# Plots.jl: interrogating Plot

**URL:** https://discourse.julialang.org/t/plots-jl-interrogating-plot/15038
**Category:** Visualization
**Created:** [September 16, 2018, 11:26pm UTC](https://discourse.julialang.org/t/plots-jl-interrogating-plot/15038 "2018-09-16T23:26:17Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![iwelch](https://avatars.discourse-cdn.com/v4/letter/i/8c91f0/32.png) [@iwelch](https://discourse.julialang.org/u/iwelch)
#### Post date: [September 16, 2018, 11:26pm UTC](https://discourse.julialang.org/t/plots-jl-interrogating-plot/15038/1 "2018-09-16T23:26:17Z")

</div>

Dear Plots experts—I want to write a function that calculates the native slope between two points, so that I can put a label there with the same angle. So, I need to find out, from the plot object, what the four corners (absolute ([0,0], [0,1], [1,0], [1,1]) correspond to in graph space. I also need the aspect ratio. For comparison with R, I need `par("plt")` and `par("usr")`. I also want to know where to place the label so that it is 1em to the x=left of a point. Same inputs needed.

I first went to dump, but this also had some odd output:

```julia
julia> dump( plot( 1:10, 11:20 ) )
...
  subplots: Array{Plots.Subplot}((1,))
    1: Plots.Subplot{Plots.GRBackend}
      parent: Plots.GridLayout
        parent: Plots.RootLayout ERROR: MethodError: no method matching size(::Plots.RootLayout)
Closest candidates are:
  size(::BitArray{1}) at bitarray.jl:70
  size(::BitArray{1}, ::Any) at bitarray.jl:74
  size(::Core.Compiler.StmtRange) at show.jl:1561
  ...

```

pointers appreciated.

/iaw