Calligra/Libs/KoAbstraction

Introduction

KoAbstraction is a library utilizing facade design pattern in order to simplify implementation of custom graphical interfaces for various applications.

Status: experimental, in development for 2.4.

Strategically, it's a showcase of #1 KOffice's advantage: portability and flexibility of the core, unmatched independence of the GUI. So far in my opinion we have not encouraged 3rd-parties to use this strength very consequently. It's much easier to expose this strength than first competing in area of features with mature competitors. --jstaniek

This is follow up of KOffice core re-usability request raised for the first time at Akademy 2005, and just recently discussed in Essen 2010 Sprint.

Implementation provided for review at http://svn.reviewboard.kde.org/r/5635/

Applications

Most important possible applications of this tool are:

• Proof of concept koffice app in "100 lines of code or so", for Techbase
  • Status: planning
• Standalone KOffice viewer widget (can be used in Designer!)
  • Status: planning
• Proof of concept koffice app for QML (hot topic!) when the APIs support non-QWidget mode
  • Status: planning
• Proof of concept even higher-level Qt-only API abstracting KOffice core
• Avoiding creating general-purpose code directly in any current and future use of KOffice core by third parties, assuming that there is a will to collaborate
  • Status: Validated, currently it's avoiding creation of general-purpose code directly in FreOffice, what is part of [1] patch
  • Rationale: previous it was hard not to keep the 3rd-party UI implementation outside of koffice/ source code tree because implementation of the UI may depend on KOffice internals or unstable API; maintaining that within the facade API simplifies a number of tasks
  • Other possible ports: port of the Kids Office
• Refreshed KPart, to make it behave in a more modern way
  • Status: planning, let's note down our future needs for integration with Okular
• Integration with plasma (non-QWidget target)
  • Status: planning

All the above is not limited to mobile technologies, and heavily validates quality of the code base and design.

See Also

Technologies utilizing similar concepts: WebKit, Plasma, KDE libs, and Qt itself

TODOs

• A lot of functionality that stays in f-office for now, including code for formatting. It's is planned for the KoAbstraction.
• Identify methods that would have better not be pure virtual. But note: providing empty methods instead of pure virtuals makes the usage more error prone for developers. The solution could be to group the API into several aspects: viewer/editor and kword/kpresenter/kspread. Then developers can pick their "taste" for their implementation.
• Document selector with live document preview with kinetic scrolling; like on iWork for iPad but more universal
• Document zoom for touch devices
  • Optimized multi-touch zoom for documents
  • Single-tap zoom feature for documents, for devices lacking multi-touch (which N900 also is)
• Shape scaling and rotationg for touch devices
  • Multi-touch scaling and rotation for shapes
  • Single-tap scaling and rotation for shapes