Change transparency of fillcolor

Question

I'm trying to change the default color of a fillcolor in Plotly to another transparent one, but when I change the fillcolor it is not transparent anymore.

trace = (go.Scatter(x=[30,45],y=[3000,3000],
                fill='tozeroy', 
#                     fillcolor='green',
#                     fillcolor='rgb(26,150,65,0.5)',
#                     fillcolor=dict(color='rgb(26,150,65,0.5)'),
#              fillcolor=dict(marker=dict(color='rgb(26,150,65,0.5)')),
                opacity=0.1,
                showlegend=False,
                hoverinfo='none',
                mode='none'))
py.offline.iplot(go.Figure(data=[trace]))

This default call results in the following:

and when I use fillcolor='green' it results in this nontransparent color:

The commented code results in the default case again.

I cannot propose an edit directly, but it would be a great addition if the title was made more explicit, like : "Plotly scatter plot: Change transparency of fillcolor for filled area" — Jacquot, Aug 07 '20 at 14:00
I don't think this is explicit to the Scatter plot, or is it? Also a fillcolor is inherently filling an area, right? — Hans Bambel, Aug 08 '20 at 15:32
No, it isn't. And yes. My comment came from the frustration of searching some time for that post, and adding specific keywords can make for a better search engine indexation. — Jacquot, Aug 17 '20 at 13:04

score 34 · Accepted Answer · answered Jun 05 '18 at 21:25

34

You would need to use rgba to specify the alpha channel as well, rgb ignores the transparency.

import plotly
trace = plotly.graph_objs.Scatter(x=[30,45],y=[3000,3000],
                                  fill='tozeroy', 
                                  fillcolor='rgba(26,150,65,0.5)',
                                  mode='none')
plotly.offline.iplot(plotly.graph_objs.Figure(data=[trace]))

answered Jun 05 '18 at 21:25

Maximilian Peters

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20

is there no option to do this by some plot-native key like 'opacity=0.3' or something, rather than to manipulate the color object/directive – mzoll Feb 18 '19 at 15:41
2

@mzoll Looks like there is for traces `opacity=0.5` is an argument. https://plotly.com/python/marker-style/ – Quint Jul 05 '21 at 17:36

score 9 · Answer 2 · answered Jul 05 '21 at 17:36

9

Looks like there is for traces. opacity=0.5 is an argument. https://plotly.com/python/marker-style/

answered Jul 05 '21 at 17:36

Quint

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23

This is the right answer if you are using `fillcolor=""` – tnwei Mar 11 '23 at 04:55

score 0 · Answer 3 · answered Jan 08 '23 at 02:09

If you have multiple traces, you can update each of them this way when using histogram.

fig = px.histogram(df_main, 
                x="follow_count", 
                nbins=50,
                color="label",
                marginal="box", # or violin, rug
                title='Distribution of the follow count per label.'
                )


fig = fig.update_layout(barmode='overlay')

opacity = {'0.0': 1, '1.0': 0.65, '3.0': 1}
fig.for_each_trace(lambda trace: trace.update(opacity = opacity[trace.name]) if trace.name in opacity.keys() else (),)

fig

It's nice to have so you can see the colors behind when using overlay. In that case, label 3 is very low, hence why you don't see it much.

Change transparency of fillcolor

3 Answers3