9
$\begingroup$

Bug introduced in V11.1 and fixed in V11.2

What happened? Is this a regression or maybe some default options were changed?

Test case:

Graphics3D[Sphere[]] // Export["Test.gif", #] &

GIF comparison

Comparison 11.1.1 vs 10.4 on Windows 10.

|improve this question
$\endgroup$
  • 1
    $\begingroup$ Eek... any impact on the file size? $\endgroup$ – Yves Klett Aug 21 '17 at 8:34
  • $\begingroup$ @YvesKlett FileByteCount /@ {"11.gif", "10.gif", "11.png", "10.png"} -> {18493, 28635, 41518, 42317} $\endgroup$ – Kuba♦ Aug 21 '17 at 8:35
  • 3
    $\begingroup$ About the file sizes: Dithering introduces noise to smoothen the appearance of gradients. Noise doesn't compress well. I would expect a dithered GIF (containing smooth gradients) to be significantly larger than a non-dithered one. If it weren't for @ChipHurst's comment I would say that the reason to change Automatic to non-dithered could only be file size reduction. $\endgroup$ – Szabolcs Aug 23 '17 at 12:01
  • $\begingroup$ @Szabolcs That would have been my guess too. $\endgroup$ – Chip Hurst Aug 23 '17 at 20:45
10
$\begingroup$

I talked to the relevant developer and it turns out this is indeed a regression.

It looks as if the default "DitheringMethod" changed from "FloydSteinberg" to None.

Compare "DitheringMethod" pointing to None, Automatic, and "FloydSteinberg" in 10.4 and 11.1:

Table[Labeled[
    ImportString[ExportString[Graphics3D[Sphere[]], "GIF", "DitheringMethod" -> d]], 
    {$VersionNumber, d}, Top], 
  {d, {None, Automatic, "FloydSteinberg"}}
]

enter image description here enter image description here

In 10.4:

$VersionNumber

10.4

Equal[
 ImportString[ExportString["Graphics3D"[Sphere[]], "GIF"]],
 ImportString[ExportString["Graphics3D"[Sphere[]], "GIF", "DitheringMethod" -> "FloydSteinberg"]]
]

True

In 11.1:

$VersionNumber

11.1

Equal[
 ImportString[ExportString["Graphics3D"[Sphere[]], "GIF"]],
 ImportString[ExportString["Graphics3D"[Sphere[]], "GIF", "DitheringMethod" -> None]]
]

True
|improve this answer
$\endgroup$
  • 1
    $\begingroup$ Was that intentional? $\endgroup$ – Kuba♦ Aug 21 '17 at 14:49
  • $\begingroup$ I don't know. Just something I observed when looking through the export options of GIF. $\endgroup$ – Chip Hurst Aug 21 '17 at 14:50
  • $\begingroup$ Thanks. Is anybody around you could ask or should I ask support? :) $\endgroup$ – Kuba♦ Aug 22 '17 at 6:54
  • 3
    $\begingroup$ I talked to the relevant developer and it turns out this is indeed a regression. $\endgroup$ – Chip Hurst Aug 23 '17 at 3:26
  • $\begingroup$ Thanks for forwarding it. $\endgroup$ – Kuba♦ Aug 23 '17 at 5:33

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.