Example only compiles with stored Cargo.lock

[eburdette0]

When I clone and run the example, it compiles and works, really cool!

If I move all the code to a new project with the same sources and Cargo.toml, the build generates an error at line 62 in src/gaussian_plot/imp.rs: expected cairo::context::Context, found gtk4::cairo::Context

It looks like this might be similar to this stackoverflow issue which was solved by resolving the dependency conflict between versions of cairo-rs in gtk4 and plotters-cairo: https://stackoverflow.com/questions/75229974/how-do-i-fix-my-compatability-errors-when-using-plotterscairobackend-with-gtk

I get very similar compiler notes after the error, with two versions of cairo-rs showing up.

What is an appropriate resolution for this? To specify versions of gtk, plotters and plotters-cairo in the repository's .toml file?

[AaronErhardt]

I think the versions should be compatible. This repo uses gtk4-rs 0.6 which depends on cairo-rs 0.17 which is the same version that the plotters-cairo backend uses.

@sdroege do you have an idea why this is happening?

Also, I think we should update to gtk4-rs 0.7 and cairo-rs 0.18 soon anyway, but I don't know if that solves the problem.

[sdroege]

The versions need to be in sync, yes. How can I reproduce the problem reported here?

Updating to the latest versions should also happen but I'm quite busy right now so if someone else has time to look into that...

[eburdette0]

"How can I reproduce the problem reported here?" Sorry I wasn't explicit:

I get a different error now (see below), but the procedure is the same: 1) clone plotters-gtk-demo 2) cargo run -> no error

3) delete cargo.lock 4) cargo run -> error

error[E0277]: the trait bound `CairoBackend<'_>: plotters::prelude::DrawingBackend` is not satisfied
  --> src/gaussian_plot/imp.rs:63:23
   |
63 |         self.plot_pdf(backend).unwrap();
   |              -------- ^^^^^^^ the trait `plotters::prelude::DrawingBackend` is not implemented for `CairoBackend<'_>`
   |              |
   |              required by a bound introduced by this call

It works if I: repeat 1,2,3) 5) Comment out #git = "https://github.com/plotters-rs/plotters" 6) add version = "0.3.5"

(I repeated this with a clean repo clone for sanity)

Can either of you reproduce that? Maybe it's my error.

.
. There seem to be a large number of changes if I diff cargo.lock. I can dump the different iterations somewhere if that will help

One thing looked strange during the failed run- there are two (different?) compiled versions of plotters-backend listed if that's relevant " Compiling plotters-backend v0.3.5 Compiling plotters-backend v0.3.5 (https://github.com/plotters-rs/plotters#7030c735) "

[sdroege]

Yes there was an API change in plotters and different versions of the crate are pulled in currently. That would have to be fixed. I don't know what the plan here is. plotters, plotters-cairo and this all have to point to consistent versions of everything. Something for @AaronErhardt to decide (e.g. should everything always point to git of plotters related crates? latest releases?)

I also get this error but that's different from the original error you reported though (expected cairo::context::Context, found gtk4::cairo::Context).