Visible Area Tag

Visible Area tag?

jQuery Plugin, MapHilight:

You might find the jQuery plugin MapHilight (dead link!!!) to be of interest here.

  • Map of the United States Demo (dead link!!!)

New link: https://github.com/kemayo/maphilight

New demo: https://home.ctw.utwente.nl/slootenvanf/wp-content/uploads/examples/archive/jquery_plugins/imagemap/

HTML/CSS Alternative

I would suggest using a div, with absolute links within. The reason being, this will degrade very nicely and show all of the options as a list of links. Image maps won't be so friendly. Furthermore, this alternative will deliver the same results, with cleaner and more modern practices.

#myImage {
position:relative; width:640px; height:100px;
background-image:url("bkg.jpg");
}
a.apples {
display:block; position:absolute;
top:0; left:0; width:100px; height:100px;
border:1px solid red;
}
a.taters {
display:block; position:absolute;
top:0; left:200px; width:25px; height:25px;
border:1px dotted orange;
}
#myImage a span {
display:none;
}

--

<div id="myImage">
<ul>
<li><a href="page1.html" class="apples"><span>Apples</span></a></li>
<li><a href="page2.html" class="taters"><span>Taters</span></a></li>
</ul>
</div>

making the area in a map tag visible during development

As far as I know, this is not possible. If you need to show those areas, you need to add absolute positioned elements, containing the links.

In case you only need that for development, there is a handy firefox extension, which can help you.

It is of course possible to generate visible area using javascript, probably this jQuery plugin can help you.

Make a hotspot area visible in html

Forgive me if I'm stating the obvious, but assuming you'd always want it to be visible, why not just edit the actual image?

Alternativley, there's a suggestion here that might help: Visible Area tag?

How to apply Hovering on html area tag?

What I did was to create a canvas element that I then position in front of the image map. Then, whenever an area is moused-over, I call a func that gets the coord string for that shape and the shape-type. If it's a poly I use the coords to draw an outline on the canvas. If it's a rect I draw a rect outline. You could easily add code to deal with circles.

You could also set the opacity of the canvas to less than 100% before filling the poly/rect/circle. You could also change the reliance on a global for the canvas's context - this would mean you could deal with more than 1 image-map on the same page.

<!DOCTYPE html>
<html>
<head>
<script>

// stores the device context of the canvas we use to draw the outlines
// initialized in myInit, used in myHover and myLeave
var hdc;

// shorthand func
function byId(e){return document.getElementById(e);}

// takes a string that contains coords eg - "227,307,261,309, 339,354, 328,371, 240,331"
// draws a line from each co-ord pair to the next - assumes starting point needs to be repeated as ending point.
function drawPoly(coOrdStr)
{
var mCoords = coOrdStr.split(',');
var i, n;
n = mCoords.length;

hdc.beginPath();
hdc.moveTo(mCoords[0], mCoords[1]);
for (i=2; i<n; i+=2)
{
hdc.lineTo(mCoords[i], mCoords[i+1]);
}
hdc.lineTo(mCoords[0], mCoords[1]);
hdc.stroke();
}

function drawRect(coOrdStr)
{
var mCoords = coOrdStr.split(',');
var top, left, bot, right;
left = mCoords[0];
top = mCoords[1];
right = mCoords[2];
bot = mCoords[3];
hdc.strokeRect(left,top,right-left,bot-top);
}

function myHover(element)
{
var hoveredElement = element;
var coordStr = element.getAttribute('coords');
var areaType = element.getAttribute('shape');

switch (areaType)
{
case 'polygon':
case 'poly':
drawPoly(coordStr);
break;

case 'rect':
drawRect(coordStr);
}
}

function myLeave()
{
var canvas = byId('myCanvas');
hdc.clearRect(0, 0, canvas.width, canvas.height);
}

function myInit()
{
// get the target image
var img = byId('img-imgmap201293016112');

var x,y, w,h;

// get it's position and width+height
x = img.offsetLeft;
y = img.offsetTop;
w = img.clientWidth;
h = img.clientHeight;

// move the canvas, so it's contained by the same parent as the image
var imgParent = img.parentNode;
var can = byId('myCanvas');
imgParent.appendChild(can);

// place the canvas in front of the image
can.style.zIndex = 1;

// position it over the image
can.style.left = x+'px';
can.style.top = y+'px';

// make same size as the image
can.setAttribute('width', w+'px');
can.setAttribute('height', h+'px');

// get it's context
hdc = can.getContext('2d');

// set the 'default' values for the colour/width of fill/stroke operations
hdc.fillStyle = 'red';
hdc.strokeStyle = 'red';
hdc.lineWidth = 2;
}
</script>

<style>
body
{
background-color: gray;
}
canvas
{
pointer-events: none; /* make the canvas transparent to the mouse - needed since canvas is position infront of image */
position: absolute;
}
</style>

<title></title>
</head>
<body onload='myInit()'>
<canvas id='myCanvas'></canvas> <!-- gets re-positioned in myInit(); -->
<center>
<img src='http://dailyaeen.com.pk/epaper/wp-content/uploads/2012/09/27+Sep+2012-1.jpg?1349003469874' usemap='#imgmap_css_container_imgmap201293016112' class='imgmap_css_container' title='imgmap201293016112' alt='imgmap201293016112' id='img-imgmap201293016112' />
<map id='imgmap201293016112' name='imgmap_css_container_imgmap201293016112'>
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="2,0,604,-3,611,-3,611,166,346,165,345,130,-2,130,-2,124,1,128,1,126" href="" alt="imgmap201293016112-0" title="imgmap201293016112-0" class="imgmap201293016112-area" id="imgmap201293016112-area-0" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,131,341,213" href="" alt="imgmap201293016112-1" title="imgmap201293016112-1" class="imgmap201293016112-area" id="imgmap201293016112-area-1" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,166,614,241" href="" alt="imgmap201293016112-2" title="imgmap201293016112-2" class="imgmap201293016112-area" id="imgmap201293016112-area-2" />
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="917,242,344,239,345,496,574,495,575,435,917,433" href="" alt="imgmap201293016112-3" title="imgmap201293016112-3" class="imgmap201293016112-area" id="imgmap201293016112-area-3" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,416,341,494" href="" alt="imgmap201293016112-4" title="imgmap201293016112-4" class="imgmap201293016112-area" id="imgmap201293016112-area-4" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,215,341,410" href="" alt="imgmap201293016112-5" title="imgmap201293016112-5" class="imgmap201293016112-area" id="imgmap201293016112-area-5" />
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="916,533,916,436,578,436,576,495,806,496,807,535" href="" alt="imgmap201293016112-6" title="imgmap201293016112-6" class="imgmap201293016112-area" id="imgmap201293016112-area-6" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="805,536,918,614" href="" alt="imgmap201293016112-7" title="imgmap201293016112-7" class="imgmap201293016112-area" id="imgmap201293016112-area-7" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="461,494,803,616" href="" alt="imgmap201293016112-8" title="imgmap201293016112-8" class="imgmap201293016112-area" id="imgmap201293016112-area-8" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,497,223,616" href="" alt="imgmap201293016112-9" title="imgmap201293016112-9" class="imgmap201293016112-area" id="imgmap201293016112-area-9" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,494,456,614" href="" alt="imgmap201293016112-10" title="imgmap201293016112-10" class="imgmap201293016112-area" id="imgmap201293016112-area-10" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="345,935,572,1082" href="" alt="imgmap201293016112-11" title="imgmap201293016112-11" class="imgmap201293016112-area" id="imgmap201293016112-area-11" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="1,617,457,760" href="" alt="imgmap201293016112-12" title="imgmap201293016112-12" class="imgmap201293016112-area" id="imgmap201293016112-area-12" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="345,760,577,847" href="" alt="imgmap201293016112-13" title="imgmap201293016112-13" class="imgmap201293016112-area" id="imgmap201293016112-area-13" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,759,344,906" href="" alt="imgmap201293016112-14" title="imgmap201293016112-14" class="imgmap201293016112-area" id="imgmap201293016112-area-14" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,850,571,935" href="" alt="imgmap201293016112-15" title="imgmap201293016112-15" class="imgmap201293016112-area" id="imgmap201293016112-area-15" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="578,761,915,865" href="" alt="imgmap201293016112-16" title="imgmap201293016112-16" class="imgmap201293016112-area" id="imgmap201293016112-area-16" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1017,226,1085" href="" alt="imgmap201293016112-17" title="imgmap201293016112-17" class="imgmap201293016112-area" id="imgmap201293016112-area-17" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,908,342,1017" href="" alt="imgmap201293016112-18" title="imgmap201293016112-18" class="imgmap201293016112-area" id="imgmap201293016112-area-18" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="229,1010,342,1084" href="" alt="imgmap201293016112-19" title="imgmap201293016112-19" class="imgmap201293016112-area" id="imgmap201293016112-area-19" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1086,340,1206" href="" alt="imgmap201293016112-20" title="imgmap201293016112-20" class="imgmap201293016112-area" id="imgmap201293016112-area-20" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1209,224,1290" href="" alt="imgmap201293016112-21" title="imgmap201293016112-21" class="imgmap201293016112-area" id="imgmap201293016112-area-21" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1290,225,1432" href="" alt="imgmap201293016112-22" title="imgmap201293016112-22" class="imgmap201293016112-area" id="imgmap201293016112-area-22" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="0,1432,340,1517" href="" alt="imgmap201293016112-23" title="imgmap201293016112-23" class="imgmap201293016112-area" id="imgmap201293016112-area-23" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="346,1432,686,1517" href="" alt="imgmap201293016112-24" title="imgmap201293016112-24" class="imgmap201293016112-area" id="imgmap201293016112-area-24" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="461,1266,686,1429" href="" alt="imgmap201293016112-25" title="imgmap201293016112-25" class="imgmap201293016112-area" id="imgmap201293016112-area-25" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,1365,455,1430" href="" alt="imgmap201293016112-26" title="imgmap201293016112-26" class="imgmap201293016112-area" id="imgmap201293016112-area-26" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="231,1291,457,1360" href="" alt="imgmap201293016112-27" title="imgmap201293016112-27" class="imgmap201293016112-area" id="imgmap201293016112-area-27" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="230,1210,342,1289" href="" alt="imgmap201293016112-28" title="imgmap201293016112-28" class="imgmap201293016112-area" id="imgmap201293016112-area-28" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="692,928,916,1016" href="" alt="imgmap201293016112-29" title="imgmap201293016112-29" class="imgmap201293016112-area" id="imgmap201293016112-area-29" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="460,616,916,759" href="" alt="imgmap201293016112-30" title="imgmap201293016112-30" class="imgmap201293016112-area" id="imgmap201293016112-area-30" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="693,1316,917,1518" href="" alt="imgmap201293016112-31" title="imgmap201293016112-31" class="imgmap201293016112-area" id="imgmap201293016112-area-31" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="344,1150,572,1219" href="" alt="imgmap201293016112-32" title="imgmap201293016112-32" class="imgmap201293016112-area" id="imgmap201293016112-area-32" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="693,1015,916,1171" href="" alt="imgmap201293016112-33" title="imgmap201293016112-33" class="imgmap201293016112-area" id="imgmap201293016112-area-33" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="577,955,686,1032" href="" alt="imgmap201293016112-34" title="imgmap201293016112-34" class="imgmap201293016112-area" id="imgmap201293016112-area-34" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="577,1036,687,1101" href="" alt="imgmap201293016112-35" title="imgmap201293016112-35" class="imgmap201293016112-area" id="imgmap201293016112-area-35" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="576,1104,689,1172" href="" alt="imgmap201293016112-36" title="imgmap201293016112-36" class="imgmap201293016112-area" id="imgmap201293016112-area-36" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="691,1232,918,1313" href="" alt="imgmap201293016112-37" title="imgmap201293016112-37" class="imgmap201293016112-area" id="imgmap201293016112-area-37" />
<area shape="rect" onmouseover='myHover(this);' onmouseout='myLeave();' coords="341,1085,573,1151" href="" alt="imgmap201293016112-38" title="imgmap201293016112-38" class="imgmap201293016112-area" id="imgmap201293016112-area-38" />
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="917,868,917,925,688,927,688,955,576,955,574,867,572,864" href="" alt="imgmap201293016112-39" title="imgmap201293016112-39" class="imgmap201293016112-area" id="imgmap201293016112-area-39" />
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="919,1173,917,1231,688,1231,688,1266,574,1267,576,1175,576,1175" href="" alt="imgmap201293016112-40" title="imgmap201293016112-40" class="imgmap201293016112-area" id="imgmap201293016112-area-40" />
<area shape="poly" onmouseover='myHover(this);' onmouseout='myLeave();' coords="572,1222,572,1265,459,1265,458,1289,339,1290,344,1225" href="" alt="imgmap201293016112-41" title="imgmap201293016112-41" class="imgmap201293016112-area" id="imgmap201293016112-area-41" />
</map>
</center>

</body>
</html>

Center element horizontally in visible area in a scroll view

The only solution I came up with is calculate it manually. Here's the code (with React):

const rowRef = useRef<HTMLDivElement>(null);

let scrollLeft: any = null;
let throttleScrollEventActive = false;



function handleScrollEvent(event: any, element: any) {
if (throttleScrollEventActive) return;
window.requestAnimationFrame(function () {
const left = element.getBoundingClientRect().left;
if (scrollLeft != left) {
scrollLeft = left;
setVisibleButtonWidth();
}
throttleScrollEventActive = false;
});
throttleScrollEventActive = true;
}

useEffect(() => {
setVisibleButtonWidth();
const el = rowRef.current;
if (!el) return;
window.addEventListener('scroll', (e) => handleScrollEvent(e, el), true);
return () => {
window.removeEventListener('scroll', (e) => handleScrollEvent(e, el), true);
};
}, [rowRef.current]);

function setVisibleButtonWidth() {
const el = rowRef.current;
if (!el) return;

const parent = el.parentElement;
if (!parent) return;
const clientWidth = parent.clientWidth;
const rect = el.getBoundingClientRect();
const left = rect.left;

const vw = Math.max(document.documentElement.clientWidth || 0, window.innerWidth || 0);
let width = null;

if (rect.left < 0 && rect.right < vw) {
width = rect.right;
} else if (rect.left < 0 && rect.right > vw) {
width = vw;
} else if (left + clientWidth > vw) {
width = vw - left;
}

if (width != null) {
el.style.maxWidth = `${width}px`;
}
}


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