Seeing the weired behaviour in flowchart, Connected arrows are missing

[piyushmagarde]

We are not getting the the arrows joining the differnt components in flowchart when we are using "export": "png". It starts giving this issue from afternoon

but in the edit mode it shows the arrows

Can someone provide an provide why arrows are missing from when trying to load png

[draw-io-triage-bot[bot]]

👋 Thank you for opening this issue!

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Summary: The user reports that connecting arrows between shapes are missing when exporting or rendering a flowchart as PNG, even though the arrows are visible in edit mode. The issue appears to have started suddenly, suggesting a possible regression or server-side rendering change.

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📝 Additional Information Needed

To help us investigate this more effectively, could you please provide:

• Environment: Which platform are you using draw.io on? (web at app.diagrams.net, desktop app, Confluence, etc.) What browser and OS are you using?
• Steps to reproduce: How exactly are you exporting to PNG? Are you using the menu (File > Export as > PNG), the API, or an embed/viewer mode? You mention 'export': 'png' in quotes suggesting a programmatic/configuration approach — please clarify.
• draw.io version: What version of draw.io are you using? This can be found in Help > About.
• Diagram XML or .drawio file: Can you share the diagram XML or .drawio file so the issue can be reproduced? This is critical for debugging rendering issues.
• Embed/viewer context: Are you embedding the diagram using the embed viewer (e.g., with URL parameters like 'export=png')? The syntax you used suggests you may be using an embed or API integration — please clarify the exact integration method.
• Timeline details: You mention 'It starts giving this issue from afternoon' — does this mean it was previously working fine with the same diagram and suddenly stopped? Did anything change (update, browser change, etc.)?

We also have some questions:

• Are you using draw.io's embed mode or viewer with a configuration parameter like "export": "png"? If so, can you share the full embed URL or configuration?
• Does the issue occur with all diagrams or only specific ones? Can you try creating a simple diagram with just two shapes and one arrow to see if the issue persists?
• If you export to SVG or PDF instead of PNG, do the arrows appear correctly?
• Have you tried clearing your browser cache or using a different browser to see if the issue persists?
• Are the arrows using default styling, or do they have custom styles (e.g., curved, orthogonal, specific colors)?

📋 Bug Report Template

**Environment:**
- draw.io version: [e.g., web app / desktop 24.x.x / Confluence plugin]
- Browser (if web): [e.g., Chrome 120, Firefox 121]
- OS: [e.g., Windows 11, macOS 14, Ubuntu 22.04]

**Steps to Reproduce:**
1. Go to ...
2. Click on ...
3. See error

**Expected Behavior:**
What you expected to happen.

**Actual Behavior:**
What actually happened.

**Screenshots/Files:**
If applicable, add screenshots or attach the .drawio file.

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_{🤖 This is an automated response to help with initial triage. A human maintainer will review this issue. If you've provided all the requested information, no further action is needed - we'll get back to you soon!}

[piyushmagarde]

Are you using draw.io's embed mode or viewer with a configuration parameter like "export": "png"? If so, can you share the full embed URL or configuration?
Answer: Embed mode with export: png
src="https://embed.diagrams.net/?embed=1&proto=json&spin=1&libraries=1&ui=min&read=1&noFocus=1"
if (msg?.event === "load") {
if (exportTimeoutRef.current) clearTimeout(exportTimeoutRef.current);

    exportTimeoutRef.current = setTimeout(() => {
      iframe.contentWindow?.postMessage(
        JSON.stringify({
          action: "export",
          format: "png",
          scale: 2,
          border: 10,
          transparent: false,
          background: "#ffffff",
        }),
        "*",
      );
    }, 300);

Does the issue occur with all diagrams or only specific ones? Can you try creating a simple diagram with just two shapes and one arrow to see if the issue persists?
Answer: we are passing XML data to draw.io and its geenrating the diagram on its own.
If you export to SVG or PDF instead of PNG, do the arrows appear correctly?
Answer: No, i tried using svg also but didnt work
Have you tried clearing your browser cache or using a different browser to see if the issue persists? Answer: Yes.
Are the arrows using default styling, or do they have custom styles (e.g., curved, orthogonal, specific colors)? Answer: default styling