292191 - If using background-image in an element, we should reverse the result of reverse selection algorithm when the element's foreground color and background color is similar

Status: NEW

(Core :: DOM: Selection, enhancement, P3)

Description

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

If an page is using background in an element, the reverse selection system is
faild when the background color is not similar to background image.
If the element's foreground color and background color is similar and existing
background image, we should reverse the current reverse selection result.

Comment 1

[Justin Wood (:Callek)]

Perhaps, but I wonder if exposing (if not already exposed, forgive me for not
knowing image related api) a method such as HasTransparant in the Image would be
worth it, and if there are transparant bits for the image, we could then assume
that the author does intend the specified background color to be 'correct'. [and
as such may be worth exchanging selection colors as currently designed]

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Justin:
If webpage author using transparent image, I think that the foreground color and
background color are _not_ similar.
So, I want to change the behavior when the colors are similar.

Comment 3

[Justin Wood (:Callek)]

Good enough for me, but just for thought, in some of my personal designs I have
done slight gradients (transparant/alpha-scale) where the actual specified
background color is very close to what the image shows, though I can easily
conceive that I am a minority in that use.

Comment 4

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

*** Bug 292660 has been marked as a duplicate of this bug. ***

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

additional testcases:
https://infosec.navy.mil/
http://mozilla.minutedesign.com/

Comment 6

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Attachment: Patch rv1.0

Comment 7

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Attachment: Patch rv1.0 -u8pw

Comment 8

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

*** Bug 294485 has been marked as a duplicate of this bug. ***

Comment 9

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

My patch doesn't work fine on http://www.uoguelph.ca/~stuartr/
This is very difficult problem. The page can look the text if we don't load
images. So, the page's text color and background color conbination has
sufficient contrast. On this case, we cannot fix with my approach.

Comment 10

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

I have an idea. But I don't like this way.

If the page uses background image and it's spcified by other element(not equal
background color specified element), we use text color for selection background
color. If so, the text color and actual background color combination may have
sufficient contrast. But I think that the looks is not good.
# If background image and color specified same element, we trust the background
color.

Comment 11

[Boris Zbarsky [:bzbarsky]]

I won't be able to review this any time in the near future (at least 2+ weeks).
 I'd really appreciate it if you could find another reviewer...

Comment 12

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Umm... I wrote test patch by comment 10. But it is not better than previous
patch. Please ignore comment 10.

Comment 13

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Comment on attachment 192919 [details] [diff] [review]
Patch rv1.0

I cancel the review. Because I try to fix bug 170951 and bug 113161 before
this.

Comment 14

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

*** Bug 345210 has been marked as a duplicate of this bug. ***

Comment 15

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

*** Bug 332612 has been marked as a duplicate of this bug. ***

Comment 16

[:Gijs (he/him)]

http://www.ed.ac.uk/studying/

is another example (text in the white column on the right will select with a white background due to the blue bg colour of the page itself).

Masayuki, now that the two bugs you mentioned in comment #13 are fixed, is there any chance you'll try to fix this one next? :-)

Comment 17

[Worcester12345]

(In reply to comment #16)
> http://www.ed.ac.uk/studying/
> 
> is another example (text in the white column on the right will select with a
> white background due to the blue bg colour of the page itself).

I'm not seeing a white column on the right here. Did the page change?

Comment 18

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Resetting assignee which I don't work on in this several months.