I need to convert a JPG image to PNG and change its white background to transparent instead. I am using ImageMagick.NET and I have found the following ImageMagick command that is supposed to do what I am trying to achieve:
convert image.jpg -fuzz XX% -transparent white result.png
I have tried converting this to c# but all I am getting is a png image with a white background. My code snippet:
using (var img = new MagickImage("image.jpg"))
{
img.Format = MagickFormat.Png;
img.BackgroundColor = MagickColors.White;
img.ColorFuzz = new Percentage(10);
img.BackgroundColor = MagickColors.None;
img.Write("image.png");
}
Any kind of help will be greatly appreciated. Thank you!!
This is a late response as it took me a while to find an answer myself, but this seems to work for me quite well. Look at where the Background property is assigned the Transparent value.
using (var magicImage = new MagickImage())
{
var magicReadSettings = new MagickReadSettings
{
Format = MagickFormat.Svg,
ColorSpace = ColorSpace.Transparent,
BackgroundColor = MagickColors.Transparent,
// increasing the Density here makes a larger and sharper output to PNG
Density = new Density(950, DensityUnit.PixelsPerInch)
};
magicImage.Read("someimage.svg", magicReadSettings);
magicImage.Format = MagickFormat.Png;
magicImage.Write("someimage.png");
}
In my case, I wanted to send this to UWP Image element, so instead of Write(), I did the following after the steps above:
// Create byte array that contains a png file
byte[] imageData = magicImage.ToByteArray();
using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream())
{
using (DataWriter writer = new DataWriter(stream.GetOutputStreamAt(0)))
{
writer.WriteBytes(imageData);
await writer.StoreAsync();
}
await bitmapImage.SetSourceAsync(stream);
}
return bitMapImage; // new BitMapImage() was scoped before all of this
Then on the UWP Image element, simply use:
imageElement.Source = bitMapImage;
Most of the arguments on the command line are either properties or method on the MagickImage class. Your command would translate to this:
using (var img = new MagickImage("image.jpg"))
{
// -fuzz XX%
img.ColorFuzz = new Percentage(10);
// -transparent white
img.Transparent(MagickColors.White);
img.Write("image.png");
}
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;
}
It's definitely possible to convert an SVG to EMF, for example this website. I wonder if it's possible to achieve this conversion in C#?
Update:
I tried to read an SVG file using SVG.NET and draw it to a Graphics object, then tried export the Image as a MetaFile in .emf extension (I followed the instruction here: GDI+ / C#: How to save an image as EMF?). The reading was done successfully and the image did get exported as .emf. However, when I opened that .emf in PowerPoint, it couldn't be un-grouped, which indicated that the drawing info of that file was actually not dumped correctly.
Update 2:
Now it does export a ungroup-able .emf, but the ungrouping shows a really poor result. I used the following code to produce the .emf:
private void OpenPictureButtonClick(object sender, EventArgs e)
{
var openFileDialog = new OpenFileDialog();
openFileDialog.ShowDialog();
_svgDoc = SvgDocument.Open(openFileDialog.FileName);
RenderSvg(_svgDoc);
}
private void SavePictureClick(object sender, EventArgs e)
{
var saveFileDialog = new SaveFileDialog {Filter = "Enhanced Meta File | *.Emf"};
saveFileDialog.ShowDialog();
var path = saveFileDialog.FileName;
var graphics = CreateGraphics();
var img = new Metafile(path, graphics.GetHdc());
var ig = Graphics.FromImage(img);
_svgDoc.Draw(ig);
ig.Dispose(); img.Dispose(); graphics.ReleaseHdc(); graphics.Dispose();
}
private void RenderSvg(SvgDocument svgDoc)
{
svgImageBox.Image = svgDoc.Draw();
}
I had the same issue but searching had no results.
Finally I ended up with my own simple solution below. I used SVG.NET.
public static byte[] ConvertToEmf(string svgImage)
{
string emfTempPath = Path.GetTempFileName();
try
{
var svg = SvgDocument.FromSvg<SvgDocument>(svgImage);
using (Graphics bufferGraphics = Graphics.FromHwndInternal(IntPtr.Zero))
{
using (var metafile = new Metafile(emfTempPath, bufferGraphics.GetHdc()))
{
using (Graphics graphics = Graphics.FromImage(metafile))
{
svg.Draw(graphics);
}
}
}
return File.ReadAllBytes(emfTempPath);
}
finally
{
File.Delete(emfTempPath);
}
}
At first I create a temp file. Then I use Draw(Graphics) method to save emf in it. And at last I read bytes from temp file.
Don't try to use MemoryStream for Metafile. Unfortunately, it's not working.
This is what I found to be currently the best solution. This is almost like the accepted answer and uses SVG.NET, but is capable of doing it in memory.
The important changes are to release the handle and to reset the position memory stream.
public static Stream ConvertSvgToEmf(string svgImage)
{
using var writeStream = new MemoryStream();
var svg = SvgDocument.FromSvg<SvgDocument>(svgImage);
var stream = new MemoryStream();
var sizedImage = new Bitmap((int)svg.Width.Value, (int)svg.Height.Value);
using (var graphicsFromSizedImage = Graphics.FromImage(Image.FromHbitmap(sizedImage.GetHbitmap())))
using (var metafile = new Metafile(stream, graphicsFromSizedImage.GetHdc(), EmfType.EmfPlusOnly)) // Specify EmfType for lesser file size
using (var graphics = Graphics.FromImage(metafile))
{
svg.Draw(graphics);
graphicsFromSizedImage.ReleaseHdc();
}
stream.Position = 0;
return stream;
}
Be aware that the underlying implementation relies on System.Drawing and therefore the gdi must be accessible. On linux based OS's (or Docker images) libgdiplus must be installed.
As System.Drawing is considered to be deprecated, alternatives like Magick.NET may be better suited for your case.
I am trying to process Canon RAW .CR2 files using C#. My code is as follows:
BitmapDecoder bmpDec = BitmapDecoder.Create(new Uri(origFile), BitmapCreateOptions.DelayCreation, BitmapCacheOption.None);
BitmapEncoder bmpEnc = new BmpBitmapEncoder();
bmpEnc.Frames.Add(bmpDec.Frames[0]);
Stream ms = new MemoryStream();
bmpEnc.Save(ms);
Image srcImage = Bitmap.FromStream(ms);
The first few lines seem to run without a hitch, but the line
bmEnc.Save(ms);
just hangs without completing and without raising any exception.
Has anyone had any success with this?
Know this is a old thread but I found a nice easy to use library (Magick.NET).
How to do a conversion:
using (MagickImage image = new MagickImage("StillLife.CR2"))
{
image.Write("StillLife.jpg");
}
https://github.com/dlemstra/Magick.NET/blob/master/docs/ReadRawImageFromCamera.md
Details of nuget package installation:
Install-Package Magick.NET-Q16-AnyCPU
https://github.com/dlemstra/Magick.NET
W8.1 or W7 after applying https://www.microsoft.com/en-us/download/details.aspx?id=26829 seems to work well
var files = Directory.GetFiles(#"D:\DCIM","*.CR2");
for(var i = 0; i < files.Length; i++) {
Console.Write("{0,-4}: {1} => ", i, files[i]);
var bmpDec = BitmapDecoder.Create(new Uri(files[i]), BitmapCreateOptions.DelayCreation, BitmapCacheOption.None);
var bmpEnc = new JpegBitmapEncoder();
bmpEnc.QualityLevel = 100;
bmpEnc.Frames.Add(bmpDec.Frames[0]);
var oldfn = Path.GetFileName(files[i]);
var newfn = Path.ChangeExtension(oldfn, "JPG");
using(var ms = File.Create(Path.Combine(#"D:\DCIM\100CANON", newfn), 10000000)) {
bmpEnc.Save(ms);
}
Console.WriteLine(newfn);
}
I don't believe BitmapDecoder understands .CR2. It is not a conventional image format by far, as it contains the raw bayer-sensor image (one color per pixel), not a standard image.
If you want to convert CR2 and other camera raw formats, you should look at DCRaw: http://www.cybercom.net/~dcoffin/dcraw/ or libraw (based on dcraw, friendly as a library): http://www.libraw.org/
I'm trying to generate a multipage TIFF file from an existing picture using code by Bob Powell:
picture.SelectActiveFrame(FrameDimension.Page, 0);
var image = new Bitmap(picture);
using (var stream = new MemoryStream())
{
ImageCodecInfo codecInfo = null;
foreach (var imageEncoder in ImageCodecInfo.GetImageEncoders())
{
if (imageEncoder.MimeType != "image/tiff") continue;
codecInfo = imageEncoder;
break;
}
var parameters = new EncoderParameters
{
Param = new []
{
new EncoderParameter(Encoder.SaveFlag, (long) EncoderValue.MultiFrame)
}
};
image.Save(stream, codecInfo, parameters);
parameters = new EncoderParameters
{
Param = new[]
{
new EncoderParameter(Encoder.SaveFlag, (long) EncoderValue.FrameDimensionPage)
}
};
for (var i = 1; i < picture.GetFrameCount(FrameDimension.Page); i++)
{
picture.SelectActiveFrame(FrameDimension.Page, i);
var img = new Bitmap(picture);
image.SaveAdd(img, parameters);
}
parameters = new EncoderParameters
{
Param = new[]
{
new EncoderParameter(Encoder.SaveFlag, (long)EncoderValue.Flush)
}
};
image.SaveAdd(parameters);
stream.Flush();
}
But it's not working (only the first frame is included in the image) and I don't know why.
What I want to do is to change a particular frame of a TIFF file (add annotations to it).
I don't know if there's a simpler way to do it but what I have in mind is to create a multipage TIFF from the original picture and add my own picture instead of that frame.
[deleted first part after comment]
I'm working with multi-page TIFFs using LibTIFF.NET; I found many quicks in handling of TIFF using the standard libraries (memory related and also consistent crashes on 16-bit gray scale images).
What is your test image? Have you tried a many-frame tiff (preferably with a large '1' on the first frame, a '2 on the next etc; this could help you to be certain on the frame included in the file.
Another useful diagnosis may be tiffdump utility, as included in LibTiff binaries (also for windows). This will tell you exactly what frames you have.
See Using LibTiff from c# to access tiled tiff images
[Edit] If you want to understand the .NET stuff: I've found a new resource on multi-page tiffs using the standard .NET functionality (although I'll stick with LibTIFF.NET): TheCodeProject : Save images into a multi-page TIFF file... If you download it, the code snippet in Form1.cs function saveMultipage(..) is similar (but still slightly different) than your code. Especially the flushing at the end is done in a differnt way, and the file is deleted before the first frame...
[/Edit]
It seems that this process doesn't change image object but it changes the stream so I should get the memory stream buffer and build another image object:
var buffer=stream.GetBuffer();
using(var newStream=new MemoryStream(buffer))
{
var result=Image.FromStream(newStream);
}
Now result will include all frames.