mirror of
https://github.com/bookwyrm-social/bookwyrm.git
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519 lines
16 KiB
Python
519 lines
16 KiB
Python
""" Generate social media preview images for twitter/mastodon/etc """
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import math
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import os
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import textwrap
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from io import BytesIO
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from uuid import uuid4
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import logging
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import colorsys
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from colorthief import ColorThief
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from PIL import Image, ImageDraw, ImageFont, ImageOps, ImageColor
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from django.core.files.base import ContentFile
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from django.core.files.uploadedfile import InMemoryUploadedFile
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from django.core.files.storage import default_storage
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from django.db.models import Avg
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from bookwyrm import models, settings
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from bookwyrm.tasks import app, LOW
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logger = logging.getLogger(__name__)
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IMG_WIDTH = settings.PREVIEW_IMG_WIDTH
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IMG_HEIGHT = settings.PREVIEW_IMG_HEIGHT
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BG_COLOR = settings.PREVIEW_BG_COLOR
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TEXT_COLOR = settings.PREVIEW_TEXT_COLOR
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DEFAULT_COVER_COLOR = settings.PREVIEW_DEFAULT_COVER_COLOR
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DEFAULT_FONT = settings.PREVIEW_DEFAULT_FONT
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TRANSPARENT_COLOR = (0, 0, 0, 0)
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margin = math.floor(IMG_HEIGHT / 10)
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gutter = math.floor(margin / 2)
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inner_img_height = math.floor(IMG_HEIGHT * 0.8)
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inner_img_width = math.floor(inner_img_height * 0.7)
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def get_imagefont(name, size):
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"""Loads an ImageFont based on config"""
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try:
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config = settings.FONTS[name]
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path = os.path.join(settings.FONT_DIR, config["directory"], config["filename"])
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return ImageFont.truetype(path, size)
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except KeyError:
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logger.error("Font %s not found in config", name)
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except OSError:
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logger.error("Could not load font %s from file", name)
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return ImageFont.load_default()
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def get_font(weight, size=28):
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"""Gets a custom font with the given weight and size"""
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font = get_imagefont(DEFAULT_FONT, size)
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try:
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if weight == "light":
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font.set_variation_by_name("Light")
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if weight == "bold":
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font.set_variation_by_name("Bold")
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if weight == "regular":
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font.set_variation_by_name("Regular")
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except AttributeError:
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pass
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return font
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def get_wrapped_text(text, font, content_width):
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"""text wrap length depends on the max width of the content"""
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low = 0
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high = len(text)
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draw = ImageDraw.Draw(Image.new("RGB", (100, 100)))
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try:
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# ideal length is determined via binary search
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while low < high:
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mid = math.floor(low + high)
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wrapped_text = textwrap.fill(text, width=mid)
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left, top, right, bottom = draw.multiline_textbbox(
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(0, 0), wrapped_text, font=font
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)
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width = right - left
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height = bottom - top
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if width < content_width:
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low = mid
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else:
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high = mid - 1
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except AttributeError:
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wrapped_text = text
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height = 26
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return wrapped_text, height
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def generate_texts_layer(texts, content_width):
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"""Adds text for images"""
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font_text_zero = get_font("bold", size=20)
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font_text_one = get_font("bold", size=48)
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font_text_two = get_font("bold", size=40)
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font_text_three = get_font("regular", size=40)
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text_layer = Image.new("RGBA", (content_width, IMG_HEIGHT), color=TRANSPARENT_COLOR)
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text_layer_draw = ImageDraw.Draw(text_layer)
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text_y = 0
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if "text_zero" in texts and texts["text_zero"]:
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# Text zero (Site preview domain name)
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text_zero, text_height = get_wrapped_text(
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texts["text_zero"], font_text_zero, content_width
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)
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text_layer_draw.multiline_text(
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(0, text_y), text_zero, font=font_text_zero, fill=TEXT_COLOR
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)
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try:
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text_y = text_y + text_height + 16
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except (AttributeError, IndexError):
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text_y = text_y + 26
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if "text_one" in texts and texts["text_one"]:
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# Text one (Book/Site title, User display name)
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text_one, text_height = get_wrapped_text(
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texts["text_one"], font_text_one, content_width
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)
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text_layer_draw.multiline_text(
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(0, text_y), text_one, font=font_text_one, fill=TEXT_COLOR
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)
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try:
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text_y = text_y + text_height + 16
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except (AttributeError, IndexError):
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text_y = text_y + 26
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if "text_two" in texts and texts["text_two"]:
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# Text two (Book subtitle)
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text_two, text_height = get_wrapped_text(
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texts["text_two"], font_text_two, content_width
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)
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text_layer_draw.multiline_text(
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(0, text_y), text_two, font=font_text_two, fill=TEXT_COLOR
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)
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try:
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text_y = text_y + text_height + 16
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except (AttributeError, IndexError):
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text_y = text_y + 26
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if "text_three" in texts and texts["text_three"]:
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# Text three (Book authors, Site tagline, User address)
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text_three, _ = get_wrapped_text(
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texts["text_three"], font_text_three, content_width
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)
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text_layer_draw.multiline_text(
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(0, text_y), text_three, font=font_text_three, fill=TEXT_COLOR
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)
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text_layer_box = text_layer.getbbox()
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return text_layer.crop(text_layer_box)
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def generate_instance_layer(content_width):
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"""Places components for instance preview"""
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font_instance = get_font("light", size=28)
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site = models.SiteSettings.objects.get()
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if site.logo_small:
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logo_img = Image.open(site.logo_small)
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else:
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try:
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static_path = os.path.join(settings.STATIC_ROOT, "images/logo-small.png")
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logo_img = Image.open(static_path)
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except FileNotFoundError:
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logo_img = None
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instance_layer = Image.new("RGBA", (content_width, 62), color=TRANSPARENT_COLOR)
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instance_text_x = 0
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if logo_img:
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logo_img.thumbnail((50, 50), Image.Resampling.LANCZOS)
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instance_layer.paste(logo_img, (0, 0))
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instance_text_x = instance_text_x + 60
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instance_layer_draw = ImageDraw.Draw(instance_layer)
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instance_layer_draw.text(
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(instance_text_x, 10), site.name, font=font_instance, fill=TEXT_COLOR
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)
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line_width = 50 + 10 + round(font_instance.getlength(site.name))
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line_layer = Image.new(
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"RGBA", (line_width, 2), color=(*(ImageColor.getrgb(TEXT_COLOR)), 50)
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)
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instance_layer.alpha_composite(line_layer, (0, 60))
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return instance_layer
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def generate_rating_layer(rating, content_width):
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"""Places components for rating preview"""
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try:
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icon_star_full = Image.open(
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os.path.join(settings.STATIC_ROOT, "images/icons/star-full.png")
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)
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icon_star_empty = Image.open(
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os.path.join(settings.STATIC_ROOT, "images/icons/star-empty.png")
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)
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icon_star_half = Image.open(
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os.path.join(settings.STATIC_ROOT, "images/icons/star-half.png")
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)
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except FileNotFoundError:
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return None
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icon_size = 64
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icon_margin = 10
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rating_layer_base = Image.new(
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"RGBA", (content_width, icon_size), color=TRANSPARENT_COLOR
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)
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rating_layer_color = Image.new("RGBA", (content_width, icon_size), color=TEXT_COLOR)
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rating_layer_mask = Image.new(
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"RGBA", (content_width, icon_size), color=TRANSPARENT_COLOR
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)
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position_x = 0
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for _ in range(math.floor(rating)):
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rating_layer_mask.alpha_composite(icon_star_full, (position_x, 0))
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position_x = position_x + icon_size + icon_margin
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if math.floor(rating) != math.ceil(rating):
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rating_layer_mask.alpha_composite(icon_star_half, (position_x, 0))
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position_x = position_x + icon_size + icon_margin
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for _ in range(5 - math.ceil(rating)):
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rating_layer_mask.alpha_composite(icon_star_empty, (position_x, 0))
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position_x = position_x + icon_size + icon_margin
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rating_layer_mask = rating_layer_mask.getchannel("A")
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rating_layer_mask = ImageOps.invert(rating_layer_mask)
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rating_layer_composite = Image.composite(
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rating_layer_base, rating_layer_color, rating_layer_mask
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)
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return rating_layer_composite
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def generate_default_inner_img():
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"""Adds cover image"""
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font_cover = get_font("light", size=28)
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default_cover = Image.new(
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"RGB", (inner_img_width, inner_img_height), color=DEFAULT_COVER_COLOR
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)
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default_cover_draw = ImageDraw.Draw(default_cover)
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text = "no image :("
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text_left, text_top, text_right, text_bottom = font_cover.getbbox(text)
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text_width, text_height = text_right - text_left, text_bottom - text_top
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text_coords = (
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math.floor((inner_img_width - text_width) / 2),
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math.floor((inner_img_height - text_height) / 2),
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)
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default_cover_draw.text(text_coords, text, font=font_cover, fill="white")
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return default_cover
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# pylint: disable=too-many-locals
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# pylint: disable=too-many-statements
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def generate_preview_image(
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texts=None, picture=None, rating=None, show_instance_layer=True
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):
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"""Puts everything together"""
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texts = texts or {}
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# Cover
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try:
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inner_img_layer = Image.open(picture)
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inner_img_layer.thumbnail(
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(inner_img_width, inner_img_height), Image.Resampling.LANCZOS
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)
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color_thief = ColorThief(picture)
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dominant_color = color_thief.get_color(quality=1)
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except: # pylint: disable=bare-except
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inner_img_layer = generate_default_inner_img()
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dominant_color = ImageColor.getrgb(DEFAULT_COVER_COLOR)
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# Color
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if BG_COLOR in ["use_dominant_color_light", "use_dominant_color_dark"]:
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red, green, blue = dominant_color
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image_bg_color = f"rgb({red}, {green}, {blue})"
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# Adjust color
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image_bg_color_rgb = [x / 255.0 for x in ImageColor.getrgb(image_bg_color)]
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image_bg_color_hls = colorsys.rgb_to_hls(*image_bg_color_rgb)
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if BG_COLOR == "use_dominant_color_light":
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lightness = max(0.9, image_bg_color_hls[1])
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else:
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lightness = min(0.15, image_bg_color_hls[1])
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image_bg_color_hls = (
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image_bg_color_hls[0],
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lightness,
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image_bg_color_hls[2],
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)
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image_bg_color = tuple(
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math.ceil(x * 255) for x in colorsys.hls_to_rgb(*image_bg_color_hls)
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)
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else:
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image_bg_color = BG_COLOR
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# Background (using the color)
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img = Image.new("RGBA", (IMG_WIDTH, IMG_HEIGHT), color=image_bg_color)
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# Contents
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inner_img_x = margin + inner_img_width - inner_img_layer.width
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inner_img_y = math.floor((IMG_HEIGHT - inner_img_layer.height) / 2)
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content_x = margin + inner_img_width + gutter
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content_width = IMG_WIDTH - content_x - margin
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contents_layer = Image.new(
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"RGBA", (content_width, IMG_HEIGHT), color=TRANSPARENT_COLOR
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)
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contents_composite_y = 0
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if show_instance_layer:
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instance_layer = generate_instance_layer(content_width)
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contents_layer.alpha_composite(instance_layer, (0, contents_composite_y))
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contents_composite_y = contents_composite_y + instance_layer.height + gutter
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texts_layer = generate_texts_layer(texts, content_width)
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contents_layer.alpha_composite(texts_layer, (0, contents_composite_y))
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contents_composite_y = contents_composite_y + texts_layer.height + gutter
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if rating:
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# Add some more margin
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contents_composite_y = contents_composite_y + gutter
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rating_layer = generate_rating_layer(rating, content_width)
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if rating_layer:
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contents_layer.alpha_composite(rating_layer, (0, contents_composite_y))
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contents_composite_y = contents_composite_y + rating_layer.height + gutter
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contents_layer_box = contents_layer.getbbox()
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contents_layer_height = contents_layer_box[3] - contents_layer_box[1]
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contents_y = math.floor((IMG_HEIGHT - contents_layer_height) / 2)
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if show_instance_layer:
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# Remove Instance Layer from centering calculations
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contents_y = contents_y - math.floor((instance_layer.height + gutter) / 2)
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contents_y = max(contents_y, margin)
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# Composite layers
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img.paste(
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inner_img_layer, (inner_img_x, inner_img_y), inner_img_layer.convert("RGBA")
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)
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img.alpha_composite(contents_layer, (content_x, contents_y))
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return img.convert("RGB")
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def save_and_cleanup(image, instance=None):
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"""Save and close the file"""
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if not isinstance(instance, (models.Book, models.User, models.SiteSettings)):
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return False
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image_buffer = BytesIO()
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try:
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try:
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file_name = instance.preview_image.name
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except ValueError:
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file_name = None
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if not file_name or file_name == "":
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uuid = uuid4()
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file_name = f"{instance.id}-{uuid}.jpg"
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# Clean up old file before saving
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if file_name and default_storage.exists(file_name):
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default_storage.delete(file_name)
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# Save
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image.save(image_buffer, format="jpeg", quality=75)
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instance.preview_image = InMemoryUploadedFile(
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ContentFile(image_buffer.getvalue()),
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"preview_image",
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file_name,
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"image/jpg",
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image_buffer.tell(),
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None,
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)
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save_without_broadcast = isinstance(instance, (models.Book, models.User))
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if save_without_broadcast:
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instance.save(broadcast=False, update_fields=["preview_image"])
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else:
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instance.save(update_fields=["preview_image"])
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finally:
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image_buffer.close()
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return True
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# pylint: disable=invalid-name
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@app.task(queue=LOW)
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def generate_site_preview_image_task():
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"""generate preview_image for the website"""
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if not settings.ENABLE_PREVIEW_IMAGES:
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return
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site = models.SiteSettings.objects.get()
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if site.logo:
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logo = site.logo
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else:
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logo = os.path.join(settings.STATIC_ROOT, "images/logo.png")
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texts = {
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"text_zero": settings.DOMAIN,
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"text_one": site.name,
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"text_three": site.instance_tagline,
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}
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image = generate_preview_image(texts=texts, picture=logo, show_instance_layer=False)
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save_and_cleanup(image, instance=site)
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# pylint: disable=invalid-name
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@app.task(queue=LOW)
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def generate_edition_preview_image_task(book_id):
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"""generate preview_image for a book"""
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if not settings.ENABLE_PREVIEW_IMAGES:
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return
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book = models.Book.objects.select_subclasses().get(id=book_id)
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rating = models.Review.objects.filter(
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privacy="public",
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deleted=False,
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book__in=[book_id],
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).aggregate(Avg("rating"))["rating__avg"]
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texts = {
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"text_one": book.title,
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"text_two": book.subtitle,
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"text_three": book.author_text,
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}
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image = generate_preview_image(texts=texts, picture=book.cover, rating=rating)
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save_and_cleanup(image, instance=book)
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@app.task(queue=LOW)
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def generate_user_preview_image_task(user_id):
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"""generate preview_image for a user"""
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if not settings.ENABLE_PREVIEW_IMAGES:
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return
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user = models.User.objects.get(id=user_id)
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if not user.local:
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return
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texts = {
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"text_one": user.display_name,
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"text_three": f"@{user.localname}@{settings.DOMAIN}",
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}
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if user.avatar:
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avatar = user.avatar
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else:
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avatar = os.path.join(settings.STATIC_ROOT, "images/default_avi.jpg")
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image = generate_preview_image(texts=texts, picture=avatar)
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save_and_cleanup(image, instance=user)
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@app.task(queue=LOW)
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def remove_user_preview_image_task(user_id):
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"""remove preview_image for a user"""
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if not settings.ENABLE_PREVIEW_IMAGES:
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return
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user = models.User.objects.get(id=user_id)
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try:
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file_name = user.preview_image.name
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except ValueError:
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file_name = None
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# Delete image in model
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user.preview_image.delete(save=False)
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user.save(broadcast=False, update_fields=["preview_image"])
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# Delete image file
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if file_name and default_storage.exists(file_name):
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default_storage.delete(file_name)
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