Override blend mode, FPS sparkline, fix api_input persistence

New features:
- Override composite blend mode: per-pixel alpha from brightness
  (black=transparent, bright=opaque). Ideal for API input over effects.
- API input test preview FPS chart uses shared createFpsSparkline
  (same look as target card charts)

Fixes:
- Fix api_input source not surviving server restart: from_dict was
  still passing removed led_count field to constructor
- Fix composite layer brightness/processing selectors not aligned:
  labels get fixed width, selects fill remaining space
- Fix CSPT input selector showing in non-CSPT CSS test mode
- Fix test modal LED/FPS controls showing for api_input sources
- Server only sends test WS frames when api_input push_generation changes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/wled_controller/api/schemas/color_strip_sources.py

@@ -31,7 +31,7 @@ class CompositeLayer(BaseModel):
     """A single layer in a composite color strip source."""
 
     source_id: str = Field(description="ID of the layer's color strip source")
-    blend_mode: str = Field(default="normal", description="Blend mode: normal|add|multiply|screen")
+    blend_mode: str = Field(default="normal", description="Blend mode: normal|add|multiply|screen|override")
     opacity: float = Field(default=1.0, ge=0.0, le=1.0, description="Layer opacity 0.0-1.0")
     enabled: bool = Field(default=True, description="Whether this layer is active")
     brightness_source_id: Optional[str] = Field(None, description="Optional value source ID for dynamic brightness")

server/src/wled_controller/core/processing/composite_stream.py

@@ -16,6 +16,7 @@ _BLEND_NORMAL = "normal"
 _BLEND_ADD = "add"
 _BLEND_MULTIPLY = "multiply"
 _BLEND_SCREEN = "screen"
+_BLEND_OVERRIDE = "override"
 
 
 class CompositeColorStripStream(ColorStripStream):
@@ -300,11 +301,34 @@ class CompositeColorStripStream(ColorStripStream):
         u16a >>= 8
         np.copyto(out, u16a, casting="unsafe")
 
+    def _blend_override(self, bottom: np.ndarray, top: np.ndarray, alpha: int,
+                        out: np.ndarray) -> None:
+        """Override blend: per-pixel alpha derived from top brightness.
+
+        Black pixels are fully transparent (bottom shows through),
+        bright pixels fully opaque (top replaces bottom). Layer opacity
+        scales the per-pixel alpha.
+        """
+        u16a, u16b = self._u16_a, self._u16_b
+        # Per-pixel brightness = max(R, G, B) for each LED
+        per_px_alpha = np.max(top, axis=1, keepdims=True).astype(np.uint16)
+        # Scale by layer opacity
+        per_px_alpha = (per_px_alpha * alpha) >> 8
+        # Lerp: out = (bottom * (256 - per_px_alpha) + top * per_px_alpha) >> 8
+        np.copyto(u16a, bottom, casting="unsafe")
+        np.copyto(u16b, top, casting="unsafe")
+        u16a *= (256 - per_px_alpha)
+        u16b *= per_px_alpha
+        u16a += u16b
+        u16a >>= 8
+        np.copyto(out, u16a, casting="unsafe")
+
     _BLEND_DISPATCH = {
         _BLEND_NORMAL: "_blend_normal",
         _BLEND_ADD: "_blend_add",
         _BLEND_MULTIPLY: "_blend_multiply",
         _BLEND_SCREEN: "_blend_screen",
+        _BLEND_OVERRIDE: "_blend_override",
     }
 
     # ── Processing loop ─────────────────────────────────────────

server/src/wled_controller/static/css/modal.css

@@ -1516,6 +1516,19 @@
     min-width: 0;
 }
 
+.composite-layer-brightness-label {
+    flex-shrink: 0;
+    width: 90px;
+    font-size: 0.8rem;
+    color: var(--text-secondary);
+}
+
+.composite-layer-brightness,
+.composite-layer-cspt {
+    flex: 1;
+    min-width: 0;
+}
+
 .composite-layer-blend {
     width: 100px;
     flex-shrink: 0;

server/src/wled_controller/static/js/features/color-strips.js

@@ -685,6 +685,7 @@ function _getCompositeBlendItems() {
         { value: 'add',      icon: _icon(P.sun),      label: t('color_strip.composite.blend_mode.add'),      desc: t('color_strip.composite.blend_mode.add.desc') },
         { value: 'multiply', icon: _icon(P.eye),      label: t('color_strip.composite.blend_mode.multiply'), desc: t('color_strip.composite.blend_mode.multiply.desc') },
         { value: 'screen',   icon: _icon(P.monitor),  label: t('color_strip.composite.blend_mode.screen'),   desc: t('color_strip.composite.blend_mode.screen.desc') },
+        { value: 'override', icon: _icon(P.zap),      label: t('color_strip.composite.blend_mode.override'), desc: t('color_strip.composite.blend_mode.override.desc') },
     ];
 }
 
@@ -741,6 +742,7 @@ function _compositeRenderList() {
                         <option value="add"${layer.blend_mode === 'add' ? ' selected' : ''}>${t('color_strip.composite.blend_mode.add')}</option>
                         <option value="multiply"${layer.blend_mode === 'multiply' ? ' selected' : ''}>${t('color_strip.composite.blend_mode.multiply')}</option>
                         <option value="screen"${layer.blend_mode === 'screen' ? ' selected' : ''}>${t('color_strip.composite.blend_mode.screen')}</option>
+                        <option value="override"${layer.blend_mode === 'override' ? ' selected' : ''}>${t('color_strip.composite.blend_mode.override')}</option>
                     </select>
                 </div>
                 <div class="composite-layer-row">

server/src/wled_controller/static/locales/en.json

@@ -1131,6 +1131,8 @@
   "color_strip.composite.blend_mode.multiply.desc": "Darkens by multiplying colors",
   "color_strip.composite.blend_mode.screen": "Screen",
   "color_strip.composite.blend_mode.screen.desc": "Brightens, inverse of multiply",
+  "color_strip.composite.blend_mode.override": "Override",
+  "color_strip.composite.blend_mode.override.desc": "Black = transparent, bright = opaque",
   "color_strip.composite.opacity": "Opacity",
   "color_strip.composite.brightness": "Brightness",
   "color_strip.composite.brightness.none": "None (full brightness)",

server/src/wled_controller/static/locales/ru.json

@@ -1131,6 +1131,8 @@
   "color_strip.composite.blend_mode.multiply.desc": "Затемняет, умножая цвета",
   "color_strip.composite.blend_mode.screen": "Экран",
   "color_strip.composite.blend_mode.screen.desc": "Осветляет, обратное умножение",
+  "color_strip.composite.blend_mode.override": "Замена",
+  "color_strip.composite.blend_mode.override.desc": "Чёрный = прозрачный, яркий = непрозрачный",
   "color_strip.composite.opacity": "Непрозрачность",
   "color_strip.composite.brightness": "Яркость",
   "color_strip.composite.brightness.none": "Нет (полная яркость)",

server/src/wled_controller/static/locales/zh.json

@@ -1131,6 +1131,8 @@
   "color_strip.composite.blend_mode.multiply.desc": "通过相乘颜色变暗",
   "color_strip.composite.blend_mode.screen": "滤色",
   "color_strip.composite.blend_mode.screen.desc": "提亮，正片叠底的反转",
+  "color_strip.composite.blend_mode.override": "覆盖",
+  "color_strip.composite.blend_mode.override.desc": "黑色=透明，亮色=不透明",
   "color_strip.composite.opacity": "不透明度",
   "color_strip.composite.brightness": "亮度",
   "color_strip.composite.brightness.none": "无（全亮度）",

server/src/wled_controller/storage/color_strip_source.py

@@ -227,7 +227,7 @@ class ColorStripSource:
             return ApiInputColorStripSource(
                 id=sid, name=name, source_type="api_input",
                 created_at=created_at, updated_at=updated_at, description=description,
-                clock_id=clock_id, tags=tags, led_count=data.get("led_count") or 0,
+                clock_id=clock_id, tags=tags,
                 fallback_color=fallback_color,
                 timeout=float(data.get("timeout") or 5.0),
             )