Hi JB Compose is pretty cool I want to use it for an embedde

Question

Hi JB Compose is pretty cool I want to use it for an embedded linux project Is there going to be a ARM 64 bit packaging target

jim · Answer

When you say ARM 64 are you referring to a raspberry pi or something else

Aru · Answer

It s yocto Linux for one of these boards But I think that shouldn t make a difference right If we have the proper graphics driver with open GL ES Implementation <https www variscite com product system on module som cortex a53 krait var som mx8m mini nxp i mx8m mini |https www variscite com product system on module som cortex a53 krait var som mx8m mini nxp i mx8m mini >

suresh · Answer

It seems `AArch64` is not supported for compose desktop <https github com JetBrains compose jb blob master gradle plugins compose src main kotlin org jetbrains compose ComposePlugin kt L65 L68>

jim · Answer

Thanks for the info it s helpful as we do planning Knowing the exact platforms people want is often helpful because in theory it wouldn t make a difference but in theory there is no difference between theory and practice but in practice there is We ve gotten a few requests for Raspberry Pi and hopefully that would work here too As < suresh> mentioned there is no official support for arm64 yet but everything is open source so a motivated individual could do a build on that platform No concrete plans to support yet but it seems likely to happen eventually given that there have been several requests at this point

olonho · Answer

Generally Compose for Desktop is pure JVM code all native code i e Skia bindings is collected in <https github com JetBrains skiko> so someone will provide port of that library adding support to Compose is pretty straightforward

jim · Answer

Yeah to be clear for those following along at home < Aru> s use case would continue to use the JVM bindings not require new native bindings but would need a build of Skia for arm64

Aru · Answer

So I build Skia for arm64 build `skiko` with bindings for arm64 Skia and Compose for Desktop should work And Skia should compile with ease for arm64 given that it s being used in Fuchsia

jim · Answer

Yes that s all correct In addition to Fuchsia both Flutter and Android build Skia on arm64 so it should be entirely supported possible Although having said that I ve never seen anyone describe Skia as compiling regardless of platform with ease rolling on the floor laughing But yes there is no reason to assume it wouldn t more or less just work if you re brave motivated enough to compile Skia

olonho · Answer

well we have set of scripts to simplify Skia compilation <https github com JetBrains skia build>

Aru · Answer

Sweet

Aru · Answer

So I ve compiled skia for arm64 Do I need to compile `skija` separately and then compile `skiko` or just building skiko is enough Also do I need `Skia linux Release arm64 zip` in the target system or will skiko build output will have it packaged

olonho · Answer

Guess best approach would be to send PR with linux arm64 build script to skia build and then adjust Skiko No need to do anything in Skija Target system doesn t need to have zip archive as Skiko build takes care about packaging Skia into JNI library

olonho · Answer

Also did you do cross build on use Raspberry for Skia builds

olonho · Answer

In <https github com JetBrains skiko pull 43> I did some improvements for cross compilation

Aru · Answer

Hey thanks for this PR I didn t do cross build for Raspberry PI It is for a System on Module based on NXP <http i MX|i MX> processor link on top of this thread I was fitting the build inside a Yocto Recipe but cross compilation was smooth by passing `cxx= $CXX cc= $CC ` in the args Similarly I ll have to pass in the native toolchain with a sysroot for cross compilation for Skiko as well

olonho · Answer

Generally if you ll provide Skia build scripts and build instructions we could reproduce we could build Skiko for linux arm64 targets as well

Aru · Answer

Alright I ll create a PR for `skia build` to cross compile to linux arm64

Aru · Answer

I looked into adjusting the gradle build script for skiko to use a cross compiler like `aarch64 linux gcc` instead of `gcc` toolchain It s not straight forward and gradle itself does not support configuring a custom toolchain yet

Aru · Answer

Posting here for continuity I ve looked at the gradle file for skiko and wrote a CMakeFiles txt that would generate `libskiko linux so` in a similar way and packaged that into `skiko linux arm64 0 0 0 SNAPSHOT jar` With a big satisfaction I wanted to test the Hello world code in the embedded device and copied the jars over and ran it I got ```Caused by java lang RuntimeException java lang IllegalArgumentException Library file libskija so not found in at org jetbrains skija impl Library extract Library java 85 at org jetbrains skija impl Library load Library java 50 at org jetbrains skija impl Library staticLoad Library java 32 at org jetbrains skija PictureRecorder lt clinit gt PictureRecorder java 8 18 more Caused by java lang IllegalArgumentException Library file libskija so not found in at org jetbrains skija impl Library extract Library java 68 21 more``` I thought skija is not needed if skiko is compiled Is that not the case

jim · Answer

Skiko is a Kotlin MPP binding around Skija for JVM and doesn t yet provide any other native skia bindings In the future Skiko may also provide bindings through KotlinNative that bind directly to Skia but that is not yet implemented

jim · Answer

So to answer your question You do still need Skija because Skija is a dependency of Skiko And you need Skia because Skia is a dependency of Skija

Aru · Answer

I am running it on a JVM only So I need something like below ``` compose example jar skiko jvm 0 1 18 jar skiko jvm runtime linux arm64 0 1 18 jar libskiko so lt This has SKIKO amp SKIJA objects along with SKIA bindings libskiko so sha256 org jetbrains skija org jetbrains skiko libskija so```

Aru · Answer

obviously with other jars for kotlin runtime and androidx