Base64压缩

2022-05-27 15:01:13 作者：互联网
<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" session="false" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <%@ include file="/WEB-INF/admin/views/watermark.jsp" %>
    <%@ include file="/WEB-INF/admin/views/common/includeHeader.jsp" %>
    <title>图片压缩</title>
</head>


<body>
    <input id="file" type="file"  capture="microphone" accept="image/*"> 
</body>

<script type="text/javascript">
$("#file").change(function(){
var m_this = this;
      cutImageBase64(m_this,null,400,0.8);  
})
function cutImageBase64(m_this,id,wid,quality) {

    var file = m_this.files[0];
    var URL = window.URL || window.webkitURL;
    var blob = URL.createObjectURL(file);
    var base64;
    var quality=0.8;
var img = new Image();
    img.src = blob;
    img.onload = function() {
        var that = this;
        //生成比例
        var w = that.width,
            h = that.height,
            scale = w / h;
            w = wid || w;
            h = w / scale;
//生成canvas
        var canvas = document.createElement('canvas');
        var ctx = canvas.getContext('2d');
        $(canvas).attr({
            width: w,
            height: h
        });
        ctx.drawImage(that, 0, 0, w, h);
    var size=file.size/1024;
    // 如想确保图片压缩到自己想要的尺寸,如要求在50-150kb之间，请加以下语句，quality初始值根据情况自定
				 while (size > 64) {
				 	quality -= 0.1;
				 	size=canvas.toDataURL('image/jpeg', quality);
				 }
				// 防止最后一次压缩低于最低尺寸，只要quality递减合理，无需考虑
				 while (size < 12) {
				 	quality += 0.1;
				 	size=canvas.toDataURL('image/jpeg', quality);
				 }

        // 生成base64            
        base64 = canvas.toDataURL('image/jpeg', quality);
        console.log(base64)
        console.log(base64.length/1024)
        console.log(file.size/1024)
    };
}
</script>
</html>
标签：canvas,base64,压缩,Base64,file,var,quality,size
来源： https://www.cnblogs.com/whtjyt/p/16317668.html