Hi Dione,
Dione Maddern schrieb am 14.11.2025 um 16:26:
I'm updating the Help page for the "Preferred resolution for images"
(File > Properties > General > Preferred resolution for images) feature
in LibreOffice, as described in this bug report:
https://bugs.documentfoundation.org/show_bug.cgi?id=168924
Can somebody explain what the setting affects, from the user's point of
view? The release notes and current help page don't make it very clear.
I've not looked into the code, but from my experiments I see this:
If the option is checked, then the rendered size of the image is
calculated using the image dimension in pixel and the entered PPI value
in the document properties. The intrinsic PPI value of the image is ignored.
Example:
The image has 147x170px and 96PPI.
If the option is not checked, its intrinsic 96PPI is used. That results
in a width of 147/96 inch ≈ 1.53 inch
If the option is checked and value 72PPI is set, then the rendered image
width will be
147/72 inch ≈ 2.04 inch
If the option is checked and value 300PPI is set, then the rendered
image width will be
147/300 inch ≈ 0.49 inch
If you change the value in the document properties while the document is
edited, already inserted images are not affected in their size. That is
done by recalculating the scale in the crop tab of the image property
dialog.
Example:
The image was originally inserted with value 300PPI in the document
properties. Thus its width is 0.49 inch.
Now you change the document property value to 72PPi. That would result
in a width of 2.04 inch.
For to keep the already existing width, but now with 72PPI, the scale is
reduced to
72/300 = 0.24 = 24%
The setting in the document properties does not change the image itself,
but only affects the size at which the image is drawn.
This setting is only useful if you know that you have a large number of
images to insert, all of which have a very high PPI value, or all of
which have a very low PPI value, or none of which have a PPI value at
all. Otherwise, you can also use the Crop dialog directly for scaling.
Kind regards,
Regina
