[BUG] Missing last marker when using plotly and specifying `marker_color`

[this-josh]

Details

The following code doesn't have a circle for the final data point

using Plots
plotly()
a= [1,2,3,25]
b = [25,9,8,4]
plot(a, b, markershape=:circle, markercolor=[1,2,3,4])

Backends

This bug occurs on ( insert x below )

Backend	yes	no	untested
gr (default)		x
pyplot			x
plotlyjs	x
pgfplotsx			x
unicodeplots			x
inspectdr			x
gaston			x

Versions

Plots.jl version: v1.31.7 Backend version (]st -m <backend(s)>): Output of versioninfo(): Julia Version 1.8.0 Commit 5544a0fab76 (2022-08-17 13:38 UTC) Platform Info: OS: macOS (arm64-apple-darwin21.3.0) CPU: 10 × Apple M1 Max WORD_SIZE: 64 LIBM: libopenlibm LLVM: libLLVM-13.0.1 (ORCJIT, apple-m1) Threads: 8 on 8 virtual cores

[curio-sitas]

The problem comes from the fact that the plot draws over segments. For N points there is N-1 segment. But the renderer draws one marker per segment, so we miss the last one.

For a plot series with scatter option, the needs_scatter_fixis the to truebut it may not behave correctly.

src/backends/plotly.jl at line 908 :

:color => needs_scatter_fix ? [mcolor, "rgba(0, 0, 0, 0.000)"] : mcolor

The last marker is transparent.

One could change the way the plot is contructed in this configuration or add an null segment to draw the last marker

[puripant]

I am new to this repo but I would like to contribute for the first time. Thanks to the pointers by @curio-sitas I can fix this bug and create the following screenshot:

However, I do it another way by checking if it is the last segment and then setting the last marker as non-transparent. If this sounds okay, I will send a pull request.