In addition to the signal editing tools described in previous sections, Design Pad G4 provides several menu-driven commands to edit a schema. These commands are described below.
Undo/Redo
Design Pad G4 provides the capability to undo and redo past commands. If you make a mistake as you modify your schema (e.g., delete an operator) and wish to revert to the previous document state (e.g., before the operator was deleted), select the Undo item from the Edit menu (or type CTRL-Z on the keyboard). Design Pad G4 maintains a history of 256 commands that can be "undone". If you perform an undo operation (or several undo operations), and then decide you would like to revert to the changed document state, select the Redo item from the Edit menu (or type CTRL-Y on the keyboard).
Cut/Copy/Paste
Design Pad G4 provides the capability to cut and/or copy objects from a schema document and then paste them into the same document or into another schema document. The Cut command in the Edit menu (CTRL-X), removes selected objects and places them on the Clipboard. The Copy command (CTRL-C) also places selected objects on the clipboard but leaves them intact. The Paste command (CTRL-V) inserts objects on the clipboard into the schema document. Pasted objects are generally exact duplicates of the originals with some minor exception. For instance, if you copy an Analog Input block, Design Pad G4 will change the operator's name so that it remains unique. (Hardware operators of the same type must have different names.)
Selecting Multiple Schema Objects
Design Pad G4 provides a selection box feature that is useful for selecting multiple operator objects at the same time. To activate the selection box, click the left mouse button over schema document (a location in the schema that does not contain an operator block, a signal wire, a text block, or any other object). Then, as you move the mouse (while holding the left button down), Design Pad G4 displays a rectangular box---the selection box. When you release the left mouse button, Design Pad G4 will select all the objects that are inside the selection box.
Selecting All Schema Objects
Occasionally, it may be useful to select all the operators and signals in a schema. To do so, activate the Select All item from the Edit menu. Design Pad G4 will then draw all the schema objects in their selected state: Operators will be drawn with a dotted border and signals will be drawn as dashed linear segments.
Deleting Operators and Signals
The Delete command mentioned in section 4.5 works with operators as well as signals. If you wish to remove an operator from your schema, select the operator with the Selection Tool and choose the Delete item from the Edit menu. (If an operator or a signal is selected, it can also be removed from the schema using the DELETE key on your keyboard.)
Removing Unconnected Signals
Remove Disconnected Signals Tool
Design Pad G4 can automatically remove any signals (or signal segments) that are not connected to anything. If you have several extraneous signals, choose the Remove Disconnected Signals item from the Edit menu, and Design Pad G4 will eliminate all the unnecessary signal segments.
Perpendicular Signal Mode
Design Pad G4 does not restrict how schema signals are laid out---signal segments can be drawn at any angle. However, schemas often "look" better if signals are drawn as horizontal and vertical line segments perpendicular to each other. (The example schema of Figure 2.1 is drawn this way.) Design Pad G4 offers a drawing mode in which signals are restricted to horizontal and vertical planes. You can activate this mode by selecting the Perpendicular Signal Mode item from the Edit menu. You can return to normal drawing mode by selecting the same menu item again (i.e., the menu item toggles perpendicular mode on or off).
Snap-To-Grid Mode
Design Pad G4 does not restrict how operators are positioned in a schema document. The fine layout granularity that the software provides can sometimes make it difficult to align operators and connect their I/O pins. Displaying a background grid in the schema document (select Grid in the View menu) is helpful but often is not sufficient for easy operator alignment. Design Pad G4 provides a snap-to-grid feature that aligns all objects, including operators, I/O pins, and signals, to the coarser background grid. When you activate this mode (select Snap-To-Grid from the Edit menu), all of the operator I/O points are positioned on grid points.
