在线录屏-通过Web API接口轻松实现录屏

在线录屏是指在互联网上进行屏幕录制的过程。它允许用户通过网络连接，将自己的屏幕活动记录下来，并可以在需要时进行播放、共享或存档。在线录屏常用于教育、培训、演示、游戏等场景，可以帮助用户展示操作步骤、解决问题、分享经验等。通常，在线录屏工具提供了丰富的功能，例如选择录制区域、添加音频注释、调整录制质量等，以满足用户的不同需求。

在线体验地址：https://amd794.com/recordscreen

工具演示视频：https://www.bilibili.com/video/BV1wC4y1U7at/

相关说明：

MediaDevices 是 Web API 中的一部分，它提供了访问媒体设备（如摄像头、麦克风等）的功能。通过 MediaDevices 接口，您可以使用 JavaScript 代码来获取和操作媒体设备的流（如音频和视频）。这使得您可以在 Web 应用程序中实现音视频通信、媒体录制和流媒体等功能。

当使用 MediaDevices 接口调用 Web API 时，可以按照以下示例代码进行操作：

// 检查浏览器是否支持 MediaDevices 接口
if (navigator.mediaDevices) {
  // 获取媒体设备的用户授权
  navigator.mediaDevices.getUserMedia({ audio: true, video: true })
    .then(function(stream) {
      // 获取到媒体流后的处理逻辑
      // 在这里可以对获取到的音视频流进行操作
      // 例如：显示视频流、播放音频流等
    })
    .catch(function(error) {
      // 处理获取媒体设备失败的情况
      console.log('获取媒体设备失败: ' + error.message);
    });
} else {
  console.log('您的浏览器不支持 MediaDevices 接口');
}

上述示例代码首先检查浏览器是否支持 MediaDevices 接口。如果支持，它会调用 `getUserMedia` 方法来请求用户授权访问媒体设备（包括音频和视频）。如果用户授权成功，将返回一个媒体流对象，可以在 `.then` 方法中对该流进行处理。如果用户拒绝授权或发生其他错误，将在 `.catch` 方法中处理错误情况。

通过这样的调用方式，您可以使用 MediaDevices 接口来获取媒体设备的流，并对其进行进一步的操作和处理。

浏览器兼容性：

可以说是大部分不支持，毕竟是新的Web API接口，详细可以去MDN中查看MediaDevices - Web API 接口参考 | MDN (mozilla.org)

相关实现代码：

潦草布局一下，毕竟只是个玩具，不需要多华丽。

  <div class="RecordScreen">
    <div class="Operate">
      <div class="Content">
        <div class="flex Start" @click="onStart" v-if="!setState">
          <el-icon size="50px" color=" var(--el-color-primary)">
            <VideoCameraFilled/>
          </el-icon>
          <el-button type="primary">{{ currentLang.start }}</el-button>
        </div>
        <div class="flex Pause" @click="onPause" v-if="setState === 'recording'">
          <el-icon size="50px" color=" var(--el-color-primary)">
            <VideoPause/>
          </el-icon>
          <el-button type="info">{{ currentLang.stop }}</el-button>
        </div>
        <div class="flex Resume" @click="onResume" v-if="setState === 'paused'">
          <el-icon size="50px" color=" var(--el-color-primary)">
            <VideoPlay/>
          </el-icon>
          <el-button type="info">{{ currentLang.continue }}</el-button>
        </div>
        <div class="flex Stop" @click="onStop" v-if="setState">
          <el-icon size="50px" color=" var(--el-color-primary)">
            <SwitchButton/>
          </el-icon>
          <el-button type="danger">{{ currentLang.end }}</el-button>
        </div>
      </div>
      <el-divider v-if="VideoURL"/>
      <div class="Operate__Download">
        <div v-if="!VideoURL"
             style="width: 100vw;height: 100vh;position: absolute;top: 0;left: 0;z-index: 99999;background-color: var(--el-bg-color);">
        </div>
        <el-input v-model="DownloadName" placeholder="please input">
          <template #append>.mp4</template>
        </el-input>
        <el-button type="primary" :icon="Download" @click="onDownload">{{ currentLang.saveVideo }}</el-button>
      </div>
    </div>
    <div class="RecordScreen__state">
      <div v-if="setState" class="REC">
        <div></div>
        <div>REC</div>
      </div>
      <el-icon v-if="!VideoURL" size="40vh" color="var(--el-color-primary)">
        <Monitor/>
      </el-icon>
      <div v-if="setState" class="Timing">
        <div>{{ Hour }}:{{ Minute }}:{{ Seconds }}</div>
        <div>{{ setState === 'paused' ? currentLang.pauseScreenRecording : currentLang.recordingScreen }}</div>
      </div>
      <video v-if="VideoURL" :src="VideoURL" controls></video>
    </div>
  </div>

简单定义几个变量

const VideoURL = ref('')
const DownloadName = ref('')
const setState = ref('')
let mediaRecorder = null
let mediaThen = null

开始录屏

const onStart = () => {
  VideoURL.value = ''
  mediaThen = null
  navigator.mediaDevices.getDisplayMedia({video: true, audio: true})
      .then(mediaStream => {
        mediaThen = mediaStream
        mediaRecorder = new MediaRecorder(mediaStream);
        Timing()
        console.log(mediaRecorder)
        const chunks = [];
        mediaRecorder.ondataavailable = event => {
          if (event.data.size > 0) {
            chunks.push(event.data);
          }
        };
        mediaRecorder.onstop = () => {
          const blob = new Blob(chunks, {type: 'video/mp4'});
          const recordedVideoURL = URL.createObjectURL(blob);
          VideoURL.value = recordedVideoURL
          setState.value = '' //inactive
        };
        mediaRecorder.start();
        setState.value = mediaRecorder.state   //recording

      })
      .catch(error => {
        // if (error == 'DOMException: Permission denied') return false
        // ElMessageBox({
        //   title: '当前浏览器或设备不支持录屏',
        //   confirmButtonText: '确定',
        //   message: h('p', null, [
        //     h('span', null, error),
        //   ]),
        // })
      });
}

暂停录屏

const onPause = () => {
  clearTimeout(timer)
  mediaRecorder.pause()
  setState.value = mediaRecorder.state   //paused
}

恢复录屏

const onResume = () => {
  Timing()
  mediaRecorder.resume()
  setState.value = mediaRecorder.state   //recording
}

结束录屏

const onStop = () => {
  mediaRecorder.stop()
  mediaThen.getTracks().forEach(track => track.stop())
  setState.value = '' //inactive
}

最后把样式补上

<style scoped lang="scss">
@mixin Flex {
  display: flex;
  align-items: center;
  justify-content: center;
}

@mixin side {
  padding: 10px;
  gap: 10px;
}

@mixin font($size: 0.9rem, $Color: red, $spacing: 0.2rem) {
  font-size: $size;
  line-height: $size;
  color: $Color;
  letter-spacing: $spacing;
}

.RecordScreen {
  @font-face {
    font-family: digital-display;
    src: url(data:font/woff2;base64,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)
  }

  $bg: 'data:image/svg+xml;base64,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';

  @include Flex;
  justify-content: space-around;
  height: 100vh;
  overflow: hidden;
  box-shadow: var(--el-box-shadow);
  position: relative;
  flex-direction: column-reverse;

  .flex {
    @include Flex;
    flex-direction: column;
  }

  .Operate {
    .Content {
      @include Flex;

      .Start {
        @include side;
      }

      .Pause {
        @include side;
      }

      .Resume {
        @include side;
      }

      .Stop {
        @include side;
      }
    }

    &__Download {
      @include Flex;
      gap: 10px;
      position: relative;
      overflow: hidden;
    }
  }

  &__state {
    position: relative;
    border-radius: 1rem;
    @include Flex;
    justify-content: space-around;
    width: 57vmax;
    height: 70vh;
    border: 1px dashed var(--el-color-primary);
    background: #022125 url($bg) center no-repeat;
    overflow: hidden;

    .REC {
      @include Flex;
      gap: 0.5rem;
      position: absolute;
      top: 0.9rem;
      left: 0.9rem;

      :first-child {
        width: 1rem;
        height: 1rem;
        border-radius: 50rem;
        background-color: red;
      }

      :last-child {
        @include font()
      }
    }

    .Timing {
      display: flex;
      align-items: flex-start;
      gap: 1rem;
      flex-direction: column;

      :first-child {
        @include font(2rem, #1fb5c9, 0.3rem);
        font-weight: 600;
        font-family: digital-display;
      }

      :last-child {
        @include font(1.8rem, #1fb5c9, 0.3rem);
        font-weight: 600;
      }
    }

    video {
      width: 100%;
      height: 100%;
      vertical-align: middle;

    }
  }
}
</style>