Graphics3d with fractional opacity will not save image

[niles]

Giving opacity as a fraction breaks the save method. No error is raised and no image is created.

plot3d(lambda x, y: x^2 + y^2, (-2,2), (-2,2),opacity=8/10).save('~/tmp.png')

This appears to be a problem with tachyon not handling fractions. Here is another example with an error message (shown with the keyword verbosity=2):

sage: S = sphere(opacity=8/10, aspect_ratio=[1,1,1], verbosity='2')
sage: S.save('~/tmp.png')

tachyon /Users/njohnson/.sage/temp/galileo/2623/tmp_zkpq5K.dat  -format PNG  -o ~/tmp.png  -res 500 500  +V ; rm -f "/Users/njohnson/.sage/temp/galileo/2623/tmp_zkpq5K.dat"
Tachyon Parallel/Multiprocessor Ray Tracer   Version 0.98.9   
Copyright 1994-2010,    John E. Stone <john.stone@gmail.com> 
------------------------------------------------------------ 
Parse Error:
   Encountered a syntax error in file /Users/njohnson/.sage/temp/galileo/2623/tmp_zkpq5K.dat
   Expected to find TEXFUNC
   Actually found: Color
   Error occured at or prior to file offset 656, line 29
   Error position is only approximate, but should be close

Parse Error:
   Encountered a syntax error in file /Users/njohnson/.sage/temp/galileo/2623/tmp_zkpq5K.dat
   Expected to find an object or other declaration
   Actually found: .4
   Error occured at or prior to file offset 660, line 29
   Error position is only approximate, but should be close

Parser failed due to an input file syntax error.
Aborting render.

Changing opacity to .8 in this example works as expected.

[yzh]

New commits:

​181dddc

fractional opacity

[jipilab]

Looks good.

Could you add a test to show that the mentioned bug is fixed?

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​d1b3450

add fixed bug example

[jipilab]

There are 2 failed doctests:

File "src/sage/plot/plot3d/index_face_set.pyx", line 964, in sage.plot.plot3d.index_face_set.IndexFaceSet.json_repr
Failed example:
    G.json_repr(G.default_render_params())
Expected:
    ['{"vertices":[{"x":0,"y":0,"z":1},{"x":1,"y":1,"z":1},{"x":2,"y":0,"z":1}], "faces":[[0,1,2]], "color":"#0000ff", "opacity":1}']
Got:
    ['{"vertices":[{"x":0,"y":0,"z":1},{"x":1,"y":1,"z":1},{"x":2,"y":0,"z":1}], "faces":[[0,1,2]], "color":"#0000ff", "opacity":1.0}']
**********************************************************************
File "src/sage/plot/plot3d/index_face_set.pyx", line 976, in sage.plot.plot3d.index_face_set.IndexFaceSet.json_repr
Failed example:
    S.json_repr(S.default_render_params())
Expected:
    ['{"vertices":[{"x":2,"y":0,"z":0},..., "face_colors":["#ff0000","#ff9900","#cbff00","#33ff00"], "opacity":1}']
Got:
    ['{"vertices":[{"x":2,"y":0,"z":0},{"x":0,"y":2,"z":0},{"x":0,"y":0,"z":2},{"x":0,"y":1,"z":1},{"x":1,"y":0,"z":1},{"x":1,"y":1,"z":0}], "faces":[[0,4,5],[3,4,5],[2,3,4],[1,3,5]], "face_colors":["#ff0000","#ff9900","#cbff00","#33ff00"], "opacity":1.0}']

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​e90a294

fix bugs in doctests

[slelievre]

Don't forget to set back to needs_review once reviewer comments are dealt with.

[jipilab]

Looks good to me. Once the bot give a green light, I would put positive review.

[chapoton]

See patchbot report:

File "src/sage/plot/plot3d/base.pyx", line 329, in sage.plot.plot3d.base.Graphics3d._rich_repr_canvas3d
Failed example:
    out.canvas3d.get()
Expected:
    '[{"vertices":[{"x":0,"y":0,"z":-1},..., "color":"#6666ff", "opacity":1}]'
Got:
    '[{"vertices":[{"x":0,"y":0,"z":-1},..., "color":"#6666ff", "opacity":1.0}]'

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​ddf16d5

fix doctest error

[jipilab]

It looks good to me.