So after 2 years, I finally found a solution for the perfect screenshot with a headless chrome.
Long story short:
- I don't use a C#/.NET wrapper anymore, I created my own NodeJS rasterize service with puppeteer.
- A REST API using express listens for incoming rasterize requests and then basically calls page.screenshot
- The rasterized result will be return as byte array
- The whole NodeJS app runs as a guest executable in service fabric
- "Why don't you use Azure Web App/Azure Functions?" you may ask => Because of GDI restrictions
- I can now call the REST API from my Web app and create screenshots from any webpage/HTML content.
Take screenshot from any webpage with the CEF wrapper CefGlue.
I wanted to rasterize SVGs to PNGs on my Windows Azure Worker Role.
MagickNet (https://magick.codeplex.com/ - .NET port of ImageMagick) works fair enough, but not every SVG is rendered perfectly. Especially external fonts and displacement maps are causing problems.
Solution: Open a headless webbrowser and take a screenshot.
There are several possible solutions:
- PhantomJS wrapper for .NET (C#) - http://www.nrecosite.com/phantomjs_wrapper_net.aspx
- Awesomium - http://www.awesomium.com/
- CEF - https://bitbucket.org/chromiumembedded/cef
- CEFSharp - http://cefsharp.github.io/
- Xilium.CefGlue - http://xilium.bitbucket.org/cefglue/
- ChromiumFX - https://bitbucket.org/chromiumfx/chromiumfx
Requirements for my project
- 64bit environment
- based on Chromium
So only CEF seems to fit.
CEFSharp looked good at the beginning (NuGet packages, nice community https://gitter.im/cefsharp/CefSharp ), but it didn't worked in my Azure Worker Role. There where some problems with calls between AppDomains.
One contributer (https://github.com/arsher) published a pull request (cefsharp/CefSharp#1556 ) which should fix this problem. But I was never able to build his solution.
CefGlue.
In contrast to CEFSharp CefGlue is uses P/Invoke calls, which aren't causing any troubles - yet. Basically I updated the solution posted here (http://joelverhagen.com/blog/2013/12/headless-chromium-in-c-with-cefglue/) and used the packages from MyGet (http://myget.org/gallery/dazaraev). Unfortunately CefGlue has no official NuGet packages yet.
Chromium version: Chrome 51.0.2704.63 | .NET version: 4.5.2 | CEF Version: 3.2704.1409 | Date: 1.6.2016
Since the CEF related binaries are quite big, I have excluded them from the repo. Visual Studio will probably show you a warning that several files are missing. To get the missing files you have to download the CEF related packages from MyGet (add sourcs for the third-party NuGet Server: https://docs.nuget.org/create/hosting-your-own-nuget-feeds ). The missing files can then be found in the directory .\packages\ChromiumEmbedded.Redistributable-win-x64.51.1.1\build. Copy them into the solution directory, select x64 instead of AnyCPU and hit start.
- Difference between CEFSharp and CefGlue - http://stackoverflow.com/questions/12224798/any-reason-to-prefer-cefsharp-over-cefglue-or-vice-versa
- Discussion about the NuGet packages in CefGlue - https://bitbucket.org/xilium/xilium.cefglue/issues/61/make-nuget-packages