code: function drawImage(canvas, rect, image) {
          if (image && image.content) {
              try {
                  eval(image.content);
              } catch (err) {
                  console.log(err);
              }
          }
      }
docs: Draw image
  @private
  @param {Canvas} canvas
  @param {Rect} rect
  @param {type.UMLImage} image