User:Jstaniek/Calligra Sprint 2011.2 presentation

My Plans

Why Kexi? - introduction for Calligra Developers
Sharing Kexi's CSV import/export engine within Calligra
Eating our dog food: use Kexi, Tables, Plan, etc. in our work

Optional topic: Better separation between engine and UI

Other Plans

(from https://sprints.kde.org/sprint/43)

Shreya: Improving UI and features of Kexi Web Element,fixing bugs, Multimedia in Kexi
Dimitrios:
- Need for Interoperability between Calligra apps
- UI perspective from a non developer
- Promoting Calligra
- Plug-ins K.I.S.S. proposal
- Calligra and DTP (ideas)
- Kexi Documentation / Making documentation roadmaps
Radek: bug hunting in kexi, futher maps plugin expand

Outline

Calligra Branding

Since the day one Calligra is THE new quality!
Contributors want recognition for THEIR work
Contributors take responsibility for THEIR work
Contributors don't block derivative works
- but not at cost of their REPUTATION

So we have

Logo vs Icon
Copyright vs Trademark
- Trademark registration: KDE e.V. as Calligra is informal group
- Copyright to be discussed (CC-BY-SA or LGPL)
- Idea: Dual logos (one free, one protected) as Debian
Avoiding Logo misuse: Clear Guidelines
- Usage in context of Calligra Suite: without permission
- Usage as source for derivatives: MUST BE out of context of Calligra Suite
- It's up to Calligra contributors to react on logo misuses and suggest right solution

Why Kexi? - introduction for Calligra Developers

Why db apps:

Databases vs Spreadsheets [1]

The Kexi Project

Started in 2002
- with KOffice/Calligra from the day one
Had full-time contributor in 2003-2007
First nontrivial KDE app on Windows
- Driving force of the KDE on Windows project
Maintained with one consistent vision since 2003
Not a MS Access clone
- less tied to the file db specifics than MS Access
- GUI does not mimick MS Access
but acknowledges advantages of desktop databases
- aimed at casual users and power users
- almost no database knowledge needed
  - user discovers features while using Kexi
- not much aimed at developers
  - default GUI not cluttered with developer-oriented features
  - lower priorities for these features

Why Kexi instead of server db + php + apache?

offline mode by default and for free
- utilizing lightweight industry-standard SQLite 3[2] file db engine
- empty database is 9KB!
- More popular/standard than LibreOffice base format (because there is no ODF for databases)
point-and-click technology
good for education
good for prototyping
good for preparing quick & dirty "office tools"
really smooth transition from file db to server db

Kexi specifics

Constant time startup! (no matter how big database is)
Cannot edit databases that it did not create
- this may be removed in 3.x to some extent
Kexi is not document-driven
- Even when file db is used, data is saved automatically at record (row) level, not whole database level
Best known for its ease of use, (partial) MS Access support and good CSV support
The GUI has always been specific compared to document-driven apps
- Kexi GUI is consisted of largely separated views (aspects) much like in current KDevelop or Qt Creator
- Large emphasis on concept of data model, data and views
- Customizable GUI
  - also serves as building block for fully-featured user applications
  - Document-driven apps' user content is the central frame
  - Kexi's user content is the whole application main window, with menus, toolbars
  - [picture]
- Modern GUI initiated in 2011 (not 1980s) pushes the differences further, addresses specific needs not met by KDE3 GUIs
  - TODO: show app, search
- Still, Qt Style awarness is kept

Why Kexi and not Qt Designer + Qt/C++ development

no need for tons of glue code
no need for knowledge of database internals/specifics
zero compilation: timesaver, architecture-independent
still, extension APIs blends well with Qt/KDE/C++ development
prepared for good built-in scripting features
- (still experimental due to unstable API, not technology problems)

Competition

Kexi is really competitive compared to FOSS alternatives
- LibreOffice Base is plagued by bad tech decissions of SUN (dependency on Java, tried to be MS Access clone, GUI based on poor framework => usability problems), lack of contributors
- GNOME's Glom[3] is PostgreSQL-only
Zero alternatives in FOSS Qt/KDE world
- KNoda no longer maintained[4]
- Rekall is abandoned

Making Calligra Unique

Plan: develop mail merge within Kexi as a service for use in other apps (especially Calligra apps)
Plan: the same for data entry/import/export support
Idea: the same for forms support
Idea: experiment with reusing Kexi GUI in other Calligra app(s)

Kexi Mobile

N900 loaned to Adam Pigg in October 2010 (Thanks Suresh!)[5]
After two months of development: usable proof of concept - mobile database viewer with forms and reports (KEXI_MOBILE build option)[6]
No development of Qt Quick-based UI for now
- Such UI would be lightweight and very similar to Harmattan Office
- There are plans to start with Kexi Mobile Forms in Qt Quick
- Experience in this technology: Kexi developer Adam Pigg

What's new in 2011

Successfull two GSoC projects: web elements (QtWebKit-based)[7] and map elements (Marble-based)[8]
- Both are good example of code reuse
- Both students (Radek, Shreya) becoming regular contributors!
- This is second Sprint for Radek
Finally: actual and maintained documentation![9]
- Done by Dimitrios, with huge attention to details and knowledge
- Dimitrios becoming Kexi developer too!
- Status: three new developers in 2011!
  - willing to take part in Calligra Academy

Integration idea: Shared Calligra Themes

Theme is a set of styles defining every visual aspect of document
Goal: enabling users to work with styles via themes
- Default theme could be selectable globally in Calligra
- When working on multiple documents in various formats (ODF, Kexi...) having common theme could contribute to more professional effect
- In some aspects theme can define GUI elements that are not well defined by QStyle/KStyle
  - spreadsheet grid and cell styles (Calligra Tables) and database tables grid (Kexi) can have common look defined by a theme; TODO: [mockup]
Current state
- MSOOXML format has notion of themes (default and user defined)
  - references them instead of embedding styles but
- ODF does not define themes, these can be built on top of ODF
Global support for themes can be used:
- in documents (odt, ods, odp)
- in reports of any types, especially KoReports
- in Kexi views, currently forms and tables
TODO: [mockup of Kexi report and Words document]

Integration idea: Sharing Kexi's CSV import/export engine within Calligra

History of CSV import/export features in Calligra
- Originally developed for in Tables
- Re-used by Kexi 0.x, planned for re-integration into Tables, never happened
  - So two copies do exists, Kexi's one is far more advanced
  - Excuse: Kexi's fork still in development, many TODOs

Specifics:
- Import of tabular data
  - so main target applications are Tabes and Kexi
  - secondary use cases: Words and Stage
- CSV export allows to use CSV as exchange format between apps when there is no better option
- In Kexi also used for clipboard handling of tabular data

Integration issues
- Size of codebase: relatively small but quite complicated
- Database-awarness vs Spreadsheet awarness
  - needs smart abstraction some layers to keep maximal efficiency
  - needs abstraction for different GUIs
- Common code can dramatically improve clipboard support for tabular data
  - Type detection
    - TODO: EXAMPLE
  - (Semi-)autodetection detection of structure
    - TODO: EXAMPLE

Integration idea: Kexi Forms for Calligra apps

Scripted functionality in LibreOffice tend to be added via forms with buttons embedded in document exampe invoice form
this is example of bad design, escaping from document paradigm to application paradigm
instead creating flake tool-compatible side-panes could be enabled with a few mouse clicks
GUI for them may be delivered with help of Kexi Form designer
The effect: so the document is not cluttered, stays just document
- the scriped functinality is injected in application(s) instead of injecting into document
Rationale: it may be of scope for Calligra to support VB/StarBasic and forms
- any partial support defined by ODF is not worth effort: compatibility with LibreOffice would have to be high

<piggz> would be very awesome to have a sidebar in words as a plugin that allows
        ad-hoc buttons to be placed that have access to qtscript + the document
        internals
<piggz> qtscipt/kross backends
<piggz> would make words almost as good as reports :)
<piggz> maybe implement in tables first, as spreadsheets have more structure :)
<piggz> and probably more useful there
<piggz> that is likely something i could get my teeth into :)

Eating our dog food

Eat Why?
- Sends clear message: this software is useful
- Testing by fellow contributors is valuable
- Generates usage scenarios and then requirements
- Brings ideas for improvements in terms of integration with other apps
  - Helps avoid feature duplication
- If right tool picked, development process improves
- Team building
- Easier to understand and acknowledge differences between apps
- Helps identify specific competences among contributors

Use Where? 3 aspects
- Reusing our features of one app in other apps (instead of reinventing)
  - Target: Calligra developers/designers
- Using our apps in the development process
  - Target: Any Calligra contributors
- Using our apps elsewhere, in activities not related to Calligra
  - Target: Any Calligra contributors and advocates

Eat What?
- Use Tables for tabular data
  - Status: used for some ods files
  - Action point: identify problems like usability
- Use Plan for project management
  - Status: some contributors use it
  - Action point: get best practices from them
- Use Kexi for relational data
  - Already good for storing and simple queries
  - Not yet good for analyzing
  - Only simple relational features
  - Status: not used, let's start!
  - Idea: Make Kexi useful as GUI for KDE Bugzilla.
    - Use bugzilla's webservices for this. Probably separate plugin could be developed. Online/offline operations with synchronization. (discussed with Inge who likes the idea)[10]
    - Use Kexi to maintain data for automatic changelogs (with server db)
  - Action point: provide usage scenarios
    - Example: CSV import/export
  - Action point: provide server infrastructure for shared databases
    - some of that public, some of that for contributors only

Eat How?
- Provide "Best practices for own dog food consumers":
  - "Keep separate setup of stable version of used Calligra apps: How and why?"
    - Separation between development (broken) version and stable (used) version
    - Minimal compilations for development (e.g. Krita-only) can be still used while having access to all needed Calligra apps
    - Already practiced by contributors anyway: they tend to keep multiple build directories with stable/broken versions; now it can be extended
  - "App user: Provide feedback to app developers in context of your use cases"
  - "App developer: Provide updates to users in context of your new possible use cases"