Dynamic Layout Support Discussion

Structured Layout Styles for Scribus

Creating complex, one-time document layouts in Scribus is easy thanks to its precise, yet easy to use frame-based interface. But often it would be desirable to create a carefully-constructed layout style that can be reused for many documents with the same general structure, that can adapt to small variations in content. This would also mean that the same content can be dynamically reformatted by applying a different layout style.

Due to the many different usage possibilities offered by this concept and the many specific features that could be useful, I plan to implement a general framework to support structured layout that can be adapted and extended to many different purposes. I will then implement a few specific applications of it in Scribus. The core of the framework will be a self-contained c++ class library for manipulating abstract structured objects and the relationships between them, designed to be usable by multiple applications in the future.

The system will be based on sequences of objects (in this case, text or image frames in a layout). Each object in a sequence can have its attributes defined relative to the previous object or the parent object (the sequence itself). Thus, frames can be kept equally spaced as their size changes, or distributed equally across the page. Other attributes, such as color, size, and even content, can be set to be the same for an entire sequence also, so that linked object "clones" will also be a possibility.

Finally, sequences can be nested or even overlap, and sequence styles can be defined and applied to any sequence with a compatible structure. Sequence styles can both define the layout (relative positions) of objects and apply specific formatting styles to each object in the sequence, so the entire look of a document can be changed by changing its style.

Initially, I will provide support in Scribus for sequences of frames in a document, by adapting the existing layout code to call my library to find the objects' positions and attributes. Eventually, it could be integrated into the text layout engine as well to provide more fine control over text layouts, even allowing for specific needs such as rendering equations from latex or user-defined sources.