fix flat render when open ends close on expansion

app.js

@@ -236,10 +236,10 @@ const script = {
         "kiri",
         "ext/three",
         "license",
-        // "ext/clip2",
+        "ext/clip2", // work.test
         "ext/tween",
         "ext/fsave",
-        // "ext/earcut",
+        "ext/earcut", // work.test
         "add/array",
         "add/three",
         "geo/base",

notes.md

@@ -36,10 +36,12 @@
 
 * `B` fix adaptive slicing. also with multi-extruder
 * `B` fix supports with grouped parts
+* `B` infill follows inside shells
 * `F` speculative background preview generation
 * `F` control for size of purge block (with 0=disabled)
 * `F` add separate fill speed control
 * `F` manual support addition / control
+* `F` control layer start position
 * `F` polishing and other non-planar work
 * `F` gradient infill https://www.youtube.com/watch?v=hq53gsYREHU&feature=emb_logo
 * `F` feather sharp tips by reducing extrusion in area of overlap

src/kiri/print.js

@@ -200,7 +200,7 @@
                     (Math.pow(pos.Y - lastPos.Y ,2))
                 );
                 let dR = (dE / dV); // filament per mm
-                if (dR < 0.025) {
+                if (dR < 0.025 || dR > 0.35) {
                     console.log(height.round(2), pos.Z.round(2), dV.round(2), dR.round(3));
                 }
             }

src/kiri/render.js

@@ -127,7 +127,13 @@
             polys.forEach(poly => {
                 let exp = off_opt.outs = [];
                 if (poly.isOpen()) {
+                    // shorten line by offset
+                    const pp = poly.points, pl = pp.length;
+                    pp[0] = pp[0].offsetPointTo(pp[1], offset);
+                    pp[pl-1] = pp[pl-1].offsetPointTo(pp[pl-2], offset);
                     exp.appendAll(POLY.expand_lines(poly, offset * 0.9, z));
+                    // force re-nest if offsets cause ends to join
+                    exp = POLY.flatten(exp,[],true);
                     this.stats.flat_line = 0;
                 } else if (offset) {
                     POLY.offset([poly],  offset * 0.9, off_opt);