我使用 LeadTools 进行扫描。
我想将扫描图像转换为字节。
void twainSession_AcquirePage(object sender, TwainAcquirePageEventArgs e)
{
ScanImage = e.Image.Clone();
ImageSource source = RasterImageConverter.ConvertToSource(ScanImage, ConvertToSourceOptions.None);
}
如何将ImageSource转换为Byte数组？
如果您使用 Xamarin，您可以使用这个：
public async Task<byte[]> ConvertImageSourceToBytesAsync(ImageSource imageSource)
{
Stream stream = await ((StreamImageSource)imageSource).Stream(CancellationToken.None);
byte[] bytesAvailable = new byte[stream.Length];
stream.Read(bytesAvailable, 0, bytesAvailable.Length);
return bytesAvailable;
}
除非您明确需要 ImageSource 对象，否则无需转换为 ImageSource 对象。您可以使用以下代码直接从 Leadtools.RasterImage 获取包含像素数据的字节数组：
int totalPixelBytes = e.Image.BytesPerLine * e.Image.Height;
byte[] byteArray = new byte[totalPixelBytes];
e.Image.GetRow(0, byteArray, 0, totalPixelBytes);
请注意，这只会为您提供原始像素数据。
如果您需要包含完整图像（例如 JPEG）的内存流或字节数组，则也不需要转换为源。您可以像这样使用 Leadtools.RasterCodecs 类：
RasterCodecs codecs = new RasterCodecs();
System.IO.MemoryStream memStream = new System.IO.MemoryStream();
codecs.Save(e.Image, memStream, RasterImageFormat.Jpeg, 24);
我在 Xamarin.Forms 中遇到了这个问题，我需要将相机拍摄的照片转换为字节数组。经过几天的尝试找出方法后，我在 Xamarin 论坛中看到了这个解决方案。
var photo = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions() { });
byte[] imageArray = null;
using (MemoryStream memory = new MemoryStream()) {
Stream stream = photo.GetStream();
stream.CopyTo(memory);
imageArray = memory.ToArray();
}
看来您可以将 .ConvertToSource 的结果转换为 BitmapSource 而不是 ImageSource。
我不是 100% 确定这如何转化为您的案例，但 LeadTools 的文档显示了此 VB 示例：
Dim source As BitmapSource
Using raster As RasterImage = RasterImageConverter.ConvertFromSource(bitmap, ConvertFromSourceOptions.None)
Console.WriteLine("Converted to RasterImage, bits/pixel is {0} and order is {1}", raster.BitsPerPixel, raster.Order)
' Perform image processing on the raster image using LEADTOOLS
Dim cmd As New FlipCommand(False)
cmd.Run(raster)
' Convert the image back to WPF using default options
source = DirectCast(RasterImageConverter.ConvertToSource(raster, ConvertToSourceOptions.None), BitmapSource)
End Using
我觉得应该是这样的
BitmapSource source = RasterImageConverter.ConvertToSource(ScanImage, ConvertToSourceOptions.None) as BitmapSource;
然后您可以使用 BitmapSource.CopyPixels
复制 BitmapSource 像素我使用 MemoryStream：
var source = RasterImageConverter.ConvertToSource(ScanImage, ConvertToSourceOptions.None) as BitmapSource;
byte[] data;
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(source));
using (MemoryStream ms = new MemoryStream())
{
encoder.Save(ms);
data = ms.ToArray();
}
我在 WPF 中使用此类来处理
Imagepublic static class ImageHelper
{
/// <summary>
/// ImageSource to bytes
/// </summary>
/// <param name="encoder"></param>
/// <param name="imageSource"></param>
/// <returns></returns>
public static byte[] ImageSourceToBytes(BitmapEncoder encoder, ImageSource imageSource)
{
byte[] bytes = null;
var bitmapSource = imageSource as BitmapSource;
if (bitmapSource != null)
{
encoder.Frames.Add(BitmapFrame.Create(bitmapSource));
using (var stream = new MemoryStream())
{
encoder.Save(stream);
bytes = stream.ToArray();
}
}
return bytes;
}
[DllImport("gdi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool DeleteObject(IntPtr value);
public static BitmapSource GetImageStream(Image myImage)
{
var bitmap = new Bitmap(myImage);
IntPtr bmpPt = bitmap.GetHbitmap();
BitmapSource bitmapSource =
System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
bmpPt,
IntPtr.Zero,
Int32Rect.Empty,
BitmapSizeOptions.FromEmptyOptions());
//freeze bitmapSource and clear memory to avoid memory leaks
bitmapSource.Freeze();
DeleteObject(bmpPt);
return bitmapSource;
}
/// <summary>
/// Convert String to ImageFormat
/// </summary>
/// <param name="format"></param>
/// <returns></returns>
public static System.Drawing.Imaging.ImageFormat ImageFormatFromString(string format)
{
if (format.Equals("Jpg"))
format = "Jpeg";
Type type = typeof(System.Drawing.Imaging.ImageFormat);
BindingFlags flags = BindingFlags.GetProperty;
object o = type.InvokeMember(format, flags, null, type, null);
return (System.Drawing.Imaging.ImageFormat)o;
}
/// <summary>
/// Read image from path
/// </summary>
/// <param name="imageFile"></param>
/// <param name="imageFormat"></param>
/// <returns></returns>
public static byte[] BytesFromImage(String imageFile, System.Drawing.Imaging.ImageFormat imageFormat)
{
MemoryStream ms = new MemoryStream();
Image img = Image.FromFile(imageFile);
img.Save(ms, imageFormat);
return ms.ToArray();
}
/// <summary>
/// Convert image to byte array
/// </summary>
/// <param name="imageIn"></param>
/// <param name="imageFormat"></param>
/// <returns></returns>
public static byte[] ImageToByteArray(System.Drawing.Image imageIn, System.Drawing.Imaging.ImageFormat imageFormat)
{
MemoryStream ms = new MemoryStream();
imageIn.Save(ms, imageFormat);
return ms.ToArray();
}
/// <summary>
/// Byte array to photo
/// </summary>
/// <param name="byteArrayIn"></param>
/// <returns></returns>
public static Image ByteArrayToImage(byte[] byteArrayIn)
{
MemoryStream ms = new MemoryStream(byteArrayIn);
Image returnImage = Image.FromStream(ms);
return returnImage;
}
}
因此，尝试不同的方法并根据需要使此类现代化。
改进 Led Machine 的答案，因为我的 ImageSource 来自未实现长度的 http 流
public async Task<byte[]> ConvertImageSourceToBytesAsync(ImageSource imageSource)
{
using MemoryStream memoryStream = new();
try
{
using Stream stream = await ((StreamImageSource)imageSource).Stream(CancellationToken.None);
await stream.CopyToAsync(memoryStream);
stream?.Dispose();
return memoryStream.ToArray();
}
catch
{
return [];
}
finally
{
memoryStream?.Dispose();
}
}