It is possible to change the appearance of the document in the different views in order to improve the legibility or to show more or less information.
The ``Zoom'' command from the ``PresentView'' sub-menu ``Present'' menu allows the size of the characters displayed in a view to be increased or decreased. This command offers a form which specifies the document and the view name as well as the character size difference compared to the ``normal'' size as it is specified in the presentation schema. Each time you press the ``Increase'' button, characters are magnified in the view in question (and only in this view) and the difference is increased by 1. The ``Decrease'' button does the opposite.
The ``Zoom'' command only acts on the document image displayed on the screen. Pagination and printing do not take into account the change made on character size.
This command has a temporary effect which is not saved with the document. See 8.3.1 to make permanent changes to the body size of a document.
The default value for zoom is read in ZOOM entry of .thotrc file (see 23.1.6).
The ``Visibility'' command from the ``Present view'' from the ``Present'' menu allows you to change the visibility threshold of a view and to vary the contents of an image displayed in a window. This command presents a form which indicates the document and view names in question and three buttons. Each time you press the ``Decrease'' button, the visibility threshold decreases by 1. The ``Increase'' button does the opposite.
The visibility level of each element type is defined by presentation rules in presentation schemas. All schemas whose visibility threshold is lower than the required threshold are removed from the display. The result of this command can be seen by applying visibility thresholds of 5 (the default threshold), 4 and 2 to the table of contents of this document.
The ``Visibility'' command only acts on the document image displayed on the screen. Pagination and printing ignore the temporary change made on the visibility threshold.
This command has a temporary effect which is not saved with the document.
The default value for visibility is read in VISIBILITY entry of .thotrc file (see 23.1.6).
The command used to change visibility (section 10.2) acts on all elements displayed in a view. If you want to modify the display of one element or of some chosen elements, use the ``Contract'' command from the ``Edit'' menu. This command displays the selected elements under the form of their type name enclosed between angle brackets; the contents of elements are no longer displayed but are stored. The type name is displayed in the same color as references. The color can be chosen by the user (see section 23.1.3).
In contrast with the change in visibility, the ``Contract'' command is applied in all views where the selected elements are visible. Also, contracted elements remain in this state when the document is saved and then loaded.
Contracted elements are printed under their contracted form (type name between angle brackets) and pagination is performed by considering the reduced dimensions of contracted elements.
To restore a contracted element to its normal state, just double-click with the left mouse button on the element name.