feat: 增加 GetPreviewData 方法

Author: ArgoZhang

src/BootstrapBlazor/Services/MediaDevices/DefaultMediaDevices.cs

@@ -45,6 +45,18 @@ public async Task Capture()
         return await module.InvokeAsync<string?>("getPreviewUrl");
     }
 
+    public async Task<Stream?> GetPreviewData()
+    {
+        Stream? ret = null;
+        var module = await LoadModule();
+        var stream = await module.InvokeAsync<IJSStreamReference?>("getPreviewData");
+        if (stream != null)
+        {
+            ret = await stream.OpenReadStreamAsync(stream.Length);
+        }
+        return ret;
+    }
+
     public async Task<bool> Apply(MediaTrackConstraints constraints)
     {
         var module = await LoadModule();

src/BootstrapBlazor/Services/MediaDevices/DefaultVideoDevice.cs

@@ -37,6 +37,11 @@ public Task Capture()
         return deviceService.Capture();
     }
 
+    public Task<Stream?> GetPreviewData()
+    {
+        return deviceService.GetPreviewData();
+    }
+
     public Task<string?> GetPreviewUrl()
     {
         return deviceService.GetPreviewUrl();

src/BootstrapBlazor/Services/MediaDevices/IMediaDevices.cs

@@ -43,6 +43,12 @@ public interface IMediaDevices
     /// <returns></returns>
     Task<string?> GetPreviewUrl();
 
+    /// <summary>
+    /// Gets the stream of the captured image.
+    /// </summary>
+    /// <returns></returns>
+    Task<Stream?> GetPreviewData();
+
     /// <summary>
     /// Apply the media track constraints.
     /// </summary>

src/BootstrapBlazor/Services/MediaDevices/IVideoDevice.cs

@@ -36,24 +36,18 @@ public interface IVideoDevice
     /// <returns></returns>
     Task Capture();
 
-    ///// <summary>
-    ///// Preview a still image from the video stream.
-    ///// </summary>
-    ///// <returns></returns>
-    //Task Preview();
-
-    ///// <summary>
-    ///// Gets the stream of the captured image.
-    ///// </summary>
-    ///// <returns></returns>
-    //Task<Stream?> GetPreviewImage();
-
     /// <summary>
     /// Gets the preview URL of the captured image.
     /// </summary>
     /// <returns></returns>
     Task<string?> GetPreviewUrl();
 
+    /// <summary>
+    /// Gets the stream of the captured image.
+    /// </summary>
+    /// <returns></returns>
+    Task<Stream?> GetPreviewData();
+
     /// <summary>
     /// Apply the media track constraints.
     /// </summary>