Bootstrap Printing and Column Resizing - html

Question

I have done some digging on SO and have found a a variety of resources regarding printing and bootstrap.css, but I have not seen a solution to this particular problem.
Lets say I have a setup like seen in this Plnkr: http://plnkr.co/edit/7ETXQyEvY7S16JTU9wYB?p=preview
and HTML like this:
<div class="col-xs-6 red">
testing
</div>
<div class="col-xs-6 blue hidden">
123
</div>
The CSS states that during printing the column will be hidden (on my real page the stle is not hidden but hidden-print), which is expected, but is there anyway to now have the col-xs-6 red now take up the empty space left by the hidden blue column.
I know you could override the style col-xs-6 to be width:100%, but that would affect other columns on the page that need to be left at width: 50%.
Has anyone had this problem before, if so how did you address it?

Answer 1

For Bootstrap 4 you need to do a modification from #Lance's answer.
#media print {
.col-print-12 {
max-width: 100%;
flex: 0 0 100%;
}
}
With the same HTML
<div class="col-xs-6 col-print-12 bg-danger">
Red Column is full width for print
</div>
<div class="col-xs-6 hidden-print bg-primary">
Blue Column is hidden for print
</div>

Answer 2

I suggest something like:
#media print {
.col-print-12{
width:100% !important;
}
}
Then your HTML can be:
<div class="col-xs-6 col-print-12 bg-danger">
Red Column is full width for print
</div>
<div class="col-xs-6 hidden-print bg-primary">
Blue Column is hidden for print
</div>
!important is needed to override the regular col widths since at least one set will also apply at print width.
I updated your plunk using xs as a proxy for the print view here to demonstrate the concept. One red column in mobile, Red and Blue columns in tablet or bigger.

Answer 3

Edit: if you want to do it with CSS only you would have to use the flex property. Take a look at this pen. Change display: flex to display: none on any column and see how they stretch to fit the available space (this renders bootstrap useless).
Create a div container inside the bootstrap column and apply visibility: hidden to it. You want to hide without removing it, meaning the browser will still show the space that the element occupies.
It's a good practice not to add your own classes to bootstrap columns but instead create a container inside it so you can apply your classes to.
display: none gets rid of the element entirely and affects the positioning of the other elements that were around it.