/CefGlueScreenshot

Take screenshot from any webpage with the CEF wrapper CefGlue.

Primary LanguageC#

Update June 2018

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.

Original Post (June 2016)

CefGlueScreenshot

Take screenshot from any webpage with the CEF wrapper CefGlue.

Problem

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.

Possible frameworks

There are several possible solutions:

Requirements for my project

  • 64bit environment
  • based on Chromium

So only CEF seems to fit.

Problem with CEFSharp

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.

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

Build info

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.

Further reading