Address 4520

We previously refused the use of a page without a /Contents object as source page in method `show_pdf_page`.
We now simply assume an empty stream and still create the Form XObject in the target PDF.

Author: JorjMcKie

docs/page.rst

@@ -1973,11 +1973,11 @@ In a nutshell, this is what you can do with PyMuPDF:
 
    .. method:: show_pdf_page(rect, docsrc, pno=0, keep_proportion=True, overlay=True, oc=0, rotate=0, clip=None)
 
-      PDF only: Display a page of another PDF as a **vector image** (otherwise similar to :meth:`Page.insert_image`). This is a multi-purpose method. For example, you can use it to:
+      PDF only: Display a page of another PDF. This is similar to :meth:`Page.insert_image` but the source page will appear like a copy of itself and will not be rasterized. This is a multi-purpose method. For example, you can use it to:
 
       * create "n-up" versions of existing PDF files, combining several input pages into **one output page** (see example `combine.py <https://github.com/pymupdf/PyMuPDF-Utilities/blob/master/examples/combine-pages/combine.py>`_),
       * create "posterized" PDF files, i.e. every input page is split up in parts which each create a separate output page (see `posterize.py <https://github.com/pymupdf/PyMuPDF-Utilities/blob/master/examples/posterize-document/posterize.py>`_),
-      * include PDF-based vector images like company logos, watermarks, etc., see `svg-logo.py <https://github.com/pymupdf/PyMuPDF-Utilities/tree/master/examples/svg-logo.py>`_, which puts an SVG-based logo on each page (requires additional packages to deal with SVG-to-PDF conversions).
+      * include PDF-based vector images like company logos, watermarks, etc., see `svg-logo.py <https://github.com/pymupdf/PyMuPDF-Utilities/tree/master/examples/svg-logo.py>`_, which puts an SVG-based logo on each page.
 
       :arg rect_like rect: where to place the image on current page. Must be finite and its intersection with the page must not be empty.
       :arg docsrc: source PDF document containing the page. Must be a different document object, but may be the same file.
@@ -1994,7 +1994,7 @@ In a nutshell, this is what you can do with PyMuPDF:
 
       :arg rect_like clip: choose which part of the source page to show. Default is the full page, else must be finite and its intersection with the source page must not be empty.
 
-      .. note:: In contrast to method :meth:`Document.insert_pdf`, this method does not copy annotations, widgets or links, so these are not included in the target [#f6]_. But all its **other resources (text, images, fonts, etc.)** will be imported into the current PDF. They will therefore appear in text extractions and in :meth:`get_fonts` and :meth:`get_images` lists -- even if they are not contained in the visible area given by *clip*.
+      .. note:: In contrast to method :meth:`Document.insert_pdf`, this method does not copy annotations, widgets or links, so these objects are not included in the target [#f6]_. But all its **other resources (text, images, fonts, etc.)** will be imported into the current PDF. They will therefore appear in text extractions and in :meth:`get_fonts` and :meth:`get_images` lists -- even if they are not contained in the visible area given by *clip*.
 
       Example: Show the same source page, rotated by 90 and by -90 degrees:
 

src/__init__.py

@@ -17240,7 +17240,7 @@ def JM_read_contents(pageref):
     elif contents.m_internal:
         res = mupdf.pdf_load_stream(contents)
     else:
-        res = b""
+        res = mupdf.FzBuffer(0)
     return res
 
 

src/utils.py

@@ -174,8 +174,6 @@ def calc_matrix(sr, tr, keep=True, rotate=0):
     while pno < 0:  # support negative page numbers
         pno += docsrc.page_count
     src_page = docsrc[pno]  # load source page
-    if src_page.get_contents() == []:
-        raise ValueError("nothing to show - source page empty")
 
     tar_rect = rect * ~page.transformation_matrix  # target rect in PDF coordinates
 

tests/test_4520.py

@@ -0,0 +1,19 @@
+import pymupdf
+
+
+def test_4520():
+    """Accept source pages without /Contents object in show_pdf_page."""
+    vsn_tuple = tuple(map(int, pymupdf.__version__.split(".")))
+    tar = pymupdf.open()
+    src = pymupdf.open()
+    src.new_page()
+    page = tar.new_page()
+    try:
+        assert page.show_pdf_page(page.rect, src, 0)
+        rc = True
+    except Exception as e:
+        rc = False
+    if vsn_tuple < (1, 26, 1):
+        assert rc is False
+    else:
+        assert rc is True