40623 - Missing 'broken image' badge icon

Status: VERIFIED DUPLICATE of bug 41924

(Core :: Layout, defect, P3)

Description

[Simon Fraser [no longer active]]

4.x shows a broken image badge icon when an image can't be loaded, and if the 
image has height and width specified, it reserves a box of that size.

Gecko briefly shows a box with height and width while loading the page (with the 
little image badge), then collapsed the box to just show the alt text when the 
page is loaded.

If there is no alt text, then the image disappears entirely, and you are left 
with no indication that there was an image there at all.

Discussion in other bugs (e.g. bug 32351) suggests that this is in accordance 
with the HTML 4.0 spec. However, I believe we should at least honor height and 
width for missing images, and, if there is no alt text, have some indication that 
there is a missing image.

Note that the problem of invisible missing images is a particular problem in the 
editor.

Comment 1

[Simon Fraser [no longer active]]

There is some inconsistency here. If the image has an 'align' attribute, then the 
height and width are honored (although the alt text is allowed to run outside the 
box if it is long, another bug). But if the image is inline, it collapses to the 
size of the alt text, if any.

Frame construction for broken images happens in 
nsCSSFrameConstructor::ConstructAlternateImageFrame().

Comment 2

[Simon Fraser [no longer active]]

Attachment: Test case; various combinations of missing images and attributes

Comment 3

[Jesse Ruderman]

in bug 23691, a suggestion was made that before the dumped alt text, a small 
icon should be displayed.  i don't think this solves all of the problems 
(mainly because not having placeholders kills backward compatibility with 
layout tricks that were necessary under old html specs), but it's better than 
having no indication at all.

Comment 4

[Hixie (not reading bugmail)]

I'll be looking at this very, very closely on June 1st to establish what we 
should do which is both standards compliant, promotes accessibility, makes
authors realise they should not rely on specific layouts, and serves the needs
of the users best.

I'm sorry, I can't do it before then because I am in the middle of my exam
period, and spending 90% of my waking time revising.

Stealing bug. See also bug 34981, bug 11011, bug 23691, 24125, bug 24126, bug
24778, bug 35756, bug 8979, bug 9796, bug 32351.

Cc'ing various interested parties.

Comment 5

[Simon Fraser [no longer active]]

In terms of implementation, a possible solution would be to use XBL to generate 
the frames that replace the missing image. When the image is discovered to be 
missing, we could set an attribute on it, then have CSS that sets the behavior, 
replacing the image with anonymous content that gives the desired appearance.

Another thing to note: in the editor (and in the browser), the missing image 
frames should be selectable as a whole. You should not be able to edit the alt 
text, as you can now. We could use a user-select style rule for this.

Comment 6

[Hixie (not reading bugmail)]

That would be a great idea. What would doing that entail? (As far as coding
and styling it is concerned.)

Exactly what do you mean by "adding an attribute", BTW? would this be an extra
attribute on the <img> element, but in a different namespace? Like:

   <img src=".." alt=".." height=".." xbl:img-state="file-not-found" />
   <img src=".." alt=".." height=".." xbl:img-state="format-not-recognised" />
   <img src=".." alt=".." height=".." xbl:img-state="no-problems" />

...or what?  How would this work with respect to <input type="image"> image
buttons? Could they be easily done as well? What does it look like to the DOM?

See also bug 21890.

Comment 7

[Simon Fraser [no longer active]]

I don't have good answers to most of those questions. Perhaps hyatt can elighten 
us.

Comment 8

[ekrock's old account (dead)]

Nom. nsbeta2, recc. nsbeta2 6/22. Whatever we're going to do for missing images 
should be in for nsbeta2. Ian--many thanks for taking on drafting the spec. 
Let's go for a simple solution here as I don't think we'll have the time to 
implement that other uber-solution bug for ALT text.

Comment 9

[Hixie (not reading bugmail)]

Reassigning to default component owner. The spec now exists, see bug 34981.
Once Matthew has given it his seal of approval, I will attach the final spec
to this bug.

Comment 10

[Simon Fraser [no longer active]]

Should this just be a dup of 34981?

Comment 11

[Hixie (not reading bugmail)]

Simon: Yes, it's a dup, I'll be going through all the alt text bugs and marking
them duplicates of a new, clean, argument free bug shortly.

Dave Hyatt: Ccould you have a look at my questions dated 2000-05-27 08:21 and 
see if you have any answers? Cheers.

Comment 12

[Phil Peterson]

[nsbeta2-] wouldn't hold beta2 for this

Comment 13

[Hixie (not reading bugmail)]

*** This bug has been marked as a duplicate of 41924 ***

Comment 14

[Diego]

Verified dupe of later bug 41924: "Change how layout handles broken images (alt
text)"