Render without Graphic Context

[Solido]

Hi Skija Team,

Thanks for the work on this lib, can't wait to see how it will integrate with yours IDE solutions.

Here are 2 questions that need some help please :

• Is is possible to render image without any graphic context directly calling cpu | gpu ?

• How compatible is it with Graal VM ?

Thank you !

Robert

[tonsky]

Is is possible to render image without any graphic context directly calling cpu | gpu ?

I think you will need a CPU :) But yes, it is possible to render to an image directly.

var surface = Surface.makeRasterN32Premul(100, 100));
var canvas = surface.getCanvas();
...
byte[] pngBytes = surface.makeImageSnapshot().encodeToData().getBytes();

How compatible is it with Graal VM ?

Don’t know, but let me know if you figure it out—I’m curious too!

[Solido]

I'm still fighting just to get skija to work :/
But if I succeed i'll put the focus on Graal !
Thx

[tonsky]

Let me know if you have some specific questions. The build scripts are not the best yet, but I hope README has all the steps you need

[Solido]

Thank you @tonsky I gladly accept your help with the setup

Currently, under OSX, I can launch the LwjGL demo but doing it with Jogl fail with
Library libskija.dylib is not found in /

My goal is to setup a Gradle project and then directly render off-canvas using Skija and save to an image format.
So I started a new project and added

repositories {
    mavenCentral()
    mavenLocal()
}

dependencies {
    api "org.jetbrains.skija:skija:0.0.0-local"
    testCompile group: 'junit', name: 'junit', version: '4.12'
}

Compilation OK but a run get me to

Caught: java.lang.UnsatisfiedLinkError: 'long org.jetbrains.skija.impl.RefCnt._nGetFinalizer()'
java.lang.UnsatisfiedLinkError: 'long org.jetbrains.skija.impl.RefCnt._nGetFinalizer()'
	at org.jetbrains.skija.impl.RefCnt._nGetFinalizer(Native Method)
	at org.jetbrains.skija.impl.RefCnt.<clinit>(RefCnt.java:23)

Do I miss some setup on the launch dir so it can find a native lib ?

[tonsky]

You need to call Library.load() before calling any of the native methods. We might get rid of it in the future. I will look into JOGL example, probably some API changes broke it. LWJGL is always working and up-to-date

[Solido]

Thx !

Made some progress but calling Surface crash the program

Unhandled exception
Type=Segmentation error vmState=0x00040000
J9Generic_Signal_Number=00000018 Signal_Number=0000000b Error_Value=00000000 Signal_Code=00000001
Handler1=0000000006AA20A0 Handler2=0000000006CACC20 InaccessibleAddress=0000000000000030
RDI=0000000000000000 RSI=0000000000000001 RAX=000070000EFB8448 RBX=00007F935E867A00
RCX=0000000000000000 RDX=000070000EFB8448 R8=00007F935CE0E4F0 R9=0000000000001FF5
R10=000070000EFB8500 R11=0000000043F170A0 R12=00007F935CE0E4F0 R13=0000000000000002
R14=000070000EFB8580 R15=0000000000000001
RIP=0000000043F52D5D GS=0000 FS=0000 RSP=000070000EFB8440
RFlags=0000000000010202 CS=002B RBP=000070000EFB8510 ERR=0000003000000004
TRAPNO=000000040000000E CPU=0030000000040000 FAULTVADDR=0000000000000030
XMM0 40c0000040c00000 (f: 1086324736.000000, d: 8.192002e+03)
XMM1 c0c00000c0c00000 (f: 3233808384.000000, d: -8.192006e+03)
XMM2 4399000043990000 (f: 1134100480.000000, d: 4.503600e+17)
XMM3 0000000000000000 (f: 0.000000, d: 0.000000e+00)
XMM4 0000000000000000 (f: 0.000000, d: 0.000000e+00)
XMM5 0000000000000000 (f: 0.000000, d: 0.000000e+00)
XMM6 00007f935d8dc668 (f: 1569572480.000000, d: 6.930304e-310)
XMM7 000070000efb8680 (f: 251364992.000000, d: 6.084199e-310)
XMM8 0000000041040000 (f: 1090781184.000000, d: 5.389175e-315)
XMM9 d0f19ea71fda8845 (f: 534415424.000000, d: -8.356767e+81)
XMM10 5489c0e5fa14f738 (f: 4195677952.000000, d: 1.760293e+99)
XMM11 6a647391c17bfd96 (f: 3246128640.000000, d: 3.206055e+204)
XMM12 05ee5eb551679e50 (f: 1365745280.000000, d: 4.182714e-280)
XMM13 cb1c601da178138c (f: 2709001216.000000, d: -6.794571e+53)
XMM14 ec1fb990e9f1e725 (f: 3924944640.000000, d: -6.675085e+212)
XMM15 fd9a82cea5538121 (f: 2773713152.000000, d: -1.083631e+297)
Module=/Users/r/Documents/Skija/build/resources/main/libskija.dylib
Module_base_address=0000000043F13000 Symbol=_ZN8SkCanvas12onDrawPointsENS_9PointModeEmPK7SkPointRK7SkPaint
Symbol_address=0000000043F52C30
Target=2_90_20191016_371 (Mac OS X 10.15.4)
CPU=amd64 (8 logical CPUs) (0x200000000 RAM)

But I can create a Bitmap and draw.
It's just hellish to get bytes.

final bt = new Bitmap()
final width = 300
final height = 300
bt.allocN32Pixels width, height
...
 new Canvas(bt)

[tonsky]

Might be related: on a mac, you need to do it from the first thread. Maybe passing -XstartOnFirstThread to the JVM options might help

[Solido]

Thanks a lot @tonsky I got everything working now, this made my day.

The previous error came from the JDK 11 J9, I moved to JDK14 and it's faster on startup.

Here are some of my works that rely mainly on Flutter which use a limited set of Skia as Engine.
https://twitter.com/BlueAquilae

I'll try to see how I can explore more of Skia using your consequent work !

[tonsky]

Looks dope! If you manage to build something like that in Skija, let me know — we might include it as an example (if you are interested)