if (lookupTable == null) |
207 | lookupTable = new G22RegionThinner_LookupTable() |
208 | .lastPhaseThreshold(lastPhaseThreshold) |
209 | .lastPhaseThreshold1(lastPhaseThreshold1)!; |
210 | |
211 | bool change; |
212 | int x1 = bounds.x, x2 = bounds.x2(); |
213 | int y1 = bounds.y, y2 = bounds.y2(); |
214 | printVars ifdef G22RegionThinner_lastPhase_debug("finalStep", +x1, +y1, +x2, +y2); |
215 | |
216 | var pingSource = pingSource(); |
217 | |
218 | for (int y = y1; y < y2; y++) { |
219 | ping(pingSource); |
220 | for (int x = x1; x < x2; x++) { |
221 | // need a set pixel |
222 | if (!contains(x, y)) continue; |
223 | |
224 | // check if this pixel is essential to hold the structure |
225 | // together by doing a floodfill in the 3x3 neighborhood |
226 | // (simulating the pixel being cleared already) |
227 | |
228 | var imgPattern = ubyteFromBits( |
229 | contains(x-1, y-1), |
230 | contains(x, y-1), |
231 | contains(x+1, y-1), |
232 | contains(x-1, y), |
233 | contains(x+1, y), |
234 | contains(x-1, y+1), |
235 | contains(x, y+1), |
236 | contains(x+1, y+1)); |
237 | |
238 | bool delete = getBit(lookupTable, imgPattern); |
239 | |
240 | printVars ifdef G22RegionThinner_lastPhase_debug( |
241 | +x, +y, +imgPattern, +pixels, +delete); |
242 | |
243 | if (delete) |
244 | change |= clearPixel(x, y); |
245 | } |
246 | } |
247 | ret change; |
248 | } |
249 | } |
Began life as a copy of #1034983
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Snippet ID: | #1035111 |
Snippet name: | G22RegionThinner_v2 - thin a region to 1 pixel wide [backup] |
Eternal ID of this version: | #1035111/1 |
Text MD5: | 2d6300eef7c1e021c9e342ae1bd61b11 |
Author: | stefan |
Category: | javax |
Type: | JavaX fragment (include) |
Public (visible to everyone): | Yes |
Archived (hidden from active list): | No |
Created/modified: | 2022-03-30 03:47:39 |
Source code size: | 7495 bytes / 249 lines |
Pitched / IR pitched: | No / No |
Views / Downloads: | 169 / 163 |
Referenced in: | [show references] |