Re: [css-backgrounds] border-position

> On Oct 3, 2017, at 3:42 AM, Benjamin De Cock <ben@stripe.com> wrote:
> 
>> On Thu, Sep 21, 2017 at 6:39 PM, fantasai <fantasai.lists@inkedblade.net> wrote:
>> One of the key differences here is that the border in CSS takes
>> up space. It does this so that it doesn't overlap other content--
>> the browser can ensure enough space where needed, and the author
>> doesn't have to adjust margins/padding every time s/he adjusts
>> the border width. This is good behavior for a layout tool.
>> 
>> Illustrator and Sketch are drawing tools, so they would output
>> SVG shapes, not CSS boxes, in which case the 'stroke' property
>> is used, and that centers on the boundary as you expect.
>> 
>> Given that, I'm not really sure CSS needs a border-position.
>> Could be convinced otherwise, but it'd need more specific
>> examples of where it's needed. :)
>> 
>> ~fantasai
> 
> Thanks for clarifying! I guess I don't really have more specific examples, it really is just a nice thing to have in the authoring process. And as much as I conceive the theoretical difference between a drawing and a layout tool, the fact is that they're closely related in the way we build web interfaces.

Yeah, the border box is always going to be outside the padding box, and ‘box-sizing’ will combine with things like ‘width’ (or ‘max-width’, ‘flex-basis’, etc.) to determine the dimensions of the border box, which then leads to how much space is used for layout. 

However, it would be possible to have something like ‘border-image-offset’ to shift the ink of the line without changing layout. I could see ‘border-offset’ being similar to that, but shifting the border ink (as determined by border-style and border-width) instead of an image. Because it could cause overlapping with existing content, you’d have to be careful with margin and padding, and it probably wouldn’t be your default way of designing layouts. But I could see that being very useful if we ever get a feature for doing multiple, overlapping borders.