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IDProjectCategoryView StatusLast Update
0016886ScribusPDFpublic2023-01-24 17:01
Reporterpmjdebruijn Assigned To 
Status newResolutionopen 
Product Version1.6.0.svn 
Summary0016886: PDF Maximum Image Resolution (resampling) isn't enabled by default
DescriptionI think RecalcPic, image resampling to (by default) 300dpi should be enabled by default.

The vast majority of print shops / print on demand services effectively recommend this.

And even for digital (online) publishing, having images with more resolution just means PDFs are slower to download/render.

So the use cases where you wouldn't want to resample your images (the current default), seem at best uncommon.
TagsNo tags attached.



2023-01-08 17:13


appprefs_recalcpic.patch (580 bytes)   
diff -Nurpd a/scribus/prefsmanager.cpp b/scribus/prefsmanager.cpp
--- a/scribus/prefsmanager.cpp	2023-01-08 13:38:08.727923073 +0100
+++ b/scribus/prefsmanager.cpp	2023-01-08 12:29:46.000000000 +0100
@@ -458,7 +458,7 @@ void PrefsManager::initDefaults()
 	appPrefs.pdfPrefs.Compress = true;
 	appPrefs.pdfPrefs.CompressMethod = PDFOptions::Compression_Auto;
 	appPrefs.pdfPrefs.Quality = 0;
-	appPrefs.pdfPrefs.RecalcPic = false;
+	appPrefs.pdfPrefs.RecalcPic = true;
 	appPrefs.pdfPrefs.embedPDF  = false;
 	appPrefs.pdfPrefs.Bookmarks = false;
 	appPrefs.pdfPrefs.PicRes = 300;
appprefs_recalcpic.patch (580 bytes)   


2023-01-23 20:49

administrator   ~0049968

Last edited: 2023-01-23 20:50

Well, I know that InDesign enables resampling by default, but I'd be cautious over enabling image resampling by default in Scribus due to insufficient control on resampling. In one of my former company, we explicitly recommended our customers to disable image resampling settings in InDesign:
- image resampling can hurt image quality, especially when resampling for eg a 320dpi image to 300dpi
- image resampling is generally to be avoided for 1bit images
- raster images containing text usually benefits from resolution over 300dpi, text being a bit fuzzy at 300dpi.

Basically we need to implement 0002745 in order to enable resampling for grayscale/color images safely.


2023-01-24 17:01

reporter   ~0049971


[1] isn't that mostly a matter of resampling algo's? I see PDFLib uses Qt::SmoothTransformation which is in essence bilinear, which explains that, so this isn't really an issue with resampling as a concept, but an issue with the implementation of resampling, something like Lanczos2 would probably be a lot better, and mostly solve this issue. But that won't be a trivial change of course.
[2] I guess that makes sense, wouldn't converting to greyscale before resampling mostly solve this?
[3] Shouldn't corner cases like that be handled via an additional combo box like an image frame has for PDF Compression where Method/Quality default to Global, but then for Resolution...

Issue History

Date Modified Username Field Change
2023-01-08 17:13 pmjdebruijn New Issue
2023-01-08 17:13 pmjdebruijn File Added: appprefs_recalcpic.patch
2023-01-23 20:49 jghali Note Added: 0049968
2023-01-23 20:50 jghali Note Edited: 0049968
2023-01-23 20:50 jghali Note Edited: 0049968
2023-01-24 17:01 pmjdebruijn Note Added: 0049971