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EnumerateElements Method

Summary
Enumerates the elements (nodes) of this SvgDocument with the specified options.
Syntax
C#
Objective-C
C++/CLI
Java
Python
public void EnumerateElements( 
   SvgEnumerateOptions options, 
   SvgEnumerateElementsCallback callback, 
   object userData 
) 
- (BOOL)enumerateElementsWithOptions:(nullable LTSvgEnumerateOptions *)options userData:(nullable id)userData callback:(BOOL (^)(LTSvgDocument *document, LTSvgNodeHandle *node, id _Nullable userData))callback error:(NSError **)error NS_SWIFT_NAME(enumerateElements(options:userData:callback:)); 
public void enumerateElements(SvgEnumerateOptions options, SvgEnumerateElementsCallback callback, Object userData) 
public: 
void EnumerateElements(  
   SvgEnumerateOptions^ options, 
   SvgEnumerateElementsCallback^ callback, 
   Object^ userData 
)  
def EnumerateElements(self,callback,userData):

Parameters

options
Options to use. Can be null.

callback
Callback to receive the elements (nodes). Cannot be null.

userData
Optional user data that will be passed to the callback.

Remarks

Use this method to enumerate the elements of this SvgDocument using the specified options.

This method will throw an exception if this document is not flat (the value of IsFlat is false) or if it does not have valid physical (pixel) bounds (the value of Bounds.IsValid is false).

If the value of  options is null, then the following default options will be used:

Member Value
SvgEnumerateOptions.EnumerateDirection

SvgEnumerateDirection.TopToBottom
Example

This example will use EnumerateElements to extract the embedded images from an SVG file and save them to disk and replace each with a link to the file.

C#
Java
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using Leadtools.Forms.DocumentWriters; 
using Leadtools.Svg; 
 
using Leadtools.Document.Writer; 
 
private static void SvgDocumentEnumerateElementsExample() 
{ 
   // The source PDF file 
   var sourceFile = $@"{LEAD_VARS.ImagesDir}\Leadtools.pdf"; 
   var beforeSvgFile = $@"{LEAD_VARS.ImagesDir}\Leadtools_before.svg"; 
   var afterSvgFile = $@"{LEAD_VARS.ImagesDir}\Leadtools_after.svg"; 
 
   // Assume this is our Virtual Directory 
   var virtualDirectory = "http://localhost/leadtools_images/svg/resources"; 
   // Assume this phrysical directory maps to the Virtual Directory 
   var physicalDirectory = $@"{LEAD_VARS.ImagesDir}\svg\resources"; 
 
   if (!Directory.Exists(physicalDirectory)) 
      Directory.CreateDirectory(physicalDirectory); 
 
   // Our SVG element enumartion callback 
   SvgEnumerateElementsCallback callback = (SvgDocument document, SvgNodeHandle node, object userData) => 
   { 
      if (node.ElementType == SvgElementType.Image) 
      { 
         // Get the href 
         var href = node.GetAttributeValue("xlink:href"); 
         if (!string.IsNullOrEmpty(href)) 
         { 
            // Parse it as data URI 
            var dataUri = SvgDataUri.Parse(href); 
            // Check if it is a data URI 
            if (dataUri.IsDataUri) 
            { 
               // Yes, create a new file in a virtual directory 
 
               // Show the dataURI properties 
               Console.WriteLine("Replacing data URI"); 
               Console.WriteLine("Format:" + dataUri.ImageFormat); 
               if (dataUri.MediaLength > 0) 
                  Console.WriteLine("Media:" + dataUri.Href.Substring(dataUri.MediaOffset, dataUri.MediaLength)); 
               if (dataUri.CharSetOffset > 0) 
                  Console.WriteLine("CharSet:" + dataUri.Href.Substring(dataUri.CharSetOffset, dataUri.CharSetLength)); 
               else 
                  Console.WriteLine("CharSet: not set"); 
               Console.WriteLine("IsBase64:" + dataUri.IsBase64); 
               Console.WriteLine("ImageFormat:" + dataUri.ImageFormat); 
               var extension = dataUri.Extension; 
               Console.WriteLine("Extension:" + dataUri.Extension); 
 
               // Get a file name 
               var name = Guid.NewGuid().ToString().Replace("-", "") + "." + dataUri.Extension; 
 
               // Save it 
               // Full physical path 
               var filePath = Path.Combine(physicalDirectory, name); 
               dataUri.DecodeToFile(filePath); 
 
               /* Alternatively you can save the data yourself using this code 
               var data = dataUri.Href.Substring(dataUri.ValueOffset, dataUri.ValueLength); 
 
               // Save the data 
               var base64String = dataUri.Href.Substring(dataUri.ValueOffset, dataUri.ValueLength); 
               byte[] rawData = Convert.FromBase64String(base64String); 
 
               // Save it to disk 
               File.WriteAllBytes(filePath, rawData); 
               */ 
 
               // Finally replace the attribute in the image element with the URI 
               var virtualPath = virtualDirectory + "/" + name; 
               node.SetAttributeValue("xlink:href", virtualPath); 
            } 
            else 
            { 
               Console.WriteLine("Does not contain a valid data URI."); 
            } 
         } 
      } 
      return true; 
   }; 
 
   using (var rasterCodecs = new RasterCodecs()) 
   { 
      // Use 300 DPI when loading document images 
      rasterCodecs.Options.RasterizeDocument.Load.Resolution = 300; 
 
      // Load the first page as SVG 
      using (var svg = rasterCodecs.LoadSvg(sourceFile, 1, null) as SvgDocument) 
      { 
         if (!svg.IsFlat) 
            svg.Flat(null); 
         if (!svg.Bounds.IsValid) 
            svg.CalculateBounds(false); 
 
         // Save this SVG to disk, report the size 
         svg.SaveToFile(beforeSvgFile, null); 
         Console.WriteLine("Before unembedding the image, size is " + new FileInfo(beforeSvgFile).Length); 
 
         // Now enumerate the elements to replace each embedded image with a URL 
         // Since we are going to modify the SVG, call BeginUpdate/EndUpdate to speed up the process 
         svg.BeginUpdate(); 
         svg.EnumerateElements(new SvgEnumerateOptions { EnumerateDirection = SvgEnumerateDirection.TopToBottom }, callback, null); 
         svg.EndUpdate(); 
 
         // Save this SVG to disk again, report the size, should be alot smaller since the image are unembedded and stored as external resources 
         svg.SaveToFile(afterSvgFile, null); 
         Console.WriteLine("Before unembedding the image, size is " + new FileInfo(afterSvgFile).Length); 
      } 
   } 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
} 
 
import java.io.ByteArrayInputStream; 
import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.ObjectInputStream; 
import java.io.ObjectOutputStream; 
import java.io.PrintStream; 
import java.nio.file.FileVisitOption; 
import java.nio.file.Files; 
import java.nio.file.Path; 
import java.nio.file.Paths; 
import java.util.stream.Stream; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.document.writer.*; 
import leadtools.svg.*; 
 
 
public void svgDocumentEnumerateElementsExample() { 
   String LEAD_VARS_ImagesDir = "C:\\LEADTOOLS23\\Resources\\Images"; 
   // The source PDF file 
   String srcFilePath = combine(LEAD_VARS_ImagesDir, "Leadtools_pdf.svg"); 
   String beforeSvgFile = combine(LEAD_VARS_ImagesDir, "Leadtools_before.svg"); 
   String afterSvgFile = combine(LEAD_VARS_ImagesDir, "Leadtools_after.svg"); 
 
   // Assume this is our Virtual Directory 
   String virtualDirectory = "http://localhost/leadtools_images/svg/resources"; 
   // Assume this phrysical directory maps to the Virtual Directory 
   String physicalDirectory = combine(LEAD_VARS_ImagesDir, "svg\\resources"); 
 
   if (!new File(physicalDirectory).exists()) 
      new File(physicalDirectory).mkdirs(); 
 
   // Our SVG element enumartion callback 
   SvgEnumerateElementsCallback callback = (SvgDocument document, SvgNodeHandle node, Object userData) -> { 
      if (node.getElementType() == SvgElementType.IMAGE) { 
         // Get the href 
         String href = node.getAttributeValue("xlink:href"); 
         if (!href.isEmpty() || href != null) { 
            // Parse it as data URI 
            SvgDataUri dataUri = SvgDataUri.parse(href); 
            // Check if it is a data URI 
            if (dataUri.isDataUri()) { 
               // Yes, create a new file in a virtual directory 
 
               // Show the dataURI properties 
               System.out.println("Replacing data URI"); 
               System.out.println("Format:" + dataUri.getImageFormat()); 
               if (dataUri.getMediaLength() > 0) 
                  System.out.println( 
                        "Media:" + dataUri.getHref().substring(dataUri.getMediaOffset(), dataUri.getMediaLength())); 
               if (dataUri.getCharSetOffset() > 0) 
                  System.out.println( 
                        "CharSet:" 
                              + dataUri.getHref().substring(dataUri.getCharSetOffset(), dataUri.getCharSetLength())); 
               else 
                  System.out.println("CharSet: not set"); 
 
               System.out.println("IsBase64:" + dataUri.isBase64()); 
               System.out.println("ImageFormat:" + dataUri.getImageFormat()); 
               String extension = dataUri.getExtension(); 
               System.out.println("Extension:" + extension); 
 
               // Get a file name 
               String name = "dstSrcFile" + extension; 
 
               // Save it 
               // Full physical path 
               String filePath = combine(physicalDirectory, name); 
               dataUri.decodeToFile(filePath); 
 
               // Finally replace the attribute in the image element with the URI 
               String virtualPath = virtualDirectory + "/" + name; 
               node.setAttributeValue("xlink:href", virtualPath); 
            } else { 
               System.out.println("Does not contain a valid data URI"); 
            } 
         } 
      } 
      return true; 
   }; 
 
   RasterCodecs codecs = new RasterCodecs(); 
   // Use 300 DPI when loading document images 
   codecs.getOptions().getRasterizeDocument().getLoad().setResolution(300); 
   // Load the first page as SVG 
   SvgDocument svgDocument = (SvgDocument) codecs.loadSvg(srcFilePath, 1, null); 
 
   if (!svgDocument.isFlat()) 
      svgDocument.flat(null); 
   if (!svgDocument.getBounds().isValid()) 
      svgDocument.calculateBounds(false); 
 
   // Save this SVG to disk, report the size 
   svgDocument.saveToFile(beforeSvgFile, null); 
   System.out.println("Before unembedding the image, size is " + new File(beforeSvgFile).length()); 
 
   // Now enumerate the elements to replace each embedded image with a URL 
   // Since we are going to modify the SVG, call BeginUpdate/EndUpdate to speed up 
   // the process 
   svgDocument.beginUpdate(); 
   SvgEnumerateOptions svgEnumerateOptions = new SvgEnumerateOptions(); 
   svgEnumerateOptions.setEnumerateDirection(SvgEnumerateDirection.TOP_TO_BOTTOM); 
 
   svgDocument.enumerateElements(svgEnumerateOptions, callback, null); 
   svgDocument.endUpdate(); 
 
   // Save this SVG to disk again, report the size, should be alot smaller since 
   // the image are unembedded and stored as external resources 
   svgDocument.saveToFile(afterSvgFile, null); 
 
   System.out.println("After unembedding the image, size is " + new File(afterSvgFile).length()); 
   assertTrue(new File(afterSvgFile).length() != new File(beforeSvgFile).length()); 
}
Requirements

Target Platforms

Help Version 23.0.2024.2.29
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Leadtools.Svg Assembly
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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.