ilog.views.sdm.renderer

Class IlvSDMRenderer

java.lang.Object

ilog.views.sdm.renderer.IlvSDMRenderer

Direct Known Subclasses:

IlvFilterSDMRenderer

public abstract class IlvSDMRenderer
extends java.lang.Object

The class IlvSDMRenderer is the base class for the renderers used in an SDM engine.

The purpose of a renderer is to implement a particular policy for rendering the objects of an SDM data model as Perforce JViews graphic objects in a Perforce JViews grapher.

The renderers attached to an SDM engine form a chained list. The first element of this list is set using the method setRenderer. All but the last element of the list are instances of IlvFilterSDMRenderer. The next element in the list is defined by the method setFilteredRenderer. The last element of the list is usually an instance of IlvStyleSheetRenderer.

Style Sheet Renderer

The main renderer is the IlvStyleSheetRenderer. The style sheet renderer reads a file in the CSS syntax, and creates and customizes JViews graphic objects according to the CSS rules. For example, the following rule states that all nodes of the SDM data model shall be represented by JViews IlvRectangle objects, and the rectangles shall be green.

    node {
      class : "ilog.views.graphic.IlvRectangle";
      foreground : "green";
    }
  

Filtering Renderers

Other renderers can be combined with the style sheet renderer to modify the look or the behavior of the graphic objects. This combination of renderers is implemented by way of "filtering" renderers (see IlvFilterSDMRenderer). Several filtering renderers can be added in front of the style sheet renderer to add different aspects to the rendering process. For example, the IlvHalfZoomingRenderer prevents nodes from zooming or unzooming too much. Another example is the IlvExpandCollapseRenderer that shows sub-graphs of the data model as special expandable and collapsible nodes.

Rendering Properties

Renderers usually require information to know how to create and customize graphic objects. This information can be specified in the style sheet file, just like the plain properties of graphic objects. For example, if a half-zooming renderer is used, you could add the following declaration to say that the nodes must not zoom beyond a zoom level of 4:

    node {
      class : "ilog.views.graphic.IlvRectangle";
      foreground : "green";
      MaxZoomLevel : "4.0";
    }
  

These special rendering properties are fetched through the method IlvRendererUtil.getGraphicProperty(ilog.views.sdm.IlvSDMEngine, java.lang.Object, java.lang.String, java.lang.String[], java.lang.Class<?>), or one of its variants that convert the property value to an appropriate type.

Note that, by convention, the rendering properties are capitalized to distinguish them from plain properties of IlvGraphic objects.

Pseudo classes

Pseudo classes are strings that can be used to mark data objects. The purpose of pseudo classes is to allow renderers to give feedback to the user on the state of an object by displaying it in a different way.

The style sheet can contain rules that apply only when the object has a particular pseudo class.

For example, the SDM engine adds the pseudo class "selected" to selected objects. The following style sheet rule says that selected objects are red:

    node:selected {
      foreground : "red";
    }
  

The pseudo classes of a data object are passed along to several methods of IlvSDMRenderer to let any renderer decide what it should do depending on the object pseudo classes.

The class IlvSDMRenderer is abstract: subclasses need to define at least the methods #createNodeGraphic and #createLinkGraphic.

CSS example:

This class cannot be instantiated because it is an abstract class.

Method Summary

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait