Input And Interaction

Input Device
• physical device
• logical device : define the type of input; not adopted in openGL

input device

Classes of Logical Device

1. String Device : returns strings of characters; physical device keyboard
2. Locator: returns; physical device mouse
3. Pick: returns the ID of the graphical object; physical device mouse button gun
4. Choice: mouse returns one of a discrete number of option;ex menu
5. Stroke: return array of location; similar to locator; ex push button, releasing the button mouse

Input Process

1. Measure process: input device returns a set of logical measures
2. Trigger process: input device returns the trigger signal

Input Modes

Request mode:

Sample mode:

Event mode:

Display Lists

• is a compiled list of intructions stored in adisplay memory(client) or on a graphics server

A SIMPLE PAINT PROGRAM

Requirements:

• Draw geometric objects.
•  Manipulate pixels.
• Control attributes, such as color, line type,
• and fill patterns.
• Include menus.
• Allow for moving and resizing the window