# PlotlyJS: modify parts of the plot

**URL:** <https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212>\
**Category:** General Usage\
**Tags:** plotlyjs\
**Created:** [August 23, 2022, 4:51pm UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212 "2022-08-23T16:51:57Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![ellocco](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ellocco/32/31331_2.png) [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Post date:** [August 23, 2022, 4:51pm UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/1 "2022-08-23T16:51:57Z")

</div>

Today I wanted to figure out, how to modify the axis type of one specific subplot.  
My question is, how do I figure out stuff like this, if I am not successful to find anything by internet search?  
What is the best approach? Trial and error? Or reading the Julia source code of the package `PlotlyJS`? Or is there some documentation of which I am not aware of?

In the end I figured out how to acchieve this task, here some code that might help other to understand better, how to analyse the structure of the plot object:

```julia
using PlotlyJS
hdl_trace1 = scatter(x=[1, 2], y=[1, 2], name="(tr1)")
hdl_trace2 = scatter(x=[1, 2], y=[2, 3], name="(tr2)")
hdl_trace3 = scatter(x=[1, 2], y=[3, 4], name="(tr3)")
# --- plot with three subplots in one column:
hdl_plt = make_subplots(rows=3, cols=1, specs = [Spec(kind="xy") missing; Spec(kind="xy") missing; Spec(kind="xy") missing])
add_trace!(hdl_plt, hdl_trace1, row=1, col=1)
add_trace!(hdl_plt, hdl_trace2, row=2, col=1)
add_trace!(hdl_plt, hdl_trace3, row=2, col=1)

# --- modify title:
relayout!(hdl_plt, title_text="Example subplots: two row by one colum plot")
# --- modyfy xaxis_type of 2nd subplot:
relayout!(hdl_plt, xaxis2_type="log")

# --- investigate plot handle / plot object:
for (a,b) in hdl_trace2
    println(a)
end

hdl_trace2["y"]
hdl_trace2["type"]
hdl_trace2["name"]
hdl_trace2["x"]

for (a,b) in hdl_plt.plot.layout
    println(a)
end

for (a,b) in hdl_plt.plot.layout.xaxis2
    println(a)
end

hdl_plt.plot.layout.xaxis2
hdl_plt.plot.layout.template.layout.xaxis

```

---

<div class="post-metadata">

**Author:** ![jd-foster](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jd-foster/32/35824_2.png) [@jd-foster](https://discourse.julialang.org/u/jd-foster)\
**Post date:** [August 24, 2022, 1:30am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/2 "2022-08-24T01:30:02Z")

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The official Plotly figure reference is useful (although it helps if you know what you need already 🤔):

> **[Single-page](https://plotly.com/julia/reference/)**
>
> Figure

---

<div class="post-metadata">

**Author:** ![jd-foster](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jd-foster/32/35824_2.png) [@jd-foster](https://discourse.julialang.org/u/jd-foster)\
**Post date:** [August 24, 2022, 1:48am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/3 "2022-08-24T01:48:52Z")

</div>

An alternative is `PlotlyJS.docs()`, which opens a new local window.  
(Actually, still not working: [PlotlyJS.docs() · Issue #161 · JuliaPlots/PlotlyJS.jl · GitHub](https://github.com/JuliaPlots/PlotlyJS.jl/issues/161))  
You can open in your browser  
`~/.julia/packages/PlotlyJS/4jzLr/deps/schema.html`  
for the same (change `4jzLr` to match your local installation).

---

<div class="post-metadata">

**Author:** ![disberd](https://avatars.discourse-cdn.com/v4/letter/d/8edcca/32.png) [@disberd](https://discourse.julialang.org/u/disberd)\
**Post date:** [August 25, 2022, 11:53am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/4 "2022-08-25T11:53:48Z")

</div>

Apart from the very good suggestion from @jd-foster about the single-page reference which I often resort to, I usually also look at the [JavaScript Documentation](https://plotly.com/javascript/) page as it often has many more examples than the julia one.  
The core library is anyway written in JS and what PlotlyJS does is mostly translating from its julia synthax to the equivalent javascript one to call the library.  
I find that once you get an understanding on how the syntax mapping between JS and Julia works (which is quite straightforward in my opinion and can be better understood from the [PlotlyJS documentation](http://juliaplots.org/PlotlyJS.jl/stable/building_traces_layouts/)), it is very easy to translate Javascript Examples to Julia equivalents.

---

<div class="post-metadata">

**Author:** ![jd-foster](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jd-foster/32/35824_2.png) [@jd-foster](https://discourse.julialang.org/u/jd-foster)\
**Post date:** [August 25, 2022, 11:56am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/5 "2022-08-25T11:56:41Z")

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This is a great point: I also do precisely as you describe.

---

<div class="post-metadata">

**Author:** ![ellocco](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ellocco/32/31331_2.png) [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Post date:** [September 13, 2022, 10:06am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/6 "2022-09-13T10:06:53Z")

</div>

Today I tried to define the axis as equally scaled and I struggled about following issue,  
I have not figured out how to specify the range of the axis.

```julia
plt_layout = PlotlyJS.Layout(;
      xaxis_range = [0, 1],
      yaxis_range = [0, 1],
)

```

Is not always sufficient:

 ![axis_range](https://global.discourse-cdn.com/julialang/original/3X/d/6/d6595e191d03240c599b7441b1cb441c9ea54916.png)

Following my example script:

```julia
using PlotlyJS
# Example for fixed Ratio Axes
# source: https://plotly.com/python/axes/#fixed-ratio-axes
# ---
x_vec = 0:0.1:pi
y1_vec = cos.(x_vec)
y2_vec = sin.(x_vec)
y_range = [min(minimum(y1_vec), minimum(y2_vec)), max(maximum(y1_vec), maximum(y2_vec))]

function plot_graph()
    hdl1 = PlotlyJS.scatter(; x= x_vec, y = y1_vec, name = "cos")
    hdl2 = PlotlyJS.scatter(; x= x_vec, y = y2_vec, name = "sin")
    plt_data = [hdl1, hdl2]
    plt_layout = PlotlyJS.Layout(;
        title_text = "Fixed Ratio Axes",
        xaxis_title_text = "Angle / rad",
        xaxis_range = [x_vec[1], x_vec[end]],
        xaxis_showgrid = true, 
        yaxis_title_text = "Amplitude / -",
        yaxis_range = y_range,
        yaxis_showgrid = true,
        # --- Fixed Ratio Axes Configuration
        yaxis_scaleanchor = "x",
        yaxis_scaleratio = 1,
        # --- Legend Configuration
        # legend_y = 0.95, legend_x = 0.9, 
        # legend = PlotlyJS.attr(x=0.1, y=0.5), # fraction of plot pane
        # margin_r = 60, # right margin of canvas, legend is also moving
    )
    hdl_plt = PlotlyJS.Plot(plt_data, plt_layout)
    return hdl_plt
end

plot_graph()

```

---

<div class="post-metadata">

**Author:** ![ellocco](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ellocco/32/31331_2.png) [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Post date:** [September 13, 2022, 11:45am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/7 "2022-09-13T11:45:55Z")

</div>

I think I found the answer:  
[compressed-domain](https://plotly.com/python/axes/#fixed-ratio-axes-with-compressed-domain)

```julia
plt_layout = PlotlyJS.Layout(;
      xaxis_range = [0, 1],
      xaxis_constrain = "domain",
)

```

---

<div class="post-metadata">

**Author:** ![jd-foster](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jd-foster/32/35824_2.png) [@jd-foster](https://discourse.julialang.org/u/jd-foster)\
**Post date:** [September 13, 2022, 11:56am UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/8 "2022-09-13T11:56:01Z")

</div>

Add this:

```julia
xaxis_range = [x_vec[1], x_vec[end]],
xaxis_constrain = "domain", # <---
xaxis_showgrid = true,
```

---

<div class="post-metadata">

**Author:** ![ellocco](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ellocco/32/31331_2.png) [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Post date:** [September 13, 2022, 12:05pm UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/9 "2022-09-13T12:05:19Z")

</div>

> [@jd-foster](#):
>
> `"domain",`

Thanks, jd!

---

<div class="post-metadata">

**Author:** ![ellocco](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ellocco/32/31331_2.png) [@ellocco](https://discourse.julialang.org/u/ellocco)\
**Post date:** [September 28, 2022, 1:46pm UTC](https://discourse.julialang.org/t/plotlyjs-modify-parts-of-the-plot/86212/10 "2022-09-28T13:46:02Z")

</div>

another wanted feature are multiple y-axis, here is my first example:

```julia
using PlotlyJS
# Multiple Axes: https://plotly.com/python/multiple-axes/#multiple-axes

function plot_multiple_yaxis()
    scatter1 = PlotlyJS.scatter(;x = 1:10, y = randn(10), name= "RND1")
    scatter2 = PlotlyJS.scatter(;x = 1:10, y = 2*randn(10), name= "RND2", yaxis= "y2")
    scatter3 = PlotlyJS.scatter(;x = 1:10, y = 1000*randn(10), name= "RND2", yaxis= "y3")
    scatter4 = PlotlyJS.scatter(;x = 1:10, y = 2000*randn(10), name= "RND2", yaxis= "y4")
    plt_traces = [scatter1, scatter2, scatter3, scatter4]
    mylayout = Layout(
        title_text = "Multiple Y Axis Example",
        xaxis_title_text = "xaxis title",
        xaxis_domain = [0.12, 0.88],
        yaxis_title_text = "yaxis title",
		# yaxis_type = "log",
        yaxis2 = PlotlyJS.attr(
            title = "yaxis2 title",
			# type = "log",
			# range = [0, 1],
            overlaying = "y",
            side = "left",
            anchor = "free",
            position = 0.05,
            ),
        yaxis3 = PlotlyJS.attr(
            title = "yaxis3 title",
            # type = "log",
            # range = [0, 1],
            overlaying = "y",
            side = "right",
            anchor = "free",
            position = 0.95,
            ),
        yaxis4 = PlotlyJS.attr(
            title = "yaxis4 title",
            # type = "log",
            # range = [0, 1],
            overlaying = "y",
            side = "right",
            ),
            
        )
    return PlotlyJS.Plot(plt_traces, mylayout)
end
plot_multiple_yaxis()

```