How to change style in a Leaflet's imageOverlay apart from opacity? - leaflet

Question

I would like to change the style of an ImageOverlay in Leaflet. As I saw from the imageOverlay instance apart from setUrl, setBounds, setOpacity methods there seems to be a setStyle method which only seems to work with opacity or with limited css attributes.
f.i
imageOverlay.setStyle({
opacity: 0.5
})
this works fine as expected.
For instance how would I change the borderColor or color or fill properties? I have used
imageOverlay.setStyle({
borderColor: '#FF0000 blue'
})
but no style is applied.
Below I give an example. I have two buttons implementing two functions. SetOpacity that works fine and setBorderColor that does not work.
Any recommendations are welcome.
#mapid {
height: 100vh;
}
body {
margin: 0px;
padding: 0px;
}
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.4.0/leaflet.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.4.0/leaflet.js"></script>
<button onclick='setOverlayOpacity()'>ChangeOpacity</button>
<button onclick='setOverlayBorderColor()'>Change Border Color</button>
<div id="mapid"></div>
<script>
var map = L.map('mapid').setView([51.505, -0.09], 13);
L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
attribution: '© OpenStreetMap contributors'
}).addTo(map);
var imageUrl = 'http://www.lib.utexas.edu/maps/historical/newark_nj_1922.jpg',
imageBounds = [
[40.712216, -74.22655],
[40.773941, -74.12544]
];
var imageOverlay = L.imageOverlay(imageUrl, imageBounds).addTo(map);
console.log(imageOverlay)
map.fitBounds(imageBounds)
function setOverlayOpacity() {
imageOverlay.setStyle({
opacity: 0.5
})
}
function setOverlayBorderColor() {
imageOverlay.setStyle({
borderColor: '#FF0000 blue'
})
}
</script>

Answer 1

The setStyle() method of L.ImageOverlay is not documented on purpose, and only for compatibility for L.FeatureGroup.setStyle(), which is mainly meant for setting style options for L.Path, not CSS rules.
In fact, the current implementation of L.ImageOverlay.setStyle() method only sets the opacity:
setStyle: function (styleOpts) {
if (styleOpts.opacity) {
this.setOpacity(styleOpts.opacity);
}
return this;
},
I think that what you want to do is to use L.ImageOverlay.getElement(), which returns a HTMLImageElement and then access its style property, e.g.:
myOverlay.getElement().style.border = '2px solid red';
Alternatively, use the className option to assign a CSS class to the ImageOverlay's HTMLImageElement, and add CSS rules accordingly.