Pass JPEG images unmodified when creating PDF image pages

src/calibre/ebooks/conversion/plugins/pdf_output.py

@@ -178,7 +178,7 @@ class PDFOutput(OutputFormatPlugin):
 
     def convert_images(self, images):
         from calibre.ebooks.pdf.image_writer import convert
-        convert(images, self.output_path, self.opts, self.metadata)
+        convert(images, self.output_path, self.opts, self.metadata, self.report_progress)
 
     def get_cover_data(self):
         oeb = self.oeb

src/calibre/ebooks/pdf/html_writer.py

@@ -5,22 +5,20 @@
 from __future__ import absolute_import, division, print_function, unicode_literals
 
 import os
+from io import BytesIO
 
-from PyQt5.Qt import (
-    QApplication, QBuffer, QMarginsF, QPageLayout, QPainter, QPdfWriter, QTimer,
-    QUrl
-)
+from PyQt5.Qt import QApplication, QTimer, QUrl
 from PyQt5.QtWebEngineWidgets import QWebEnginePage
 
 from calibre.constants import iswindows
 from calibre.ebooks.oeb.polish.container import Container as ContainerBase
 from calibre.ebooks.oeb.polish.split import merge_html
 from calibre.ebooks.pdf.image_writer import (
-    PDFMetadata, draw_image_page, get_page_layout, update_metadata
+    Image, PDFMetadata, draw_image_page, get_page_layout, update_metadata
 )
+from calibre.ebooks.pdf.render.serialize import PDFStream
 from calibre.gui2 import setup_unix_signals
 from calibre.gui2.webengine import secure_webengine
-from calibre.utils.img import image_from_data
 from calibre.utils.logging import default_log
 from calibre.utils.podofo import get_podofo
 from polyglot.builtins import range
@@ -103,20 +101,14 @@ class Renderer(QWebEnginePage):
 
 
 def add_cover(pdf_doc, cover_data, page_layout, opts):
-    buf = QBuffer()
-    buf.open(QBuffer.ReadWrite)
-    cover_layout = QPageLayout(page_layout)
-    cover_layout.setMargins(QMarginsF(0, 0, 0, 0))
-    img = image_from_data(cover_data)
-    writer = QPdfWriter(buf)
-    writer.setPageLayout(cover_layout)
-    painter = QPainter()
-    painter.begin(writer)
-    try:
-        draw_image_page(painter, img, preserve_aspect_ratio=opts.preserve_cover_aspect_ratio)
-    finally:
-        painter.end()
-    cover_pdf = buf.data().data()
+    buf = BytesIO()
+    page_size = page_layout.fullRectPoints().size()
+    img = Image(cover_data)
+    writer = PDFStream(buf, (page_size.width(), page_size.height()), compress=True)
+    writer.apply_fill(color=(1, 1, 1))
+    draw_image_page(writer, img, preserve_aspect_ratio=opts.preserve_cover_aspect_ratio)
+    writer.end()
+    cover_pdf = buf.getvalue()
     podofo = get_podofo()
     cover_pdf_doc = podofo.PDFDoc()
     cover_pdf_doc.load(cover_pdf)

src/calibre/ebooks/pdf/image_writer.py

@@ -8,11 +8,14 @@ from io import BytesIO
 
 from PyQt5.Qt import QMarginsF, QPageLayout, QPageSize, QSize
 
-from calibre.ebooks.pdf.render.common import cicero, cm, didot, inch, mm, pica
+from calibre.constants import filesystem_encoding
 from calibre.ebooks.metadata.xmp import metadata_to_xmp_packet
+from calibre.ebooks.pdf.render.common import cicero, cm, didot, inch, mm, pica
 from calibre.ebooks.pdf.render.serialize import PDFStream
-from calibre.utils.img import image_from_path
+from calibre.utils.img import image_and_format_from_data
+from calibre.utils.imghdr import identify
 from calibre.utils.podofo import get_podofo, set_metadata_implementation
+from polyglot.builtins import as_unicode
 
 
 class PDFMetadata(object):  # {{{
@@ -89,12 +92,34 @@ def get_page_layout(opts, for_comic=False):
 # }}}
 
 
+class Image(object):  # {{{
+
+    def __init__(self, path_or_bytes):
+        if not isinstance(path_or_bytes, bytes):
+            with open(path_or_bytes, 'rb') as f:
+                path_or_bytes = f.read()
+        self.img_data = path_or_bytes
+        fmt, width, height = identify(path_or_bytes)
+        if width > 0 and height > 0 and fmt == 'jpeg':
+            self.fmt = fmt
+            self.width, self.height = width, height
+            self.cache_key = None
+        else:
+            self.img, self.fmt = image_and_format_from_data(path_or_bytes)
+            self.width, self.height = self.img.width(), self.img.height()
+            self.cache_key = self.img.cacheKey()
+# }}}
+
+
 def draw_image_page(writer, img, preserve_aspect_ratio=True):
-    ref = writer.add_image(img, img.cacheKey())
+    if img.fmt == 'jpeg':
+        ref = writer.add_jpeg_image(img.img_data, img.width, img.height, img.cache_key)
+    else:
+        ref = writer.add_image(img.img, img.cache_key)
     page_size = tuple(writer.page_size)
     scaling = list(writer.page_size)
     translation = [0, 0]
-    img_ar = img.width() / img.height()
+    img_ar = img.width / img.height
     page_ar = page_size[0]/page_size[1]
     if preserve_aspect_ratio and page_ar != img_ar:
         if page_ar > img_ar:
@@ -114,7 +139,7 @@ def update_metadata(pdf_doc, pdf_metadata):
             pdf_metadata.mi.book_producer, pdf_metadata.mi.tags, xmp_packet)
 
 
-def convert(images, output_path, opts, metadata):
+def convert(images, output_path, opts, metadata, report_progress):
     buf = BytesIO()
     page_layout = get_page_layout(opts, for_comic=True)
     page_size = page_layout.fullRectPoints().size()
@@ -122,7 +147,7 @@ def convert(images, output_path, opts, metadata):
     writer.apply_fill(color=(1, 1, 1))
     pdf_metadata = PDFMetadata(metadata)
     for i, path in enumerate(images):
-        img = image_from_path(path)
+        img = Image(as_unicode(path, filesystem_encoding))
         draw_image_page(writer, img)
         writer.end_page()
     writer.end()

src/calibre/ebooks/pdf/render/serialize.py

@@ -416,6 +416,9 @@ class PDFStream(object):
         self.objects.commit(r, self.stream)
         return r
 
+    def add_jpeg_image(self, img_data, w, h, cache_key=None):
+        return self.write_image(img_data, w, h, 32, dct=True)
+
     def add_image(self, img, cache_key):
         ref = self.get_image(cache_key)
         if ref is not None: