How to crop uploaded image in html without using plugins?

Question

需要在不使用任何裁剪插件的情况下裁剪上传的图像

Answer 1

you can use canvas :

in html

<canvas id="corpImg" width="578" height="300"></canvas>

in js

<script>
      var canvas = document.getElementById('corpImg');
      var context = canvas.getContext('2d');
      var imageObj = new Image();

      imageObj.onload = function() {
        // draw cropped image
        var sourceX = 150;
        var sourceY = 0;
        var sourceWidth = 150;
        var sourceHeight = 150;
        var destWidth = sourceWidth;
        var destHeight = sourceHeight;
        var destX = canvas.width / 2 - destWidth / 2;
        var destY = canvas.height / 2 - destHeight / 2;

        context.drawImage(imageObj, sourceX, sourceY, sourceWidth, sourceHeight, destX, destY, destWidth, destHeight);
      };
      imageObj.src = 'image url';
    </script>