librarian/cover.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
   4 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   5 #
   6 import re
   7 from PIL import Image, ImageFont, ImageDraw, ImageFilter
   8 from StringIO import StringIO
   9 from librarian import get_resource, IOFile
  10
  11
  12 class TextBox(object):
  13     """Creates an Image with a series of centered strings."""
  14
  15     SHADOW_X = 3
  16     SHADOW_Y = 3
  17     SHADOW_BLUR = 3
  18
  19     def __init__(self, max_width, max_height, padding_x=None, padding_y=None):
  20         if padding_x is None:
  21             padding_x = self.SHADOW_X + self.SHADOW_BLUR
  22         if padding_y is None:
  23             padding_y = self.SHADOW_Y + self.SHADOW_BLUR
  24
  25         self.max_width = max_width
  26         self.max_text_width = max_width - 2 * padding_x
  27         self.padding_y = padding_y
  28         self.height = padding_y
  29         self.img = Image.new('RGBA', (max_width, max_height))
  30         self.draw = ImageDraw.Draw(self.img)
  31         self.shadow_img = None
  32         self.shadow_draw = None
  33
  34     def skip(self, height):
  35         """Skips some vertical space."""
  36         self.height += height
  37
  38     def text(self, text, color='#000', font=None, line_height=20,
  39              shadow_color=None):
  40         """Writes some centered text."""
  41         text = re.sub(r'\s+', ' ', text)
  42         if shadow_color:
  43             if not self.shadow_img:
  44                 self.shadow_img = Image.new('RGBA', self.img.size)
  45                 self.shadow_draw = ImageDraw.Draw(self.shadow_img)
  46         while text:
  47             line = text
  48             line_width = self.draw.textsize(line, font=font)[0]
  49             while line_width > self.max_text_width:
  50                 parts = line.rsplit(' ', 1)
  51                 if len(parts) == 1:
  52                     line_width = self.max_text_width
  53                     break
  54                 line = parts[0]
  55                 line_width = self.draw.textsize(line, font=font)[0]
  56             line = line.strip() + ' '
  57
  58             pos_x = (self.max_width - line_width) / 2
  59
  60             if shadow_color:
  61                 self.shadow_draw.text(
  62                         (pos_x + self.SHADOW_X, self.height + self.SHADOW_Y),
  63                         line, font=font, fill=shadow_color
  64                 )
  65
  66             self.draw.text((pos_x, self.height), line, font=font, fill=color)
  67             self.height += line_height
  68             # go to next line
  69             text = text[len(line):]
  70
  71     def image(self):
  72         """Creates the actual Image object."""
  73         image = Image.new('RGBA', (self.max_width,
  74                                    self.height + self.padding_y))
  75         if self.shadow_img:
  76             shadow = self.shadow_img.filter(ImageFilter.BLUR)
  77             image.paste(shadow, (0, 0), shadow)
  78             image.paste(self.img, (0, 0), self.img)
  79         else:
  80             image.paste(self.img, (0, 0))
  81         return image
  82
  83
  84 class Cover(object):
  85     """Abstract base class for cover images generator."""
  86     width = 600
  87     height = 800
  88     background_color = '#fff'
  89     background_img = None
  90
  91     author_top = 100
  92     author_margin_left = 20
  93     author_margin_right = 20
  94     author_lineskip = 40
  95     author_color = '#000'
  96     author_shadow = None
  97     author_font = None
  98
  99     title_top = 100
 100     title_margin_left = 20
 101     title_margin_right = 20
 102     title_lineskip = 54
 103     title_color = '#000'
 104     title_shadow = None
 105     title_font = None
 106
 107     logo_bottom = None
 108     logo_width = None
 109     uses_dc_cover = False
 110
 111     format = 'JPEG'
 112
 113     exts = {
 114         'JPEG': 'jpg',
 115         'PNG': 'png',
 116     }
 117
 118     mime_types = {
 119         'JPEG': 'image/jpeg',
 120         'PNG': 'image/png',
 121     }
 122
 123     def __init__(self, book_info, format=None):
 124         try:
 125             self.author = ", ".join(auth.readable() for auth in book_info.authors)
 126         except AttributeError:
 127             self.author = ""
 128         self.title = book_info.title
 129         if format is not None:
 130             self.format = format
 131
 132     def pretty_author(self):
 133         """Allows for decorating author's name."""
 134         return self.author
 135
 136     def pretty_title(self):
 137         """Allows for decorating title."""
 138         return self.title
 139
 140     def image(self):
 141         img = Image.new('RGB', (self.width, self.height), self.background_color)
 142
 143         if self.background_img:
 144             background = Image.open(self.background_img)
 145             img.paste(background, None, background)
 146             del background
 147
 148         # WL logo
 149         if self.logo_width:
 150             logo = Image.open(get_resource('res/wl-logo.png'))
 151             logo = logo.resize((self.logo_width, logo.size[1] * self.logo_width / logo.size[0]))
 152             img.paste(logo, ((self.width - self.logo_width) / 2, img.size[1] - logo.size[1] - self.logo_bottom))
 153
 154         top = self.author_top
 155         tbox = TextBox(
 156             self.width - self.author_margin_left - self.author_margin_right,
 157             self.height - top)
 158         author_font = self.author_font or ImageFont.truetype(
 159             get_resource('fonts/DejaVuSerif.ttf'), 30)
 160         tbox.text(self.pretty_author(), self.author_color, author_font,
 161                   self.author_lineskip, self.author_shadow)
 162         text_img = tbox.image()
 163         img.paste(text_img, (self.author_margin_left, top), text_img)
 164
 165         top += text_img.size[1] + self.title_top
 166         tbox = TextBox(
 167             self.width - self.title_margin_left - self.title_margin_right,
 168             self.height - top)
 169         title_font = self.author_font or ImageFont.truetype(
 170             get_resource('fonts/DejaVuSerif.ttf'), 40)
 171         tbox.text(self.pretty_title(), self.title_color, title_font,
 172                   self.title_lineskip, self.title_shadow)
 173         text_img = tbox.image()
 174         img.paste(text_img, (self.title_margin_left, top), text_img)
 175
 176         return img
 177
 178     def mime_type(self):
 179         return self.mime_types[self.format]
 180
 181     def ext(self):
 182         return self.exts[self.format]
 183
 184     def save(self, *args, **kwargs):
 185         return self.image().save(format=self.format, *args, **kwargs)
 186
 187     def output_file(self, *args, **kwargs):
 188         imgstr = StringIO()
 189         self.save(imgstr, *args, **kwargs)
 190         return IOFile.from_string(imgstr.getvalue())
 191
 192     def for_pdf(self):
 193         return IOFile.from_filename(get_resource('pdf/cover_image.sty'), {
 194             'cover.png': self.output_file(),
 195         })