Pixmap x- and y-coordinate are immutable

[hex-yes]

Description of the bug

This might be a documentation bug rather than a functional one. I need to copy a region of a source Pixmap to a destination Pixmap. The recipe for doing so does not work as written.

To Reproduce

The recipe code fails at this line:

src.x = src.width * i # modify input's x coord

...with the error:

AttributeError: can't set attribute

Expected behavior

If the x and y coordinates of a Pixmap are intended to be mutable, this is a functional bug and the expected behavior would be as shown in the recipe.

If the x and y coordinates of a Pixmap are intended to be immutable, some documentation of the current best practice for copying a portion of one Pixmap to another would be welcomed. For example, is it necessary to apply a translation Matrix to the source Pixmap before copying, or is there a better way?

My configuration

>>> print(sys.version, "\n", sys.platform, "\n", fitz.__doc__)
3.8.5 (v3.8.5:580fbb018f, Jul 20 2020, 12:11:27) 
[Clang 6.0 (clang-600.0.57)] 
 darwin 
 
PyMuPDF 1.17.5: Python bindings for the MuPDF 1.17.0 library.
Version date: 2020-08-06 06:31:06.
Built for Python 3.8 on darwin (64-bit).

PyMuPDF was installed with a wheel using pip install PyMuPDF

[hex-yes]

Related to this, the documentation for Pixmap.copyPixmap includes this text:

Between irect and the target pixmap’s rectangle, an “intersection” is calculated at first. This takes into account the rectangle coordinates and the current attribute values source.x and source.y (which you are free to modify for this purpose).

This suggests the intent is consistent with the recipe code that the x- and y-coordinate of a Pixmap should be settable.

[JorjMcKie]

Correct - thanks for reporting this.
Will change with next version. Any urgency?

[hex-yes]

No urgency at all. Thanks for your work on this.

[JorjMcKie]

New version 1.17.7 addresses this and is being uploaded right now.

[hex-yes]

I updated to 1.17.7 with pip, but the issue persists. My updated configuration:

>>> print(sys.version, "\n", sys.platform, "\n", fitz.__doc__)
3.8.5 (v3.8.5:580fbb018f, Jul 20 2020, 12:11:27) 
[Clang 6.0 (clang-600.0.57)] 
 darwin 
 
PyMuPDF 1.17.7: Python bindings for the MuPDF 1.17.0 library.
Version date: 2020-09-14 06:33:06.
Built for Python 3.8 on darwin (64-bit).

[JorjMcKie]

Weird, here is my snippet:

>>> import fitz
>>> print(fitz.__doc__)

PyMuPDF 1.17.7: Python bindings for the MuPDF 1.17.0 library.
Version date: 2020-09-14 06:33:06.
Built for Python 3.7 on win32 (64-bit).

>>> pix=fitz.Pixmap("page8.png")
>>> pix
Pixmap(DeviceRGB, IRect(0, 0, 596, 794), 0)
>>> pix.setOrigin(5, 5)
>>> pix
Pixmap(DeviceRGB, IRect(5, 5, 601, 799), 0)
>>> 

[JorjMcKie]

The attributes pix.x, pix.y can indeed not be changed directly - that hasn't changed ...
This is rooted in an internal change of MuPDF.

[hex-yes]

setOrigin() does work as described. I modified the recipe code to use setOrigin() as follows:

import fitz

src = fitz.Pixmap('img-7edges.png')      # create pixmap from a picture
col = 3                                  # tiles per row
lin = 4                                  # tiles per column
tar_w = src.width * col                  # width of target
tar_h = src.height * lin                 # height of target

# create target pixmap
tar_pix = fitz.Pixmap(src.colorspace, (0, 0, tar_w, tar_h), src.alpha)

# now fill target with the tiles
for i in range(col):
    for j in range(lin):
        src.setOrigin(src.width * i, src.height * j)
        tar_pix.copyPixmap(src, src.irect) # copy input to new loc

tar_pix.writePNG('tar.png')

Thank you for your help with this.