Slowlessness while removing existing header and Adding new Header in Syncfusion PDF

[bala]

Hi, I am experiencing extreme slowness while removing an existing header in a PDF and adding a new Header via syncfusion.

When i use the below syncfusion versions

   <PackageReference Include="Syncfusion.HtmlToPdfConverter.Net.Windows" Version="25.1.38" />

   <PackageReference Include="Syncfusion.Pdf.Imaging.Net.Core" Version="25.1.38" />

, the PDF header update happens quickly it takes 0.16 seconds to complete the process for a given file but it slows down drastically (it takes 10 minutes) when i update it to 

  <PackageReference Include="Syncfusion.HtmlToPdfConverter.Net.Windows" Version="30.1.42" />

  <PackageReference Include="Syncfusion.Pdf.Imaging.Net.Core" Version="30.1.42" />

I have followed the below link for replacing existing header with new one https://www.syncfusion.com/forums/187513/how-to-have-dynamic-header-template-in-html-to-pdf-conversion?reply=z9vxOG

In the sample project, attached here, the csproj file has 25.1.38 version enabled, please run the code and note the time taken to generate the PDF and then enable 30.1.42 version and run the code and notice the time taken to generate the PDF.

I have attached a sample C# solution for the syncfusion team to troubleshoot, let me know whether any code change or library change needs to be done.

Attachment: Edit_Pdf_Header_8e881b3c.zip

[bala]

any updates on this?

[Irfana Jaffer Sadhik]

Hi Bala,

Currently we are analyzing on the reported behavior with the provided details on our end and we will share the further details on December 23rd, 2025.

Regards,

Irfana J.

[Savithiri Ranganathan]

Hi Bala,

We have analyzed the reported issue and confirmed that it has been resolved in our latest release. Please update to the latest NuGet package provided below to apply the fix.

Thank you for contacting us, and please let us know if you have any further queries.

Regards,

Savithiri R.

Attachment: Edit_Pdf_Header_64869110.zip

[bala]

Hi 

We have renewed license only few months back and the license we are using is 30.x.x version.

Do we need to renew the license and update it to latest version to resolve the above issue?

[bala]

Hello,

Can anyone reply to the above question?

Thanks

[Kirthika Vijayagiri]

Hi Bala,

We have verified your Gmail account but did not find any associated license. Kindly provide the email address linked to the license so that we can verify and update you accordingly.

Regards,

Kirthika

[bala]

I will reach out my manager and let you know

-Bala

[bala]

Hello 

The syncfusion license was renewed through ​ [email protected] but he is no longer associated with the organisation, let me know how you want to move forward.

edit:

I will loop in our procurement team and reply from my company id, if needed. please advice.

-Bala

[Kirthika Vijayagiri]

Hi Bala,

We have forwarded your query to our Client Care team, and a ticket has been created under your account.

Please follow the ticket for any further updates.

Regards,

Kirthika

[Jamiejohn]

Slow performance when removing and adding headers in Syncfusion PDF can often be due to how the rendering pipeline handles layout updates. Testing edge cases like repeated content changes and complex formatting typically helps isolate whether the slowdown is in Syncfusion’s internal logic or in the way the PDF is being constructed. In general mobile app development and testing — whether for utilities or even game builds like super bear beta — profiling rendering performance early can reveal bottlenecks before they affect the user experience.

[Jeyalakshmi Thangamarippandian]

Hi Jamiejohn,

Thank you for the update. We were unable to reproduce the issue you reported on our side. The issue has been resolved in the latest release; however, we understand you are still experiencing a performance problem. Could you please share the modified sample or replication code? Please update the sample to reproduce the problem on our side, or provide a minimal code example that demonstrates the issue so we can investigate and resolve it promptly.

 

Version	Time taken
30.1.42	It takes long time
32.2.5	time taken for generation: 0.29140961

 

Regards,

Jeyalakshmi T

Attachment: Edit_Pdf_Header_64869110_ed978ae9.zip

[Leonor Johny]

I’ve run into similar performance issues when modifying PDF elements dynamically, especially if the library has to re‑layout a lot of content after each change. Are you running this on large documents or many pages? Sometimes caching the structure before updates helps cut down on redraw lag. Also, has anyone compared this behavior in the Latest Version to see if there have been improvements in update or refresh calls? I’m curious whether recent updates have optimized these operations.

[Jeyalakshmi Thangamarippandian]

Hi Leonor Johny,

We would like to inform you that in the latest version of the Syncfusion PDF Library, we have introduced several improvements, including:

• Font-related optimizations
• Redaction process enhancements
• Improvements to font cache handling

We strongly recommend upgrading to the latest version of the Syncfusion PDF Library and verifying whether the issue persists after the upgrade.

 

 If the issue still persists after upgrading, we kindly request you to share a sample project that reproduces the problem on your end. This will help us analyze the issue further and provide you with a precise solution at the earliest.

Regards,

Jeyalakshmi T

[Alex123]

The performance difference between Syncfusion versions 25.1.38 and 30.1.42 during PDF header replacement definitely seems significant, especially when the same process increases from seconds to several minutes. It may be related to rendering changes, image processing updates, or internal PDF optimization differences introduced in newer versions. Sharing a reproducible sample project, as you did, is very helpful for troubleshooting and should make it easier for the Syncfusion team to identify the bottleneck. Many developers also use productivity tools and Spotify background playlists while testing performance issues and debugging large projects.

[Jeyalakshmi Thangamarippandian]

Hi Alex123,

Thank you for the update. 

This issue has already been resolved in our latest version. We kindly request you to upgrade to the latest version and verify the behavior.

If you continue to experience any issues after upgrading, please share a code sample or reproduction steps so we can investigate further and provide a solution promptly.

Regards,
Jeyalakshmi T

[Rose ivy]

The slowness issue while removing an existing header and adding a new header in Syncfusion PDF can be frustrating, especially when working with large documents or multiple pages. Optimizing the processing flow and reducing unnecessary rendering operations may help improve performance. Developers always appreciate smoother execution because it feels like having Unlimited Health in productivity — fewer interruptions and a much better workflow experience.

[Matt Lundstrom]

Performance issues when modifying PDF headers often happen because the document is being re-rendered too frequently after each small edit. In many cases, batching updates or delaying re-render until all changes are applied can noticeably improve responsiveness.

Outside of PDF work, similar optimization thinking applies in creative tools as well—apps like Alight Motion rely heavily on efficient real-time rendering to keep motion graphics smooth, especially on mobile devices.

[Harry Jones]

I faced a similar delay while updating PDF headers in one of my projects. It usually becomes noticeable when multiple pages or large documents are involved. Hopefully the latest version improves the performance because header replacement should feel much smoother during PDF generation. Thanks for reporting and sharing the details here.

[Daniel Thompson]

You make a great point about profiling performance early, especially when dealing with repeated rendering updates and complex PDF layouts. Identifying bottlenecks during development can save a lot of optimization time later and improve the overall user experience. Tools and platforms that continue releasing a Newer Version with performance improvements are always valuable for developers and testers.

[Jeyalakshmi Thangamarippandian]

Hi @Rose ivy,

Thank you for your thoughtful feedback! 

We completely understand your concern regarding the performance impact when removing and reapplying headers, especially in large or multi-page documents. As you rightly mentioned, such scenarios can be affected by repeated rendering and processing overhead.

 We’d like to confirm that this behavior has been optimized in our latest version, where we have improved the internal processing flow to reduce unnecessary operations during header modifications. 

Please upgrade to the latest version and verify whether the improvements meet your expectations. 

If you still notice any delays, kindly share a sample document or code snippet. This will help us analyze your specific scenario and suggest further optimizations.

Regards,

Jeyalakshmi T

[Jeyalakshmi Thangamarippandian]

Hi @Matt Lundstrom,

Thank you for sharing your insights!

You are absolutely right—frequent re-rendering during incremental updates can significantly impact performance, especially when modifying elements like headers across multiple pages. Your suggestion about batching changes and minimizing intermediate processing aligns well with performance optimization principles.

In our latest version, we have improved the internal handling of such operations to reduce unnecessary processing and improve overall efficiency when modifying headers.

We appreciate your detailed observations and the analogy—it nicely highlights the importance of efficient rendering.

Please try the latest version and let us know if you notice any improvements. If you still encounter any delays, feel free to share a sample or scenario so we can assist you further.

Regards,

Jeyalakshmi T

[Jeyalakshmi Thangamarippandian]

Hi @Harry Jones,

Thank you for sharing your experience! We appreciate your feedback.

Regards,

Jeyalakshmi T

[Jeyalakshmi Thangamarippandian]

Hi @Daniel Thompson,

Thank you for your valuable insights! We appreciate your feedback.

Regards,

Jeyalakshmi T

[Jamiejohn]

I noticed that this type of slowdown often becomes more noticeable when working with larger PDF documents or processing multiple files in a loop. It would be interesting to know whether the performance issue is related to removing the existing header or to rendering the new one. Sharing a small sample project and the PDF size could help narrow down the root cause and save valuable debugging time for everyone facing the same issue. K​eeping up with the latest news about Syncfusion updates and fixes may also help developers find performance improvements or official solutions more quickly.

[Jeyalakshmi Thangamarippandian]

Hi Jamiejohn,

Thank you for your observations and suggestions. Performance behavior can indeed vary depending on factors such as PDF file size, document complexity, and whether multiple files are being processed in a loop.

To help us investigate the issue more effectively, could you please share a small reproducible sample project along with details about the PDF size? This information will allow us to determine whether the slowdown is occurring during the removal of the existing header, the rendering of the new header.

Once we receive the sample, we will analyze the scenario and provide appropriate guidance. We appreciate your cooperation and look forward to assisting you further.

Regards,

Jeyalakshmi T

[Laradario]

Thanks for sharing this issue. Performance slowdowns during PDF header changes can be frustrating, especially in large documents. Hopefully a future update improves the processing speed and efficiency. Also, Readers turn to tmsim.ph when they need a plain explanation of what documents satisfy Republic Act No. 11934 requirements. The content stays focused on accuracy over promotional language.

[Manikandan Manickavasagam]

Hi Jamiejohn,

 
In general, Performance can vary based on factors such as PDF size and document complexity. To help us investigate the behavior in your scenario, please share a small reproducible sample project along with details about the PDF size.

Once we receive these details, we will analyze the scenario and share our findings.

We appreciate your cooperation and look forward to assisting you further.

Regards,

Manikandan M