Loading layout parameters from .ivl files

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The following example shows how to load and recover the parameters of the three layout instances when the layout settings are stored in an .ivl file:

// Read the IVL file. This reads all named properties as well.
grapher.read("abcd.ivl");
IlvGrapherAdapter adapter1 = (IlvGrapherAdapter)layout1.getGraphModel();
IlvGrapherAdapter adapter2 = (IlvGrapherAdapter)layout2.getGraphModel();
IlvGrapherAdapter adapter3 = (IlvGrapherAdapter)layout3.getGraphModel();
// Transfer the parameter settings from the named properties to the layouts.
adapter3.loadParametersFromNamedProperties(layout3);
adapter2.loadParametersFromNamedProperties(layout2);
adapter1.loadParametersFromNamedProperties(layout1);
// just to be sure that no named layout properties remain in the memory
adapter1.removeParametersFromNamedProperties();
adapter2.removeParametersFromNamedProperties();
adapter3.removeParametersFromNamedProperties();

When reading an .ivl file, you usually do not know how many named layout properties are stored in the file. In the previous example, if there are less than three sets of named layout properties stored in the .ivl file, any unsuccessful call of the method loadParametersFromNamedProperties has simply no effect, that is, it does not change the parameters of the corresponding layout. If there are more than three sets, the final calls of the method removeParametersFromNamedProperties guarantee that no memory is wasted by the remaining unused layout properties. As mentioned in Saving layout parameters to .ivl files, only one call to the method removeParametersFromNamedProperties is necessary if only one grapher adapter is attached to all three layout instances.

Note

Parameters are loaded in the reverse order with respect to the order in which they are stored. This is not important if all three layout instances are of different classes because a layout automatically loads only parameters that fit the layout class. However, if, for example, all three layouts are instances of IlvTreeLayout, the last saved set of named properties for any Tree Layout is the first set of named properties that is loaded for a Tree Layout.

To load layout parameters, use one of the following methods:

loadParametersFromNamedProperties

This method transfers a set of layout parameters from the named layout properties to the input layout. It automatically determines which layout properties fit the input layout. If several sets fit, it transfers the set that was stored last, removes this set of named layout properties from the grapher, and returns true . If no set fits and loading cannot be done, it returns false .
loadParametersFromNamedProperties

This method transfers a set of layout parameters from the layout properties having the input property name to the input layout. It returns true if successful, and false otherwise.
loadParametersFromNamedProperties

This method transfers a set of layout parameters from the layout properties having the input property name to a newly created instance of IlvGraphLayout . It returns the new instance. It returns null if no set of layout properties with the input name is found.

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Saving layout parameters and preferred layouts