SuperEdit ’s capability of handling composite documents is useful while comparing different versions made of the same raster image.

Click the Open button on the Main toolbar, for File Type choose Tessel Composite Doc (TCD), and open the electric.tcd document in the DOC subdirectory. The document should appear in the Drawing window as a scanned electrical drawing in blue, with a few red lines. In the TCD Contents window, the structure of electric.tcd document is displayed. You can see that there are two subdocuments: electric.tif and electnew.tif in the composite document. On the SuperEdit ’stitle bar, you should see the same information in the form: e lectric.tcd (electric.tif, electnew.tif) . In order to find more detailed information, choose the CDM Properties option for the electric.tif node. You should see Parameters dialog of this image. Click the Color tab to see the tab that defines the presentation color for this monochrome raster image: 5-blue . Click Cancel to close the Raster Image Properties dialog. Check this color for electnew.tif subdocument. Notice that it is: 1-red , as shown in the figure below.

Choose the CDM Properties option for the root electric.tcd node. When the Composite Document dialog pops up, click at the second entry on the Subdocuments list, so that electnew.tif is highlighted. Then click the Bring forward button on the right side of the Subdocuments list, so that this drawing’s entry moves to the top of the list. Click the Close button to close the Composite Document dialog and to regenerate the view of the composite document according to the new order of subdocuments (observe the change of succession in the TCD Contents window, too). The color of the image on the screen will turn red, as the red electnew.tif is now covering most of the blue electric.tif , except of the small part that has been deleted from electnew.tif and remains visible in blue.

Notice that the Raster toolbar buttons are grayed. Double-click the electnew.tif node on TCD Contents window using the left mouse button, to select it (or choose the CDM Select option). The name of the node electnew.tif in TCD Contents window becomes bold. SuperEdit displays thin, black frame with rectangular tracker marks at their corners and midpoints around raster image in Drawing window; the frame shows extents of the selected image. Notice that the Raster toolbar buttons become active. We say that the image is selected , so that it is ready for editing.

Click the Clear rectangle button on the Raster toolbar and choose a rectangular area of the red image to be cleared. Click the left mouse button in one corner; move the mouse cursor and click the other corner to define the rectangle. Accept the clearing operation by OTM Accept option and watch as another part of the blue image underneath gets uncovered. Close SuperEdit without saving the changes made to the electric.tcd document, which also cancels all changes made to the subdocuments.