feat(weather): add satellite cloud filter strength slider

Blend the existing infrared brightness key from Full (0%) to Clouds only (100%), preserving Soft/Vivid as independent opacity presets. Commit filter changes on slider release and retain legacy share-link mode codes.

src/layers/weather/index.js

@@ -50,7 +50,7 @@ export function createWeatherLayer({
   const satellite = !radar && !lightning;
   let product = radar ? 'radar' : lightning ? 'lightning' : 'clouds-regional';
   let opacity = 'strong';
-  let infrared = 'filtered';
+  let infrared = 100;
   let viewer = null,
     rendering = null,
     manifest = null,
@@ -382,11 +382,20 @@ export function createWeatherLayer({
       }
     },
     setParams(params = {}) {
+      const nextInfrared = satellite
+        ? params.infrared === 'full'
+          ? 0
+          : params.infrared === 'filtered'
+            ? 100
+            : params.infrared
+        : null;
       const infraredChanged =
         satellite &&
-        ['filtered', 'full'].includes(params.infrared) &&
-        params.infrared !== infrared;
-      if (infraredChanged) infrared = params.infrared;
+        Number.isInteger(nextInfrared) &&
+        nextInfrared >= 0 &&
+        nextInfrared <= 100 &&
+        nextInfrared !== infrared;
+      if (infraredChanged) infrared = nextInfrared;
       if (['light', 'strong'].includes(params.opacity)) {
         opacity = params.opacity;
         rendering?.setAlpha(opacity === 'light' ? 0.4 : satellite ? 0.7 : 0.8);
@@ -594,17 +603,17 @@ export function createWeatherLayer({
                 {
                   id: 'filtered',
                   label: 'Clouds only',
-                  active: infrared === 'filtered',
-                  params: { infrared: 'filtered' },
+                  active: infrared === 100,
+                  params: { infrared: 100 },
                   title:
-                    'Dim everything but the bright, cold cloud tops; a brightness filter, not a cloud mask',
+                    'Apply the full cloud brightness key; 100% filter strength',
                 },
                 {
                   id: 'full',
                   label: 'Full',
-                  active: infrared === 'full',
-                  params: { infrared: 'full' },
-                  title: 'The complete infrared image at the chosen opacity',
+                  active: infrared === 0,
+                  params: { infrared: 0 },
+                  title: 'Show the complete infrared image; 0% filter strength',
                 },
               ]
             : []),
@@ -656,7 +665,21 @@ export function createWeatherLayer({
               {
                 id: 'image',
                 label: 'IMAGE',
-                chips: controls.chips.filter(({ params }) => params.infrared),
+                chips: controls.chips.filter(
+                  ({ params }) => params.infrared !== undefined,
+                ),
+                range: {
+                  id: 'cloud-filter',
+                  param: 'infrared',
+                  min: 0,
+                  max: 100,
+                  step: 1,
+                  value: infrared,
+                  label: 'FILTER',
+                  unit: '%',
+                  ariaLabel: 'Cloud filter strength',
+                  commitOnChange: true,
+                },
               },
             ]
           : []),

src/layers/weather/infraredAlpha.js

@@ -1,10 +1,18 @@
 export const INFRARED_ALPHA_T0 = 0.4;
 export const INFRARED_ALPHA_T1 = 0.7;
 
-/** Return display pixels without changing RGB or the source RGBA bytes. */
-export function infraredAlpha(rgba, mode = 'filtered') {
+/** Return display pixels without changing RGB or the source RGBA bytes.
+ * `strength` is 0–100: zero is the full image and 100 is the cloud key.
+ */
+export function infraredAlpha(rgba, strength = 'filtered') {
   const pixels = new Uint8ClampedArray(rgba);
-  if (mode === 'full') return pixels;
+  const amount =
+    strength === 'full'
+      ? 0
+      : strength === 'filtered' || !Number.isFinite(strength)
+        ? 1
+        : Math.max(0, Math.min(100, strength)) / 100;
+  if (amount === 0) return pixels;
   for (let i = 0; i < pixels.length; i += 4) {
     // Match Cesium's czm_srgbToLinear conversion in draped imagery.
     const linearMax =
@@ -17,7 +25,8 @@ export function infraredAlpha(rgba, mode = 'filtered') {
           (INFRARED_ALPHA_T1 - INFRARED_ALPHA_T0),
       ),
     );
-    pixels[i + 3] = rgba[i + 3] * t * t * (3 - 2 * t);
+    const filtered = t * t * (3 - 2 * t);
+    pixels[i + 3] = rgba[i + 3] * (1 - amount + filtered * amount);
   }
   return pixels;
 }

src/layers/weather/infraredAlpha.test.mjs

@@ -40,6 +40,21 @@ test('filtered infrared preserves RGB and input bytes, scales existing alpha, an
   );
 });
 
+test('filter strength interpolates between the full infrared image and the cloud key', () => {
+  const pixels = new Uint8ClampedArray([
+    0, 0, 0, 255, 194, 0, 0, 200, 12, 50, 217, 128,
+  ]);
+  assert.deepEqual([...infraredAlpha(pixels, 0)], [...pixels]);
+  assert.deepEqual(
+    infraredAlpha(pixels, 100),
+    infraredAlpha(pixels, 'filtered'),
+  );
+  assert.deepEqual(
+    [...infraredAlpha(pixels, 50)],
+    [0, 0, 0, 128, 194, 0, 0, 149, 12, 50, 217, 128],
+  );
+});
+
 test('full infrared preserves every channel including partial and zero alpha', () => {
   const pixels = new Uint8ClampedArray([
     12, 50, 194, 80, 0, 0, 0, 255, 255, 200, 0, 0,

src/layers/weather/infraredImage.test.mjs

@@ -32,6 +32,15 @@ test('decoded pixels are processed once on a same-sized canvas', () => {
   assert.equal(output.height, 1);
   assert.equal(output.image, image);
   assert.deepEqual([...output.pixels], [194, 0, 0, 98]);
+  assert.deepEqual(
+    [...processInfraredImage(image, 50, canvas).pixels],
+    [194, 0, 0, 149],
+    'half-strength filter retains a midpoint haze',
+  );
+  assert.deepEqual(
+    [...processInfraredImage(image, 0, canvas).pixels],
+    [194, 0, 0, 200],
+  );
   assert.deepEqual(
     [...processInfraredImage(image, 'full', canvas).pixels],
     [194, 0, 0, 200],

src/layers/weather/weather.test.mjs

@@ -444,11 +444,14 @@ function layerHarness({
   let active = null;
   let clearCount = 0;
   let hidden = false;
+  let alpha = null;
   const rendering = {
     rehome() {
       active?.finish(false);
     },
-    setAlpha() {},
+    setAlpha(value) {
+      alpha = value;
+    },
     setHidden(value) {
       hidden = value;
       if (value) active?.finish(false);
@@ -514,6 +517,7 @@ function layerHarness({
     documentRef,
     moveEnd,
     clears: () => clearCount,
+    getAlpha: () => alpha,
   };
 }
 
@@ -1591,8 +1595,8 @@ test('satellite mode chips restage history without changing time or latest-follo
   await flush();
   h.layer.setParams({ infrared: 'full' });
   assert.equal(h.stages[2].time, times[1]);
-  assert.equal(h.stages[2].infrared, 'full');
-  assert.equal(h.layer.getParams().infrared, 'full');
+  assert.equal(h.stages[2].infrared, 0);
+  assert.equal(h.layer.getParams().infrared, 0);
   assert.deepEqual(
     h.layer
       .getRowControls()
@@ -1605,11 +1609,59 @@ test('satellite mode chips restage history without changing time or latest-follo
   assert.equal(h.layer.getDiagnostics().followLatest, false);
   assert.equal(h.layer.getDiagnostics().time, times[1]);
   h.layer.setParams({ infrared: 'invalid' });
-  assert.equal(h.layer.getParams().infrared, 'full');
+  assert.equal(h.layer.getParams().infrared, 0);
   assert.equal(h.stages.length, 3);
   h.layer.destroy();
 });
 
+test('satellite cloud filter spans Full to Clouds only without changing layer opacity', () => {
+  const h = layerHarness({ id: 'weather-satellite' });
+  assert.equal(h.layer.getParams().infrared, 100);
+  assert.equal(h.layer.getParams().opacity, 'strong');
+  assert.equal(h.getAlpha(), 0.7);
+  const setting = h.layer
+    .getRowControls()
+    .summary.settings.find(({ id }) => id === 'image');
+  assert.equal(setting.range.param, 'infrared');
+  assert.equal(setting.range.value, 100);
+  assert.equal(setting.range.min, 0);
+  assert.equal(setting.range.max, 100);
+  assert.equal(setting.range.step, 1);
+  assert.equal(setting.range.commitOnChange, true);
+
+  const full = h.layer.getRowControls().chips.find(({ id }) => id === 'full');
+  h.layer.setParams(full.params);
+  assert.equal(h.layer.getParams().infrared, 0);
+  assert.equal(h.getAlpha(), 0.7);
+  assert.equal(
+    h.layer.getRowControls().chips.find(({ id }) => id === 'full').active,
+    true,
+  );
+
+  h.layer.setParams({ infrared: 53 });
+  assert.equal(h.layer.getParams().infrared, 53);
+  assert.equal(h.getAlpha(), 0.7, 'filter strength is not overall opacity');
+  assert.equal(
+    h.layer.getRowControls().summary.settings.find(({ id }) => id === 'image')
+      .range.value,
+    53,
+  );
+  h.layer.setParams({ opacity: 'light' });
+  assert.equal(h.layer.getParams().opacity, 'light');
+  assert.equal(
+    h.getAlpha(),
+    0.4,
+    'Soft remains the independent opacity preset',
+  );
+  h.layer.setParams({ infrared: 101 });
+  assert.equal(
+    h.layer.getParams().infrared,
+    53,
+    'invalid filter values are ignored',
+  );
+  h.layer.destroy();
+});
+
 test('a rapid third selection waits for retirement before installing, and clear cancels that wait', async () => {
   for (const clear of [false, true]) {
     const h = renderingHarness();
@@ -1914,8 +1966,14 @@ test('observed descriptors keep configuration only and label satellite clouds by
       );
       assert.equal(
         controls.chips.find(({ id }) => id === 'filtered').title,
-        'Dim everything but the bright, cold cloud tops; a brightness filter, not a cloud mask',
+        'Apply the full cloud brightness key; 100% filter strength',
       );
+      const imageSetting = controls.summary.settings.find(
+        ({ id }) => id === 'image',
+      );
+      assert.equal(imageSetting.range.param, 'infrared');
+      assert.equal(imageSetting.range.value, 100);
+      assert.equal(imageSetting.range.commitOnChange, true);
       h.layer.setParams({ product: 'clouds' });
       assert.equal(
         h.layer.getRowControls().summary.coverage,
@@ -2196,7 +2254,7 @@ test('layer warms the next advertised observation only after a successful playin
     warmed.map(({ time }) => time),
     [times[0]],
   );
-  assert.deepEqual(warmed[0].options, { infrared: 'filtered' });
+  assert.deepEqual(warmed[0].options, { infrared: 100 });
   const next = clock.setTarget(times[0]);
   await flush();
   h.stages.at(-1).finish();