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Content controls in Writer: dropdown, picture and date types

Posted on: Wed 01 June 2022

Estimated read time: 5 minutes

Writer already had rich text and checkbox content controls: a new way to set properties on a piece of text, primarily for form filling purposes. This feature now gained 3 additional types: dropdown, picture and date picker types. This improves compatibility with the DOCX format: there are now 5 inline content control types we can now import.

https://share.vmiklos.hu/blog/sw-content-controls2/feature.png
Figure 1. Word-style inline content controls in Writer.

First, thanks to NGI DAPSI who made this work by Collabora possible.

https://share.vmiklos.hu/blog/sw-content-controls/eu.png
Figure 2. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871498

Motivation

Word users expect to be able to import their document to Writer and experience a matching feature set: form filling is not an exception. Word provides several content control kinds (inline, block, row and cell content controls), this project focuses on inline ("run") content controls.

In the scope of inline content controls, the above linked blog post already described the rich text and checkbox types. In this post, we’ll focus on the new dropdown, picture and date content controls.

You might wonder why content controls are useful, since Writer already has form controls and fieldmarks, which provide something similar. Here are some benefits:

  • Dropdown content controls have a list of dropdown items. Each item is a display-text and value pair, allowing to differentiate between a human-readable string and a machine-readable value. Fieldmarks only handled (machine-readable) values, resulting in document text different from Word.

  • Picture content controls allow the author of a form to pre-format the image before the filler of the form inserts the actual image. Writer already had placeholder fields for images in the past, but that was just text, allowing image format only after insertion of the actual image.

  • Date content controls were emulated with Writer fieldmarks in the past, which created trouble during export, since Word itself doesn’t have a date form-field.

Results

The feature consists of menu items to insert dropdown/picture/date content controls, and then you can interact with the inserted content controls or with their properties:

https://share.vmiklos.hu/blog/sw-content-controls2/menu.png
Figure 3. Menu items to insert drop-down, picture and date content controls.

Drop-down content controls show a dropdown button when you’re inside the content control:

https://share.vmiklos.hu/blog/sw-content-controls2/dropdown.png
Figure 4. A drop-down content control.

This is similar to dropdown fields, just allows display-text and value pairs, not limited to just values.

Picture content controls contain a single as-character image, but you can interact with them: clicking on the content control opens the file open dialog to provide a replacement for the placeholder:

https://share.vmiklos.hu/blog/sw-content-controls2/picture.png
Figure 5. Picture controls.

And these content controls can be saved to ODT and DOCX.

There is also a content control properties dialog, which allows setting if the content controls are in placeholder mode or not:

https://share.vmiklos.hu/blog/sw-content-controls2/properties.png
Figure 6. Content control properties.

It has additional widgets for dropdowns. There is UI to create, update or delete these list items:

https://share.vmiklos.hu/blog/sw-content-controls2/properties-inner.png
Figure 7. Content control properties inner UI for list items.

How is this implemented?

If you would like to know a bit more about how this works, continue reading… :-)

As usual, the high-level problem was addressed by a series of incremental commits:

To make this more interesting, Rashesh Padia of Collabora continued exposing this in Collabora Online, see the PR at https://github.com/CollaboraOnline/online/pull/4803.

Want to start using this?

You can get a snapshot / demo of Collabora Office 22.05 and try it out yourself right now: try unstable snapshot. Collabora intends to continue supporting and contributing to LibreOffice, the code is merged so we expect all of this work will be available in TDF’s next release too (7.4).

Category: libreoffice – Tags: en

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