双线性插值放大缩小图像

编写一个通过双线性插值来缩放和缩小图像的计算机程序。(Zooming and Shrinking Images by Bilinear Interpolation
　 (a) Write a computer program capable of zooming and shrinking an image by bilinear interpolation. The input to your program is the desired size of the resulting image in the horizontal and vertical direction. You may ignore aliasing effects.
　 (b) Download Fig. 2.19 and use your program to shrink this image from 1024 x 1024 to 256 x 256 pixels.
　 (c) Use your program to zoom the image in (b) back to 1024 x 1024. Explain the reasons for their differences.)