Download - The Unusual Suspect: Layouts for sleeker KDE applications

The Unusual Suspect:

Layouts for sleeker KDE applications

Caio Marcelo de Oliveira FilhoEduardo Madeira FleuryJuly 6th, 2009

Who are we?

• Nokia research institute in Brazil – INdT

• openBossa – FOSS stream at INdT

• Collaborating with Qt Software / KDE:

- Qt Kinetic that's us :-)←

- Qt Webkit

- Plasma Netbook

- ItemViews-NG

Background

• Fluid and Rich UIs have become a standard

• Collaborative work: designers and developers

• Several initiatives to enhance KDE looks

- High level

- Low level

• Layouting tools needed to evolve

Layouts in Qt

• Engine that handles geometry of items

• Widgets can use layouts to manage its children

• Today: Linear, Grid, Stacked and Form

Covered in this presentation

• Flexible Layouts

• Custom Layouts

• Application of Layouts and Widgets

• Multiple Layouts

• Integration with Declarative UI

FLEXIBLE LAYOUTS

Flexible Layouts

• Layout behavior based on its configuration

• Designers can interact with the layout

• More power, less layouts

• AnchorLayout available at Qt Gitorious

• Edje relative positioning is similar

CUSTOM LAYOUTS

Custom Layouts

• Layout behavior rules based on its engine

• Developers implement custom algorithms

• Abstract / Hide internal decisions

• Powerful handling of item addition / removal

• Internal animations

Usage of Flexible vs Custom

• C++: Call methods x Create subclass

• Call methods: Good for high level tool or QML

• Subclasses: More control, require a developer

LAYOUTSOR

CONTAINER WIDGETS

Container Widgets

• Also responsible for children geometries

• Usually create its own items

• ItemViews: “delegates” or “item creators”

• Can be flexible too (e.g. ItemViews-NG)

• Container Widget = Engine + Widget Factory

Layouts or Container Widgets?

• Layouts handle child widgets

• Container Widgets handle data (e.g. models)

• Container Widget = Layout + Widget Factory

MULTIPLE LAYOUTS

Multiple Layouts

• Application screens are dynamic

• Different states associated to the interface

• Single set of widgets, multiple layouts

• Animate from one layout to another

DECLARATIVE UI INTEGRATION

Declarative UI Integration

• Layouts are declarative!

• Layout integration still in discussion

• Use property propagation to “anchor” items

• Support for layouts would be useful:

- Different layouts

- Optimization

Thank you! :-)

Qt Labs America

• Qt / KDE place in America, starting in Brazil

• Promotion and mentoring of FOSS projects

• Tech-days in universities

• Working together with KDE

Caio Marcelo de Oliveira [email protected]

Eduardo Madeira [email protected]

http://eduardofleury.com

Freenode #qt-kinetic