邻近法与两次线性法

PY

from PIL import Image
img=Image.open("1.png")
#邻近法
def near(img):
    width=img.size[0]
    height=img.size[1]
    newim=Image.new("RGB",(2*width,2*height),(0,0,0))
    for j in range(height*2):
        ory=int(j/2)
        for i in range(width*2):
            orx=int(i/2)
            orpixel=img.getpixel((orx,ory))
            newim.putpixel((i,j),orpixel)
    newim.save('near.png')
#双线性
def biline(img):
    width=img.size[0]
    height=img.size[1]
    newim=Image.new("RGB",(2*width,2*height),(0,0,0))
    #求中点
    ori_mw=(width-1)/2
    ori_mh=(height-1)/2
    cur_mw=(width*2-1)/2
    cur_mh=(height*2-1)/2
    #先坐标变换，再找临近四个基准点,第j列(y)，第i行(x)
    for j in range(height*2):
        ref_y=ori_mh-(ori_mh*(cur_mh-j))/cur_mh
        for i in range(width*2):
            ref_x=ori_mw-(ori_mw*(cur_mw-i))/cur_mw
            y1=int(ref_y)
            y2=y1+1
            x1=int(ref_x)
            x2=x1+1
            #得到当前点的pixel属性,rgb
            pixel=[]
            for k in range(3):
                if x2>width-1:
                    x2=width-1
                    x1-=1
                if y2>height-1:
                    y2=height-1
                    y1-=1
                pixel.append(int(img.getpixel((x1,y1))[k]*(x2-ref_x)*(y2-ref_y)+img.getpixel((x2,y1))[k]*(ref_x-x1)*(y2-ref_y)+img.getpixel((x1,y2))[k]*(x2-ref_x)*(ref_y-y1)+img.getpixel((x2,y2))[k]*(ref_x-x1)*(ref_y-y1)))
            pixel.append(255)
            newim.putpixel((i,j),tuple(pixel))
    newim.save('line.png')