60 lines
1.9 KiB
TypeScript
60 lines
1.9 KiB
TypeScript
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// ============================================================
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// CameraManager — 摄像头流采集
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// 职责：获取用户摄像头 MediaStream，提供给 VideoPreview 和 EdgeProcessor
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// ============================================================
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import { useCallback, useRef, useState } from "react";
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export interface CameraManagerHandle {
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/** 获取当前视频轨道 */
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stream: MediaStream | null;
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/** 捕获当前帧为 JPEG DataURL */
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captureFrame: () => string | null;
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}
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export function useCamera() {
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const videoRef = useRef<HTMLVideoElement>(null);
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const [stream, setStream] = useState<MediaStream | null>(null);
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const [error, setError] = useState<string | null>(null);
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const startCamera = useCallback(async () => {
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try {
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const mediaStream = await navigator.mediaDevices.getUserMedia({
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video: { facingMode: "environment", width: 640, height: 480 },
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audio: false,
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});
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setStream(mediaStream);
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if (videoRef.current) {
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videoRef.current.srcObject = mediaStream;
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}
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setError(null);
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} catch (err) {
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const message = err instanceof Error ? err.message : "无法访问摄像头";
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setError(message);
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console.error("[Camera] 获取摄像头失败:", err);
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}
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}, []);
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const stopCamera = useCallback(() => {
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stream?.getTracks().forEach((track) => track.stop());
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setStream(null);
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}, [stream]);
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/** 从 video 元素捕获当前帧为 JPEG DataURL */
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const captureFrame = useCallback((): string | null => {
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const video = videoRef.current;
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if (!video || video.readyState < 2) return null;
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const canvas = document.createElement("canvas");
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canvas.width = video.videoWidth;
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canvas.height = video.videoHeight;
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const ctx = canvas.getContext("2d");
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if (!ctx) return null;
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ctx.drawImage(video, 0, 0);
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return canvas.toDataURL("image/jpeg", 0.7);
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}, []);
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return { videoRef, stream, error, startCamera, stopCamera, captureFrame };
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}
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