simplify (use reclip for HEALPix)

src/reclip.js

@@ -1,4 +1,4 @@
-import {merge, range} from "d3-array";
+import {merge} from "d3-array";
 import {geoInterpolate} from "d3-geo";
 import {
   geoBerghaus as berghaus,
@@ -19,17 +19,17 @@ import geoClipPolygon from "./clip/polygon.js";
  */
 export function geoBerghaus() { return reclip(berghaus.apply(this, arguments)); }
 export function geoGingery() { return reclip(gingery.apply(this, arguments)); }
-export function geoHealpix() {return clipInterrupted(healpix.apply(this, arguments)); }
+export function geoHealpix() { return reclip(healpix.apply(this, arguments), true); }
 export function geoInterrupt() { return clipInterrupted(interrupt.apply(this, arguments)); }
 export function geoInterruptedBoggs() { return clipInterrupted(interruptedBoggs.apply(this, arguments)); }
-export function geoInterruptedHomolosine() {return clipInterrupted(interruptedHomolosine.apply(this, arguments)); }
-export function geoInterruptedMollweide() {return clipInterrupted(interruptedMollweide.apply(this, arguments)); }
-export function geoInterruptedMollweideHemispheres() {return clipInterrupted(interruptedMollweideHemispheres.apply(this, arguments)); }
-export function geoInterruptedSinuMollweide() {return clipInterrupted(interruptedSinuMollweide.apply(this, arguments)); }
-export function geoInterruptedSinusoidal() {return clipInterrupted(interruptedSinusoidal.apply(this, arguments)); }
+export function geoInterruptedHomolosine() { return clipInterrupted(interruptedHomolosine.apply(this, arguments)); }
+export function geoInterruptedMollweide() { return clipInterrupted(interruptedMollweide.apply(this, arguments)); }
+export function geoInterruptedMollweideHemispheres() { return clipInterrupted(interruptedMollweideHemispheres.apply(this, arguments)); }
+export function geoInterruptedSinuMollweide() { return clipInterrupted(interruptedSinuMollweide.apply(this, arguments)); }
+export function geoInterruptedSinusoidal() { return clipInterrupted(interruptedSinusoidal.apply(this, arguments)); }
 
-function reclip(projection) {
-  const { lobes } = projection;
+function reclip(projection, vertical = false) {
+  const {lobes} = projection;
   function reset(projection) {
     const rotate = projection.rotate();
     const scale = projection.scale();
@@ -40,26 +40,29 @@ function reclip(projection) {
     };
 
     projection.preclip((stream) => stream); // clipNone
+    const R = 1 - 1e-7;
+    const Rx = vertical ? 1 : R;
     let points = [];
     projection
       .stream({
-        point(x, y) {points.push(([x, y]));},
+        point(x, y) {
+          points.push([x * Rx, y * R]);
+        },
         lineStart() {},
         lineEnd() {},
         polygonStart() {},
         polygonEnd() {},
-        sphere() {}
+        sphere() {},
       })
       .sphere();
 
-    projection.scale(scale * 1.0001);
+    projection.scale(scale);
     points = points.map(projection.invert);
     points.push(points[0]);
 
     return projection
       .rotate(rotate)
       .translate(translate)
-      .scale(scale)
       .preclip(geoClipPolygon({ type: "Polygon", coordinates: [points] }));
   }
   return reset(projection);
@@ -68,27 +71,7 @@ function reclip(projection) {
 function clipInterrupted(projection) {
   const { lobes } = projection;
   function reset(projection) {
-    let l = lobes?.();
-
-    // Special treatment for HEALpix
-    if (typeof l === "number") {
-      const hp = 41 + 48 / 36 + 37 / 3600; // healpixParallel, for K=3
-      const step = 360 / (l + 1e-10);
-      l = [
-        range(l).map((i) => [
-          [-180 + i * step, hp],
-          [-180 + ((2 * i + 1) / 2) * step, 90],
-          [-180 + (i + 1) * step, hp],
-        ]),
-        range(l).map((i) => [
-          [-180 + i * step, -hp],
-          [-180 + ((2 * i + 1) / 2) * step, -90],
-          [-180 + (i + 1) * step, -hp],
-        ]),
-      ];
-    }
-    if (!Array.isArray(l)) return projection;
-
+    const l = lobes?.();
     const polygon = merge(
       Array.from(l, (d, i) => {
         const hemisphere = d.flatMap(