This time I will bring you JS to realize the picture Magnifying glass effectUse cases, what are the Notes for JS to realize the picture magnifying glass effect, the following is a practical case, let's take a look.
Preface
We all often visit various e-commerce websites, and the details of the products require the use of a magnifying glass. This must be familiar to everyone. Today we will make a picture magnifying glass plug-in to see how the picture is enlarged...
Let’s first take a look at what the final effect will be if we achieve it
After reading the effect, do you have any ideas? If not, let’s take a look at how to achieve it~
1 Implementation ideas
① To achieve the effect of zooming in after pointing up, you need to make three ps, one is used to place the original image, the other is used to place the p for the enlargement effect, and the last one is the part of p that needs to be enlarged after the mouse is pointed up (we use this p p tag instead).
② Determine the magnification ratio. The most important point is that the p on the mouse finger and the p of the magnification effect should be equal to the ratio of the original image and the enlarged image.
③ Display the magnification effect after pointing the mouse over.
2 Specific implementation steps
First, let’s build three p’s.
<p id="wrapper"> <!--小图--> <p id="img_min"> <!--图片--> <img src="img/11.png" alt="min"> <!--跟随鼠标的白块--> <p id="mousebg"></p> </p> <!--大图--> <p id="img_max"> <img id="img2_img" src="img/11.png" alt="max"> </p> </p>
Our HTML code part has been completed. Next, we use JS to implement the function:
Add three events to the original image, namely, mouse entry, mouse movement, and mouse movement out.
When the mouse is moved into the original image, the p when the mouse is pointing up and the p of the magnification effect are displayed at the same time.
img1.onmouseover = function () { //鼠标进入 img2.style.display = 'block'; mousebg.style.display = 'block'; }
Mouse out event:
img1.onmouseout = function () { //鼠标离开 img2.style.display = 'none'; mousebg.style.display = 'none'; }
The point is that when the mouse moves, the part of the large image that needs to be enlarged is displayed based on the position of the p tag and the original image.
var _event = event||window.event;//兼容性处理 var mouseX = _event.clientX - img1.offsetLeft; //计算鼠标相对与小图的位置 var mouseY = _event.clientY - img1.offsetTop;
When doing location analysis, four critical situations need to be considered:
That is, when the mouse just enters from the top, bottom, left or right of the picture, and the distance is less than half the width of the p on the mouse finger, the magnified p is displayed and does not move.
//特殊情况处理,分别靠近四条边的时候 if(mouseX<mousebg.offsetWidth/2){ mouseX = mousebg.offsetWidth/2; } if(mouseX>img1.offsetWidth-mousebg.offsetWidth/2){ mouseX = img1.offsetWidth-mousebg.offsetWidth/2; } if(mouseY<mousebg.offsetHeight/2){ mouseY = mousebg.offsetHeight/2; } if(mouseY>img1.offsetHeight-mousebg.offsetHeight/2){ mouseY = img1.offsetHeight-mousebg.offsetHeight/2; }
Finally, calculate the display range of the large image:
//计算大图的显示范围 img2_img.style.left = -mul*mouseX+img2.offsetWidth/2+"px"; img2_img.style.top = -mul*mouseY+img2.offsetHeight/2+"px"; //使鼠标在白块的中间 mousebg.style.left = mouseX-mousebg.offsetWidth/2+"px"; mousebg.style.top = mouseY-mousebg.offsetHeight/2+"px";
In this way, we have completed the plug-in for implementing the picture magnifying glass using JS.
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!
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