PIL shows two identical arrays as different images-CodePudding

I am creating a function to "color" matrices given the indices to be colored.

Simplified example: I have a 2x2 matrix made of 0s and I want to "color" the 2nd and 4th element in the matrix with 1s. The output will be:

[[0,1]
 [0,1]]

Now, here's the code I have (trying to color in white all odd elements of the matrix):

def createMatrix(w, h, bg, value, seq):
    data = np.full((h, w, 3), bg, dtype=uint8)
    rows = (seq-1)//w
    cols = (seq-1)%w
    if rows.size and cols.size:
        data[rows,cols] = value
    return data
data = createMatrix(w=4, h=4, bg=0, value=255, seq=array([1,3,5,7,9,11,13,15]))
Image.fromarray(data, 'RGB').resize((1024, 1024), Image.BOX).show()

This code works just fine, but it only allows me to use colors where the values for Red, Green and Blue are the same. I was then trying to generalize the function like this:

def createMatrix1(w, h, bg, value, seq):
    data = np.tile(bg, (h, w, 1))
    rows = (seq-1)//w
    cols = (seq-1)%w
    if rows.size and cols.size:
        data[rows,cols] = value
    return data

But for some reason this code returns two very different results:

data = createMatrix(w=4, h=4, bg=0, value=255, seq=array([1,3,5,7,9,11,13,15]))
data1 = createMatrix1(w=4, h=4, bg=(0,0,0), value=(255,255,255), seq=array([1,3,5,7,9,11,13,15]))
if np.array_equal(data, data1): print('The matrices are identical')
Image.fromarray(data, 'RGB').resize((1024, 1024), Image.BOX).show()
Image.fromarray(data1, 'RGB').resize((1024, 1024), Image.BOX).show()

Even though data and data1 are identical. What's going on?

CodePudding user response：

They are different data types, even if they evaluate to true.

data.dtype
dtype('unit8')

data1.dtype
dtype('int32')

You can convert it and the image will become a color image.

data = data.astype('int32')

or modify the function to use int32