Rendering issue (mismatch with other SVG libraries)

Question

Rendering issue (mismatch with other SVG libraries)

m-carrasco opened this issue a year ago · comments

Hi,

I found this SVG file causing LunaSVG (b66e224) to generate a different image to GNOME Image Viewer (v3.36.3), ReSVG (v0.29.0), and Firefox (v111.0).

LunaSVG PNG

The PNG generated by LunaSVG mismatches in drawing the two-ends tail of the triangle, at the top left side of the image. The next image is a side by side comparison of LunaSVG (top) and Image Viewer (bottom), and the mismatch region in red (added by me):

If possible, I'd like to ask/confirm if this is a bug in LunaSVG or it is a legal difference between the SVG libraries.

Thanks for sharing this project o/

Best regards,
Manuel

Samuel Ugochukwu · Answer 1 · Fri Mar 24 2023 20:25:54 GMT+0800 (China Standard Time)

Dear Manuel,

After investigating the issue further, I can confirm that the problem is indeed a bug in LunaSVG. The issue is not related to any legal difference between the SVG libraries.

I am reaching out to request the original source site for the file that you provided. I am currently working on fixing a code bug and I believe that the information on the original source site may be necessary for me to successfully resolve the issue.

Would it be possible for you to provide me with the original source site so that I can access the information needed to fix the code bug? Your assistance would be greatly appreciated and I look forward to hearing back from you soon.

Best regards,
Sam

Manuel Carrasco · Answer 2 · Sat Mar 25 2023 04:01:57 GMT+0800 (China Standard Time)

Hi Sam,

Thanks a lot for checking on this bug!

I am reaching out to request the original source site for the file that you provided. I am currently working on fixing a code bug and I believe that the information on the original source site may be necessary for me to successfully resolve the issue.

The reported SVG file was generated by us in the context of our research. I am not sure if I understand what you mean by source site. Could you tell me what information in specific would be helpful to solve the bug?

Best regards,
Manuel.

Samuel Ugochukwu · Answer 3 · Mon Mar 27 2023 18:06:21 GMT+0800 (China Standard Time)

Could you please provide an explanation of the purpose of this file in relation to bug testing?

For instance, this file was created to be used for testing the behavior of the round line-cap when applied to paths with zero length? #40

Manuel Carrasco · Answer 4 · Mon Mar 27 2023 21:00:45 GMT+0800 (China Standard Time)

Hi Sam,

I can't provide a particular use case for the given input since the SVG has been generated in an automated way. We understand that the SVG specification determines the semantics of the test case and the expected behaviour is validated by checking the result with different SVG libraries (as reported).

Our research goal is to automatically generate a valid SVG for LunaSVG, which exhibits a rendering bug. The technique analyzes LunaSVG and ensures generating an SVG that LunaSVG accepts. Then, we classify it as a bug when there is a divergence with several other SVG rendering libraries.

Thanks again for your time!

Best regards,
Manuel.