Javascript 使用canvas压缩图片

来源：互联网发布：夏季联赛数据编辑：程序博客网时间：2024/05/16 03:44

<input class="upload-input" type="file" capture="camera" accept="image/*" id="cameraInput0" name="cameraInput" /><img id="resultImage" src="" alt=""/><canvas id="canvas0""></canvas>

img.onchage = function(files){  files=files.files;        for (var i = 0; i < files.length; i++) {            var file = files[i];            var reader = new FileReader();            reader.onload = function (e) {                var reImg = document.getElementById("resultImage");                reImg.src = this.result;                var quality =  50;                var imgCom = compress(reImg,quality);                reImg.src = imgCom.src;        };      reader.readAsDataURL(file);    }}

function compress(source_img_obj, quality, output_format){        var mime_type = "image/jpeg";         if(output_format!=undefined && output_format=="png"){            mime_type = "image/png";         }         var cvs = document.createElement('canvas');         //naturalWidth真实图片的宽度         cvs.width = source_img_obj.naturalWidth;         cvs.height = source_img_obj.naturalHeight;         var ctx = cvs.getContext("2d");//           ctx.drawImage(source_img_obj, 0, 0);         var newImageData = cvs.toDataURL(mime_type, quality/100);         var result_image_obj = new Image();         result_image_obj.src = newImageData;         return result_image_obj;    }

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