Using presentation styles

What are presentation styles
Presentation styles centralize the attributes related to the decoration of the graphical user interface elements.

Defining a style
Styles can be defined to be global (for all elements), for an element in general, or for specific types of an element.

Pseudo selectors
Pseudo selectors can be used to apply only when some conditions are fulfilled.

Using a specific presentation style
To apply a specific style, set the style-name in the style attribute of the node representing the graphical element in the abstract user interface tree.

Combining styles
You can combine several styles by using the space character as a separator in the style attribute.

Style attribute inheritance
A style attribute may be inherited by the descendants of a given node in the abstract user interface tree.

Presentation styles in the AUI tree
Presentation styles are loaded in the abstract user interface tree, under the UserInterface node, in a StyleList node following the presentation style syntax.

Loading presentation styles
Presentation styles are defined in an XML file with a 4st extension. In order to load the presentation styles, the engine needs to locate the appropriate style file.

Style (4st) file example
A style file is an XML file comprised of StyleList, Style, and StyleAttribute elements.

Combining TTY and style attributes
TTY attributes can be specific to a form element or can be inherited by an element from a parent node (such as the form or window).

Element types
Styles may apply to any graphical elements of the user interface, such as Button, Edit, ComboBox, ButtonEdit, Table, Window.

Colors
When providing a value for style attributes that define a color, you can specify a generic color name or its RGB value.

Fonts
A desktop application should follow the current desktop settings. The front-end tries to determine the default font for the desktop, and also offers a global font chooser to let the end-user define which font best matches his expectations.