Interactive Input Techniques

Interactive Input Interactive Input TechniquesTechniques

Interactive Input Techniques Basic positioning methods Constraints Grids Gravity fields Rubber-band methods Sketching Dragging

Positioning techniquesPositioning techniques

There are various techniques used for positioning.

Positioning means location, which is one of the basic graphical input techniques.

For geometrical modelling, positioning is very important, as the user frequently designs a new element of the model or repositioning an existing one.

While working on the screen the position is used to insert a symbol or to indicate the end point of a line or three points on a curve.

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For positioning the desired spot on the screen , the cursor or tracking cross is moved to that location and then the information is passed to the computer memory by pressing a button or key.

There are positioning constraints which can be overcome by using symbols guidelines, feedback and the use of rubber band techniques.

Basic positioning techniquesBasic positioning techniques Used to specify a location for an object or a character

string The cursor is moved to the desired location. A button is pressed to fix the object at this location.


Used to draw lines


Used to place the cursor at a predetermined position

ConstraintsConstraints

Used to achieve predetermined orientations and alignments

Common constraints Horizontal alignment


Vertical alignment

GridsGrids

Used to round coordinates positions to the nearest grid to round coordinates positions to the nearest grid intersectionintersection


Useful for positioning and aligning objects and text

Grids can be displayed or invisible

Gravity fieldGravity field

Used to connect a new line to a previously drawn line

Normally the gravity field is not displayed

Rubber band MethodsRubber band Methods

Used to construct and position straight lines


Used to construct circular arcs

Used to scale objects


Used to distort objects by allowing only the line segments attached to a single vertex to change


SketchingSketching

Uses rubber-band methods to create objects consisting of connected line segments

Uses stroke techniques to create curved figures


A variety of brushes can be provided Different thicknesses Different textures Different colors (including background) Even patterns


DraggingDragging Used to reposition objects Select an object from the menu Position the object Release the objects

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Interactive Input Techniques

Documents

new line

desired location

drawn line

use of rubber band techniques

various techniques

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predetermined orientations