1.首先,需要在Blazor应用程序中安装ExifLib NuGet包,以便读取图像的元数据。
2.在Blazor组件中添加以下代码来获取图像元数据和方向:
private async Task LoadImage(IMatFileUploadEntry entry)
{
// read image metadata to get rotation information
using (var metadataReader = new JpegMetadataAdapter(await entry.OpenReadStream()))
{
var rotation = metadataReader.GetOrientation();
if (rotation == ImageOrientation.Rotate90 || rotation == ImageOrientation.Rotate270)
{
// if the image is rotated 90 or 270 degrees, swap height and width
var tempHeight = _imageHeight;
_imageHeight = _imageWidth;
_imageWidth = tempHeight;
}
}
// process and display image
using (var stream = new MemoryStream())
{
await entry.UploadToStreamAsync(stream);
// create image source with appropriate width and height values
var imageDataUrl = $"data:{entry.ContentType};base64,{Convert.ToBase64String(stream.ToArray())}";
_imageSrc = imageDataUrl;
}
}
3.这段代码中,通过调用JpegMetadataAdapter.GetOrientation()方法获取图像的方向。如果方向为旋转90度或270度,则要交换图像的高度和宽度。
4.然后上传图像流并创建一个数据URL,以便在组件中显示图像。可以使用以下代码在Blazor组件中显示图像: