背景位置百分比不起作用 [英] background-position percentage not working
问题描述
我读过的每个地方都说它应该可以正常工作,但是由于某种原因,它不是很好.
Everywhere I read says this should be working fine, but for some reason it's not.
这是为了解决其他人的问题,因此对我来说无关紧要,我只想知道为什么.问题出在.br .bg-image
上.我知道我正在尝试使用calc()
,但是使用简单的background-position: 50%
也不起作用.
This was to fix someone else's issue so fixing it doesn't matter to me, I just want to know why. The problem is on .br .bg-image
. I know I'm trying to use calc()
but using a simple background-position: 50%
doesn't work either.
http://jsfiddle.net/uLaa9fnu/2/
html {
height: 100%;
width: 100%;
}
body {
margin: 0px;
height: 100%;
width: 100%;
overflow: hidden;
}
.bg-image {
height: 600px;
width: 800px;
background-image: url('http://media1.santabanta.com/full1/Outdoors/Landscapes/landscapes-267a.jpg');
background-size: 100%;
background-repeat: no-repeat;
}
.relative {
position: relative;
}
.containeroverlay {
background-color: rgba(0, 0, 0, 0.6);
height: 100%;
width: 100%;
}
.framesizer {
height: 340px;
width: 300px;
overflow: hidden;
position: absolute;
}
.frame {
background-image: url('http://i.imgur.com/4AcIXsD.png');
background-repeat: no-repeat;
background-size: 100%;
height: 340px;
width: 300px;
}
.tl {
top: 30px;
left: 30px;
}
.tl .bg-image {
background-position: right 30px bottom 30px;
}
.br {
top: calc(100% - 340px - 30px);
/* Height of frame, plus 30px spacing */
left: calc(100% - 300px - 30px);
/* Width of frame, plus 30px spacing */
}
.br .bg-image {
background-position: right calc(800px - 300px - 30px) bottom calc(600px - 340px - 30px);
/* Background Position doesn't like percentages for some reason */
}
<div class="bg-image">
<div class="containeroverlay relative">
<div class="framesizer tl">
<div class="bg-image">
<div class="frame"></div>
</div>
</div>
<div class="framesizer br">
<div class="bg-image">
<div class="frame"></div>
</div>
</div>
</div>
</div>
推荐答案
解决问题
经过一番摆弄之后,我发现了导致此问题的原因.当背景与其包含的框架一样大(或更大)时,background-position
停止工作.
这也是为什么犬之鼻的解决方案有效的原因.它会删除background-size
.
Solving the problem
After some fiddling I've found what is causing the issue. background-position
stops working when the background is as big (or bigger) as the frame it contains.
This is also why dognose's solution works. It removes the background-size
.
作为证明,我将.br
-frame和.br .bg-image
的CSS更改为以下内容:
As proof, I've changed the CSS of the .br
-frame and .br .bg-image
to the following:
.br {
top:calc(100% - 340px - 30px);
left:calc(100% - 300px - 30px);
}
.br .bg-image {
background-position: calc(100% + 30px) calc(100% + 30px);
/* 100% puts it bottom right, + 30px offset from .br */
background-position: right -30px bottom -30px;
/* or simply use this */
height: 100%;
width: 100%;
background-size: 800px 600px;
}
这样,background-size
不再等于框架,导致background-position
正常工作.
This way the background-size
doesn't equal the frame anymore, causing the background-position
to work as it is supposed to.
请参见小提琴
之所以不能使用百分比,是因为background-position
从字面上依赖于background-size
.因为background-position: 0% 0%;
在左上方,而background-position: 100% 100%;
在右下方.如果背景图片与包含框架的图片一样大,则0%和100%之间没有更多区别.
The reason it doesn't work with percentages, is because the background-position
depends on the background-size
, literally. Because background-position: 0% 0%;
is top left, and background-position: 100% 100%;
is bottom right. If the background image is as big as it's containing frame, there is no more difference between 0% and 100%.
将此理论与calc()
结合使用时,所做的只是:
Using this theory in combination with calc()
, all it does is:
calc(100% - 340px - 30px)
将其放置在右侧(100%),它根本不会移动,然后将其总共向左移动370px(-340px-30px).
calc(100% - 340px - 30px)
place it to the right (100%), which doesn't move it at all, then move it a total of 370px (-340px - 30px) to the left.
在您的情况下,它位于右侧,因为您在calc()
之前添加了right
前缀.
In your case it goes to the right, because you prefixed right
before your calc()
.
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