Please take a look at this JSFiddle: https://jsfiddle.net/a08vkmew/light/
I created a compass with CSS/Html/Javascript that reacts to horizontal mouse movement on the page. If you move the mouse slowly you will see that the lines change their width slightly which results in a flickering appearance of the compass. I think this effect occurs when a line does not exactly match up with the according pixels on the screen, so that only half the width of the line can be shown. In some GUI frameworks we can choose to display the GUI as pixel perfect. Is something like this possible within CSS?
HTML
<div id="compass-container">
<div class="arrow down"></div>
<div class="arrow up"></div>
<div id="viewport">
<div id="compass-scale">
</div>
</div>
</div>
CSS
div#compass-container {
position:relative;
height: 6em;
}
div#viewport{
position:relative;
height:40%;
width:50%;
left:50%;
top:1.2em;
margin-left:-25%;
overflow: hidden;
}
div#compass-scale {
position:relative;
width: auto;
height: 100%;
}
.mini-container {
width:1em;
height:95%;
top:0em;
border: 0px solid black;
float:left;
}
.line {
position: relative;
left:45%;
width:.1em;
background-color:black;
}
.line.small {
height: 15%;
}
.line.medium {
height: 30%;
}
.line.big {
height: 45%;
}
.compass-text {
position:relative;
height:100%;
width:100%;
margin-top:.4em;
text-align: center;
font-family: sans-serif;
color:dodgerblue;
}
.compass-text.small {
font-size: .6em;
}
.compass-text.big {
font-size: .8em;
}
.arrow {
position:absolute;
width: 0;
height: 0;
left:50%;
}
.arrow.up {
margin-left:-1em;
border-left: 1em solid transparent;
border-right: 1em solid transparent;
border-bottom: 2em solid dodgerblue;
bottom: 0em;
}
.arrow.down {
margin-left:-0.5em;
border-left: 0.5em solid transparent;
border-right: 0.5em solid transparent;
border-top: 1em solid dodgerblue;
top: 0em;
}
