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kcc/kindlecomicconverter/inter_panel_crop_alg.py
2025-10-21 20:41:18 -07:00

79 lines
2.9 KiB
Python

from PIL import Image, ImageFilter, ImageOps, ImageFile
import numpy as np
from typing import Literal
from .common_crop import threshold_from_power, group_close_values
ImageFile.LOAD_TRUNCATED_IMAGES = True
'''
Crops inter-panel empty spaces (ignores empty spaces near borders - for that use crop margins).
Parameters:
img (PIL image): A PIL image.
direction (horizontal or vertical or both): To crop rows (horizontal), cols (vertical) or both.
keep (float): Distance to keep between panels after cropping (in percentage relative to the original distance).
background_color (string): 'white' for white background, anything else for black.
Returns:
img (PIL image): A PIL image after cropping empty sections.
'''
def crop_empty_inter_panel(img, direction: Literal["horizontal", "vertical", "both"], keep=0.04, background_color='white'):
img_temp = img
if img.mode != 'L':
img_temp = ImageOps.grayscale(img_temp)
if background_color != 'white':
img_temp = ImageOps.invert(img_temp)
img_mat = np.array(img)
power = 1
img_temp = ImageOps.autocontrast(img_temp, 1).filter(ImageFilter.BoxBlur(1))
img_temp = img_temp.point(lambda p: 255 if p <= threshold_from_power(power) else 0)
if direction in ["horizontal", "both"]:
rows_idx_to_remove = empty_sections(img_temp, keep, horizontal=True)
img_mat = np.delete(img_mat, rows_idx_to_remove, 0)
if direction in ["vertical", "both"]:
cols_idx_to_remove = empty_sections(img_temp, keep, horizontal=False)
img_mat = np.delete(img_mat, cols_idx_to_remove, 1)
return Image.fromarray(img_mat)
'''
Finds empty sections (excluding near borders).
Parameters:
img (PIL image): A PIL image.
keep (float): Distance to keep between panels after cropping (in percentage relative to the original distance).
horizontal (boolean): True to find empty rows, False to find empty columns.
Returns:
Itertable (list or NumPy array): indices of rows or columns to remove.
'''
def empty_sections(img, keep, horizontal=True):
axis = 1 if horizontal else 0
img_mat = np.array(img)
img_mat_max = np.max(img_mat, axis=axis)
img_mat_empty_idx = np.where(img_mat_max == 0)[0]
empty_sections = group_close_values(img_mat_empty_idx, 1)
sections_to_remove = []
for section in empty_sections:
if section[1] < img.size[1] * 0.99 and section[0] > img.size[1] * 0.01: # if not near borders
sections_to_remove.append(section)
if len(sections_to_remove) != 0:
sections_to_remove_after_keep = [(int(x1+(keep/2)*(x2-x1)), int(x2-(keep/2)*(x2-x1))) for x1,x2 in sections_to_remove]
idx_to_remove = np.concatenate([np.arange(x1, x2) for x1,x2 in sections_to_remove_after_keep])
return idx_to_remove
return []