Category Editor

The category editor is a mode of the QViewer that can be used with the QEditor to graphically change the category layout and category child layout properties of categories.

The category editor replaces the viewer's display area with a two-dimensional view showing the layout of categories in the category plane.

When the category editing mode is turned on, some commands in the menu and toolbar are removed and replaced with category layout editing commands. The mode has a different set of commands when the QViewer is started by the QEditor than it does when the QViewer is started by itself or by a browser.

Categories are drawn as boxes in the category editor. The color of the outline indicates how the category itself should be sized and positioned:


Red The category is free, has no size or location, and should be inside a category with automatic layout.
Black The category is fixed, has both a size and location, and should be inside a category without automatic layout.
Blue The category is proportional, its width and height have a fixed ratio, but it needs to be inside a category with automatic layout.
Magenta A rectangle for automatic layout inside a category that allows both free and fixed children. This is not a category, but it is a fixed area in the category where free or proportional children are automatically laid out.

Commands Common to Standard and QEditor Modes

grid mode

The grid mode is used when multiple categories need to be positioned or resized consistently.

The command brings up a dialog box that lets you set up the grid. Moving or resizing a category "snaps" to the nearest grid line. In the dialog, the grid is the distance between the grid lines and the offset shifts the entire grid by some small value.

The grid mode can be turned off with the zero button in the dialog box.

Enable/Disable Category Labels

The boxes that represent categories are labeled in two ways. A pop-up label appears when the mouse cursor pauses over a category for a small amount of time. Also, when a category is above a certain size, a label is draw in its lower left corner. This second kind of label can be turned on and off with this command.

QEditor Mode Commands

Fixed Child Layout

This sets the selected category to layout its own child categories using the fixed layout method. This method is simple in that each child is expected to already have location and size information relative to the interior of this category. Free or proportional child categories cannot be placed in the fixed child layout and will be ignored.

Mixed Child Layout

If the selected category would like to be able to accept all kinds of child categories, it can use this command. The category itself is given a fixed child layout method and a smaller area (called $auto$) is placed inside it. Fixed children are placed in the outside area and free and proportional children are placed in the inner region. The $auto$ region is not a category, but it acts like one in the layout procedure.

The top category in the QViewer has a mixed child layout. A large area is available for use by categories. A smaller $auto$ area is centered in the top category for the layout of free or proportional categories that are immediate children of the top category.

Automatic Child Layout

This sets the selected category to compute the size and position of all its child categories. All the children should be free or proportional. Fixed children's position will positioned as they request, but the automatic method is likely to assign the same position automatically to other categories also.

Fixed Position

This command turns the selected category into a fixed layout category. It will be given its current x position, y position, height and width relative to its parent..

Free Position

This commands turns the selected category into a free category. Free categories have no position, size or proportion data.


This commands turns the selected category into a proportional category. Proportional categories have no position, or size. They have a single number that represents the ratio of its height to its width. This is used by the automatic layout method when setting the categories size. They are given a location in the same manner as free categories.

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