wagtail/wagtail/wagtailimages/utils/crop.py

121 lines
3.6 KiB
Python

from __future__ import division
from wagtail.wagtailimages.utils.focal_point import FocalPoint
class CropBox(object):
def __init__(self, left, top, right, bottom):
self.left = int(left)
self.top = int(top)
self.right = int(right)
self.bottom = int(bottom)
def __getitem__(self, key):
return (self.left, self.top, self.right, self.bottom)[key]
@property
def width(self):
return self.right - self.left
@property
def height(self):
return self.bottom - self.top
@property
def size(self):
return self.width, self.height
def as_tuple(self):
return self.left, self.top, self.right, self.bottom
def __eq__(self, other):
return self.as_tuple() == other.as_tuple()
def __ne__(self, other):
return not (self == other)
def __repr__(self):
return 'CropBox(left: %d, top: %d, right: %d, bottom: %d)' % (
self.left, self.top, self.right, self.bottom
)
def crop_to_centre(image_size, crop_size):
(original_width, original_height) = image_size
(crop_width, crop_height) = crop_size
# final dimensions should not exceed original dimensions
final_width = min(original_width, crop_width)
final_height = min(original_height, crop_height)
left = (original_width - final_width) / 2
top = (original_height - final_height) / 2
return CropBox(left, top, left + final_width, top + final_height)
def crop_to_point(image_size, crop_size, focal_point):
(original_width, original_height) = image_size
(crop_width, crop_height) = crop_size
if not focal_point:
focal_point = FocalPoint(original_width / 2, original_height / 2)
# Make sure that the crop size is no smaller than the focal point
crop_width = max(crop_width, focal_point.width)
crop_height = max(crop_height, focal_point.height)
# Make sure final dimensions do not exceed original dimensions
final_width = min(original_width, crop_width)
final_height = min(original_height, crop_height)
# Get UV for focal point
focal_point_u = focal_point.x / original_width
focal_point_v = focal_point.y / original_height
# Get crop box
left = focal_point.x - focal_point_u * final_width
top = focal_point.y - focal_point_v * final_height
right = focal_point.x - focal_point_u * final_width + final_width
bottom = focal_point.y - focal_point_v * final_height + final_height
# Make sure the entire focal point is in the crop box
focal_point_left = focal_point.x - focal_point.width / 2
focal_point_top = focal_point.y - focal_point.height / 2
focal_point_right = focal_point.x + focal_point.width / 2
focal_point_bottom = focal_point.y + focal_point.height / 2
if left > focal_point_left:
right -= left - focal_point_left
left = focal_point_left
if top > focal_point_top:
bottom -= top - focal_point_top
top = focal_point_top
if right < focal_point_right:
left += focal_point_right - right;
right = focal_point_right
if bottom < focal_point_bottom:
top += focal_point_bottom - bottom;
bottom = focal_point_bottom
# Don't allow the crop box to go over the image boundary
if left < 0:
right -= left
left = 0
if top < 0:
bottom -= top
top = 0
if right > original_width:
left -= right - original_width
right = original_width
if bottom > original_height:
top -= bottom - original_height
bottom = original_height
return CropBox(left, top, right, bottom)