| import numpy as np |
| import math |
| from PIL import Image |
| import torch |
| import copy |
| import string |
| import random |
|
|
|
|
| def align_to(value, alignment): |
| """align hight, width according to alignment |
| |
| Args: |
| value (int): height or width |
| alignment (int): target alignment factor |
| |
| Returns: |
| int: the aligned value |
| """ |
| return int(math.ceil(value / alignment) * alignment) |
|
|
|
|
| def black_image(width, height): |
| """generate a black image |
| |
| Args: |
| width (int): image width |
| height (int): image height |
| |
| Returns: |
| _type_: a black image |
| """ |
| black_image = Image.new("RGB", (width, height), (0, 0, 0)) |
| return black_image |
|
|
|
|
| def get_closest_ratio(height: float, width: float, ratios: list, buckets: list): |
| """get the closest ratio in the buckets |
| |
| Args: |
| height (float): video height |
| width (float): video width |
| ratios (list): video aspect ratio |
| buckets (list): buckets generate by `generate_crop_size_list` |
| |
| Returns: |
| the closest ratio in the buckets and the corresponding ratio |
| """ |
| aspect_ratio = float(height) / float(width) |
| closest_ratio_id = np.abs(ratios - aspect_ratio).argmin() |
| closest_ratio = min(ratios, key=lambda ratio: abs(float(ratio) - aspect_ratio)) |
| return buckets[closest_ratio_id], float(closest_ratio) |
|
|
|
|
| def generate_crop_size_list(base_size=256, patch_size=32, max_ratio=4.0): |
| """generate crop size list |
| |
| Args: |
| base_size (int, optional): the base size for generate bucket. Defaults to 256. |
| patch_size (int, optional): the stride to generate bucket. Defaults to 32. |
| max_ratio (float, optional): th max ratio for h or w based on base_size . Defaults to 4.0. |
| |
| Returns: |
| list: generate crop size list |
| """ |
| num_patches = round((base_size / patch_size) ** 2) |
| assert max_ratio >= 1.0 |
| crop_size_list = [] |
| wp, hp = num_patches, 1 |
| while wp > 0: |
| if max(wp, hp) / min(wp, hp) <= max_ratio: |
| crop_size_list.append((wp * patch_size, hp * patch_size)) |
| if (hp + 1) * wp <= num_patches: |
| hp += 1 |
| else: |
| wp -= 1 |
| return crop_size_list |
|
|
|
|
| def align_floor_to(value, alignment): |
| """align hight, width according to alignment |
| |
| Args: |
| value (int): height or width |
| alignment (int): target alignment factor |
| |
| Returns: |
| int: the aligned value |
| """ |
| return int(math.floor(value / alignment) * alignment) |
|
|
