Magic VLSI Layout Tool Version 8.2 *


Query or manipulate feedback entry areas.


feedback option

where option may be one of the following:
add text [style] [x1 y1 ...]
Create a new feedback area. If positions x1 y1 ... are not specified, then the feedback area created corresponds to the area of the cursor box. The feedback entry will be associated with the text text, which will be reported on execution of a feedback why query. The feedback area will be drawn in style style, which may be one of the following:
  • dotted
  • medium
  • outline
  • pale
  • solid
From magic version 7.3.110, any style from the ".dstyle" file may be specified (e.g., "yellow1"). If points x1 y1 ... are specified, then they represent a polygonal area for the feedback entry. This area may be a point, line, or polygon, and may be specified in internal units or metric units. If the feedback area is a point, line, or degenerate polygon (polygon with zero internal area), then the style must be an outlined style; otherwise, the style is changed to style outline so that the feedback area is ensured to be visible.
clear [substring]
Without the argument substring, clears all feedback info. When substring is specified, only feedback entries containing the text substring will be removed. For example, if "cif see CMF" is followed by "cif see CCC", the contact cuts will not be seen due to being overlapped by the feedback for metal1. However, if this is followed by "feedback clear CMF", the feedback area for metal1 will be removed, leaving the contact cuts visible.
Count the number of feedback entries
find [nth]
Put the cursor box over next (or nth) entry
Print help information
save file
Save feedback area information into file file
Print text associated with all feedback areas under the cursor box.


The feedback command queries or manipulates feedback areas, which are areas drawn on top of the layout and may be used for annotations and markers. Internally, magic uses feedback areas to report CIF/GDS layers (cif see command), and errors generated by the extract command. CIF/GDS feedback is placed on the output (usually centimicron) grid, which cannot be done with the feedback add command directly from the command-line.

Feedback information and areas are not saved in the layout file.

Implementation Notes:

feedback is implemented as a built-in magic command.


Small feedback areas were previously drawn solid to prevent them from disappearing entirely; however, this created bizarre results in CIF/GDS feedback when several narrow feedback areas are tiled together, so it was removed. This leaves the possibility that feedback areas smaller than the spacing between feedback crosshatch lines might not be drawn; an inconvenience, but not a serious problem.

There should be a mechanism for removing only the feedback entries under the cursor box, or the current feedback entry.

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Last updated: March 7, 2020 at 1:06pm