Camera selector, focus controls, and decode improvements

- Camera picker with auto-selection of main back camera (index 0)
- Manual/auto focus toggle button with focus distance slider
- Dual binarizer (Hybrid + GlobalHistogram) for blur tolerance
- Only vibrate on new unique scan result
- Band canvas to restrict decoding to aim line region
- Camera select overlaid in viewfinder corner

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

app.mjs

@@ -11,7 +11,8 @@ const cam_info = document.getElementById('cam-info');
 const focus_row = document.getElementById('focus-row');
 const focus_slider = document.getElementById('focus-slider');
 const focus_val_el = document.getElementById('focus-val');
-const focus_auto = document.getElementById('focus-auto');
+const focus_auto_btn = document.getElementById('focus-auto-btn');
+let focus_auto = true;
 // Canvases for ZXing decode pipeline
 const strip_canvas = document.createElement('canvas');
 const strip_ctx = strip_canvas.getContext('2d', { willReadFrequently: true });
@@ -76,11 +77,18 @@ async function start_camera(device_id = null) {
 		}
 
 		if (!has_continuous) {
-			focus_auto.checked  = false;
+			focus_auto = false;
-			focus_auto.disabled = true;
+			focus_auto_btn.disabled = true;
+		} else {
+			focus_auto_btn.disabled = false;
 		}
-
+		focus_auto_btn.classList.toggle('active', focus_auto);
-		focus_auto.onchange = () => apply_focus(track, has_continuous, has_distance);
+		focus_auto_btn.onclick = async () => {
+			focus_auto = !focus_auto;
+			focus_auto_btn.classList.toggle('active', focus_auto);
+			focus_slider.disabled = focus_auto;
+			await apply_focus(active_track, has_continuous, has_distance);
+		};
 		await apply_focus(track, has_continuous, has_distance);
 
 		// Tap to focus (replace listener on camera switch)
@@ -98,8 +106,7 @@ async function start_camera(device_id = null) {
 // --- Focus ---
 
 async function apply_focus(track, has_continuous, has_distance) {
-	const auto = focus_auto.checked;
+	const auto = focus_auto;
-	focus_slider.disabled = auto;
 	try {
 		if (auto && has_continuous) {
 			await track.applyConstraints({ advanced: [{ focusMode: 'continuous' }] });
@@ -276,9 +283,7 @@ function attempt_decode() {
 		band_canvas.width  = strip_canvas.width;
 		band_canvas.height = band_h;
 	}
-	band_ctx.filter = 'contrast(1.8) brightness(1.05)';
 	band_ctx.drawImage(strip_canvas, 0, band_y, strip_canvas.width, band_h, 0, 0, strip_canvas.width, band_h);
-	band_ctx.filter = 'none';
 
 	decode_attempts++;
 	const source = new ZXing.HTMLCanvasElementLuminanceSource(band_canvas);

index.html

@@ -55,6 +55,20 @@
 			height: 100%;
 		}
 
+		#camera-select {
+			position: absolute;
+			bottom: 8px;
+			right: 8px;
+			max-width: 60%;
+			padding: 4px 6px;
+			background: rgba(0,0,0,0.6);
+			color: #dce4ef;
+			border: 1px solid #1e2a38;
+			border-radius: 6px;
+			font-family: inherit;
+			font-size: 11px;
+		}
+
 		#debug {
 			position: absolute;
 			top: 6px;
@@ -117,6 +131,24 @@
 			font-size: 13px;
 		}
 
+		#focus-auto-btn {
+			padding: 8px 14px;
+			border-radius: 6px;
+			border: 1px solid #1e2a38;
+			background: #181e28;
+			color: var(--dim);
+			font-family: inherit;
+			font-size: 13px;
+			cursor: pointer;
+			white-space: nowrap;
+		}
+
+		#focus-auto-btn.active {
+			background: #0d1f15;
+			border-color: var(--accent);
+			color: var(--accent);
+		}
+
 		#focus-slider {
 			flex: 1;
 			accent-color: var(--accent);
@@ -147,19 +179,16 @@
 		<video id="video" autoplay playsinline muted></video>
 		<canvas id="overlay"></canvas>
 		<div id="debug"></div>
+		<select id="camera-select" style="display:none;"></select>
 	</div>
 	<div id="bottom-panel">
 		<div id="cam-info" style="width:100%;font-size:11px;color:#5a6475;word-break:break-all;"></div>
 		<div id="result">Point camera at a barcode</div>
 		<div id="focus-row">
-			<label style="display:flex;align-items:center;gap:4px;cursor:pointer;">
+			<button id="focus-auto-btn">Auto</button>
-				<input id="focus-auto" type="checkbox" checked>
-				Auto
-			</label>
 			<input id="focus-slider" type="range" min="0" max="1.62" step="0.01" value="0.3" disabled>
 			<span id="focus-val">0.30m</span>
 		</div>
-		<select id="camera-select" style="display:none; width:100%; padding:8px; background:#181e28; color:#dce4ef; border:1px solid #1e2a38; border-radius:8px; font-family:inherit;"></select>
 		<button id="start-btn">Start Camera</button>
 	</div>
 </div>