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Drawing Tool Active Ruler Disclosure Number: IPCOM000108530D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 125K

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Hock, DJ: AUTHOR [+3]


A method for copying, within a computer drawing tool, the size of one object to another object is described.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 51% of the total text.

Drawing Tool Active Ruler

       A method for copying, within a computer drawing tool, the
size of one object to another object is described.

      Consider a computer drawing tool.  There are a number of such
commercial products available, including PowerPoint from Microsoft,
Freelance from Lotus, and Harvard Graphics from Software Publishing.
These programs allow the drawing of circles, lines, squares, and
other shapes. The size of the resulting objects is set using a mouse
or the key pad, or a combination of the two.  It is often desired
that non- identical shapes have the same size such as a line the
length of a circle's diameter, a screen-shape with a box of text of
the same size, and a rectangle with sides equal to the major and
minor axes of an ellipse. It is also often desirable to have a shape
with an exact size such as a rectangle 3 x 4.97 inches.

      Many tools provide just two means for sizing objects. A grid of
lines or dots is laid over (or as a background) to the drawing area.
There is an option to "snap" a drawing tool to the grid points such
that the start and end points of newly created objects are at points
of known distance. The second means is a numeric indicator of size
shown as the drawing pointer (e.g., the mouse) is moved.

      Rulers are objects that can selected from the list of available
drawing tools.  They appear as a normal desk ruler, a rectangular
shape, with major and minor markings showing length in traditional
units, for example, centimeter/millimeter, inch/eighth-inch. Rulers
can be placed over the drawing surface and moved and rotated to
measure the length of an object.  Current art allows the user of a
traditional computer ruler to "eyeball" the length of the object
similar to the way a real desk ruler would be used to measure the
dimension of an object.  These rulers are described as "passive"

      A better way is to have an "active ruler". An active ruler is
the subject of this article. An active ruler will "catch" the length
of an object dropped onto it, and will transfer a length to an object
on which it is dropped. An object's length is captured as follows:
      1.   The object is first drawn to the desired size.
      2.   An active ruler is selected from the toolbox and placed
anywhere in the drawing area.
      3.   The drawn object is "dragged" to the ruler and "dropped"
using standard direct manipulation techniques.

      As a result of the drop, the ruler copies the length of the
object dropped.  This can be done in an object-oriented language,
such as Smalltalk, by the ruler sending a message to the dropped
object requesting its dimension. The ruler then displays that length.

      The ruler can also be set to a specific length directly, by
manipulating a length control on the ruler, using the mouse or

      Once a length is set on the ruler, the ruler can be used to
set the length of other drawn objects....