I'm trying to load an emf file in to an Image Object, however the RawFormat is always incorrect {[ImageFormat: b96b3cac-0728-11d3-9d7b-0000f81ef32e]} instead of Emf. I've tried loading from a file stream and memory stream. I've also tried creating a MetaFile object instead of an Image but to no avail. Is this a bug or there some other trick I don't know about?
MemoryStream stream = new MemoryStream(imageData);//imageData is a byte array
Image tempImage = Image.FromStream(stream);
Does this help?
System.Drawing.Imaging.ImageFormat.Emf.Guid = {b96b3cac-0728-11d3-9d7b-0000f81ef32e}
Dan
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Actually the bitmap created has a file size larger than the input bitmap. I opened the bitmap that was created and it looked completely different to what i inputted. why is that ?
I read a bitmap through FileStream and then i write its contents to a bitmap object.Next i write it as a bitmap file onto harddisk. I cant figure out why the output bitmap is larger than the input bitmap. Could someone please help me.
Bitmap.Save (Image.Save) will, by default, save the image as in PNG format.
If you call Save with an ImageFormat value, you should get your bitmap.
b.Save("test.bmp", ImageFormat.Bmp);
When a bitmap file is created there is often padding added to each row to ensure that each row is a multiple of 4 bytes. When you read the bitmap file into a FileStream the padding is also read.
This can mean that the FileStream is larger than expected and when you write it to a bitmap it will display unexpected behaviour since when you write it to a new Bitmap it treats the padding as if it were your image data.
Sorry I did not understand your problem well. But did you try like this?
private System.Drawing.Bitmap readfromFile(string filename)
{
FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
byte[] bytes = new byte[fs.Length];
fs.Read(bytes, 0, Convert.ToInt32(fs.Length));
MemoryStream ms = new MemoryStream(bytes);
System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(ms);
return bmp;
}
and saved like this:
System.Drawing.Bitmap bmp = readfromFile("xxxx --- Path");
bmp.Save("test.bmp", ImageFormat.Bmp);
I tried that and it always returns the same image for me.
I have a imagestream in c# and i want to save them on the hard drive using the c# code. when i trying to do that i found Out of Memory whennever i have much enough Memory.
so i am sure that my code leak the resources so can someone show me how i can do that
HttpPostedFileBase file
file.SaveAs(location);
Image image = Image.FromFile(location,false);
image.Save(location, System.Drawing.Imaging.ImageFormat.Png);
image.fromFile line [3] caused Exception that out of Memory. can someone show me how i can do this in c#.
The file come from PNG using Ajax Request are come as octet type as Mime type so how i can do that.
Assuming you want to convert the image to PNG (otherwise there's no need to save the image once, reload it and re-save it again), it might be a good idea to avoid loading the image twice. See if something like this helps:
Image.FromStream(file.InputStream, false).Save(location, System.Drawing.Imaging.ImageFormat.Png);
file.SaveAs(location);
already saved the image at the given location or threw an exception, so the following lines are unnecessary.
Bitmap bmp = new Bitmap(file.InputStream);
bmp.Save(filename, ImageFormat.Png);
I am using this C# code to access an image file in order to read metadata from it.
BitmapSource img = BitmapFrame.Create(uri);
Unfortunately the image file specified by uri becomes locked until the program ends. How do I prevent the image from being locked?
maybe this could help ?
edit
BitmapSource img = BitmapFrame.Create(uri,BitmapCreateOptions.None,BitmapCacheOption.OnLoad);
BitmapCreateOptions.None = default option
BitmapCacheOption.OnLoad = Caches the entire image into memory at load time. All requests for image data are filled from the memory store.
from here
If you want to be able to delete/change the file immediately afterwards, read the whole file into memory, and then give it the MemoryStream instead. For example:
MemoryStream data = new MemoryStream(File.ReadAllBytes(file));
BitmapSource bitmap = BitmapFrame.Create(data);
You can also use generic stream:
Stream stream = File.OpenRead(filename);
Bitmap template = new Bitmap(stream); // or (Bitmap) Bitmap.FromStream(stream)
stream.Close();
I was loading a Bitmap Image from a File. When I tried to save the Image to another file I got the following error "A generic error occurred in GDI+". I believe this is because the file is locked by the image object.
Ok so tried calling the Image.Clone function. This still locks the file.
hmm. Next I try loading a Bitmap Image from a FileStream and load the image into memory so GDI+ doesn't lock the file. This works great except I need to generate thumbnails using Image.GetThumbnailImage method it throws an out of memory exception. Apparently I need to keep the stream open to stop this exception but if I keep the stream open then the file remains locked.
So no good with that method. In the end I created a copy of the file. So now I have 2 versions of the file. 1 I can lock and manipulate in my c# program. This other original file remains unlocked to which I can save modifications to. This has the bonus of allowing me to revert changes even after saving them because I'm manipulating the copy of the file which cant change.
Surely there is a better way of achieving this without having to have 2 versions of the image file. Any ideas?
Well if you're looking for other ways to do what you're asking, I reckon it should work to create a MemoryStream, and read out the FileStream to it, and load the Image from that stream...
var stream = new FileStream("original-image", FileMode.Open);
var bufr = new byte[stream.Length];
stream.Read(bufr, 0, (int)stream.Length);
stream.Dispose();
var memstream = new MemoryStream(bufr);
var image = Image.FromStream(memstream);
Or something prettier to that extent.
Whether or not that's the way you should go about solving that problem, I don't know. :)
I've had a similar problem and wound up fixing it like this.
I have since found an alternative method to clone the image without locking the file. Bob Powell has it all plus more GDI resources.
//open the file
Image i = Image.FromFile(path);
//create temporary
Image t=new Bitmap(i.Width,i.Height);
//get graphics
Graphics g=Graphics.FromImage(t);
//copy original
g.DrawImage(i,0,0);
//close original
i.Dispose();
//Can now save
t.Save(path)
I had a similar problem. But I knew, that I will save the image as a bitmap-file. So I did this:
public void SaveHeightmap(string path)
{
if (File.Exists(path))
{
Bitmap bitmap = new Bitmap(image); //create bitmap from image
image.Dispose(); //delete image, so the file
bitmap.Save(path); //save bitmap
image = (Image) bitmap; //recreate image from bitmap
}
else
//...
}
Sure, thats not the best way, but its working :-)
I am binding an Image.Source property to the result of the property shown below.
public BitmapSource MyImageSource
{
get
{
BitmapSource source = null;
PngBitmapDecoder decoder;
using (var stream = new FileStream(#"C:\Temp\logo.png", FileMode.Open, FileAccess.Read, FileShare.Read))
{
decoder = new PngBitmapDecoder(stream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.None);
if (decoder.Frames != null && decoder.Frames.Count > 0)
source = decoder.Frames[0];
}
return source;
}
}
For some reason this is failing during the rendering of the image (Deep in the PresentationCore assembly). I am certain the image is not corrupt as I can successfully show the same image w/o the binding
<Image Name="FooImage" Source="/logo.png" />
I have to bind the image source in code because I will eventually be creating the image stream from a base64 string.
Anyone know if this is a bug w/ WPF? or am I doing something incorrectly?
The problem was the BitmapCacheOption option, changing to BitmapCacheOption.OnLoad works.
With BitmapCacheOption.None the BitmapSource isn’t decoded until the image is rendered, but the stream with the png in it is already disposed at that point. If you cache OnLoad, it’ll decode right away and cache the results, rather than trying to decode later when the stream no longer exists.
Also, have you tried just using a BitmapImage to load the image? It works fine with PNG, BMP, and JPEG.
It's also a specialized type of BitmapSource, so you could just replace your code in your property with this:
BitmapImage img = new BitmapImage(new Uri(#"C:\Temp\logo.png"));
return img;
Are you positive it's a PNG and not just a renamed Bitmap or Jpeg? If you create a new Bitmap image and then just rename it and change the file extension, this error is reproducible.
If I use a known PNG with your code, I don't get your issue, but a COM exception is thrown:
The handle is invalid. (Exception from HRESULT: 0x80070006 (E_HANDLE))
Can you try it out with a random PNG off the web and see if you get the same result?