Generate colors from random color palette in draw_bounding_boxes

🚀 The feature

The current default white color looks bad. Maybe we can generate colors from palette as we do in drawing masks?

Motivation, pitch

It should be simple tweak to _generate_color_palette to pass num_boxes and get a List of RGB values. Instead of List[Tensor]. The fix is simple and that can be passed to get RGB colors.

Alternatives

Users can anyway use color="white" to get white boxes.

Additional context

It’s simple issue and good-first. We can probably wait for some new contributor 😃 to join.

[oke-aditya]

@ABD-01 I spent some time and thought a bit more.

Here is a brief pseudocode (highly untested, written on paper), this can be simplified / optimized as per needs 😃

if colors is None:
   if labels is None:
       # We have no choice to create colors equal to number of boxes
       # gen_colors is  List[Tuple[int, int, int]]

        gen_colors = genereate_color_palette(len(img_boxes))
   else:
      # One way is to generate number of colors equal to number of unique labels.
      # Or alternatively, just generate excess colors and map each label just once.
      gen_colors = generate_color_palette(len(labels)) (or probably even len(img_boxes))
      
     # Since dictionary will have only unique keys.  
      label_color_map = {}
      for label, color in zip(label, gen_colors):
          label_color_map[label] = color

# Now we have color palette we can enumerate over boxes.
for i, bbox in enumerate(img_boxes):
    if colors is None:
        if labels is None:
            # No labels so just use the generated box colors
           color = gen_colors[i]
            # We have labels, so simply make use of label_color_map
        else:
           color = label_color_map[labels[i]]     
   else:
          # Main code continues.

[oke-aditya]

Yes and use the colors the generated from the palette in draw_bounding_boxes. Create colors upto num_labels.

Map each label to a color.

Since labels is a list and generated color palette is also a list. Both have the same length. (As we generated colors equal to num_labels)

Use these colors to draw boxes.