fix: Optimize monotone interpolator by precomputing segment constants (#9111)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/curve/curveUtils.ts

@@ -51,6 +51,17 @@ export function createMonotoneInterpolator(
     }
   }
 
+  const segCount = n - 1
+  const segDx = new Float64Array(segCount)
+  const segM0dx = new Float64Array(segCount)
+  const segM1dx = new Float64Array(segCount)
+  for (let i = 0; i < segCount; i++) {
+    const dx = xs[i + 1] - xs[i]
+    segDx[i] = dx
+    segM0dx[i] = slopes[i] * dx
+    segM1dx[i] = slopes[i + 1] * dx
+  }
+
   return (x: number): number => {
     if (x <= xs[0]) return ys[0]
     if (x >= xs[n - 1]) return ys[n - 1]
@@ -63,7 +74,7 @@ export function createMonotoneInterpolator(
       else hi = mid
     }
 
-    const dx = xs[hi] - xs[lo]
+    const dx = segDx[lo]
     if (dx === 0) return ys[lo]
 
     const t = (x - xs[lo]) / dx
@@ -75,39 +86,10 @@ export function createMonotoneInterpolator(
     const h01 = -2 * t3 + 3 * t2
     const h11 = t3 - t2
 
-    return (
-      h00 * ys[lo] +
-      h10 * dx * slopes[lo] +
-      h01 * ys[hi] +
-      h11 * dx * slopes[hi]
-    )
+    return h00 * ys[lo] + h10 * segM0dx[lo] + h01 * ys[hi] + h11 * segM1dx[lo]
   }
 }
 
-function quickSelect(arr: Uint32Array, k: number): number {
-  let lo = 0
-  let hi = arr.length - 1
-  while (lo < hi) {
-    const pivot = arr[hi]
-    let i = lo
-    for (let j = lo; j < hi; j++) {
-      if (arr[j] <= pivot) {
-        const tmp = arr[i]
-        arr[i] = arr[j]
-        arr[j] = tmp
-        i++
-      }
-    }
-    const tmp = arr[i]
-    arr[i] = arr[hi]
-    arr[hi] = tmp
-    if (i === k) return arr[i]
-    else if (i < k) lo = i + 1
-    else hi = i - 1
-  }
-  return arr[lo]
-}
-
 /**
  * Convert a 256-bin histogram into an SVG path string.
  * Normalizes using the 99.5th percentile to avoid outlier spikes.
@@ -115,8 +97,8 @@ function quickSelect(arr: Uint32Array, k: number): number {
 export function histogramToPath(histogram: Uint32Array): string {
   if (!histogram.length) return ''
 
-  const copy = new Uint32Array(histogram)
-  const max = quickSelect(copy, Math.floor(255 * 0.995))
+  const sorted = Array.from(histogram).sort((a, b) => a - b)
+  const max = sorted[Math.floor(255 * 0.995)]
   if (max === 0) return ''
 
   const invMax = 1 / max