python - Mathematica 到 Python/C 代码

Question

我试图理解 Mathematica 中的一些代码，但不熟悉它的语法。我似乎无法理解这里的逻辑。

anamorph3[img_, angle_: 270 Degree, imgWidth_: 512] :=
Module[{data, f, matrix, dim, rOuter, rInner = 1.},
dim = ImageDimensions[img];
rOuter = rInner (1 + angle #2/#1 & @@ dim);
data = Table[
ListInterpolation[#[[All, All, i]], 
{{rOuter, rInner}, {-angle/2, angle/2}}], {i, 3}] &@ImageData[img];
f[i_, j_] := If[Abs[j] <= angle/2 && rInner <= i <= rOuter, 
Through[data[i, j]], {1., 1., 1.}];
Image@Table[f[Sqrt[i^2 + j^2], ArcTan[i, -j]], 
{i, -rOuter, rOuter, 2 rOuter/(imgWidth - 1)},
{j, -rOuter, rOuter, 2 rOuter/(imgWidth - 1)}]]

有关此代码的更多详细信息可以在此处找到

How to make ImageTransformation produce an anamorphic version of image .

如果有人可以为此编写伪代码/Python 代码，那就太好了。

Answer 1

我想最终会是这样的:

def anamorph3(img, angle = math.radians(270), imgWidth = 512):
    rInner = 1.
    dim = ImageDimensions(img)
    rOuter = rInner * (1 + angle * dim[2]/dim[1])
    data = list()
    for i in range(3):
        channelData = [[x[i] for x in v] for v in ImageData(img)]
        data.append(ListInterpolate(channelData, [[rOuter, rInner],[-angle/2,angle/2]]))
    def f(i, j):
        if abs(j) <= angle/2 && rInner <= i <= rOuter:
            l = list()
            for fun in data:
                l.append(fun(i, j))
            return l
        else:
            return [1, 1, 1]
    newImageData = list()
    for i in range(-rOuter, rOuter, 2*rOuter/(imgWidth-1)):
        l = list()
        for j in range(-rOuter, rOuter, 2*rOuter/(imgWidth-1)):
            l.append(f(math.sqrt(i**2 + j**2), math.atan(i, -j)))
        newImageData.append(l)
    return Image(newImageData) 

这里 ImageDimensions 返回图像的尺寸，ImageData 返回一个 3D 矩阵，其中每个像素的每个颜色 channel 的颜色数据标准化为 0-1 范围， ListInterpolate 创建一个在指定 x 和 y 坐标范围内的一组数字之间进行插值的函数。 Image 采用 3D 矩阵并将其转换为 RGB 图像。