Donald Stanley Craig

US Patent:

47558113, Jul 5, 1988

Filed:

Mar 24, 1987

Appl. No.:

7/030758

Inventors:

Keith R. Slavin - Aloha OR
Donald Craig - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G09G 116
G06F 314

US Classification:

340731

Abstract:

Touch controlled zoom of a waveform display uses a touch screen for the display surface. Function buttons for moving or expanding the waveform display and for determining the axis of such movement or expansion operate in conjunction with a rotary encoder. Expansion, or zoom, is accomplished by contacting the screen overlying a point on the waveform about which zoom is desired. Such contact or activation of the expand function button results in movement of the rotary encoder providing a gain parameter to a zoom function. The zoom function operates on the waveform display in an exponential manner as a function of the gain parameter to expand or contract the waveform display about the zoom point according to the direction of rotation of the rotary encoder.