feat: add scope checkbox and improve HUD text readability

src/scopeMask.test.mjs

@@ -18,6 +18,9 @@ import {
   SCOPE_TERMINUS_MIN_PCT,
   SCOPE_TERMINUS_MAX_PCT,
   SCOPE_FEATHER_RATIO_DEFAULT,
+  SCOPE_FEATHER_RATIO_MAX,
+  clampScopeFeatherPct,
+  getScopeMaskFeather,
   SCOPE_OUTSIDE_ALPHA,
   SCOPE_TERMINUS_ALPHA_NEAR,
   SCOPE_TERMINUS_FAR_M,
@@ -47,16 +50,34 @@ test('zero feather produces a hard edge exactly at the keyhole radius', () => {
   assert.equal(geo.outerR, keyholeR);
 });
 
-test('feather ratio is clamped to [0,1] and bad input falls back to 0', () => {
+test('feather ratio reaches the center at 200% and clamps larger input', () => {
   const wide = scopeMaskGeometry(1000, 800, 7);
-  const one = scopeMaskGeometry(1000, 800, 1);
-  assert.equal(wide.innerR, one.innerR);
-  assert.equal(wide.outerR, one.outerR);
+  const maximum = scopeMaskGeometry(1000, 800, SCOPE_FEATHER_RATIO_MAX);
+  const keyholeR = 800 * 0.5 * KEYHOLE_OUTER_RADIUS;
+  assert.equal(maximum.innerR, 0);
+  assert.equal(maximum.outerR, keyholeR * 2);
+  assert.equal(wide.innerR, maximum.innerR);
+  assert.equal(wide.outerR, maximum.outerR);
+  for (const ratio of [1, 1.5, 2]) {
+    setScopeMaskFeather(ratio);
+    assert.equal(getScopeMaskFeather(), ratio);
+    const geometry = scopeMaskGeometry(1000, 800);
+    assert.equal((geometry.innerR + geometry.outerR) / 2, keyholeR);
+    assert.equal(geometry.outerR - geometry.innerR, keyholeR * ratio);
+  }
+  setScopeMaskFeather(7);
+  assert.equal(getScopeMaskFeather(), SCOPE_FEATHER_RATIO_MAX);
   const nan = scopeMaskGeometry(1000, 800, Number.NaN);
   const zero = scopeMaskGeometry(1000, 800, 0);
   assert.equal(nan.innerR, zero.innerR);
 });
 
+test('UI and share feather percentages share one bounded integer range', () => {
+  for (const [value, expected] of [[0, 0], [11, 11], [175.6, 176], [200, 200], [350, 200], [-4, 0], [Number.NaN, 0]]) {
+    assert.equal(clampScopeFeatherPct(value), expected);
+  }
+});
+
 test('degenerate viewport yields null instead of a broken gradient', () => {
   assert.equal(scopeMaskGeometry(0, 0), null);
   assert.equal(scopeMaskGeometry(-5, 100), null);