[css-text-3] When is allowed to break before the first preserved white-space after a word ?

[javifernandez]

It may be other cases, but I'd like some clarification regarding how to deal with preserved white-spaces character generated by the white-space: break-spaces feature.

According to the spec,it must break AFTER any white-space:

A line breaking opportunity exists after every preserved white space character, including between white space characters.

However, depending on the case and in combination with other CSS properties, there may be soft-breaking opportunities BEFORE the first space after a word. The following table describes what I think is the expected behavior when using white-space: break-spaces in combination with other properties:

property	value	break before	Conditional
overflow-wrap	normal	No	Never
break-word	Yes	If no previous opportunity
anywhere	Yes	If no previous opportunity
word-break	normal	No	Never
break-all	No	Never
keep-all	No	Never
line-break	anywhere	yes	Always

Is the content of this table correct, according to the last draft of the spec ?

Assuming it's correct, lets consider the following example:

<style>
div {
  width: 4ch;
  line-height: 1;
  border: 1px solid;
}
</style>

<div>X XX X</div>

The table bellow shows Chrome's current behavior when loading the example above with the different combination of the line-breaking properties:

case	word-break	overflow-wrap	line-break	result
0	normal	normal	auto
1	normal	break-word	auto
2	normal	anywhere	auto
3	break-all	normal	auto
4	break-all	break-word	auto
5	normal	normal	anywhere
6	break-all	normal	anywhere
7	normal	break-word	anywhere
8	break-all	break-word	anywhere

Are all these cases correctly rendered ?

[emilio]

Blink doesn't implement overflow-wrap: anywhere, is that right?

[javifernandez]

Blink doesn't implement overflow-wrap: anywhere, is that right?

Right, but it's in my todo list; right after implementing line-break: anywhere

[frivoal]

Is the content of this table correct, according to the last draft of the spec ?

Yes, that matches my own understanding.

Are all these cases correctly rendered ?

All cases assume white-space: break-spaces ? In that case, then I think it has bugs. I would expect this instead (i.e. case 0 to 4 are different, case 5 to 8 are the same):

case	word-break	overflow-wrap	line-break	result
0	normal	normal	auto	X XX X
1	normal	break-word	auto	X XX X
2	normal	anywhere	auto	X XX X
3	break-all	normal	auto	X X X X
4	break-all	break-word	auto	X X X X
5	normal	normal	anywhere
6	break-all	normal	anywhere
7	normal	break-word	anywhere
8	break-all	break-word	anywhere

@fantasai, do you agree?

[frivoal]

@javifernandez Is there a spec issue to be discussed further, or can we consider this question answered and close this?

[javifernandez]

Why breaking after the last letter is not allowed in cases 1 (overflow-wrap: break-word) and 2 (oveflow-wrap: anywhere) ?

[javifernandez]

Why breaking after the last letter is not allowed in cases 1 (overflow-wrap: break-word) and 2 (oveflow-wrap: anywhere) ?

I see, it's because there is a previous breaking opportunity.

[javifernandez]

@frivoal I think everything is clear now and we can close this issue now.