UIImageview 拉伸

The X and Y values seem to be the positions for the stretch starting point, relative to the entire width and height of the image, i.e. 0.5 would mean a point in the middle of the image.

翻译：X和Y值是拉伸开始的点的位置，是相对于图像的整个宽和高的，如0.5就意味着图片的中间点。

Same thing for the Width and Height: sizes for the stretchable area, relative to the image size, i.e. setting it to a value of 1 / imageWidth would mean the stretchable area is 1 pixel wide. The strange thing is 0 also work fine for the blue pill button (could
be for convenience reasons?).

翻译：同样的，对于宽和高：拉伸区域的尺寸，是相对于图片的尺寸的，如设置为1/imageWidth意味着拉伸区域为1像素宽。奇怪的是，0对于蓝色水晶按钮也可以起效。