pixmap made from Annot seems to have no owner

[PowerSnail]

Describe the bug (mandatory)

Annot.get_pixmap returns a pixmap object without a owner.

To Reproduce (mandatory)

import fitz

doc = fitz.Document()
page = doc.new_page()

page.add_line_annot((1, 1), (100, 100))
page = doc.reload_page(page)

annot = page.first_annot
p = annot.get_pixmap()
print(p.alpha) 

And I get RuntimeError:

Traceback (most recent call last):
  File "/projectpath/test_pymupdf.py", line 11, in <module>
    print(p.alpha)
  File "/projectpath/.venv/lib/python3.10/site-packages/fitz/fitz.py", line 7422, in alpha
    EnsureOwnership(self)
  File "/projectpath/.venv/lib/python3.10/site-packages/fitz/fitz.py", line 2944, in EnsureOwnership
    raise RuntimeError("object destroyed")
RuntimeError: object destroyed

Expected behavior (optional)

No error thrown.

Your configuration (mandatory)

3.10.0 (default, Oct  5 2021, 23:09:35) [GCC 11.2.1 20210816 [revision 056e324ce46a7924b5cf10f61010cf9dd2ca10e9]]
linux

PyMuPDF 1.19.6: Python bindings for the MuPDF 1.19.0 library.
Version date: 2022-03-03 00:00:01.
Built for Python 3.10 on linux (64-bit).

Additional context (optional)

It seems that the problem is this snippet in fitz.py:

    def get_pixmap(
        self,
        matrix: AnyType = None,
        dpi: AnyType = None,
        colorspace: "Colorspace" = None,
        alpha: int = 0,
    ) -> "Pixmap":
        """annotation Pixmap"""

        CheckParent(self)
        cspaces = {"gray": csGRAY, "rgb": csRGB, "cmyk": csCMYK}
        if type(colorspace) is str:
            colorspace = cspaces.get(colorspace.lower(), None)
        if dpi:
            matrix = Matrix(dpi / 72, dpi / 72)

        val = _fitz.Annot_get_pixmap(self, matrix, dpi, colorspace, alpha)

        if dpi:
            val.set_dpi(dpi, dpi)

        return val

val.thisown isn't set to True, as compared to

    def get_pixmap(
        self,
        matrix: AnyType = None,
        colorspace: "Colorspace" = None,
        alpha: int = 0,
        clip: rect_like = None,
    ) -> "Pixmap":
        val = _fitz.DisplayList_get_pixmap(self, matrix, colorspace, alpha, clip)
        val.thisown = True

        return val

[JorjMcKie]

I forgot to include one statement in pixmap creation. As a circumvention do this:

pix=a.get_pixmap()
pix.thisown=True
pix
Pixmap(DeviceRGB, IRect(71, 72, 91, 87), 0)

[julian-smith-artifex-com]

@JorjMcKie, this diff seems to make the test work, do you think it's the right fix?

diff --git a/fitz/fitz.i b/fitz/fitz.i
index 2ee8bbc..569dacb 100644
--- a/fitz/fitz.i
+++ b/fitz/fitz.i
@@ -10551,6 +10551,7 @@ if dpi:
 %}
         %pythonappend get_pixmap
 %{
+        val.thisown = True
         if dpi:
             val.set_dpi(dpi, dpi)
 %}

[JorjMcKie]

Yes it will, I have tested it already.