问题
I'm trying to get an image zoomed in & out by two zoom buttons (+) & (-). The problem is that "zooming in" stops when the image is full screen size (width 100%). I need to zoom the image much bigger than the screen size. Just can't figure it out how to o that. I'm beginner with Javascript so I hope someone have motivation to help me this little Javascript problem.
I wonder is there any simple zoom in/out/reset plugins that works with zoom buttons? Image grab would be more than cool also.
Thanks again!
function zoomin(){
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
if(currWidth == 2500) return false;
else{
myImg.style.width = (currWidth + 100) + "px";
}
}
function zoomout(){
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
if(currWidth == 100) return false;
else{
myImg.style.width = (currWidth - 100) + "px";
}
}
*body {
margin: 0;
}
#navbar {
overflow: hidden;
background-color: #099;
position: fixed;
top: 0;
width: 100%;
padding-top: 3px;
padding-bottom: 3px;
padding-left: 20px;
}
#navbar a {
float: left;
display: block;
color: #666;
text-align: center;
padding-right: 20px;
text-decoration: none;
font-size: 17px;
}
#navbar a:hover {
background-color: #ddd;
color: black;
}
#navbar a.active {
background-color: #4CAF50;
color: white;
}
.main {
padding: 16px;
margin-top: 30px;
}
.main img {
max-width: 100%;
height: auto;
}
.button {
width: 300px;
height: 60px;
}
</head>
<body>
<div id="navbar">
<button type="button" onclick="zoomin()"> Zoom In</button>
<button type="button" onclick="zoomout()"> Zoom Out</button>
</div>
<div class="main">
<img id="map" src="http://www.worldatlas.com/webimage/countrys/europelargesm.jpg" />
</div>
" />
回答1:
As the previous answers stated your code is absolutely fine with the exception of, you have limited the max-width of your image with max-width: 100%
. If you remove that, it will give you the desired output.
function zoomin() {
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
if (currWidth == 2500) return false;
else {
myImg.style.width = (currWidth + 100) + "px";
}
}
function zoomout() {
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
if (currWidth == 100) return false;
else {
myImg.style.width = (currWidth - 100) + "px";
}
}
*body {
margin: 0;
}
#navbar {
overflow: hidden;
background-color: #099;
position: fixed;
top: 0;
width: 100%;
padding-top: 3px;
padding-bottom: 3px;
padding-left: 20px;
}
#navbar a {
float: left;
display: block;
color: #666;
text-align: center;
padding-right: 20px;
text-decoration: none;
font-size: 17px;
}
#navbar a:hover {
background-color: #ddd;
color: black;
}
#navbar a.active {
background-color: #4CAF50;
color: white;
}
.main {
padding: 16px;
margin-top: 30px;
width: 100%;
height: 100vh;
overflow: auto;
cursor: grab;
cursor: -o-grab;
cursor: -moz-grab;
cursor: -webkit-grab;
}
.main img {
height: auto;
width: 100%;
}
.button {
width: 300px;
height: 60px;
}
<script type="text/javascript" src="https://cdn.rawgit.com/asvd/dragscroll/master/dragscroll.js"></script>
<body>
<div id="navbar">
<button type="button" onclick="zoomin()"> Zoom In</button>
<button type="button" onclick="zoomout()"> Zoom Out</button>
</div>
<div class="main dragscroll">
<img id="map" src="http://www.worldatlas.com/webimage/countrys/europelargesm.jpg" />
</div>
Edits:
- Since you wanted the initial width to be 100% (full size), instead of max-width, just set width to 100% like done in the last edit.
- For implementing the drag feature to scroll the image, another CSS class has been added to the
main
container called dragscroll and it's js is imported as needed.
回答2:
Remove max-width: 100%; from .main img css
回答3:
Your zoom method is working good just remove the css max width, and change your js validation to allow the image, get bigger.
function zoomin(){
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
//if(currWidth == 2500) return false;
// else{
// myImg.style.width = (currWidth + 100) + "px";
//}
myImg.style.width = (currWidth + 100) + "px";
}
function zoomout(){
var myImg = document.getElementById("map");
var currWidth = myImg.clientWidth;
if(currWidth == 100) return false;
else{
myImg.style.width = (currWidth - 100) + "px";
}
}
*body {
margin: 0;
}
#navbar {
overflow: hidden;
background-color: #099;
position: fixed;
top: 0;
width: 100%;
padding-top: 3px;
padding-bottom: 3px;
padding-left: 20px;
}
#navbar a {
float: left;
display: block;
color: #666;
text-align: center;
padding-right: 20px;
text-decoration: none;
font-size: 17px;
}
#navbar a:hover {
background-color: #ddd;
color: black;
}
#navbar a.active {
background-color: #4CAF50;
color: white;
}
.main {
padding: 16px;
margin-top: 30px;
}
.main img {
/* max-width: 100%; */
height: auto;
}
.button {
width: 300px;
height: 60px;
}
</head>
<body>
<div id="navbar">
<button type="button" onclick="zoomin()"> Zoom In</button>
<button type="button" onclick="zoomout()"> Zoom Out</button>
</div>
<div class="main">
<img id="map" src="http://www.worldatlas.com/webimage/countrys/europelargesm.jpg" />
</div>
On the other hand I would recommend magic zoom as a zoom library
来源:https://stackoverflow.com/questions/47635341/zooming-in-out-an-image-by-clicking-zoom-buttons-javascript