119167 - offsetLeft & offsetTop wrong

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Michal Schulz]

the offsetLeft and offsetTop of parents of DIV element are broken. Let's look at
given URL. THere is:

{div}   x=6    y=6 (OK)
{TD}    x=130  y=10 (should be 134,14)
{TR}    x=0    y=10 (should be 14,14)
{TBODY} x=0    y=10 (should be 14,14)
{TABLE} x=8    y=8 (OK)

This is true for mozilla 0.9.7 (BUILD ID: 2002010803). For previous browser the
offset values were wrong, but hopefully offsetLeft and offsetTop for ANY element
were the absolute positions (instead of relative)

you should add the width of the border to y value of TD TR and TBODY, x value of
TD. BEsides you should add cellspacing to x value of TR and TBODY

THat's all for today :)

Comment 1

[Johnny Stenback (:jst)]

Hmm, this brings back vauge unpleasant memories of trying to make mozilla's
offset* properties match IE's as closely as possible. Have a look at the if 0'ed
code at:

http://lxr.mozilla.org/seamonkey/source/content/html/content/src/nsGenericHTMLElement.cpp#715

The code that includes the borders of the element itself in .offsetLeft/Top was
taken out to make those properties match IE's better, the reason was IIRC that
IE incorrectly lays ouy absolutely positioned elements with borders, IIRC the
width you specify in CSS for the element will include the borders in IE, where
it correclty doesn't in Mozilla.

Michal, would you be able to experiment with this and prove me wrong? :-) If you
do, and there turns out to be a better compromise, I'll be happy to fix mozilla.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Michal, any chance of providing the info jst asked for?

Comment 3

[Michal Schulz]

The comment You've asked for. Due to low-bandwitch connection I cannot 
experiment with the code so here are my thought about that:

1. problems ;-)

I was looking a bit at the nsGenericHTMLElement.cpp you've proposed. I
agree with you with this #if 0 there. It would be more IE-incompatible
with this section of code. But OTOH if you've missed other thing:

when I query for offset values of TR and TBODY, mozilla should give me:
x=mx + border value of the TABLE that TR belongs to
y=my + border value of the same TABLE as above

where mx and my are the values calculated in given cpp code right now.

when I query for offset values of TD, mozilla should do a bit more werid
calculations:

x=mx + border*(col+2)/2
y=my + border*(row+2)/2

where border is the same border value as above and col means the current
collumn of the table (starting from 0) and row is the current row in
the table (starting from 0).

I did this assumptions by creating dommy table with parameters changed by
me. For the (0,0) position in the table I got the following (x,y)'s of TD:
(10,10 => border=0), (14,14 => border=4). For the (0,1) position I've got:
(130,10 => border=0), but (136, 14 => border=4). For (0,2) there is
(250,10 => border=0) and (258,10 => border=4).

2. big problems.

Dunno why, by your code reports offsetLeft=0 for both TR and TBODY
elements while it should be (for my example) equal cellspacing (10)
without assumptions given above. Could you check it please?

Comment 4

[Michal Schulz]

Attachment: this example shows the problem

Comment 5

[Boris Zbarsky [:bzbarsky]]

The patch in bug 163923 seems to fix this bug.

Comment 6

[Boris Zbarsky [:bzbarsky]]

fixed by checkin for bug 163923