code: function captureShape(container) {
  		// SVG had width as object
  		if (!width || typeof width !== 'number') width = container && container.shape && container.shape[0] || container.width || container.w || container.drawingBufferWidth
  		if (!height || typeof height !== 'number') height = container && container.shape && container.shape[1] || container.height || container.h || container.drawingBufferHeight
  	}
docs: try to figure out width/height from container