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IDProjectCategoryView StatusLast Update
0016940ScribusPDFpublic2023-06-19 21:14
ReporterMoplanti Assigned To 
PrioritynormalSeverityminorReproducibilityalways
Status newResolutionopen 
Product Version1.5.8 
Summary0016940: Transparency gradient on transparent PNGs not working in PDF 1.6
DescriptionPNG-images with transparent background embedded in Scribus, which have assigned linear gradient transparency, are not generated correctly as PDF 1.6 (or lower). When viewing the PDF in Acrobat Reader, Foxit Reader, Okular, mupdf and evince, the transparent gradient is not shown and the image has no assigned transparency at all.

Firefox and Waterfox are showing the transparency correctly. Also when exporting the document as an image, the linear gradient transparency is fine.
TagsNo tags attached.
PatchNo

Activities

Moplanti

2023-05-09 06:58

reporter  

Image1.jpg (96,247 bytes)   
Testdruck 1.0.pdf (55,679 bytes)
Testdruck 1.0.sla (205,223 bytes)   

Moplanti

2023-05-09 07:05

reporter   ~0050160

Thread: https://forums.scribus.net/index.php/topic,4586.new.html

JLuc

2023-06-11 10:58

developer   ~0050214

Last edited: 2023-06-11 11:45

I seem to also have PDF issues with included PNG transparencies on scribus 1.5.8 (23 Janvier 2022 appimage version),
without gradients btw.
The forum thread mentions gimp as a possible fix but i dont understand how that's a solution or maybe just a way to understand where is the issue.
What is actually the way to produce correct PDFs using PNGs with transparencies ?

Hmm this is not the same issue since no scribus gradient is involved.

JLuc

2023-06-11 12:15

developer   ~0050216

Actualy there is an issue with produced PDF when using an image frame containing an image (a JPG also) and having a transparency gradient.

The workarounds i used is : use an empty white frame (because background is white) with transparency gradient, on top of image frame and under other components.

jghali

2023-06-19 21:14

administrator   ~0050235

It looks like combining an image mask with a gradient mask in PDF might be a bit tricky. Currently I do not see how to do this.

In PDF ISO 32000 specs, we can read this beside SMask entry for Image Dictionaries (point 8.9.5.1) :
"If present, this entry shall override the current soft mask in the graphics state, as well as the image’s Mask entry, if any. However, the other transparency-related graphics state parameters—blend mode and alpha constant—shall remain in effect."

Reading this, my conclusion is also that Firefox and Waterfox rendering, while showing the desired result, are not conformant to specs.

Issue History

Date Modified Username Field Change
2023-05-09 06:58 Moplanti New Issue
2023-05-09 06:58 Moplanti File Added: Image1.jpg
2023-05-09 06:58 Moplanti File Added: Testdruck 1.0.pdf
2023-05-09 06:58 Moplanti File Added: Testdruck 1.0.sla
2023-05-09 07:05 Moplanti Note Added: 0050160
2023-06-11 10:58 JLuc Note Added: 0050214
2023-06-11 11:00 JLuc Note Edited: 0050214
2023-06-11 11:00 JLuc Note Edited: 0050214
2023-06-11 11:45 JLuc Note Edited: 0050214
2023-06-11 12:15 JLuc Note Added: 0050216
2023-06-19 21:14 jghali Note Added: 0050235