Nim Plotly not closing webview window after saveImage()

[facorazza]

Is it possible to close the webview window once the image has been saved?

[pietroppeter]

The expected behaviour when using the webview target with threads on is that the web view window indeed is closed automatically, so if it does not this is a bug.

Note though that webview target is not the same as browser which is the default target and needs to be activated with a -d:webview switch. And specifically for saving image you will need to activate threads with --threads:on.

See comments in https://github.com/SciNim/nim-plotly/blob/master/examples/fig12_save_figure.nim

We probably want to add a short explanation of what the webview target and how it is activated in the readme. As far as I can tell right now the only way to understand this is looking at the source in plotly_display

[facorazza]

Indeed at first it wasn't clear to me that -d:webview is supposed to be used. There is a warning about threads, but I had to find someone else's issue using it to figure it out. In any case I'm compiling and running with nim c -r -d:release --threads:on -d:webview main.nim but the windows don't close as expected. I'm on Ubuntu 22.04 with nim 1.6.6. I should probably post a code snippet to reproduce the error. Unfortunately, I deleted the original code so I'll try to rewrite it as it was.

[facorazza]

Here's the code snippet:

import os
import plotly

var d = Trace[float](mode: PlotMode.Lines, `type`: PlotType.Scatter)

d.xs = @[1.0, 2, 3, 4, 5]
d.ys = @[1.0, 2, 1, 9, 5]

var layout = Layout(
    title: "testing",
    width: 1200, height: 400,
    xaxis: Axis(title:"my x-axis"),
    yaxis:Axis(title: "y-axis too"),
    autosize:false
)
var p = Plot[float](layout:layout, traces: @[d])
p.saveImage("img.png")

echo "Do some other stuff"
os.sleep(10000)

Again compiled and run with nim c -r -d:release --threads:on -d:webview main.nim. The window gets closed only when the program terminates.

[pietroppeter]

The window gets closed only when the program terminates.

Ok, then is probably an expected behaviour of the library, although it is clearly a limit of current api.

As far as I understand (have not checked code, please maintainers correct if I am wrong), since plotly is a js library in order to save the file we use webview to be able to run js and create svg.

In order to be able to just save a file without using webview maybe an option could be to use some js interpreter (such as duktape or quickjs, there are Nim wrappers for both but I have not tried them) and run the plotly code with that.

Again this is just speculation on my side, not sure if the above is correct/feasible.

[Vindaar]

I only see this discussion now (had too many notifications accumulated, oops).

If I remember correctly from when I last worked on it, the ability to close the webview window programatically is problematic. I think I managed to get it to automatically close sometimes. But there were times when it wouldn't close / it would only close the next time the window was active. Especially in a tiling window manager that meant having to manually focus on the webview window and then it auto closed.

I didn't feel like investing more time into it, as ggplotnim was already coming along nice enough for cases where I want static plots.

In order to be able to just save a file without using webview maybe an option could be to use some js interpreter (such as duktape or quickjs, there are Nim wrappers for both but I have not tried them) and run the plotly code with that.

I suppose something like that can be done, yes. I don't know either of those interpreters though.