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/data/layerState.js

@@ -296,6 +296,24 @@ function imageryPinOption(key, token) {
   });
 }
 
+function satelliteFilterOption() {
+  const percentage = boundedIntegerOption('infrared', 'i', 100, {
+    min: 0,
+    max: 100,
+  });
+  return Object.freeze({
+    ...percentage,
+    normalize: (value) =>
+      value === 'filtered'
+        ? 100
+        : value === 'full'
+          ? 0
+          : percentage.normalize(value),
+    decode: (value) =>
+      value === 'f' ? 100 : value === 'a' ? 0 : percentage.decode(value),
+  });
+}
+
 const OPTION_GROUPS = Object.freeze({
   traffic: Object.freeze([
     enumOption('roadMode', 'r', null, ['tomtom', 'osm', 'hybrid'], {
@@ -317,10 +335,7 @@ const OPTION_GROUPS = Object.freeze({
     }),
   ]),
   'weather-satellite': Object.freeze([
-    enumOption('infrared', 'i', 'filtered', ['filtered', 'full'], {
-      filtered: 'f',
-      full: 'a',
-    }),
+    satelliteFilterOption(),
     enumOption('opacity', 'o', 'strong', ['light', 'strong'], {
       light: 'l',
       strong: 's',

src/data/layerState.test.mjs

@@ -2422,23 +2422,74 @@ test('wind appearance shares round trip while old links retain weather defaults'
   assert.deepEqual(invalid.options.wind, defaults);
 });
 
-test('observed weather round trips product and opacity without persisting historical playback', () => {
+test('observed weather round trips product and presets without persisting historical playback', () => {
   const state = normalizeLayerState({
     enabledLayerIds: ['weather-radar', 'weather-satellite'],
     options: {
       'weather-radar': { opacity: 'light', play: true },
-      'weather-satellite': { product: 'clouds', opacity: 'light', step: -1 },
+      'weather-satellite': {
+        product: 'clouds',
+        opacity: 'light',
+        infrared: 'filtered',
+        step: -1,
+      },
     },
   });
   const params = new URLSearchParams(encode(state));
   const decoded = decodeLayerStateParams(params);
   assert.deepEqual(decoded, state);
   assert.equal(state.options['weather-satellite'].product, 'clouds');
+  assert.equal(state.options['weather-satellite'].opacity, 'light');
+  assert.equal(state.options['weather-satellite'].infrared, 100);
   assert.equal(Object.hasOwn(state.options['weather-radar'], 'play'), false);
 });
 
-test('satellite infrared display mode round trips and invalid or absent values use filtered', () => {
-  for (const infrared of ['full', 'filtered', undefined, 'invalid']) {
+test('satellite filter strength percentages round-trip and legacy mode codes remain readable', () => {
+  const state = normalizeLayerState({
+    enabledLayerIds: ['weather-satellite'],
+    options: { 'weather-satellite': { infrared: 53, opacity: 'light' } },
+  });
+  const params = encodeLayerStateParams(
+    new URLSearchParams([['v', '2']]),
+    state,
+  );
+  assert.deepEqual(decodeLayerStateParams(params), state);
+  assert.equal(state.options['weather-satellite'].infrared, 53);
+  assert.equal(state.options['weather-satellite'].opacity, 'light');
+  for (const [legacy, expected] of [
+    ['f', 100],
+    ['a', 0],
+  ]) {
+    const decoded = decodeLayerStateParams(
+      new URLSearchParams(`v=2&l=o&lo=o.i.${legacy}`),
+    );
+    assert.equal(decoded.options['weather-satellite'].infrared, expected);
+  }
+  for (const [legacy, expected] of [
+    ['filtered', 100],
+    ['full', 0],
+  ]) {
+    const normalized = normalizeLayerState({
+      enabledLayerIds: ['weather-satellite'],
+      options: { 'weather-satellite': { infrared: legacy } },
+    });
+    assert.equal(normalized.options['weather-satellite'].infrared, expected);
+  }
+  const invalid = normalizeLayerState({
+    enabledLayerIds: ['weather-satellite'],
+    options: { 'weather-satellite': { infrared: 101 } },
+  });
+  assert.equal(invalid.options['weather-satellite'].infrared, 100);
+});
+
+test('satellite cloud filter round trips and invalid or absent values default to Clouds only', () => {
+  for (const [infrared, expected] of [
+    ['full', 0],
+    ['filtered', 100],
+    [53, 53],
+    [undefined, 100],
+    ['invalid', 100],
+  ]) {
     const state = normalizeLayerState({
       enabledLayerIds: ['weather-satellite'],
       options: {
@@ -2454,10 +2505,7 @@ test('satellite infrared display mode round trips and invalid or absent values u
       decodeLayerStateParams(new URLSearchParams(encode(state))),
       state,
     );
-    assert.equal(
-      state.options['weather-satellite'].infrared,
-      infrared === 'full' ? 'full' : 'filtered',
-    );
+    assert.equal(state.options['weather-satellite'].infrared, expected);
     assert.equal(
       Object.hasOwn(state.options['weather-satellite'], 'step'),
       false,

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();

src/ui/railCardBlocks.js

@@ -30,6 +30,7 @@ export function createRailCardBlocks({ container, cardId, onParams }) {
   };
   const dispose = (block) => {
     block.removeClick?.();
+    block.removeInput?.();
     block.children?.destroy();
     block.root.remove();
   };
@@ -74,6 +75,64 @@ export function createRailCardBlocks({ container, cardId, onParams }) {
             );
             block.chips = make('div', 'rail-card-chips', root);
             block.chips.setAttribute('role', 'group');
+            block.rangeRow = make('div', 'rail-card-setting-range-row', root);
+            block.rangeLabel = make(
+              'span',
+              'rail-card-setting-range-label',
+              block.rangeRow,
+            );
+            block.rangeInput = make(
+              'input',
+              'rail-card-setting-range',
+              block.rangeRow,
+            );
+            block.rangeInput.type = 'range';
+            block.rangeValue = make(
+              'span',
+              'rail-card-setting-range-value',
+              block.rangeRow,
+            );
+            const rangeParams = () => {
+              const range = block.props.range;
+              const value = Number(block.rangeInput.value);
+              if (
+                !range?.param ||
+                range.disabled ||
+                !Number.isFinite(value) ||
+                value < Number(range.min) ||
+                value > Number(range.max)
+              )
+                return null;
+              return { params: { [range.param]: value } };
+            };
+            const onInput = () => {
+              const range = block.props.range;
+              const value = Number(block.rangeInput.value);
+              const params = rangeParams();
+              if (!params) return;
+              set(
+                block.rangeValue,
+                'textContent',
+                `${value}${range.unit || ''}`,
+              );
+              attribute(
+                block.rangeInput,
+                'aria-valuetext',
+                `${value}${range.unit || ''}`,
+              );
+              if (!range.commitOnChange) dispatch(params);
+            };
+            const onChange = () => {
+              if (!block.props.range?.commitOnChange) return;
+              const params = rangeParams();
+              if (params) dispatch(params);
+            };
+            block.rangeInput.addEventListener('input', onInput);
+            block.rangeInput.addEventListener('change', onChange);
+            block.removeInput = () => {
+              block.rangeInput.removeEventListener('input', onInput);
+              block.rangeInput.removeEventListener('change', onChange);
+            };
             bind((event) => {
               const button = event.target?.closest?.('[data-chip-id]');
               dispatch(
@@ -124,17 +183,48 @@ export function createRailCardBlocks({ container, cardId, onParams }) {
           blocks.set(props.id, block);
         }
         block.props = props;
-        if (props.type === 'settings')
+        if (props.type === 'settings') {
           block.children.update(
             (props.settings || []).map((setting) => ({
               ...setting,
               type: 'setting',
             })),
           );
-        else if (props.type === 'setting') {
+        } else if (props.type === 'setting') {
           set(block.label, 'textContent', props.label);
           attribute(block.chips, 'aria-label', props.label);
           syncChipGroup(block.chips, props.chips);
+          const range = props.range;
+          set(block.rangeRow, 'hidden', !range);
+          if (range) {
+            const min = Number(range.min);
+            const max = Number(range.max);
+            const step = Number(range.step);
+            const candidate = Number(range.value);
+            const value = Math.min(
+              max,
+              Math.max(min, Number.isFinite(candidate) ? candidate : min),
+            );
+            set(block.rangeLabel, 'textContent', range.label || '');
+            set(block.rangeLabel, 'hidden', !range.label);
+            set(block.rangeInput.dataset, 'rangeId', range.id || props.id);
+            set(block.rangeInput, 'min', String(min));
+            set(block.rangeInput, 'max', String(max));
+            set(block.rangeInput, 'step', String(step));
+            set(block.rangeInput, 'value', String(value));
+            set(block.rangeInput, 'disabled', Boolean(range.disabled));
+            attribute(
+              block.rangeInput,
+              'aria-label',
+              range.ariaLabel || props.label,
+            );
+            attribute(
+              block.rangeInput,
+              'aria-valuetext',
+              `${value}${range.unit || ''}`,
+            );
+            set(block.rangeValue, 'textContent', `${value}${range.unit || ''}`);
+          }
         } else if (props.type === 'list') syncRowList(block.root, props.list);
         else if (props.type === 'result') {
           set(block.label, 'textContent', props.label);

src/ui/railCards.test.mjs

@@ -119,6 +119,81 @@ test('footer buttons retain focus and current callbacks; links use safe new tabs
   button.click();
   assert.deepEqual(calls, [2]);
 });
+test('setting ranges stay below presets and commit expensive filters on release', () => {
+  const f = railFixture();
+  const calls = [];
+  const view = createRailCards({
+    ...f,
+    onParams: (...args) => calls.push(args),
+  });
+  const model = (value) => ({
+    ...card,
+    blocks: [
+      {
+        id: 'settings',
+        type: 'settings',
+        settings: [
+          {
+            id: 'image',
+            label: 'IMAGE',
+            chips: [
+              {
+                id: 'clouds-only',
+                label: 'Clouds only',
+                params: { infrared: 100 },
+              },
+              { id: 'full', label: 'Full', params: { infrared: 0 } },
+            ],
+            range: {
+              id: 'cloud-filter',
+              param: 'infrared',
+              min: 0,
+              max: 100,
+              step: 1,
+              value,
+              label: 'FILTER',
+              unit: '%',
+              ariaLabel: 'Cloud filter strength',
+              commitOnChange: true,
+            },
+          },
+        ],
+      },
+    ],
+  });
+  view.update([model(100)]);
+  const setting = f.find((node) => node.dataset.blockId === 'image');
+  assert.equal(setting.children[1].className, 'rail-card-chips');
+  assert.equal(setting.children[2].className, 'rail-card-setting-range-row');
+  assert.equal(setting.children[2].children[0].textContent, 'FILTER');
+  const slider = f.find((node) => node.dataset.rangeId === 'cloud-filter');
+  assert.equal(slider.tagName, 'INPUT');
+  assert.equal(slider.type, 'range');
+  assert.equal(slider.min, '0');
+  assert.equal(slider.max, '100');
+  assert.equal(slider.step, '1');
+  assert.equal(slider.value, '100');
+  assert.equal(slider.getAttribute('aria-label'), 'Cloud filter strength');
+  slider.focus();
+  slider.value = '53';
+  slider.dispatchEvent(new Event('input'));
+  assert.equal(calls.length, 0, 'expensive image work waits until release');
+  assert.equal(
+    f.find((node) => node.className === 'rail-card-setting-range-value')
+      .textContent,
+    '53%',
+  );
+  slider.dispatchEvent(new Event('change'));
+  assert.deepEqual(calls.at(-1), ['a', { infrared: 53 }]);
+  view.update([model(53)]);
+  assert.equal(slider.value, '53');
+  assert.equal(f.document.activeElement, slider);
+  view.destroy();
+  slider.value = '41';
+  slider.dispatchEvent(new Event('change'));
+  assert.equal(calls.length, 1, 'destroy removes the range listener');
+});
+
 test('legend validates colors, preserves the freezing anchor and ignores CSSOM normalization', () => {
   let writes = 0;
   const f = railFixture(() => writes++);

src/ui/styles/weather.css

@@ -327,6 +327,35 @@ body.recording-mode .gev-wind-inspection-marker {
 .rail-card-setting .rail-card-chips {
   margin-top: 0;
 }
+.rail-card-setting-range-row {
+  display: flex;
+  grid-column: 2;
+  align-items: center;
+  gap: 7px;
+  min-width: 0;
+}
+.rail-card-setting-range-label {
+  flex: 0 0 6ch;
+  color: var(--text-dim);
+  font: 8px var(--font-mono);
+  white-space: nowrap;
+}
+.rail-card-setting-range {
+  width: 100%;
+  min-width: 0;
+  accent-color: var(--accent);
+  cursor: pointer;
+}
+.rail-card-setting-range:focus-visible {
+  outline: 2px solid var(--text-primary);
+  outline-offset: 3px;
+}
+.rail-card-setting-range-value {
+  min-width: 3ch;
+  color: var(--text-primary);
+  font: 9px var(--font-mono);
+  text-align: right;
+}
 .rail-card-result {
   display: grid;
   gap: 4px;