Why will the intersection of two line become white

[Doctor748]

OS version = windows 11 pro 22H2 (22621.2715)
LO version = 7.6.2.1 (x86_64)

Currently i am working on my assigment. i prefer to do it in onenote and export it as pdf. When i try to edit my assignment in libre draw, i found that the intersection of those string become white.(just like the img, the handwriting line contain some white point which is not exist in the original file.) i sure i did nothing to the file. the setting of libre office is also defult except i turn on the “force skia software rendering” and turn off OpenCL cause my cpu have no gpu intergrated and it will very slow when i turn it on and start editing my assignment.

Tell me if it can be tweak inside the setting plz.

i am using my laptop, ROG flow Z13 with asus pen to input handwriting.

my pc spec is
i7 14700kf with Z790 motherboard
4070TI

[ajlittoz]

Please edit your question to reword it (=modify it, don’t use a comment or,worse, an answer). As is, we have absolute no idea of the problem.

Start by naming your OS and LO version.

How do you enter what looks like handwriting? With mouse? Some graphical pad and stylus? Which tool is enabled in Draw while you’re doing this?

What do you mean by “intersection”? Do you add some hand writing over the previous one?

Attach the sample file since a screenshot don’t allow to experiment.

[Doctor748]

ok i edited it , is it enough to find the problem?

[ajlittoz]

Attach a sample 1-page PDF.
What is “onenote”? Does it create directly the PDF?
Be aware that LO considers PDFs as graphics file and they open in Draw to be edited like images. Don’t expect any other function because Draw is not a PDF viewer, even less a PDF editor.
Does the “whiting” appear while you edit the PDF in Draw? Does is already exist when you open the file?

[Hrbrgr]

@ajlittoz , to the info:

Onenote is a Windows-App, example:

[Doctor748]

before LO saved.pdf (579.9 KB)
this is how it suppose to be look like.

after LO saved.pdf (812.2 KB)
this is how it look like right now, and i did nothing except save it using LO. it also occur when editing.

This problem will not appear when i write with mouse on my desktop. But all handwriting from my laptop will appear this problem.

this is my pdf export option

[ajlittoz]

The “before LO saved” displays correctly under any PDF viewer and even after importing into GIMP. The “whiting” appears as soon as I open the file in Draw. No processing or editing has already taken place. This means the “whiting” is inherent to the way Draw interprets the PDF.

I see that the image is a collection of strokes. A stroke is a path between down-“click” and up-‘click’ of your stylus. It is likely recorded as a sequence of “moves” for this path. I can’t tell because the various strokes are hidden under a compression algorithm and I didn’t spend the pain to retrieve clear-text. It may be encoded as an SVG path or something similar.

The “whiting” makes me think of an XOR-like property for the stokes. If the stylus creates an intersection with 2 moves over a single point black XOR black = white. With 3 moves black XOR black XOR black = black. An even number of overlays = white, an odd number of overlays = black.

Draw probably interprets too strictly the drawing instructions while PDF viewers use more relaxed rules. Draw-exported PDF reflects exactly what it has understood.

From my point of view, there is no bug. Probably OneNote has given wrong attributes to the strokes. See if can change some settings relative to graphical “algebra” modes. I remembr, long ago, you could specify the drawing mode as OR, AND, XOR, NOR, NAND, … and more sophisticated modes with colour.

[mikekaganski]

FTR: OP has created tdf#158246. Thanks!

[Doctor748]

Nope i can not find something that similar to graphical “algebra” modes, i don’t know where to change it. I can only edit the pattern of stroke but none of them can change drawing mode to “AND” option. Do you know where i can change it?

[ajlittoz]

Can you attach the original SVG? I don’t know how to extract it from the PDF (it is encoded – Base64?).

[keme1]

I added a PDF demonstrating the issue to the bug report, with my observations in the comments.

It seems that when an object with bold line curls up on itself, the overlap is XOR-ed. This does not happen when separate objects overlap. Neither do objects drawn with default line width for the OneNote “pen” tool yield this “rendering artifact” (the thinner line scribble at the top).

[keme1]

@ajlittoz

Can you attach the original SVG?

The embedded object may be a SVG, IDK, but to the end user there is no “original svg” available (not in the versions I have available, at least). Assuming that the OP uses a fairly recent version of OneNote, the concept of “save to file” is not applicable. The notebook content is inherently saved in the “Microsoft ecosystem” (locally or to OneDrive, but not visible as a file) upon entry.

Also, I find that I can’t copy graphics from OneNote and paste into “foreign” apps like LO Draw. I can paste into other MS apps, and copy the pasted objects for subsequent pasting into LO. The overlap artifacts then disappear.
This supports your suspicion that the issue is caused by some Microsoft internals, which other PDF-supporting apps treat differently. I guess that doesn’t help much, but just in case: attached is a Draw file with my scribble intermediately pasted into MS Word, and copied from there.
copypastetwice.odg (49.0 KB)