[syncfusion_flutter_pdf] Checkboxes (☑ / □) not displayed — PDF uses ZapfDingbats font

[gltiennd]

Bug description

I have a PDF file that contains checkboxes rendered using the ZapfDingbats font. When opening this PDF in a Flutter application using SfPdfViewer.network(...), the checkboxes do not appear. The boxes look empty or completely invisible.

However, the same PDF displays correctly in Adobe Acrobat, Chrome PDF Viewer, and macOS Preview, so the issue seems related to the rendering inside syncfusion_flutter_pdfviewer.

Here is the sample PDF used to reproduce the issue:
PDF URL:
https://dragonxstaging2.blob.core.windows.net/userdocument/UserPortfolio/34a01231-b649-429d-a00e-7d7b143a3be0/Preview_Contract_34a01231-b649-429d-a00e-7d7b143a3be0_Signed_202511070602408523.pdf?sv=2021-12-02&se=2025-12-10T10%3A44%3A18Z&sr=b&sp=r&sig=Ro3vwD9Nj8BnMpvVWv6JPXki9w1UTp1qCSMMrXt7VAE%3D

Steps to reproduce

1. Create a Flutter project with the syncfusion_flutter_pdfviewer package.

2. Load the PDF using:

SfPdfViewer.network('https://dragonxstaging2.blob.core.windows.net/userdocument/UserPortfolio/34a01231-b649-429d-a00e-7d7b143a3be0/Preview_Contract_34a01231-b649-429d-a00e-7d7b143a3be0_Signed_202511070602408523.pdf?sv=2021-12-02&se=2025-12-10T10%3A44%3A18Z&sr=b&sp=r&sig=Ro3vwD9Nj8BnMpvVWv6JPXki9w1UTp1qCSMMrXt7VAE%3D');

3. Run the app on Android/iOS.

4. Observe that the checkboxes do not appear.

5. Compare with opening the same PDF in Adobe Acrobat or Chrome — all checkboxes display normally.

Code sample

Code sample

SfPdfViewer.network(
          controller.pdfUrl.value,
          enableDoubleTapZooming: true,
          enableTextSelection: true,
          canShowScrollHead: false,
          canShowScrollStatus: false,
          onDocumentLoadFailed: (PdfDocumentLoadFailedDetails details) {
          },
        );

Screenshots or Video

Screenshots / Video demonstration

Stack Traces

Stack Traces

[Add the Stack Traces here]

On which target platforms have you observed this bug?

iOS, Android

Flutter Doctor output

Doctor output

[Add your output here]

[immankumarsync]

Hi @gltiennd,

We are able to replicate the reported issue where the check mark in the checkboxes is not rendered in a specific PDF document. Currently, we are validating this issue and will provide further updates on December 16, 2025.

Regards,
Imman Kumar P

[immankumarsync]

Hi @gltiennd,

We have confirmed that the issue where the check marks of certain checkbox fields are not rendered on a specific PDF document is a defect in our product and logged a bug report for the same. The fix for this issue will be included in the weekly release scheduled for December 30, 2025.

Please use the feedback link to track the status of the bug, Checked state is not rendered for certain checkbox fields on a specific document

Disclaimer: "Inclusion of this solution in the weekly release may change due to other factors including but not limited to QA checks and works reprioritization."

Regards,
Imman Kumar P

[immankumarsync]

Hi @gltiennd,

We have resolved the issue where the check marks of certain checkbox fields are not rendered on a specific PDF document, and the fix has been included in the latest weekly release.

Package link: syncfusion_flutter_pdfviewer v32.1.20

Root cause:
The PdfRadioButtonListField items were relying only on the /Kids array in the field dictionary, which was missing in the provided PDF. We fixed this by adding a fallback: if /Kids is absent, the code checks the /Parent dictionary for child entries; if none exist, it uses the field’s own dictionary as a single PdfRadioButtonListItem when the item has a non-empty value.

We thank you for your support and appreciate your patience in waiting for this release. Please get in touch with us if you require any further assistance.

Regards,
Imman Kumar P