问题
THE ANSWER: background-attachment
----- JSBin Example ----
The answer is to use background-attachment
ORIGINAL QUESTION
I'm working on a project where we want to display a modal that "sees through" to the backdrop, but everywhere outside of the modal panel is slightly masked.
I have successfully used border: 10000px rgba(0,0,0,0.3)
with border-radius: 10010px
but this is a hack, and I can't outline the modal with a box-shadow
Is there any standard way for doing this? Bonus points if you can think of a way to apply a transparency filter gradient to an image.
回答1:
I think the best option you got here is to have a 3-rows where the middle one contains 3 columns and the top-bottom rows & left-right columns (of the middle row) have darkened background:
$(function() {
$('button').click(function() {
tpl = '<div class="modal-reverse-container"><div class="r1"></div><div class="r2"><div class="c1"></div><div class="c2"></div><div class="c3"></div></div><div class="r3"></div></div>'
$('body').append($(tpl));
$('.modal-reverse-container').width($(document).width());
$('.modal-reverse-container').height($(document).height());
$('.modal-reverse-container r1, .modal-reverse-container r2').height($(document).height());
});
$(document).on('click', '.modal-reverse-container', function() {
$(this).remove();
});
});
td {
text-align: center;
background: red;
}
.modal-reverse-container {
position: absolute;
top: 0;
left: 0;
}
.modal-reverse-container .r1, .modal-reverse-container .r2, .modal-reverse-container .r3 {
height: 33%;
}
.modal-reverse-container .r1, .modal-reverse-container .r3 {
background: rgba(0, 0, 0, 0.7);
}
.modal-reverse-container .r2 .c1, .modal-reverse-container .r2 .c2, .modal-reverse-container .r2 .c3 {
width: 33%;
height: 100%;
float: left;
}
.modal-reverse-container .r2 .c3 {
float: right;
}
.modal-reverse-container .r2 .c1, .modal-reverse-container .r2 .c3 {
background: rgba(0, 0, 0, 0.7);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table width="100%">
<tr>
<td>1</td>
<td>2</td>
<td>3</td>
</tr>
</table>
<img src="https://dummyimage.com/600x400/d950d9/fff" />
<div>
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</div>
<button>Set reverse-modal</button>
回答2:
---- JSBin Example ----
The answer is to use background-attachment
background-attachment: fixed;
background-size: cover;
background-position: center center;
background-image: linear-gradient(rgba(0,0,0,0.4), rgba(0,0,0,0.4)), url(http://imgur.com/oVaQJ8F.png);
.modal-backdrop {
background: url(myurl.png) center center / cover no-repeat fixed
}
.modal-panel {
background: url(myurl.png) center center / cover no-repeat fixed
}
The best value would be fixed
(not all devices support fixed) so that your backdrop and your modal can share the same viewport X
and Y
(0, 0)
by default
You then scale with background-size
percentages or cover
When using background:
shorthand, make sure to use a /
to separate background-position
from background-scale
amounts
I ran into a bug on an older device, so I used local
then manually computed leftX
and topY
to line up backdrop and modal-panel background-position
at (0, 0)
on my viewport.
I then scaled both images with the same percentage, to cover the screen
I also used a gradient, credit -- How to darken a background Image
来源:https://stackoverflow.com/questions/40010761/css-transparent-glass-modal-everything-else-darkened