Update voice demo camera drawer

examples/webpage/app.js

@@ -78,6 +78,7 @@ const els = {
   cameraPhoto: document.getElementById("camera-photo"),
   cameraCanvas: document.getElementById("camera-canvas"),
   cameraStartBtn: document.getElementById("camera-start-btn"),
+  cameraDeviceRow: document.getElementById("camera-device-row"),
   cameraDeviceSelect: document.getElementById("camera-device-select"),
   cameraUpload: document.getElementById("camera-upload"),
   cameraSamples: document.getElementById("camera-samples"),
@@ -257,9 +258,6 @@ function syncCameraDrawer(value) {
     els.cameraQuestion.textContent = prompt;
     renderSampleThumbnails();
     selectDefaultImage();
-    refreshVideoDevices().then(() => {
-      if (!state.cameraActive) populateDeviceSelect();
-    });
   } else {
     els.cameraState.textContent = "状态 -";
     els.cameraQuestion.textContent = "";
@@ -987,6 +985,8 @@ async function startCamera(deviceId) {
     state.cameraStream.getVideoTracks?.()[0]?.getSettings?.().deviceId ||
     deviceId;
   populateDeviceSelect(activeId);
+  // Reveal the camera device dropdown only while the camera is in use.
+  els.cameraDeviceRow.hidden = false;
   setCameraButtonEnabled();
 }
 
@@ -998,6 +998,7 @@ function stopCameraStream() {
   els.cameraVideo.srcObject = null;
   state.cameraActive = false;
   els.cameraStartBtn.classList.remove("is-active");
+  els.cameraDeviceRow.hidden = true;
 }
 
 function captureFromCamera() {

examples/webpage/index.html

@@ -108,51 +108,15 @@
 
                 <p id="camera-question" class="camera-drawer__question"></p>
 
+                <div
+                  id="camera-samples"
+                  class="camera-drawer__samples"
+                  aria-label="示例图片，点击选择"
+                ></div>
+
                 <div class="camera-drawer__sources">
-                  <div class="camera-drawer__camera-row">
-                    <label class="device-picker">
-                      <span class="device-picker__label">摄像头</span>
-                      <select
-                        id="camera-device-select"
-                        class="device-picker__select"
-                        disabled
-                      >
-                        <option value="">默认摄像头</option>
-                      </select>
-                    </label>
-                    <button
-                      id="camera-start-btn"
-                      class="mic-btn cam-btn"
-                      type="button"
-                      title="打开摄像头"
-                    >
-                      <svg
-                        class="mic-btn__icon"
-                        viewBox="0 0 24 24"
-                        width="24"
-                        height="24"
-                        aria-hidden="true"
-                      >
-                        <path
-                          d="M4 8h3l1.2-1.6A1 1 0 0 1 9 6h6a1 1 0 0 1 .8.4L17 8h3a1 1 0 0 1 1 1v8a1 1 0 0 1-1 1H4a1 1 0 0 1-1-1V9a1 1 0 0 1 1-1Z"
-                          fill="none"
-                          stroke="currentColor"
-                          stroke-width="1.6"
-                        />
-                        <circle
-                          cx="12"
-                          cy="13"
-                          r="3.2"
-                          fill="none"
-                          stroke="currentColor"
-                          stroke-width="1.6"
-                        />
-                      </svg>
-                      <span class="mic-btn__label">使用摄像头</span>
-                    </button>
-                  </div>
                   <label
-                    class="btn btn--ghost camera-drawer__source camera-drawer__source--upload"
+                    class="btn btn--ghost camera-drawer__source"
                   >
                     上传图片
                     <input
@@ -162,13 +126,30 @@
                       hidden
                     />
                   </label>
+                  <button
+                    id="camera-start-btn"
+                    class="btn btn--ghost camera-drawer__source"
+                    type="button"
+                    title="打开摄像头"
+                  >
+                    使用摄像头
+                  </button>
                 </div>
 
-                <div
-                  id="camera-samples"
-                  class="camera-drawer__samples"
-                  aria-label="示例图片，点击选择"
-                ></div>
+                <label
+                  id="camera-device-row"
+                  class="device-picker camera-drawer__device-row"
+                  hidden
+                >
+                  <span class="device-picker__label">选择摄像头</span>
+                  <select
+                    id="camera-device-select"
+                    class="device-picker__select"
+                    disabled
+                  >
+                    <option value="">默认摄像头</option>
+                  </select>
+                </label>
 
                 <button
                   id="camera-done-btn"

examples/webpage/styles.css

@@ -270,36 +270,29 @@ body {
   cursor: not-allowed;
 }
 
+/* 上传图片 + 使用摄像头 share one row. */
 .camera-drawer__sources {
   display: flex;
-  flex-direction: column;
   gap: 8px;
 }
 
-/* Mirror the mic controls: labeled device select + an action pill button. */
-.camera-drawer__camera-row {
-  display: flex;
-  align-items: flex-end;
-  gap: 8px;
-}
-
-.camera-drawer__camera-row .device-picker {
-  flex: 1 1 auto;
+/* The camera device dropdown only appears after "使用摄像头" is selected. */
+.camera-drawer__device-row {
   max-width: none;
 }
 
-.cam-btn {
-  flex-shrink: 0;
+.camera-drawer__device-row[hidden] {
+  display: none;
 }
 
-.cam-btn.is-active {
-  background: var(--success);
+/* Active state for the "使用摄像头" button once the camera is live. */
+.camera-drawer__source.is-active {
   border-color: var(--success);
-  color: #fff;
-  box-shadow: 0 0 0 6px rgba(45, 210, 139, 0.18);
+  color: var(--success);
 }
 
 .camera-drawer__source {
+  flex: 1 1 0;
   display: inline-flex;
   align-items: center;
   justify-content: center;