使用edsdk 2.8拍照并直接将图像保存到电脑

Question

我是 EDSDK 2.8 的新手

目前，我的程序可以拍照。然而，当拍摄照片时，该照片会暂时存储在佳能相机的缓冲区中。我想知道如何将其目录保存到PC上？

有人有什么想法吗？或者 c# 或 vb.net 中的示例代码？

Answer 1

我正在做同样的事情，因为我的相机中没有存储卡，并且想在发送拍照命令后将图像传输到主机。以下是当佳能 EOS50D 中未安装存储卡时调用 ObjectEventHandler 回调的方法。

EdsUInt32 setsaveto = kEdsSaveTo_Both;
err = EdsSetPropertyData(camera, kEdsPropID_SaveTo, 0, sizeof(setsaveto), &setsaveto);

瞧，回调被调用，然后我可以继续执行 getCapturedItem() 函数，正如 Wayne 在之前的帖子中发布的那样。

Answer 2

这是我所做的：

首先，您必须在创建对象（即图片）时注册回调事件。我在创建的 registerEvents 方法中执行了此操作：

//  Register OBJECT events
edsObjectEventHandler = new EDSDK.EdsObjectEventHandler(objectEventHandler);
error = EDSDK.EdsSetObjectEventHandler(this.CameraDevice, 
                EDSDK.ObjectEvent_All, edsObjectEventHandler, IntPtr.Zero);
if (EDSDK.EDS_ERR_OK != error)
{
    throw new CameraEventRegistrationException("Unable to
        register object events with the camera!", error);
}

objectEventHandler 是创建图片时将调用的方法。

该方法需要符合 API 规定的接口。下面是该方法的一个示例实现：

/// <summary>
/// Registered callback function for recieving object events
/// </summary>
/// <param name="inEvent">Indicate the event type supplemented.</param>
/// <param name="inRef">Returns a reference to objects created by the event.</param>
/// <param name="inContext">Passes inContext without modification</param>
/// <returns>Status 0 (OK)</returns>
private uint objectEventHandler(uint inEvent, IntPtr inRef, IntPtr inContext)
{
    switch (inEvent)
    {
        case EDSDK.ObjectEvent_DirItemCreated:
             this.invokeNewItemCreatedEvent(new NewItemCreatedEventArgs(getCapturedItem(inRef)));
             Console.WriteLine("Directory Item Created");
             break;
        case EDSDK.ObjectEvent_DirItemRequestTransfer:
             Console.WriteLine("Directory Item Requested Transfer");
             break;
         default:
             Console.WriteLine(String.Format("ObjectEventHandler: event {0}, ref {1}", inEvent.ToString("X"), inRef.ToString()));
             break;
    }

    return 0x0;
}

在这个示例中，我转身并生成我自己的事件，该事件具有对流对象的引用。这是通过以下代码处理的：

        /// <summary>
        /// Gets a photo or video clip from the camera
        /// </summary>
        /// <param name="directoryItem">Reference to the item that the camera captured.</param>
        /// <returns></returns>
        private CapturedItem getCapturedItem(IntPtr directoryItem)
        {
            uint err = EDSDK.EDS_ERR_OK;
            IntPtr stream = IntPtr.Zero;

            EDSDK.EdsDirectoryItemInfo dirItemInfo;

            err = EDSDK.EdsGetDirectoryItemInfo(directoryItem, out dirItemInfo);

            if (err != EDSDK.EDS_ERR_OK)
            {
                throw new CameraException("Unable to get captured item info!", err);
            }

            //  Fill the stream with the resulting image
            if (err == EDSDK.EDS_ERR_OK)
            {
                err = EDSDK.EdsCreateMemoryStream((uint)dirItemInfo.Size, out stream);
            }

            //  Copy the stream to a byte[] and 
            if (err == EDSDK.EDS_ERR_OK)
            {
                err = EDSDK.EdsDownload(directoryItem, (uint)dirItemInfo.Size, stream);
            }

            //  Create the returned item
            CapturedItem item = new CapturedItem();

            if (err == EDSDK.EDS_ERR_OK)
            {
                IntPtr imageRef = IntPtr.Zero;

                err = EDSDK.EdsCreateImageRef(stream, out imageRef);

                if (err == EDSDK.EDS_ERR_OK)
                {
                    EDSDK.EdsImageInfo info;
                    err = EDSDK.EdsGetImageInfo(imageRef, EDSDK.EdsImageSource.FullView, out info);

                    if (err == EDSDK.EDS_ERR_OK)
                    {
                        item.Dimensions = new com.waynehartman.util.graphics.Dimension((int)info.Width, (int)info.Height);

                        EDSDK.EdsRelease(imageRef);
                    }
                }
            }

            if (err == EDSDK.EDS_ERR_OK)
            {
                byte[] buffer = new byte[(int)dirItemInfo.Size];

                GCHandle gcHandle = GCHandle.Alloc(buffer, GCHandleType.Pinned);

                IntPtr address = gcHandle.AddrOfPinnedObject();

                IntPtr streamPtr = IntPtr.Zero;

                err = EDSDK.EdsGetPointer(stream, out streamPtr);

                if (err != EDSDK.EDS_ERR_OK)
                {
                    throw new CameraDownloadException("Unable to get resultant image.", err);
                }

                try
                {
                    Marshal.Copy(streamPtr, buffer, 0, (int)dirItemInfo.Size);

                    item.Image = buffer;
                    item.Name = dirItemInfo.szFileName;
                    item.Size = (long)dirItemInfo.Size;
                    item.IsFolder = Convert.ToBoolean(dirItemInfo.isFolder);

                    return item;
                }
                catch (AccessViolationException ave)
                {
                    throw new CameraDownloadException("Error copying unmanaged stream to managed byte[].", ave);
                }
                finally
                {
                    gcHandle.Free();
                    EDSDK.EdsRelease(stream);
                    EDSDK.EdsRelease(streamPtr);
                }
            }
            else
            {
                throw new CameraDownloadException("Unable to get resultant image.", err);
            }
        }