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The layer Button: Selection Control Panel

\epsfbox{layer.eps}

The layer (``C'') button in the Selection Control button group displays the Selection Control Panel which provides a number of mode switches which control object selection.

There are three ``radio button'' groups. The Pointer Mode group sets the mode for selections initiated with button 1 while outside of commands. There are three choices:

Normal
Standard select/modify behavior.
Select
Allow selections only.
Modify
Allow move/copy/stretch on selected objects only.

The Area Mode group provides three modes for area (drag-over) selections.

Normal
Standard area selection behavior, objects are chosen if the object touches but does not completely cover the selection area.
Enclosed
Chosen objects must exist completely within the selection area.
All
Any object that touches the selection box is chosen.

The Selections group modifies how chosen objects are processed.

Normal
Standard behavior.
Toggle
Reverse the selected/deselected status of all chosen objects.
Add
Select all unselected objects chosen.
Remove
Deselect all selected objects chosen.

While selecting, and the Selections group is Normal, during completion of the selection operation, the modifier keys are recognized:

Shift
Select all unselected objects chosen.
Ctrl
Deselect all selected objects chosen.
Shift-Ctrl
Reverse the selected/deselected status of all objects chosen.

Thus, the Toggle/Add/Remove modes can be established transiently with the modifier keys. For area selection, the normal operation is to toggle the selections. For a point select (mouse click), if more than one underlying object is selected, one of the selected objects is deselected, and there is no new selection.

The Objects group specifies the type of objects that can be selected and deselected with mouse operations. The buttons are labeled Cells, Boxes, Polys, Wires, and Labels. These buttons control whether or not the indicated type of object can be selected or deselected with the mouse. This is useful, for example, when one needs to select cells that are covered by geometric objects, since the geometric objects will always be selected with a mouse click, and not the cells.

The Layer Specific button sets whether Xic is in layer-specific mode. Layer-specific mode can also be set with the S button in the Selection Control button group.

In layer-specific mode, only objects on the current layer, or subcells containing objects on the current layer, can be selected and deselected with mouse operations. Otherwise, any visible object can be be selected or deselected. Instances are selected during a layer specific point select if there is no other qualifying geometry where the user clicked, and only instances that contain objects on the current layer can be selected in layer-specific mode. The layer-specific mode affects many of the commands and operations in Xic, typically limiting the operation to objects on the current layer when active.

Layer-specific mode is indicated by a small box icon in the far right side of the layer table. Clicking on this icon with button 1 will also toggle layer-specific mode on and off.

Normally, when scanning through the database for objects that are within the selection area, layers are searched top to bottom (right to left in the layer table). Thus, in some modes objects on upper layers will be selected preferentially over objects on lower layers. The search ordering has no effect if layer-specific node is active.

If the Search Up button is active, this ordering is reversed, layers are searched from bottom to top (left to right in the layer table).

In the extraction system, the search order will affect the default association of terminals to layers. It also applies to the operations in the extract Path Selection Control panel.


next up previous contents index
Next: The lspec Button: Set Up: Selection Control Button Group Previous: The desel Button: Deselect   Contents   Index
Stephen R. Whiteley 2012-04-01