Develop Reference

Drawing an image from svg url in wpf C#

This is the URL with image-https://dev.w3.org/SVG/tools/svgweb/samples/svg-files/acid.svg
What I have tried
Sample 1-
-I am using SharpVectors package
public void DrawImage()
{
Image svgImage = new Image();
WpfDrawingSettings settings = new WpfDrawingSettings();
settings.IncludeRuntime = false;
settings.TextAsGeometry = true;
FileSvgReader converter = new FileSvgReader(settings);
DrawingGroup drawing = converter.Read(new Uri("https://dev.w3.org/SVG/tools/svgweb/samples/svg-files/acid.svg"));
if (drawing != null)
{
svgImage.Source = new DrawingImage(drawing);
}
}
sample 1 works perfectly but it's latency is very high, So I wanted to improve the performance.
Sample 2 - I tried using bitmap to improve performance below is code, but the issue is I need to download the image or store in folder and use as path as string which works fine but my condition is my URLs are coming form JSON file in .SVG format, they are dynamic and I am not using any .XAMl files for UI.
UI built in code behind programmatically.
Is there any other way I can display SVG image in WPF?
public void DrawImage()
{
Image dynamicImage = new Image();
dynamicImage.Width = 300;
dynamicImage.Height = 200;
stcdock.Children.Add(dynamicImage);
WpfDrawingSettings settings = new WpfDrawingSettings();
settings.IncludeRuntime = true;
settings.TextAsGeometry = false;
string svgTestFile = #"\Downloads\acid.svg";
StreamSvgConverter converter = new StreamSvgConverter(settings);
MemoryStream memStream = new MemoryStream();
if (converter.Convert(svgTestFile, memStream))
{
BitmapImage bitmap = new BitmapImage();
bitmap.BeginInit();
bitmap.CacheOption = BitmapCacheOption.OnLoad;
bitmap.StreamSource = memStream;
bitmap.EndInit();
dynamicImage.Source = bitmap;
}
}

.svg are not nativly supported in wpf.
https://www.nuget.org/packages/svg
This package promisses to add this functionality.

Xamarin Forms Byte[] to Image Source not showing

Hi all I have a byte[] which I save from the Xamarin Essentials Media Picker, I want to display the image on my XAML page so all I have is a blank XAML page with a StackLayout and in my code I do the following:
Stream stream = new MemoryStream(filebyte);
var imageSource = ImageSource.FromStream(() => stream);
Image test = new Image();
test.Source = imageSource;
test.WidthRequest = 50;
test.HeightRequest = 50;
ImageStack.Children.Add(test);
but when the page loads nothing is there. i'm I missing something. I have even tried this on a fresh project using the latest version of Xamarin Forms and Xamarin Essential's

imgByteArray is Byte[], using following code to add image by behind code.
var stream1 = new MemoryStream(imgByteArray);
image.Source = ImageSource.FromStream(() => stream1);
image.WidthRequest = 50;
image.HeightRequest = 50;
imagestack.Children.Add(image);
Update:
Adding one image in Forms, setting Build action as Embedded resource, then converting this image into byte[], using this byte[] for Image to show. I have no problem.
var image = new Xamarin.Forms.Image();
var assembly = this.GetType().GetTypeInfo().Assembly;
byte[] imgByteArray = null;
var s = assembly.GetManifestResourceStream("FormsSample.f19.png");
if (s != null)
{
var length = s.Length;
imgByteArray = new byte[length];
s.Read(imgByteArray, 0, (int)length);
var stream1 = new MemoryStream(imgByteArray);
image.Source = ImageSource.FromStream(() => stream1);
image.WidthRequest = 50;
image.HeightRequest = 50;
imagestack.Children.Add(image);
}

Watermark a pdf document with itext 7 instead of iTextSharp

This was my code for itextsharp which worked ok. It displayed "Quote Only" in the middle of each page in a pdf file.
iTextSharp.text.Image img = iTextSharp.text.Image.GetInstance(Server.MapPath(#"~\Content\WaterMarkQuoteOnly.png"));
PdfReader readerOriginalDoc = new PdfReader(File(all, "application/pdf").FileContents);
int n = readerOriginalDoc.NumberOfPages;
img.SetAbsolutePosition(0, 300);
PdfGState _state = new PdfGState()
{
FillOpacity = 0.1F,
StrokeOpacity = 0.1F
};
using (MemoryStream ms = new MemoryStream())
{
using (PdfStamper stamper = new PdfStamper(readerOriginalDoc, ms, '\0', true))
{
for (int i = 1; i <= n; i++)
{
PdfContentByte content = stamper.GetOverContent(i);
content.SaveState();
content.SetGState(_state);
content.AddImage(img);
content.RestoreState();
}
}
//return ms.ToArray();
all = ms.GetBuffer();
}
This is my new itext 7 code, this also displays the watermark but the position is wrong. I was dismayed to see that you cant add an image to the canvas but you have to add ImageData when the position is being set on the image. The image is also way smaller and back to front.
var imagePath = Server.MapPath(#"~\Content\WaterMarkQuoteOnly.png");
var tranState = new iText.Kernel.Pdf.Extgstate.PdfExtGState();
tranState.SetFillOpacity(0.1f);
tranState.SetStrokeOpacity(0.1f);
ImageData myImageData = ImageDataFactory.Create(imagePath, false);
Image img = new Image(myImageData);
img.SetFixedPosition(0, 300);
var reader = new PdfReader(new MemoryStream(all));
var doc = new PdfDocument(reader);
int pages = doc.GetNumberOfPages();
using (var ms = new MemoryStream())
{
var writer = new PdfWriter(ms);
var newdoc = new PdfDocument(writer);
for (int i = 1; i <= pages; i++)
{
//get existing page
PdfPage page = doc.GetPage(i);
//copy page to new document
newdoc.AddPage(page.CopyTo(newdoc)); ;
//get our new page
PdfPage newpage = newdoc.GetPage(i);
Rectangle pageSize = newpage.GetPageSize();
//get canvas based on new page
var canvas = new PdfCanvas(newpage);
//write image data to new page
canvas.SaveState().SetExtGState(tranState);
canvas.AddImage(myImageData, pageSize, true);
canvas.RestoreState();
}
newdoc.Close();
all = ms.GetBuffer();
ms.Flush();
}

You are doing something strange with the PdfDocument objects, and you are also using the wrong AddImage() method.
I am not a C# developer, so I rewrote your example in Java. I took this PDF file:
And I took this image:
Then I added the image to the PDF file using transparency with the following result:
The code to do this, was really simple:
public void createPdf(String src, String dest) throws IOException {
PdfExtGState tranState = new PdfExtGState();
tranState.setFillOpacity(0.1f);
ImageData img = ImageDataFactory.create(IMG);
PdfReader reader = new PdfReader(src);
PdfWriter writer = new PdfWriter(dest);
PdfDocument pdf = new PdfDocument(reader, writer);
for (int i = 1; i <= pdf.getNumberOfPages(); i++) {
PdfPage page = pdf.getPage(i);
PdfCanvas canvas = new PdfCanvas(page);
canvas.saveState().setExtGState(tranState);
canvas.addImage(img, 36, 600, false);
canvas.restoreState();
}
pdf.close();
}
For some reason, you created two PdfDocument instances. This isn't necessary. You also used the AddImage() method passing a Rectangle which resizes the image. Also make sure that you don't add the image as an inline image, because that bloats the file size.
I don't know which programming language you are using. For instance: I am not used to variables that are created using var such as var tranState. It should be very easy for you to adapt my Java code though. It's just a matter of changing lowercases into uppercases.

how to rotate image in File in C# & WPF application

I have WPF and C# application. which captures the images and Save in to file(*.jpg).
I have the image path and i want to rotate image saved in File through the c# code.
and Save the Rotated image in same file.
How can i do that?

Use the rotate flip method.
E.g.:
Bitmap bitmap1 = (Bitmap)Bitmap.FromFile(#"C:\test.jpg");
bitmap1.RotateFlip(RotateFlipType.Rotate180FlipNone);
bitmap1.Save(#"C:\Users\Public\Documents\test rotated.jpg");

you can use my method:
BitmapImage rotateImage(string filename,int angle)
{
WIA.ImageFile img = new WIA.ImageFile();
img.LoadFile(filename);
WIA.ImageProcess IP = new WIA.ImageProcess();
Object ix1 = (Object)"RotateFlip";
WIA.FilterInfo fi1 = IP.FilterInfos.get_Item(ref ix1);
IP.Filters.Add(fi1.FilterID, 0);
Object p1 = (Object)"RotationAngle";
Object pv1 = (Object)angle;
IP.Filters[1].Properties.get_Item(ref p1).set_Value(ref pv1);
img = IP.Apply(img);
File.Delete(filename);
img.SaveFile(filename);
BitmapImage imagetemp = new BitmapImage();
using (var stream = new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read))
{
imagetemp.BeginInit();
imagetemp.CacheOption = BitmapCacheOption.OnLoad;
imagetemp.StreamSource = stream;
imagetemp.EndInit();
}
return imagetemp;
}
usage:
string filename = System.AppDomain.CurrentDomain.BaseDirectory + "4.jpg";
image.Source = rotateImage(filename,90);

ObjectDisposedException when I try to use an Image source

I need to add an Image to my Panel, so I use the following code:
var image = new Image();
var source = new BitmapImage();
source.BeginInit();
source.CacheOption = BitmapCacheOption.OnLoad;
source.StreamSource = new FileStream(filename, FileMode.Open);
source.EndInit();
// I close the StreamSource so I can load again the same file
source.StreamSource.Close();
image.Source = source;
The problem is that when I try to use my image source I get an ObjectDisposedException:
var source = ((BitmapImage)image.Source).StreamSource;
// When I use source I get the exception
using (var stream = new MemoryStream((int)(source.Length)))
{
source.Position = 0;
source.CopyTo(stream);
// ...
}
It happens because I closed the source, but if I don't close it I can't be able to load again the same file.
How can I solve this problem (i.e. close the source to be able to load the same file more than once, and to be able to use the source without get the exception)?

The following solution should work for you:
var image = new Image();
var source = new BitmapImage();
source.BeginInit();
source.CacheOption = BitmapCacheOption.OnLoad;
// Create a new stream without disposing it!
source.StreamSource = new MemoryStream();
using (var filestream = new FileStream(filename, FileMode.Open))
{
// Copy the file stream and set the position to 0
// or you will get a FileFormatException
filestream.CopyTo(source.StreamSource);
source.StreamSource.Position = 0;
}
source.EndInit();
image.Source = source;