Jython (JES) - 90度旋转功能

Question

我需要写一个函数spin(pic，x)，它将拍摄一张照片，并将其逆时针旋转90度X次。我在一个函数中只有90度顺时针旋转：

def rotate(pic):
    width = getWidth(pic)
    height = getHeight(pic)
    new = makeEmptyPicture(height,width)
    tarX = 0
    for x in range(0,width):
        tarY = 0
        for y in range(0,height):
            p = getPixel(pic,x,y)
            color = getColor(p)
            setColor(getPixel(new,tarY,width-tarX-1),color)
            tarY = tarY + 1
        tarX = tarX +1
    show(new)
    return new

。。但是我不知道如何去写一个旋转X次的函数。有人知道我是怎么做到的吗？

Answer 1

您可以多次调用rotate() X：

def spin(pic, x):
    new_pic = duplicatePicture(pic)
    for i in range(x):
         new_pic = rotate(new_pic)
    return new_pic


a_file = pickAFile()
a_pic = makePicture(a_file)
show(spin(a_pic, 3))

但这显然不是最优化的方法，因为您将计算X图像，而不是您感兴趣的图像。我建议您首先尝试一个基本的switch...case方法(即使这个语句在Python中不存在;)：

xx = (x % 4)     # Just in case you want (x=7) to rotate 3 times...

if (xx == 1):
    new = makeEmptyPicture(height,width)
    tarX = 0
    for x in range(0,width):
        tarY = 0
        for y in range(0,height):
            p = getPixel(pic,x,y)
            color = getColor(p)
            setColor(getPixel(new,tarY,width-tarX-1),color)
            tarY = tarY + 1
        tarX = tarX +1
    return new
elif (xx == 2):
    new = makeEmptyPicture(height,width)
    # Do it yourself...
    return new
elif (xx == 3):
    new = makeEmptyPicture(height,width)
    # Do it yourself...
    return new
else:
    return pic

然后，您可能会看到一种将这些案例合并到单个(但更复杂)double for loop中的方法……玩得开心..。