No fillalpha after eps export?

eps
opacity

asked 12 years ago

pinwheel
51 ●3 ●3 ●7

updated 10 years ago

FrédéricC

5426 ●4 ●44 ●121

Hey guys,

this is a slightly modified example from the sage help pages:

(plot(1+e^(-x^2), xmin=-2, xmax=2, ymin=0, ymax=2.5, fill=0.5, fillcolor='green', fillalpha=0.5)).save('t.eps')

It shows an exponential function which is filled from below by green color. The option fillalpha=0.5 should make this filling slightly transparent, which works perfectly when exporting to pdf, but repdroducably fails when exporting to eps. Is there any workaround?

add a comment

2 Answers

Sort by » oldest newest most voted

answered 12 years ago

fidbc

2423 ●4 ●26 ●61

Hi,

Not really a sage solution and far from optimal. You can try

sage: P=plot(1+e^(-x^2), xmin=-2, xmax=2, ymin=0, ymax=2.5, fill=0.5, fillcolor='green', fillalpha=0.5)
sage: P.save( 't.pdf')

And then

$ pdftops t.pdf
$ ps2eps t.ps

link

Comments

Long story short, (e)ps does not properly support alpha. So, this is probably the best solution at present. There is no automatic way to make figures with alpha in (e)ps.

ppurka ( 12 years ago )

add a comment

answered 12 years ago

kcrisman
12242 ●42 ●136 ●255

The problem is in our Polygon class - somehow it's not saving correctly. Compare these.

sage: polygon([(0,0), (1,1), (0,1)],alpha=.1).save('test.pdf')
sage: polygon([(0,0), (1,1), (0,1)],alpha=.1).save('test.eps')

If I can narrow it down a little more, I'll open a ticket. It's conceivable that it's a matplotlib issue, but I'd guess it's ours first.

link

Comments

See http://trac.sagemath.org/sage_trac/ticket/14074 - my guess is still that we are doing something wrong, but it could be an mpl bug, in principle.

kcrisman ( 12 years ago )

I have updated the ticket after opening an upstream mpl bug https://github.com/matplotlib/matplotlib/issues/1740

ppurka ( 12 years ago )

And now matplotlib says this is actually not supported by ps.

kcrisman ( 12 years ago )

That is not correct. eps supports alpha channels. Here's proof: http://ompldr.org/vaGViZg/drawing.eps Ok. It is not so clear whether ps really really supports alpha. Some libraries use some tricks to get in some alpha support.

ppurka ( 12 years ago )

add a comment

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

No fillalpha after eps export?

2 Answers

Comments

Comments

Your Answer

Question Tools

Stats

Related questions

No fillalpha after eps export? savecancel

2 Answers

Comments

Comments

Your Answer

Question Tools

Stats

Related questions

No fillalpha after eps export?