76703 - Interlaced GIFs should display solid while downloading

Status: VERIFIED DUPLICATE of bug 73195

(Core :: Graphics: ImageLib, defect)

Description

[Daniel Mario Vega (Restore MNG Support --> #18574)]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:0.8.1+) Gecko/20010417
BuildID:    2001041704

Interlaced GIF images display progressive while downloading. But the effect is
done with horizontal lines (see the URL). It should be done in "solid" way,
filling in between lines with repeatead lines or interpolated lines ( see bug
75077 ). And getting more detail as image downloads.

It works this way in NN 4.x and MSIE

Reproducible: Always
Steps to Reproduce:
Go to http://fog.ccsf.cc.ca.us/~pthiry/multimedia/monalisabig.gif 

Or to
http://illinois.online.uillinois.edu/Presentations/WebGraphicsWorkshop/Untitled.gif

Or to
http://www.dnr.state.oh.us/odnr/water/eeco99/Images/laced.gif

Or any other Interlaced GIF.


Actual Results:  The image displays with progressive stripes

Expected Results:  The image should display as a solid block that gets more
detail as image downloads 

The effect is more noticeable with big images or slow connections

Comment 1

[Tim Powell]

Trying to find a dup, I found similar comments in bug 73969.

Comment 2

[Tim Powell]

Confirming. Still haven't found a dupe (doesn't mean there isn't one). I think
it'd be a good idea for progressive images to render similarly. I prefer the
older "solid" approach of NS4, since it makes it feel like the image loads faster.

Comment 3

[Terri Preston]

Changing status to [imglib]

Comment 4

[Daniel Mario Vega (Restore MNG Support --> #18574)]

Verified also in Linuz. Changing OS

Comment 5

[Skewer]

Same bug occurs in build 20010426. Interlaced GIF images load with black stripes
instead of the proper pixel-block method. Interlaced PNG images seem to be normal.

Comment 6

[u27431]

I've observed this under Linux with the April 30th nightly build of the 0.9
branch.  However, I get garbage (not black lines) for the unrendered lines. I
can see bits UI imagery, old mail messages, and all sorts of weird stuff
interlaced with the partially rendered GIF.  

It looks pretty bad.  Just commenting since I don't see the exact behaviour
described in this bug.  Looks like some buffer is being reused that possibly
should be cleared first?

Video details: Redhat 7.1, XFree 4.03, Nvidia's Geforce2 GTS driver 0.9-69

Comment 7

[Stuart Parmenter]

over to saari

Comment 8

[Skewer]

Because of the high visibility of this bug, I think this should be fixed for
nsbeta1. Someone please add appropriate keyword...

Comment 9

[saari (gone)]

I would tend to agree with you, but drivers and pdt won't. So it gets fixed
early in 0.9.2.

Comment 10

[saari (gone)]

-> tor who has a fix in hand

Comment 11

[Skewer]

Fixed by bug 73195 in 2001060104 Win98.

Comment 12

[tor]

*** This bug has been marked as a duplicate of 73195 ***

Comment 13

[Jacek Piskozub]

Veryfying on Skewer's oservations in bug 73195

Comment 14

[Daniel Mario Vega (Restore MNG Support --> #18574)]

I agree, the bug is fixed on Windows build 2001060104.

I don't like it to be closed as duplicate. Both bugs describe different problems.

Nevertheless, the important thing is this bug is fixed.

Good job!