Add skip LEDs feature with physical resampling and per-edge tick labels

Skip LEDs at the start/end of the strip are blacked out while the full
screen perimeter is resampled onto the remaining active LEDs using linear
interpolation. Calibration canvas tick labels show per-edge display
ranges clipped to the active LED range. Moved LED offset control from
inline overlay to a dedicated form row alongside the new skip inputs.

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

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

@@ -50,6 +50,9 @@ class Calibration(BaseModel):
     span_bottom_end: float = Field(default=1.0, ge=0.0, le=1.0, description="End of bottom edge coverage")
     span_left_start: float = Field(default=0.0, ge=0.0, le=1.0, description="Start of left edge coverage")
     span_left_end: float = Field(default=1.0, ge=0.0, le=1.0, description="End of left edge coverage")
+    # Skip LEDs at start/end of strip
+    skip_leds_start: int = Field(default=0, ge=0, description="LEDs to skip (black out) at the start of the strip")
+    skip_leds_end: int = Field(default=0, ge=0, description="LEDs to skip (black out) at the end of the strip")
 
 
 class CalibrationTestModeRequest(BaseModel):

server/src/wled_controller/core/calibration.py

@@ -76,6 +76,9 @@ class CalibrationConfig:
     span_bottom_end: float = 1.0
     span_left_start: float = 0.0
     span_left_end: float = 1.0
+    # Skip LEDs: black out N LEDs at the start/end of the strip
+    skip_leds_start: int = 0
+    skip_leds_end: int = 0
 
     def build_segments(self) -> List[CalibrationSegment]:
         """Derive segment list from core parameters."""
@@ -263,8 +266,12 @@ class PixelMapper:
             ValueError: If border pixels don't match calibration
         """
         total_leds = self.calibration.get_total_leds()
+        skip_start = self.calibration.skip_leds_start
+        skip_end = self.calibration.skip_leds_end
+        active_count = max(0, total_leds - skip_start - skip_end)
         use_fast_avg = self.interpolation_mode == "average"
 
+        # Phase 1: Map full perimeter to total_leds positions
         if use_fast_avg:
             led_array = np.zeros((total_leds, 3), dtype=np.uint8)
         else:
@@ -304,16 +311,51 @@ class PixelMapper:
                     color = self._calc_color(pixel_segment)
                     led_colors[led_idx] = color
 
+        # Phase 2: Offset rotation
         offset = self.calibration.offset % total_leds if total_leds > 0 else 0
 
         if use_fast_avg:
             if offset > 0:
                 led_array = np.roll(led_array, offset, axis=0)
+
+            # Phase 3: Physical skip — resample full perimeter to active LEDs
+            # Maps the entire screen to active_count positions so each active LED
+            # covers a proportionally larger slice of the perimeter.
+            if active_count > 0 and active_count < total_leds:
+                src = np.linspace(0, total_leds - 1, active_count)
+                full_f = led_array.astype(np.float64)
+                x = np.arange(total_leds, dtype=np.float64)
+                resampled = np.empty((active_count, 3), dtype=np.uint8)
+                for ch in range(3):
+                    resampled[:, ch] = np.round(
+                        np.interp(src, x, full_f[:, ch])
+                    ).astype(np.uint8)
+                led_array[:] = 0
+                end_idx = total_leds - skip_end
+                led_array[skip_start:end_idx] = resampled
+            elif active_count <= 0:
+                led_array[:] = 0
+
             return [tuple(c) for c in led_array]
         else:
             if offset > 0:
                 led_colors = led_colors[total_leds - offset:] + led_colors[:total_leds - offset]
-            logger.debug(f"Mapped border pixels to {total_leds} LED colors (offset={offset})")
+
+            # Phase 3: Physical skip — resample full perimeter to active LEDs
+            if active_count > 0 and active_count < total_leds:
+                arr = np.array(led_colors, dtype=np.float64)
+                src = np.linspace(0, total_leds - 1, active_count)
+                x = np.arange(total_leds, dtype=np.float64)
+                resampled = np.empty((active_count, 3), dtype=np.float64)
+                for ch in range(3):
+                    resampled[:, ch] = np.interp(src, x, arr[:, ch])
+                led_colors = [(0, 0, 0)] * total_leds
+                for i in range(active_count):
+                    r, g, b = resampled[i]
+                    led_colors[skip_start + i] = (int(round(r)), int(round(g)), int(round(b)))
+            elif active_count <= 0:
+                led_colors = [(0, 0, 0)] * total_leds
+
             return led_colors
 
     def test_calibration(self, edge: str, color: Tuple[int, int, int]) -> List[Tuple[int, int, int]]:
@@ -419,6 +461,8 @@ def calibration_from_dict(data: dict) -> CalibrationConfig:
             span_bottom_end=data.get("span_bottom_end", 1.0),
             span_left_start=data.get("span_left_start", 0.0),
             span_left_end=data.get("span_left_end", 1.0),
+            skip_leds_start=data.get("skip_leds_start", 0),
+            skip_leds_end=data.get("skip_leds_end", 0),
         )
 
         config.validate()
@@ -457,4 +501,9 @@ def calibration_to_dict(config: CalibrationConfig) -> dict:
         if start != 0.0 or end != 1.0:
             result[f"span_{edge}_start"] = start
             result[f"span_{edge}_end"] = end
+    # Include skip fields only when non-default
+    if config.skip_leds_start > 0:
+        result["skip_leds_start"] = config.skip_leds_start
+    if config.skip_leds_end > 0:
+        result["skip_leds_end"] = config.skip_leds_end
     return result

server/src/wled_controller/static/app.js

@@ -1057,6 +1057,10 @@ async function showCalibration(deviceId) {
         document.getElementById('cal-bottom-leds').value = calibration.leds_bottom || 0;
         document.getElementById('cal-left-leds').value = calibration.leds_left || 0;
 
+        // Set skip LEDs
+        document.getElementById('cal-skip-start').value = calibration.skip_leds_start || 0;
+        document.getElementById('cal-skip-end').value = calibration.skip_leds_end || 0;
+
         // Initialize edge spans
         window.edgeSpans = {
             top: { start: calibration.span_top_start ?? 0, end: calibration.span_top_end ?? 1 },
@@ -1075,6 +1079,8 @@ async function showCalibration(deviceId) {
             bottom: String(calibration.leds_bottom || 0),
             left: String(calibration.leds_left || 0),
             spans: JSON.stringify(window.edgeSpans),
+            skip_start: String(calibration.skip_leds_start || 0),
+            skip_end: String(calibration.skip_leds_end || 0),
         };
 
         // Initialize test mode state for this device
@@ -1123,7 +1129,9 @@ function isCalibrationDirty() {
         document.getElementById('cal-right-leds').value !== calibrationInitialValues.right ||
         document.getElementById('cal-bottom-leds').value !== calibrationInitialValues.bottom ||
         document.getElementById('cal-left-leds').value !== calibrationInitialValues.left ||
-        JSON.stringify(window.edgeSpans) !== calibrationInitialValues.spans
+        JSON.stringify(window.edgeSpans) !== calibrationInitialValues.spans ||
+        document.getElementById('cal-skip-start').value !== calibrationInitialValues.skip_start ||
+        document.getElementById('cal-skip-end').value !== calibrationInitialValues.skip_end
     );
 }
 
@@ -1260,11 +1268,14 @@ function renderCalibrationCanvas() {
         leds_bottom: parseInt(document.getElementById('cal-bottom-leds').value || 0),
         leds_left: parseInt(document.getElementById('cal-left-leds').value || 0),
     };
+    const skipStart = parseInt(document.getElementById('cal-skip-start').value || 0);
+    const skipEnd = parseInt(document.getElementById('cal-skip-end').value || 0);
 
     const segments = buildSegments(calibration);
     if (segments.length === 0) return;
 
     const totalLeds = calibration.leds_top + calibration.leds_right + calibration.leds_bottom + calibration.leds_left;
+    const hasSkip = (skipStart > 0 || skipEnd > 0) && totalLeds > 1;
 
     // Theme-aware colors
     const isDark = document.documentElement.getAttribute('data-theme') !== 'light';
@@ -1314,6 +1325,16 @@ function renderCalibrationCanvas() {
         const count = seg.led_count;
         if (count === 0) return;
 
+        // Per-edge display range: clip to active LED range when skip is set
+        const edgeDisplayStart = hasSkip ? Math.max(seg.led_start, skipStart) : seg.led_start;
+        const edgeDisplayEnd = hasSkip ? Math.min(seg.led_start + count, totalLeds - skipEnd) : seg.led_start + count - 1;
+        const edgeDisplayRange = edgeDisplayEnd - edgeDisplayStart;
+        const toEdgeLabel = (i) => {
+            if (!hasSkip) return totalLeds > 0 ? (seg.led_start + i) % totalLeds : seg.led_start + i;
+            if (count <= 1) return edgeDisplayStart;
+            return Math.round(edgeDisplayStart + i / (count - 1) * edgeDisplayRange);
+        };
+
         // Edge boundary ticks (first/last LED on edge) and special ticks (LED 0 position)
         const edgeBounds = new Set();
         edgeBounds.add(0);
@@ -1356,8 +1377,7 @@ function renderCalibrationCanvas() {
 
             for (let i = 1; i < count - 1; i++) {
                 if (specialTicks.has(i)) continue;
-                const idx = totalLeds > 0 ? (seg.led_start + i) % totalLeds : seg.led_start + i;
-                if (idx % step === 0) {
+                if (toEdgeLabel(i) % step === 0) {
                     const px = tickPx(i);
                     if (!placed.some(p => Math.abs(px - p) < minSpacing)) {
                         labelsToShow.add(i);
@@ -1393,7 +1413,7 @@ function renderCalibrationCanvas() {
         labelsToShow.forEach(i => {
             const fraction = count > 1 ? i / (count - 1) : 0.5;
             const displayFraction = seg.reverse ? (1 - fraction) : fraction;
-            const ledIndex = totalLeds > 0 ? (seg.led_start + i) % totalLeds : seg.led_start + i;
+            const displayLabel = toEdgeLabel(i);
             const tickLen = edgeBounds.has(i) ? tickLenLong : tickLenShort;
 
             if (geo.horizontal) {
@@ -1408,7 +1428,7 @@ function renderCalibrationCanvas() {
 
                 ctx.textAlign = 'center';
                 ctx.textBaseline = seg.edge === 'top' ? 'bottom' : 'top';
-                ctx.fillText(String(ledIndex), tx, axisY - tickDir * 1);
+                ctx.fillText(String(displayLabel), tx, axisY - tickDir * 1);
             } else {
                 const ty = geo.y1 + displayFraction * (geo.y2 - geo.y1);
                 const axisX = axisPos[seg.edge];
@@ -1421,7 +1441,7 @@ function renderCalibrationCanvas() {
 
                 ctx.textBaseline = 'middle';
                 ctx.textAlign = seg.edge === 'left' ? 'right' : 'left';
-                ctx.fillText(String(ledIndex), axisX - tickDir * 1, ty);
+                ctx.fillText(String(displayLabel), axisX - tickDir * 1, ty);
             }
         });
 
@@ -1752,6 +1772,8 @@ async function saveCalibration() {
         span_bottom_end: spans.bottom?.end ?? 1,
         span_left_start: spans.left?.start ?? 0,
         span_left_end: spans.left?.end ?? 1,
+        skip_leds_start: parseInt(document.getElementById('cal-skip-start').value || 0),
+        skip_leds_end: parseInt(document.getElementById('cal-skip-end').value || 0),
     };
 
     try {
@@ -1913,10 +1935,11 @@ const calibrationTutorialSteps = [
     { selector: '#cal-top-leds', textKey: 'calibration.tip.led_count', position: 'bottom' },
     { selector: '.corner-bottom-left', textKey: 'calibration.tip.start_corner', position: 'right' },
     { selector: '.direction-toggle', textKey: 'calibration.tip.direction', position: 'bottom' },
-    { selector: '.offset-control', textKey: 'calibration.tip.offset', position: 'bottom' },
+    { selector: '#cal-offset', textKey: 'calibration.tip.offset', position: 'top' },
     { selector: '.edge-span-bar[data-edge="top"]', textKey: 'calibration.tip.span', position: 'bottom' },
     { selector: '.toggle-top', textKey: 'calibration.tip.test', position: 'top' },
-    { selector: '.preview-screen-total', textKey: 'calibration.tip.toggle_inputs', position: 'top' }
+    { selector: '.preview-screen-total', textKey: 'calibration.tip.toggle_inputs', position: 'top' },
+    { selector: '#cal-skip-start', textKey: 'calibration.tip.skip_leds', position: 'top' }
 ];
 
 const deviceTutorialSteps = [

server/src/wled_controller/static/index.html

@@ -95,10 +95,6 @@
                                 <span id="direction-icon">↻</span> <span id="direction-label">CW</span>
                             </button>
                             <div class="preview-screen-total" onclick="toggleEdgeInputs()" title="Toggle edge LED inputs"><span id="cal-total-leds-inline">0</span> / <span id="cal-device-led-count-inline">0</span></div>
-                            <label class="offset-control" title="LED offset from LED 0 to start corner">
-                                <span>⊕</span>
-                                <input type="number" id="cal-offset" min="0" value="0" oninput="updateCalibrationPreview()">
-                            </label>
                         </div>
 
                         <!-- Edge bars with span controls and LED count inputs -->
@@ -167,6 +163,34 @@
                 </div>
 
 
+                <!-- Offset & Skip LEDs -->
+                <div style="display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 16px; padding: 0 24px;">
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="cal-offset" data-i18n="calibration.offset">LED Offset:</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="calibration.offset.hint">Distance from physical LED 0 to the start corner (along strip direction)</small>
+                        <input type="number" id="cal-offset" min="0" value="0" oninput="updateCalibrationPreview()">
+                    </div>
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="cal-skip-start" data-i18n="calibration.skip_start">Skip LEDs (Start):</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="calibration.skip_start.hint">Number of LEDs to turn off at the beginning of the strip (0 = none)</small>
+                        <input type="number" id="cal-skip-start" min="0" value="0" oninput="updateCalibrationPreview()">
+                    </div>
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="cal-skip-end" data-i18n="calibration.skip_end">Skip LEDs (End):</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="calibration.skip_end.hint">Number of LEDs to turn off at the end of the strip (0 = none)</small>
+                        <input type="number" id="cal-skip-end" min="0" value="0" oninput="updateCalibrationPreview()">
+                    </div>
+                </div>
+
                 <!-- Tutorial Overlay -->
                 <div id="tutorial-overlay" class="tutorial-overlay">
                     <div class="tutorial-backdrop"></div>

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

@@ -176,6 +176,7 @@
   "calibration.tip.span": "Drag green bars to adjust coverage span",
   "calibration.tip.test": "Click an edge to toggle test LEDs",
   "calibration.tip.toggle_inputs": "Click total LED count to toggle edge inputs",
+  "calibration.tip.skip_leds": "Skip LEDs at the start or end of the strip — skipped LEDs stay off",
   "calibration.tutorial.start": "Start tutorial",
   "calibration.start_position": "Starting Position:",
   "calibration.position.bottom_left": "Bottom Left",
@@ -189,6 +190,12 @@
   "calibration.leds.right": "Right LEDs:",
   "calibration.leds.bottom": "Bottom LEDs:",
   "calibration.leds.left": "Left LEDs:",
+  "calibration.offset": "LED Offset:",
+  "calibration.offset.hint": "Distance from physical LED 0 to the start corner (along strip direction)",
+  "calibration.skip_start": "Skip LEDs (Start):",
+  "calibration.skip_start.hint": "Number of LEDs to turn off at the beginning of the strip (0 = none)",
+  "calibration.skip_end": "Skip LEDs (End):",
+  "calibration.skip_end.hint": "Number of LEDs to turn off at the end of the strip (0 = none)",
   "calibration.button.cancel": "Cancel",
   "calibration.button.save": "Save",
   "calibration.saved": "Calibration saved successfully",

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

@@ -176,6 +176,7 @@
   "calibration.tip.span": "Перетащите зелёные полосы для настройки зоны покрытия",
   "calibration.tip.test": "Нажмите на край для теста LED",
   "calibration.tip.toggle_inputs": "Нажмите на общее количество LED для скрытия боковых полей",
+  "calibration.tip.skip_leds": "Пропуск LED в начале или конце ленты — пропущенные LED остаются выключенными",
   "calibration.tutorial.start": "Начать обучение",
   "calibration.start_position": "Начальная Позиция:",
   "calibration.position.bottom_left": "Нижний Левый",
@@ -189,6 +190,12 @@
   "calibration.leds.right": "Светодиодов Справа:",
   "calibration.leds.bottom": "Светодиодов Снизу:",
   "calibration.leds.left": "Светодиодов Слева:",
+  "calibration.offset": "Смещение LED:",
+  "calibration.offset.hint": "Расстояние от физического LED 0 до стартового угла (по направлению ленты)",
+  "calibration.skip_start": "Пропуск LED (начало):",
+  "calibration.skip_start.hint": "Количество LED, которые будут выключены в начале ленты (0 = нет)",
+  "calibration.skip_end": "Пропуск LED (конец):",
+  "calibration.skip_end.hint": "Количество LED, которые будут выключены в конце ленты (0 = нет)",
   "calibration.button.cancel": "Отмена",
   "calibration.button.save": "Сохранить",
   "calibration.saved": "Калибровка успешно сохранена",

server/src/wled_controller/static/style.css

@@ -1195,40 +1195,6 @@ input:-webkit-autofill:focus {
     gap: 6px;
 }
 
-.offset-control {
-    display: flex;
-    align-items: center;
-    gap: 3px;
-    height: 26px;
-    padding: 0 10px;
-    background: rgba(255, 255, 255, 0.15);
-    border: 1px solid rgba(255, 255, 255, 0.3);
-    border-radius: 12px;
-    font-size: 12px;
-    color: rgba(255, 255, 255, 0.9);
-    box-sizing: border-box;
-    cursor: pointer;
-    user-select: none;
-}
-
-.offset-control input {
-    width: 36px;
-    padding: 0;
-    background: transparent;
-    border: none;
-    color: white;
-    font-size: 12px;
-    text-align: center;
-    outline: none;
-    -moz-appearance: textfield;
-}
-
-.offset-control input::-webkit-outer-spin-button,
-.offset-control input::-webkit-inner-spin-button {
-    -webkit-appearance: none;
-    margin: 0;
-}
-
 .preview-edge {
     position: absolute;
     display: flex;