From 73858688886ec363048373f7e8253a33497fe3cd Mon Sep 17 00:00:00 2001
From: Radek Czajka <rczajka@rczajka.pl>
Date: Wed, 27 Jan 2021 13:25:06 +0100
Subject: [PATCH] Response images.

---
 CHANGELOG.md                      |  6 ++++++
 setup.py                          |  2 +-
 src/librarian/html.py             | 31 +++++++++++++++++++++++++++++--
 src/librarian/xslt/book2html.xslt | 12 +++++++++++-
 4 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98b62e4..6f17bfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,12 @@
 This document records all notable changes to Librarian.
 
 
+## 1.13 (2021-01-27)
+
+### Changed
+- Responsive images in HTML. This changes the html.transform API.
+
+
 ## 1.12 (2021-01-27)
 
 ### Added
diff --git a/setup.py b/setup.py
index 055ec93..c1af4e3 100755
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@ def whole_tree(prefix, path):
 
 setup(
     name='librarian',
-    version='1.12',
+    version='1.13',
     description='Converter from WolneLektury.pl XML-based language to XHTML, TXT and other formats',
     author="Marek Stępniowski",
     author_email='marek@stepniowski.com',
diff --git a/src/librarian/html.py b/src/librarian/html.py
index 9ec6583..d262198 100644
--- a/src/librarian/html.py
+++ b/src/librarian/html.py
@@ -12,6 +12,7 @@ import copy
 from lxml import etree
 from librarian import XHTMLNS, ParseError, OutputFile
 from librarian import functions
+from PIL import Image
 
 from lxml.etree import XMLSyntaxError, XSLTApplyError
 import six
@@ -50,7 +51,32 @@ def transform_abstrakt(abstrakt_element):
     return re.sub('</?blockquote[^>]*>', '', html)
 
 
-def transform(wldoc, stylesheet='legacy', options=None, flags=None, css=None):
+def add_image_sizes(tree, gallery_path, gallery_url):
+    widths = [360, 600, 1200, 1800]
+    for ilustr in tree.findall('//ilustr'):
+        rel_path = ilustr.attrib['src']
+        img = Image.open(gallery_path + rel_path)
+        srcset = []
+        for w in widths:
+            if w < img.size[0]:
+                height = round(img.size[1] * w / img.size[0])
+                th = img.resize((w, height))
+
+                fname = ('.W%d.' % w).join(rel_path.rsplit('.', 1))
+                th.save(gallery_path + fname)
+                srcset.append(" ".join((
+                    gallery_url + fname,
+                    '%dw' % w
+                    )))
+        srcset.append(" ".join((
+            gallery_url + rel_path,
+            '%dw' % img.size[0]
+        )))
+        ilustr.attrib['srcset'] = ", ".join(srcset)
+        ilustr.attrib['src'] = gallery_url + rel_path
+
+
+def transform(wldoc, stylesheet='legacy', options=None, flags=None, css=None, gallery_path='img/', gallery_url='img/'):
     """Transforms the WL document to XHTML.
 
     If output_filename is None, returns an XML,
@@ -75,7 +101,8 @@ def transform(wldoc, stylesheet='legacy', options=None, flags=None, css=None):
 
         if not options:
             options = {}
-        options.setdefault('gallery', "''")
+
+        add_image_sizes(document.edoc, gallery_path, gallery_url)
 
         css = (
             css
diff --git a/src/librarian/xslt/book2html.xslt b/src/librarian/xslt/book2html.xslt
index 7576413..04e2658 100644
--- a/src/librarian/xslt/book2html.xslt
+++ b/src/librarian/xslt/book2html.xslt
@@ -135,7 +135,17 @@
 <xsl:template match="ilustr">
     <img>
         <xsl:attribute name="src">
-            <xsl:value-of select="$gallery" /><xsl:value-of select="@src" />
+            <xsl:value-of select="@src" />
+        </xsl:attribute>
+        <xsl:attribute name="srcset">
+          <xsl:value-of select="@srcset" />
+        </xsl:attribute>
+        <xsl:attribute name="sizes">
+          (min-width: 718px) 600px,
+          (min-width: 600px) calc(100vw - 118px),
+          (min-width: 320px) calc(100vw - 75px),
+          (min-width: 15em) calc(100wv - 60px),
+          calc(100wv - 40px)
         </xsl:attribute>
         <xsl:attribute name="alt">
             <xsl:value-of select="@alt" />
-- 
2.20.1