JavaScript-Load-Image

如何将图片显示为canvas

https://github.com/blueimp/JavaScript-Load-Image/blob/master/js/load-image-scale.js

https://github.com/blueimp/JavaScript-Load-Image/blob/master/js/load-image-scale.js#L106

// Determines if the target image should be a canvas element:
  loadImage.hasCanvasOption = function (options) {
    return options.canvas || options.crop || !!options.aspectRatio
  }