I have code that serializes/deserializes bitmap objects. For some image files (especially png files) I found out that the size of the file is reduced after deserializing it, and the image quality is reduced. And if I serialize the deserialized image again, the resulting byte array is different compared to what it was before. Has anyone experienced the same problem? If so, how were you able to solve it?
Here is my code snippet:
private byte[] GetBytes(Bitmap image)
{
BinaryFormatter formatter = new BinaryFormatter();
using (MemoryStream ms = new MemoryStream())
{
formatter.Serialize(ms, image);
byte[] _bytes = ms.ToArray();
return _bytes;
}
}
private Bitmap GetImage(byte[] _bytes)
{
BinaryFormatter formatter = new BinaryFormatter();
using (MemoryStream ms = new MemoryStream(_bytes))
{
Bitmap bmp = (Bitmap)formatter.Deserialize(ms);
return bmp;
}
}
PS: Using an Image object instead of Bitmap seems to solve the problem, but I'd rather not change the object type due to external dependencies.
I'm doing a C# web service soap receiving an image.
I send a string contain the byte characters.
I transform the string in byte[] and next I world like to create the Bitmap.
The line Bitmap img = new Bitmap(ms); generate an exception : invalid argument.
I have a in the ms object this error : System.InvalidOperationException
value contain the correct string, imgBytes contain the good number of sell.
public string GetImage(string value)
{
byte[] imgBytes = Encoding.ASCII.GetBytes(value);
MemoryStream ms = new MemoryStream(imgBytes, true);
Bitmap img = new Bitmap(ms);
Code with debug mode
Exception
Thank you for your help.
It looks like your string holds base64 encoded data. Try to decode it to a byte array via Convert.FromBase64String
I had a similar problem. Basically you write into your memory stream (in the constructor) and the position pointer is at the end. So before reuse the memory stream you can try setting its position pointer to the beginning. Like this:
MemoryStream ms = new MemoryStream(imgBytes, true);
ms.Position = 0;
Bitmap img = new Bitmap(ms);
or the more general approach:
MemoryStream ms = new MemoryStream(imgBytes, true);
ms.Seek(0, SeekOrigin.Begin);
Bitmap img = new Bitmap(ms);
Hope this will solve your Problem.
Update
I think #heinbeinz answer is also important: First decode your string from the right encoding (normally base64), then set the position.
i've got some binary data which i want to save as an image. When i try to save the image, it throws an exception if the memory stream used to create the image, was closed before the save. The reason i do this is because i'm dynamically creating images and as such .. i need to use a memory stream.
this is the code:
[TestMethod]
public void TestMethod1()
{
// Grab the binary data.
byte[] data = File.ReadAllBytes("Chick.jpg");
// Read in the data but do not close, before using the stream.
Stream originalBinaryDataStream = new MemoryStream(data);
Bitmap image = new Bitmap(originalBinaryDataStream);
image.Save(#"c:\test.jpg");
originalBinaryDataStream.Dispose();
// Now lets use a nice dispose, etc...
Bitmap2 image2;
using (Stream originalBinaryDataStream2 = new MemoryStream(data))
{
image2 = new Bitmap(originalBinaryDataStream2);
}
image2.Save(#"C:\temp\pewpew.jpg"); // This throws the GDI+ exception.
}
Does anyone have any suggestions to how i could save an image with the stream closed? I cannot rely on the developers to remember to close the stream after the image is saved. In fact, the developer would have NO IDEA that the image was generated using a memory stream (because it happens in some other code, elsewhere).
I'm really confused :(
As it's a MemoryStream, you really don't need to close the stream - nothing bad will happen if you don't, although obviously it's good practice to dispose anything that's disposable anyway. (See this question for more on this.)
However, you should be disposing the Bitmap - and that will close the stream for you. Basically once you give the Bitmap constructor a stream, it "owns" the stream and you shouldn't close it. As the docs for that constructor say:
You must keep the stream open for the
lifetime of the Bitmap.
I can't find any docs promising to close the stream when you dispose the bitmap, but you should be able to verify that fairly easily.
A generic error occurred in GDI+.
May also result from incorrect save path!
Took me half a day to notice that.
So make sure that you have double checked the path to save the image as well.
Perhaps it is worth mentioning that if the C:\Temp directory does not exist, it will also throw this exception even if your stream is still existent.
Copy the Bitmap. You have to keep the stream open for the lifetime of the bitmap.
When drawing an image: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI
public static Image ToImage(this byte[] bytes)
{
using (var stream = new MemoryStream(bytes))
using (var image = Image.FromStream(stream, false, true))
{
return new Bitmap(image);
}
}
[Test]
public void ShouldCreateImageThatCanBeSavedWithoutOpenStream()
{
var imageBytes = File.ReadAllBytes("bitmap.bmp");
var image = imageBytes.ToImage();
image.Save("output.bmp");
}
I had the same problem but actually the cause was that the application didn't have permission to save files on C. When I changed to "D:\.." the picture has been saved.
You can try to create another copy of bitmap:
using (var memoryStream = new MemoryStream())
{
// write to memory stream here
memoryStream.Position = 0;
using (var bitmap = new Bitmap(memoryStream))
{
var bitmap2 = new Bitmap(bitmap);
return bitmap2;
}
}
This error occurred to me when I was trying from Citrix. The image folder was set to C:\ in the server, for which I do not have privilege. Once the image folder was moved to a shared drive, the error was gone.
A generic error occurred in GDI+. It can occur because of image storing paths issues,I got this error because my storing path is too long, I fixed this by first storing the image in a shortest path and move it to the correct location with long path handling techniques.
I was getting this error, because the automated test I was executing, was trying to store snapshots into a folder that didn't exist. After I created the folder, the error resolved
One strange solution which made my code to work.
Open the image in paint and save it as a new file with same format(.jpg). Now try with this new file and it works. It clearly explains you that the file might be corrupted in someway.
This can help only if your code has every other bugs fixed
It has also appeared with me when I was trying to save an image into path
C:\Program Files (x86)\some_directory
and the .exe wasn't executed to run as administrator, I hope this may help someone who has same issue too.
For me the code below crashed with A generic error occurred in GDI+on the line which Saves to a MemoryStream. The code was running on a web server and I resolved it by stopping and starting the Application Pool that was running the site.
Must have been some internal error in GDI+
private static string GetThumbnailImageAsBase64String(string path)
{
if (path == null || !File.Exists(path))
{
var log = ContainerResolver.Container.GetInstance<ILog>();
log.Info($"No file was found at path: {path}");
return null;
}
var width = LibraryItemFileSettings.Instance.ThumbnailImageWidth;
using (var image = Image.FromFile(path))
{
using (var thumbnail = image.GetThumbnailImage(width, width * image.Height / image.Width, null, IntPtr.Zero))
{
using (var memoryStream = new MemoryStream())
{
thumbnail.Save(memoryStream, ImageFormat.Png); // <= crash here
var bytes = new byte[memoryStream.Length];
memoryStream.Position = 0;
memoryStream.Read(bytes, 0, bytes.Length);
return Convert.ToBase64String(bytes, 0, bytes.Length);
}
}
}
}
I came across this error when I was trying a simple image editing in a WPF app.
Setting an Image element's Source to the bitmap prevents file saving.
Even setting Source=null doesn't seem to release the file.
Now I just never use the image as the Source of Image element, so I can overwrite after editing!
EDIT
After hearing about the CacheOption property(Thanks to #Nyerguds) I found the solution:
So instead of using the Bitmap constructor I must set the Uri after setting CacheOption BitmapCacheOption.OnLoad.(Image1 below is the Wpf Image element)
Instead of
Image1.Source = new BitmapImage(new Uri(filepath));
Use:
var image = new BitmapImage();
image.BeginInit();
image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
image.CacheOption = BitmapCacheOption.OnLoad;
image.UriSource = new Uri(filepath);
image.EndInit();
Image1.Source = image;
See this: WPF Image Caching
Try this code:
static void Main(string[] args)
{
byte[] data = null;
string fullPath = #"c:\testimage.jpg";
using (MemoryStream ms = new MemoryStream())
using (Bitmap tmp = (Bitmap)Bitmap.FromFile(fullPath))
using (Bitmap bm = new Bitmap(tmp))
{
bm.SetResolution(96, 96);
using (EncoderParameters eps = new EncoderParameters(1))
{
eps.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, 100L);
bm.Save(ms, GetEncoderInfo("image/jpeg"), eps);
}
data = ms.ToArray();
}
File.WriteAllBytes(fullPath, data);
}
private static ImageCodecInfo GetEncoderInfo(string mimeType)
{
ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
for (int j = 0; j < encoders.Length; ++j)
{
if (String.Equals(encoders[j].MimeType, mimeType, StringComparison.InvariantCultureIgnoreCase))
return encoders[j];
}
return null;
}
I used imageprocessor to resize images and one day I got "A generic error occurred in GDI+" exception.
After looked up a while I tried to recycle the application pool and bingo it works. So I note it here, hope it help ;)
Cheers
I was getting this error today on a server when the same code worked fine locally and on our DEV server but not on PRODUCTION. Rebooting the server resolved it.
public static byte[] SetImageToByte(Image img)
{
ImageConverter converter = new ImageConverter();
return (byte[])converter.ConvertTo(img, typeof(byte[]));
}
public static Bitmap SetByteToImage(byte[] blob)
{
MemoryStream mStream = new MemoryStream();
byte[] pData = blob;
mStream.Write(pData, 0, Convert.ToInt32(pData.Length));
Bitmap bm = new Bitmap(mStream, false);
mStream.Dispose();
return bm;
}
My friends,
I am trying convert a image to a Base64 String in a c# console app (.net 4.0).
The method:
public static String ConvertBitmapToBase64String(Bitmap bitmap,
ImageFormat imageFormat)
{
String generatedString = string.Empty;
MemoryStream memoryStream = new MemoryStream();
bitmap.Save(memoryStream, imageFormat);
memoryStream.Position = 0;
byte[] byteBuffer = memoryStream.ToArray();
memoryStream.Close();
generatedString = Convert.ToBase64String(byteBuffer);
byteBuffer = null;
return generatedString;
}
But when I invoke this method it is throwing an exception saying: "generic gdi+ error" and the error number is -2147467259.
Invoker code:
StreamReader streamReader = new StreamReader(#"C:\Anita.jpg");
Bitmap bitmap = new Bitmap(streamReader.BaseStream);
streamReader.Close();
String base64String = ImageUtil.ConvertBitmapToBase64String(bitmap, ImageFormat.Jpeg);
Anybody can give me a help?
Thanks.
The only likely problem I see is that the image is too large or big. Perhaps, instead of using a MemoryStream, you can use File.ReadAllBytes directly instead of passing around the Bitmap object, saving directly to a MemoryStream, and saving.
Also, you're reading the data in with a StreamReader, which is meant for text! Moving to just reading the bytes into an array and calling Convert.ToBase64String() should handle what you want to do.
I am doing a project in which a built in class for DICOM giving me the ImageSource,I want to use that ImageSource in My silverlight Image control. This conversion I am doing through WCF services. I found WCF does not support ImageSource, so I need to convert the output of built in class into Image or else in byte[]. So that I can send that output to Silverlight and in Silverlight client I'll reconvert it to ImageSource and can assign it to Image Control easily.
I googled for this but I did not find any help in there. Can anybody help me to fix this problem or provide me any alternate solution for this. Any help will be appreciated, Thanks in advance.
Note:- I do not have any permission for code modification on the built in class. As its a third party library.
UPDATE:-
Brief Description:
I have a class let say GetImageSource and in that I have a method say giveImgSource(). Now my questions is:
In WCF I have to call this method and after getting ImageSource from this method I need to pass it to my silverlight Client. As WCF doesn't know about ImageSource, so I need to convert the output of this method to some one out of the following or any alternate if you knows:
byte[]
Image
FileStream
MemoryStream etc
Is it a png image? Then use this to convert to byte[]:
var image = (BitmapSource)value;
BitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(image));
using (var ms = new MemoryStream())
{
encoder.Save(ms);
return ms.ToArray();
}
UPDATE:
Decoding:
var bytes = (byte[])value;
var image = new BitmapImage();
image.BeginInit();
if (bytes == null)
{
// Processing null case
}
else
{
using (var ms = new MemoryStream(bytes))
{
image.CacheOption = BitmapCacheOption.OnLoad;
image.StreamSource = ms;
image.EndInit();
}
}
return image;
Please refer to the below links for converting ImageSource to byte[]. They use the BitmapSource and WriteableBitmap classes which are available under PresentationCore library.
(1) How to Convert ImageSource to byte[]?
(2) How to Convert ImageSource to byte[] and back to ImageSource?
Hope that it will solve your problem.
The following two helper methods should be able to do the trick:
public BitmapImage ImageFromBuffer(Byte[] bytes)
{
MemoryStream stream = new MemoryStream(bytes);
BitmapImage image = new BitmapImage();
image.BeginInit();
image.StreamSource = stream;
image.EndInit();
return image;
}
public Byte[] BufferFromImage(BitmapImage imageSource)
{
Stream stream = imageSource.StreamSource;
Byte[] buffer = null;
if (stream != null && stream.Length > 0)
{
using (BinaryReader br = new BinaryReader(stream))
{
buffer = br.ReadBytes((Int32)stream.Length);
}
}
return buffer;
}