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HTMLToPDFConverter does not print diagram's image nodes

Thread ID:





151132 Jan 31,2020 03:48 PM UTC Feb 3,2020 12:21 PM UTC Angular - EJ 2 2
Tags: Diagram
Asked On January 31, 2020 04:27 PM UTC

Hello Syncfusion Team,

My diagramming app uses the following syncfusion components:
- angular 8 front-end: "@syncfusion/ej2-angular-buttons": "^17.4.43"
- asp.net core 3.1 back-end: "Syncfusion.HtmlToPdfConverter.QtWebKit.Net.Core" Version="" 

I'm following instructions from following article to export diagram to PNG/JPG: https://www.syncfusion.com/kb/8749/how-to-convert-html-to-pdf-in-linux-docker-container 

This exports all connectors and html, svg, basicshapes, text nodes just fine. However it DOES NOT export image nodes (they show up as a blue box with question mark).

Original diagram


Exported to PNG or JPG

Here are the contents of my Dockerfile

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
RUN apt-get update && apt-get -y upgrade && apt-get -y install xvfb && apt-get -y install fontconfig && apt-get -y install libssl1.1 && apt-get -y install libx11-dev libx11-xcb-dev libxcb-icccm4-dev libxcb-image0-dev libxcb-keysyms1-dev libxcb-randr0-dev libxcb-render-util0-dev libxcb-render0-dev libxcb-shm0-dev libxcb-util0-dev libxcb-xfixes0-dev libxcb-xkb-dev libxcb1-dev libxfixes-dev libxrandr-dev libxrender-dev
COPY /app /app
ENTRYPOINT ["dotnet", "myaspnetcorewebapi.dll"]

  • I've replaced libssl1.0-dev with libssl1.1 since the former has been deprecated and no longer available in the apt-get registry.
  • I've tried converting the app to dotnetcore 2.1. Same results, issue still persists
  • This issue seems specific to dockerized apps. While I was using zip-deploy to azure app service, it worked fine. However after converting it to a dockerized image, the image node issues started happening. This leads me to believe that some additional, necessary apt-get package might be needed in the dockerfile.

Any ideas on what might be going wrong?

Replied On February 1, 2020 12:39 AM UTC

Ok, I was able to resolve the issue by rolling back to aspnet core 2.1 from 3.1 for my containerized web api.

Some observations: 

1. The base image needs to be "mcr.microsoft.com/dotnet/core/aspnet:2.1.15-bionic". If you use the regular 2.1 tag instead of 2.1.15-bionic then image nodes cannot be printed/exported (probably because some crucial apt-get packages are missing in that tagged image). The full list of tags can be seen here.

2. Upgrading to dotnetcore 3.1 (with 3.1-bionic tag) does not resolve the issue.  

Shyam G [Syncfusion]
Replied On February 3, 2020 12:21 PM UTC

Hi Mithun, 
Before proceeding further on your requirement, Could you please share an HTML content which you pass from the client side(Angular) to the server side(ASP.NET core) and the contents of the docker file for ASP.NET core version 2.1 and the 3.1. so that we can validate further and provide you an update on it. 
Shyam G 


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