db68897e78
- Move thumbnailing code into separate module - Port GdkPixbuf thumbnailer to gtk3 - Make GdkPixbuf thumbnailer more efficient - Better exception logging - Some code reformatting
91 lines
3.8 KiB
Python
91 lines
3.8 KiB
Python
from gi.repository import GdkPixbuf
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import base64
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from io import BytesIO
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import os
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import sys
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import logging
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from urllib.parse import quote as urlquote
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try:
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from PIL import Image
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pil_available = True
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except:
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pil_available = False
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log = logging.getLogger('gajim.plugin_system.httpupload.thumbnail')
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def scale_down_to(pixbuf, size):
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# Creates a pixbuf that fits in the specified square of sizexsize
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# while preserving the aspect ratio
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# Returns scaled_pixbuf
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image_width = pixbuf.get_width()
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image_height = pixbuf.get_height()
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if image_width > image_height:
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if image_width > size:
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image_height = int(size / float(image_width) * image_height)
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image_width = int(size)
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else:
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if image_height > size:
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image_width = int(size / float(image_height) * image_width)
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image_height = int(size)
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crop_pixbuf = pixbuf.scale_simple(image_width, image_height, GdkPixbuf.InterpType.BILINEAR)
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return crop_pixbuf
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max_thumbnail_size = 2048
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max_thumbnail_dimension = 160
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base64_size_factor = 4/3
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def thumbnail(path_to_file):
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"""
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Generates a JPEG thumbnail and base64-encodes, ensuring that the encoded
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size is less than max_thumbnail_size bytes. If this is not possible, returns
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None.
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"""
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thumb = None
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quality_steps = (100, 80, 60, 50, 40, 35, 30, 25, 23, 20, 18, 15, 13, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1)
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# If the whole file is small enough, we'll just use that as a thumbnail
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# without downsampling.
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if os.path.getsize(path_to_file) * base64_size_factor < max_thumbnail_size:
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with open(path_to_file, 'rb') as content_file:
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thumb = urlquote(base64.standard_b64encode(content_file.read()), '')
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log.info("Image small enough (%d bytes), not resampling" % len(thumb))
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return thumb
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elif pil_available:
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log.info("PIL available, using it for image downsampling")
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try:
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for quality in quality_steps:
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thumb = Image.open(path_to_file)
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thumb.thumbnail((max_thumbnail_dimension, max_thumbnail_dimension), Image.ANTIALIAS)
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output = BytesIO()
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thumb.save(output, format='JPEG', quality=quality, optimize=True)
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thumb = output.getvalue()
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output.close()
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thumb = urlquote(base64.standard_b64encode(thumb), '')
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log.debug("pil thumbnail jpeg quality %d produces an image of size %d...", quality, len(thumb))
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if len(thumb) < max_thumbnail_size:
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log.debug("Size is acceptable.")
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return thumb
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except:
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log.info("Exception occurred during PIL downsampling", exc_info=sys.exc_info())
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thumb = None
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# If we haven't returned by now we couldn't use PIL for one reason or
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# another, so let's pass on to GdkPixbuf
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log.info("using GdkPixBuf for image downsampling")
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temp_file = None
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try:
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pixbuf = GdkPixbuf.Pixbuf.new_from_file(path_to_file)
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scaled_pb = scale_down_to(pixbuf, max_thumbnail_dimension)
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for quality in quality_steps:
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success, thumb_raw = scaled_pb.save_to_bufferv("jpeg", ["quality"], [str(quality)])
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log.debug("gdkpixbuf thumbnail jpeg quality %d produces an image of size %d...",
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quality,
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len(thumb_raw) * base64_size_factor)
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if len(thumb_raw) * base64_size_factor < max_thumbnail_size:
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log.debug("Size is acceptable.")
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return urlquote(base64.standard_b64encode(thumb_raw))
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except:
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log.info("Exception occurred during GdkPixbuf downsampling, not providing thumbnail", exc_info=sys.exc_info())
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return None
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log.info("No acceptably small thumbnail was generated.")
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