More Pre-Built Linux Libraries

[mattleibow]

Right now there is a pre-built library for Linux x64 that goes with each release. I want to add more to make life easier.

Leave comments and other feedback so that I can add other distros and architectures. Also for feedback is the platforms that a binary can be re-used. (For example, the Ubuntu 14.04 binary can also work on CentOS 7)

This doc has the list for .NET Core:
https://docs.microsoft.com/en-us/dotnet/core/linux-prerequisites?tabs=netcore2x
This is the platforms supported by mono:
https://www.mono-project.com/download/stable/#download-lin

Current Support

• Musl-based using Alpine 3.7 (x64) (Add Alpine Native Libraries #1339)
• Debian-based using Ubuntu 16.04 (x64)
• Debian-based using Ubuntu 16.04 (ARM) (Build for Linux ARM32 (armhf) and ARM64 (aarch64) #1382)
• Debian-based using Ubuntu 16.04 (ARM64) (Build for Linux ARM32 (armhf) and ARM64 (aarch64) #1382)

Proposed Support

• Debian (x86)

Dropped

• Raspberry Pi (ARM) (steps)
  Not actually because we have the PR Build for Linux ARM32 (armhf) and ARM64 (aarch64) #1382 that automatically supports it.
• CentOS (x64)
  Not really because this should work with the Debian binaries.
• RHEL 6/7 (x64)
  Not really because this should work with the Debian binaries.

VS bug #733081

[jcyuan]

Ahhhh. a tip although not related to this topic (but it takes a little of my time to settle things done, so this is just for those who are not familiar with linux OS like me):
yum install libfontconfig1-dev will do nothing because there is no such entry. (as mentioned in https://github.com/mono/SkiaSharp/wiki/Building-on-Linux by @mattleibow )
apt-get is only for ubuntu while yum is for redhat (CentOS)
so on RH please do:
yum install fontconfig instead
and for OpenGL lib:
yum install libGL (note: I'm not sure whether this one is corresponding to libglu1-mesa-dev or not)

so steps to install libSkiaSharp for your CentOS:
1, copy the published .so file by @mattleibow to your NetCore container folder on your OS https://github.com/mono/SkiaSharp/releases/tag/v1.59.3
2, ldd libSkiaSharp.so to inspect dependencies (normally it will only show libfontconfig.so.1 not found)
3, yum install fontconfig
4, yum install libGL (emmm, have to be confirmed)

Actually i found that the lib works well after only setp 3 is done. (maybe I do not use some of OpenGL features?)

done, what a good day.

[mattleibow]

@jcyuan OpenGL is not required, but will be used if you are using the GPU surfaces. It is also loaded at runtime, and thus not needed at compile-time.

[mattleibow]

@jcyuan Could the package name for fontconfig may differ across distros?

[jcyuan]

@mattleibow I don't know, actually once installed, I found the lib you mentioned 'libfontconfig.so.1' is located in /usr/lib64/ path, and actually the 'libSkiaSharp.so' uses it correctly as the ldd command shows libSkiaSharp.so refers to this path.
so I think that is only a different package name used between apt-get and yum?

[mattleibow]

To make life easier for everyone, I moved code around and added a new target to the GN files. Now, the native libSkiaSharp build is done with GN and ninja directly: https://github.com/mono/SkiaSharp/wiki/Building-on-Linux

[mattleibow]

Just linking some repos here that do raspberry things:

• https://github.com/terwoord/skiasharp-raspberry
• https://github.com/toburger/skiasharp-raspberry/releases/tag/arm

[wuzzeb]

Just FYI, I just used SkiaSharp.NativeAssets.Linux version 1.68.0-preview28 from nuget on ArchLinux and basic drawing works! I haven't done extensive testing, but the library does initialize and I can draw on a canvas and export the SKImage to a PNG.