1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889 |
- # -*- coding: utf-8 -*-
- # Copyright 2014 OpenMarket Ltd
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
- import PIL.Image as Image
- from io import BytesIO
- class Thumbnailer(object):
- FORMATS = {
- "image/jpeg": "JPEG",
- "image/png": "PNG",
- }
- def __init__(self, input_path):
- self.image = Image.open(input_path)
- self.width, self.height = self.image.size
- def aspect(self, max_width, max_height):
- """Calculate the largest size that preserves aspect ratio which
- fits within the given rectangle::
- (w_in / h_in) = (w_out / h_out)
- w_out = min(w_max, h_max * (w_in / h_in))
- h_out = min(h_max, w_max * (h_in / w_in))
- Args:
- max_width: The largest possible width.
- max_height: The larget possible height.
- """
- if max_width * self.height < max_height * self.width:
- return (max_width, (max_width * self.height) // self.width)
- else:
- return ((max_height * self.width) // self.height, max_height)
- def scale(self, output_path, width, height, output_type):
- """Rescales the image to the given dimensions"""
- scaled = self.image.resize((width, height), Image.BILINEAR)
- return self.save_image(scaled, output_type, output_path)
- def crop(self, output_path, width, height, output_type):
- """Rescales and crops the image to the given dimensions preserving
- aspect::
- (w_in / h_in) = (w_scaled / h_scaled)
- w_scaled = max(w_out, h_out * (w_in / h_in))
- h_scaled = max(h_out, w_out * (h_in / w_in))
- Args:
- max_width: The largest possible width.
- max_height: The larget possible height.
- """
- if width * self.height > height * self.width:
- scaled_height = (width * self.height) // self.width
- scaled_image = self.image.resize(
- (width, scaled_height), Image.BILINEAR
- )
- crop_top = (scaled_height - height) // 2
- crop_bottom = height + crop_top
- cropped = scaled_image.crop((0, crop_top, width, crop_bottom))
- else:
- scaled_width = (height * self.width) // self.height
- scaled_image = self.image.resize(
- (scaled_width, height), Image.BILINEAR
- )
- crop_left = (scaled_width - width) // 2
- crop_right = width + crop_left
- cropped = scaled_image.crop((crop_left, 0, crop_right, height))
- return self.save_image(cropped, output_type, output_path)
- def save_image(self, output_image, output_type, output_path):
- output_bytes_io = BytesIO()
- output_image.save(output_bytes_io, self.FORMATS[output_type])
- output_bytes = output_bytes_io.getvalue()
- with open(output_path, "wb") as output_file:
- output_file.write(output_bytes)
- return len(output_bytes)
|