Characteristics
Class hierarchy and HTML tags. A theme is defined as a hierarchical structure whose root is the theme's name. Going down along this structure, we find a "Classes" node and an "HTML tags" node on the first tree level. A set of pre-defined elements is displayed from the "Classes" node. These elements correspond to classes of objects that are like "brothers" in making up the structure. Likewise, they can result in forming other classes in order to make up a hierarchy.
The pre-defined classes:
- Attribute
- FreeSubfile
- Subfile
- Table
- Image
- Button
Users may define the main characteristics of an HTML tag through "HTML tags". Such characteristics are reflected in the web page as long as those same tags are present in the page's HTML. They may have been included by simply editing the GeneXus object HTML source, by including a control, or by any other action that may have caused the HTML source to incorporate some of those tags for which the properties were defined in the theme. The properties of tags configured within the theme will be reflected in the design of objects related to the theme that is defining them, and at runtime, in the generated webpages; for instance, the color of the active and visited links, the alignment of the headings, and the color of the tables.
A context may be even defined in which a tag that is nested in other HTML tags (with n nesting levels) will have special characteristics. The font of the visited links which are within a table that is nested inside another table is an example of this.
This feature achieves two things. On one hand, it is possible to standardize the different HTML pages by simply updating the theme, and without the need to refer to the form's properties of each object. On the other hand, there is more functionality since a whole context may be defined, in which tag properties will apply (as mentioned earlier).
In order to define it, an HTML Tags hierarchy is applied, which in this case, unlike classes, conceptually means defining the characteristics of an HTML tag in a context.
In other words, the themes editor is initially introduced as a basic tree with the controls that GeneXus uses on the Web. These controls represent classes. What GeneXus users will do is change the look of such controls, by configuring the different properties available and depending on the characteristics of the control. Adding derivatives from those classes in order to define the hierarchy previously mentioned will be possible. Likewise, an "HTML Tags" folder will be available, in which the characteristics desired for the tags to have in the web page will be defined for a pre-determined set of HTML tags.
Once the theme has been put together, it may be associated to the knowledge base, to the model, or to a given object.