Plots.jl: Need arg to control the viewing angle of 3D plots

[gabrielgellner]

Currently when using a 3D plotting routine we are given the default view angle with no way of changing it.

For the name, matplotlib uses view_init, matlab uses view, Mathematica uses ViewAngle. I like the last one the most (that is view_angle or viewangle) as it feels the least likely to be confused with something out of context.

[tbreloff]

I think camera is the most obvious representation, as view might mean a lot of things. It would be super helpful if someone could compile links to API docs for setting this with each backend.

[diegozea]

+1 to camera

[gabrielgellner]

Matplotlib

http://matplotlib.org/mpl_toolkits/mplot3d/api.html
with the specific api information:

view_init(elev=None, azim=None)
Set the elevation and azimuth of the axes.

This can be used to rotate the axes programatically.

‘elev’ stores the elevation angle in the z plane. ‘azim’ stores the azimuth angle in the x,y plane.

if elev or azim are None (default), then the initial value is used which was specified in the Axes3D constructor.

Plotly/JS

https://plot.ly/javascript/reference/#layout-scene-camera
with some examples in python
https://plot.ly/python/3d-camera-controls/

It looks like you make the json information of the form

camera = {
"up": [x, y, z]
"center": [x, y, z]
"eye": [x, y, z]
}

where eye + center seems to control how the view angle works.

GR

can't figure out were to find the information :(

pgfplots?

Not sure if it is mapped in the julia package, but for raw pgfplots it is described
on pg.287 (section 4.11.1) under the "View Configuration". In brief:

/pgfplots/view={<azimuth>}{<elevation>} (initially {25}{30})
Changes both view angles of a 3D axis. The azimuth (first argument) is the horizontal angle which is rotated around the z axis. For a 3D plot, the z axis always points to the top. The elevation (second argument) is the vertical rotation around the (rotated) x axis. Positive elevation values indicate a view from above, negative a view from below. All values are measured in degree (but see trig format).

[gabrielgellner]

camera does jive with the plotly api, might be nice to have the type like they do as well with the center/eye/up.

[tbreloff]

Thanks @gabrielgellner!

[gabrielgellner]

I wonder if instead of the eye field it maybe should be lens or view since eye might be confusing with the good ol matrix function.

[juliohm]

I also miss such option, it would be great to have it added.

[SimonDanisch]

camera = {
"up": [x, y, z]
"center": [x, y, z]
"eye": [x, y, z]
}

Would also work well with GLVisualize!

[juliohm]

Is the option available already somehow?

[anriseth]

For future reference, here's how I've dealt with this using the PyPlot-backend:

x = linspace(0,1)
plt = surface(x,x,(x,y)->x+y)
fig = plt.subplots[1].o
fig[:view_init](elev=50,azim=100)
PyPlot.draw()

It seems like calling savefig(plt, "img.png") resets the camera though...

[baggepinnen]

I managed to create a gif using the following hack

strings = String[]
for (i,a) = enumerate(1:4:360)
    fig = plt.subplots[1].o
    fig[:view_init](azim=a)
    s = i >= 10 ? "image$(i).png" : "image0$(i).png"
    push!(strings,s)
    PyPlot.savefig("/tmp/"*strings[end])
    println(round(a/360,3), "% done")
end
anim = Plots.Animation("/tmp/", strings)
gif(anim, "/tmp/anim_fps20.gif", fps = 20)

A few caveats

• The animation creator takes all png images in the folder and creates a gif using them. It is thus safer to create a temp folder and put the images there.
• The animation creator puts img1.png and img10.png in the wrong order, it does not respect or even look at the list of strings in the Animation object, hence the extra 0 for images with numbers < 10.

[tkoolen]

The temporary solution provided by @anriseth doesn't seem to be working (anymore?) for me; I get:

MethodError: no method matching getindex(::Void, ::Symbol)

because plt.subplots[1].o is nothing before the plot is actually displayed, and after the plot has been displayed, changes made to the underlying PyObject don't seem to have any effect anymore.

[mkborregaard]

This was fixed in #1141