📺 View channels

---

chans

def chans(
    x:ndarray, # Input array
    cmap:str='twilight', # Use matplotlib colormap by this name
    cm_below:str='blue', cm_above:str='red', cm_ninf:str='cyan', cm_pinf:str='fuchsia', cm_nan:str='yellow',
    gutter_px:int=3, # Draw write gutters when tiling the images
    frame_px:int=1, # Draw black frame around each image
    scale:int=1, # Stretch the image. Only itegers please.
    cl:Any=True, view_width:int=966, ax:Optional=None
)->ChanProxy:

Map x values to colors. RGB[A] color is added as channel-last

in_stats = ( (0.485, 0.456, 0.406), (0.229, 0.224, 0.225) )

image = np.load("mysteryman.npy").transpose(1,2,0)
image = ((image * np.array(in_stats[1])) + np.array(in_stats[0])).clip(0, 1)

print(lo(image))
rgb(image)

array[196, 196, 3] n=115248 (0.9Mb) x∈[0., 1.000] μ=0.361 σ=0.248

display(chans(image)) # 3d array is tiled
display(chans(image[:,:,0])) # Works with 2d arrays too

# In R
image[0:32, 32:64,  0] = -1.1 # Below min
image[0:32, 96:128, 0] = 1.1 # Above max
# In G
image[0:32, 64:96,  1] = float("nan")

# In B
image[0:32, 0:32,   2] = float("-inf")
image[0:32, 128:160,2] = float("+inf")

image[0:32, 160:176,1] = 0.
image[0:32, 176:   ,1] = 1.

chans(image, cmap="bwr", cm_below="black", cm_above="white")

lo(np.stack([image]*4))

array[4, 196, 196, 3] n=460992 (3.5Mb) x∈[-1.100, 1.100] μ=0.360 σ=0.298 +Inf! -Inf! NaN!

# 4 images, stacked 2x2
chans(np.stack([image]*4).reshape((2,2,196,196,3)))

one_chan = image[:,:,0] # 1-channel image
chans(one_chan)

try:
    chans(np.array([]).reshape(0,0,0))
except AssertionError as e:
    test_eq(e.args[0], "Expecting non-empty input, got shape=((0, 0, 0, 3))")
else:
    raise AssertionError("Expected AssertionError, but got nothing")