Bug report: Custom part SVG silently fails to render in Fritzing 1.0.7 on macOS

[cortinagil]

Dear Fritzing team,

I am writing to report a significant issue with custom part rendering in Fritzing 1.0.7 on macOS that makes it impossible to use certain third-party parts.

The problem:
When importing a custom .fzpz part (specifically the Analog Discovery Studio part from Digilent), the part appears briefly on the breadboard canvas and then immediately disappears. No meaningful error message is shown to the user — the part simply vanishes after being dragged.

After extensive investigation, I identified several root causes:

1. Qt SVG renderer limitations: Fritzing's Qt-based SVG renderer silently fails on SVGs containing certain elements or attributes that are valid SVG but unsupported by Qt, including:

   • CSS <style> blocks with class-based selectors (Qt ignores them, making all elements invisible)
   • linearGradient elements
   • tags
   • bare elements with no attributes
   • custom attributes such as data-* and gorn=

2. Shape complexity limit: Qt's SVG renderer appears to have an undocumented limit on the number of shapes it can render. SVGs with more than approximately 700 shape elements cause the renderer to silently fail and the part disappears.

3. File extraction behavior: Fritzing 1.0.7 on macOS extracts only the .fzp file from the .fzpz archive to disk, but reads SVG files directly from the original zip archive. This behavior is undocumented and different from what the Fritzing documentation implies.

The Digilent Analog Discovery Studio breadboard SVG contains approximately 6,931 shape elements (representing the breadboard holes and component details), which far exceeds the rendering limit.

System information:

• Fritzing version: 1.0.7
• macOS version: current
• Part: Analog Discovery Studio by Digilent

I am happy to provide the modified .fzpz files and SVGs I produced during debugging if that would be helpful.

Thank you for your time and for maintaining Fritzing.

Best regards,
Eduardo Cortina Gil

[KjellMorgenstern]

Can you please attach the part?

How did you determine the 700 shape limit? I think it is more likely to be a size limit. If the SVG uses a scale of 10000 dpi or more you quickly end up with internal rasterization of more than 100 megapixels (a "pixel bomb"), which triggers a cutoff.

Because github also protects against such SVGs, try uploading the packaged part, not the SVG.

[cortinagil]

ads_original.fzpz.zip

Dear Kjell,

Here is the original part. I just added a .zip to let the file upload. you should rename it. I
The 700 limit I got it just restricting the number of shapes directly in the .svg. (thanks Claude!)

[KjellMorgenstern]

Can you post the exact version hash that Fritzing shows in the about screen?
The file loads a bit slow, and linter shows plenty of issues (CSS use, dead connector references etc) , but basically works fine.

[cortinagil]

It is the last version.
Here it is:
Version 1.0.7
(CD-2576-0-394a8bb4 2026-04-14) Cocoa [Qt 6.8.3]

[jfmorgenstern]

I tried it on an M2 MacBook Air with Tahoe.

When I drag and drop the part directly, it pops up and then disappears shortly afterwards.

However, when I drag it from the parts inspector to the breadboard view, wait for it to appear, and then drop it, it stays and I can interact with it as expected.

I don't see it in schematic or PCB view (?)

[KjellMorgenstern]

@cortinagil Can you elaborate more on point 3? What documentation are you referring to? Filename or link please.

The fzpz is an archive, and all the files, fzp+svg are read from it, and stored in a parts directory derived from the parts moduleID. If you run Fritzing < 1.0.7 and Fritzing = 1.0.7 at the same time, this can cause a conflict in file strucure. Recoverable, since the original fzpz is not touched, and resolved in 1.0.8. But running two different versions at the same time is a bit of an edge case, mostly affects developers only.
It could however explain some hard to reproduce effects.

[cortinagil]

Thanks a lot Josh! I tried your recipe and it works also for me. It’s slow to place the part, but at least it works. On 9 Jun 2026, at 15:37, Josh Morgenstern ***@***.***> wrote: Vous n’obtenez pas souvent d’e-mail à partir de ***@***.*** Pourquoi c’est important<https://aka.ms/LearnAboutSenderIdentification> [https://avatars.githubusercontent.com/u/18153740?s=20&v=4]jfmorgenstern left a comment (fritzing/fritzing-app#4316)<#4316 (comment)> I tried it on an M2 MacBook Air with Tahoe. When I drag and drop the part directly, it pops up and then disappears shortly afterwards. However, when I drag it from the parts inspector to the breadboard view, wait for it to appear, and then drop it, it stays and I can interact with it as expected. I don't see it in schematic or PCB view (?) — Reply to this email directly, view it on GitHub<#4316?email_source=notifications&email_token=AJSIRGCHZT3F2GOKU234CI347AHHZA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGAZDKOJSGE2KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L#issuecomment-4660259214>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AJSIRGEITPKTRY2NWHEO6T347AHHZAVCNFSM6AAAAACZ64TOVGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DMNRQGI2TSMRRGQ>. Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS<https://github.com/notifications/mobile/ios/AJSIRGBTWNZSJBYGCPVL5XT47AHHZA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGAZDKOJSGE2KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2KUZTPN52GK4S7NFXXG> and Android<https://github.com/notifications/mobile/android/AJSIRGA2NAE5YM76EKSMJZT47AHHZA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGAZDKOJSGE2KM4TFMFZW63VGMF2XI2DPOKSWK5TFNZ2K4ZTPN52GK4S7MFXGI4TPNFSA>. Download it today! You are receiving this because you authored the thread.Message ID: ***@***.***>

[cortinagil]

Yes, I took care not to run both versions at the same time and I took care to “clean” the users area and reinstalling the part when changing from one version to the other. On 9 Jun 2026, at 17:26, Kjell ***@***.***> wrote: Vous n’obtenez pas souvent d’e-mail à partir de ***@***.*** Pourquoi c’est important<https://aka.ms/LearnAboutSenderIdentification> [https://avatars.githubusercontent.com/u/6494025?s=20&v=4]KjellMorgenstern left a comment (fritzing/fritzing-app#4316)<#4316 (comment)> @cortinagil<https://github.com/cortinagil> Can you elaborate more on point 3? What documentation are you referring to? Filename or link please. The fzpz is an archive, and all the files, fzp+svg are read from it, and stored in a parts directory derived from the parts moduleID. If you run Fritzing < 1.0.7 and Fritzing = 1.0.7 at the same time, this can cause a conflict in file strucure. Recoverable, since the original fzpz is not touched, and resolved in 1.0.8. But running two different versions at the same time is a bit of an edge case, mostly affects developers only. It could however explain some hard to reproduce effects. — Reply to this email directly, view it on GitHub<#4316?email_source=notifications&email_token=AJSIRGCL4XLM3OPFDJLQKRD47AUCHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGEZDMOBSGMYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-4661268230>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AJSIRGFS72KJ25VAIKE54WL47AUCHAVCNFSM6AAAAACZ64TOVGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DMNRRGI3DQMRTGA>. Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS<https://github.com/notifications/mobile/ios/AJSIRGHFRVWVHMFNPBUIG5347AUCHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGEZDMOBSGMYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJKTGN5XXIZLSL5UW64Y> and Android<https://github.com/notifications/mobile/android/AJSIRGF3FOOKZYGZEDC7FFD47AUCHA5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTINRWGEZDMOBSGMYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLTGN5XXIZLSL5QW4ZDSN5UWI>. Download it today! You are receiving this because you were mentioned.Message ID: ***@***.***>

[KjellMorgenstern]

I think the issue might be: You expected the part to be added directly to the sketch. Fritzing behavior however is, to import the part to "My Parts" bin.

That this large part loads slow probably doesn't help.

This is more an UX issue than an actual bug.
An improvement could be to focus the my parts bin, and preselect the part to show it also in the Inspector.

Anyway I think there are also two severe issues with the part itself:

• The distance between row E and row F should be 300mil, but it is only around 250mil. Most standard DIP components won't fit. The original part has a 300mil distance:

• It is using using the part layer for the breadboards, not the breadboard layer (see by disabling the layers in View menu).