Unable to call VipsForeignLoadPngFile

[sjkim04]

I'm tampering with lua-vips on a Raspberry Pi with a custom-built libvips, and I can't seem to get the module to work.

Here's the simple code I used:

local vips = require "vips"
local base = vips.Image.new_from_file("base.png")

and here's the traceback (run with luvit):

$ luvit test.lua
Uncaught exception:
./vips/voperation.lua:216: unable to call VipsForeignLoadPngFile

stack traceback:
	[C]: in function 'error'
	./vips/voperation.lua:216: in function 'new_from_file'
	/home/sjkim04/Desktop/test.lua:2: in function 'fn'
	[string "bundle:deps/require.lua"]:310: in function 'require'
	[string "bundle:/main.lua"]:128: in function <[string "bundle:/main.lua"]:20>
stack traceback:
	[C]: in function 'error'
	[string "bundle:/deps/utils.lua"]:41: in function 'assertResume'
	[string "bundle:/init.lua"]:52: in function <[string "bundle:/init.lua"]:47>
	[C]: in function 'xpcall'
	[string "bundle:/init.lua"]:47: in function 'fn'
	[string "bundle:deps/require.lua"]:310: in function <[string "bundle:deps/require.lua"]:266>

What's the problem with this? I installed most of the optional dependencies, including libspng, and the code still fails. I would appreciate some help.

[jcupitt]

Hi @sjkim04,

I suppose I would first try to verify that your libvips is working. You can do:

$ vips --vips-config | grep -i png
PNG load/save with libspng: false
PNG load/save with libpng: true

To check that it picked up libspng (or libpng, for me) correctly. Then maybe:

$ vipsheader ~/pics/k2.png
/home/john/pics/k2.png: 1450x2048 uchar, 3 bands, srgb, pngload

To make sure it can call it.

I see:

$ luajit
LuaJIT 2.1.0-beta3 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
JIT: ON SSE2 SSE3 SSE4.1 AMD BMI2 fold cse dce fwd dse narrow loop abc sink fuse
> vips = require "vips"
> base = vips.Image.new_from_file("k2.png")
> print(base:width())
1450
> 

[sjkim04]

$ vips --vips-config | grep -i png
memory: high-water mark 0 bytes
PNG load with libspng: true
PNG load/save with libpng: false

$ vipsheader ./base.png
./base.png: 1280x720 uchar, 4 bands, srgb, pngload
memory: high-water mark 0 bytes

$ luajit
LuaJIT 2.1.0-beta3 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
JIT: ON fold cse dce fwd dse narrow loop abc sink fuse
> vips = require "vips"
> base = vips.Image.new_from_file("base.png")
./vips/voperation.lua:216: unable to call VipsForeignLoadPngFile

stack traceback:
	[C]: in function 'error'
	./vips/voperation.lua:216: in function 'new_from_file'
	stdin:1: in main chunk
	[C]: at 0xaaaadcb40994
> 

So it's not vips' problem, as far as I can tell from your comment. What could it be? One thing I can expect is the environment (I didn't install any of the Lua development packages). If that matters, I'll try to fix it.

Edit: As I said, I am running this on a Raspberry Pi 4, running Ubuntu 21.04 LTS (ARM64). Just thought I'd tell you this.

[jcupitt]

I'll see if I can make a dockerfile that reproduces this.

[jcupitt]

I had a quick go:

https://github.com/jcupitt/docker-builds/blob/master/lua-vips-ubuntu21.04/Dockerfile

But canonical seem to be having some DNS problems so I can't test it, unfortunately. I might try again later.

[jcupitt]

Oh, just me being dumb, 21.04 is not an LTS, so it's out of support. Assuming you meant 20.04 I made this:

https://github.com/jcupitt/docker-builds/blob/master/lua-vips-ubuntu20.04/Dockerfile

It seems to work, I see:

$ docker run -it --rm -v $PWD:/data lua-vips-ubuntu20.04
root@b3bf1d41c7c2:/usr/local/src# cd /data/
root@b3bf1d41c7c2:/data# ls
Dockerfile  README.md  astronauts.png
root@b3bf1d41c7c2:/data# luajit
LuaJIT 2.1.0-beta3 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
JIT: ON SSE2 SSE3 SSE4.1 AMD BMI2 fold cse dce fwd dse narrow loop abc sink fuse
> vips = require("vips")
> x = vips.Image.new_from_file("astronauts.png")
> print(x:width())
900
> 

Could you test that on your rpi?