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mayan-edms/apps/converter/backends/python/base.py

94 lines
3.5 KiB
Python

import slate
from PIL import Image
from django.utils.translation import ugettext_lazy as _
from converter.literals import QUALITY_DEFAULT, QUALITY_SETTINGS
from converter.exceptions import ConvertError, UnknownFormat, IdentifyError
from converter.backends import ConverterBase
from converter.literals import TRANSFORMATION_RESIZE, \
TRANSFORMATION_ROTATE, TRANSFORMATION_ZOOM
from converter.literals import QUALITY_DEFAULT, DEFAULT_PAGE_NUMBER, \
DEFAULT_FILE_FORMAT
from converter.utils import get_mimetype
class ConverterClass(ConverterBase):
def get_page_count(self, input_filepath):
page_count = 1
mimetype, encoding = get_mimetype(input_filepath)
if mimetype == 'application/pdf':
# If file is a PDF open it with slate to determine the page
# count
with open(input_filepath) as fd:
pages = slate.PDF(fd)
return len(pages)
try:
im = Image.open(input_filepath)
except IOError: #cannot identify image file
# Return a page count of 1, to atleast allow the document
# to be created
return 1
try:
while 1:
im.seek(im.tell()+1)
page_count += 1
# do something to im
except EOFError:
pass # end of sequence
return page_count
def convert_file(self, input_filepath, output_filepath, transformations=None, quality=QUALITY_DEFAULT, page=DEFAULT_PAGE_NUMBER, file_format=DEFAULT_FILE_FORMAT):
try:
im = Image.open(input_filepath)
except Exception: # Python Imaging Library doesn't recognize it as an image
raise UnknownFormat
current_page = 0
try:
while current_page == page - 1:
im.seek(im.tell() + 1)
current_page += 1
# do something to im
except EOFError:
pass # end of sequence
if transformations:
for transformation in transformations:
aspect = 1.0 * im.size[1] / im.size[0]
if transformation['transformation'] == TRANSFORMATION_RESIZE:
width = int(transformation['arguments']['width'])
height = int(transformation['arguments'].get('height', 1.0 * width * aspect))
im = im.resize((width, height), Image.ANTIALIAS)
elif transformation['transformation'] == TRANSFORMATION_ZOOM:
decimal_value = float(transformation['arguments']['percent']) / 100
im = im.transform((im.size[0] * decimal_value, im.size[1] * decimal_value), Image.EXTENT, (0, 0, im.size[0], im.size[1]))
elif transformation['transformation'] == TRANSFORMATION_ROTATE:
# PIL counter degress counter-clockwise, reverse them
im = im.rotate(360 - transformation['arguments']['degrees'])
if im.mode not in ('L', 'RGB'):
im = im.convert('RGB')
im.save(output_filepath, format=file_format)
def get_format_list(self):
"""
Introspect PIL's internal registry to obtain a list of the
supported file types
"""
formats = []
for format_name in Image.ID:
formats.append((format_name, u''))
return formats
def get_available_transformations(self):
return [
TRANSFORMATION_RESIZE, TRANSFORMATION_ROTATE, \
TRANSFORMATION_ZOOM
]