What do you mean by device based and screen based control, Explain

Q. Write short note on: Device Based Control (5 M)(MAY 18/MAY 19)

Q. Write short note on: Screen Based Control (5 M) (MAY 18)

Q. What do you mean by device based and screen based control, Explain? (10 M)(DEC 16)

Q. Provide different device based and screen based control for following.   (10 M) (MAY 17)

           (i) Filling up Online Application for Admission to Engineering Course.

          (ii) Online payment of Utility Bills such as Telephone, Electricity and Water charges etc.              

Ans:-

1.Device Based Control:

• Are nothing but input devices,are the mechanisms through which people communicate their desires to the system.
• There are two types of Devices:- 
•  Direct Devices :-operated on the screen itself. e.g. the light pen, the finger, and voice
• Indirect Devices :-operated in a location other than the screen, most often on the desktop
• Some Characteristics of  Device-Based Controls:
• point at an object on the screen.
• For select the object or identify it as the focus of attention.
• Drag an object across the screen.
• Draw something free form on the screen.
• To track or follow a moving object.
• To orient or position an object.
• To enter or manipulate data or information.
• Trackball:-
• A spherical object (ball) that rotates freely in all directions in its socket.
• Direction and speed is tracked and translated into cursor movement.
• Advantages:-
• Direct relationship between hand and pointer movement in terms of direction and speed.
• Does not obscure vision of screen.
• Does not require additional desk space (if mounted on keyboard).
• Disadvantages:-
• No direct relationship exists between hand and pointer movement in terms of distance.
• Requires a degree of eye-hand coordination.
• Requires hand to be removed from keyboard keys.
• Requires different hand movements.
• Graphic Tablet:-
• Pressure-, heat-, light-, or light-blockage-sensitive horizontal surfaces that lie on the desktop or keyboard.
• May be operated with fingers, light pen, or objects like a stylus or pencil.
• Pointer imitates movements on tablet.
• Advantages:-
• Direct relationship between touch movements and pointer movements in terms of direction, distance, and speed.
• More comfortable horizontal operating plane.
• Does not obscure vision of screen.
• Disadvantages:-
• Movement is indirect, in a plane different from screen.
• Requires hand to be removed from keyboard.
• Requires hand to be removed from keyboard keys.
• Requires different hand movements to use.
• Requires additional desk space.

2.Screen Based Control:

• sometimes called widgets,are the elements of a screen that constitute its body.
• These are the graphic components which we can see on the screen and can interact with them.
• Screen based controls do can:
• selection of a particular value.
• Editing of a particular value.
• Display a particular piece of text, value,or graphic.
• Cause an action to be performed.
• Types:
• Buttons
• A square or rectangular-shaped control with a label inside that indicates action to be accomplished
• Label may consist of text,graphics or both
• Purpose:- i] To start actions    ii] To change properties

• Text entry/read-only controls
• Control is usually rectangular in shape,in which text may be entered or may be displayed for read-only purposes.

• Selection controls
• To select a particular values
• Type:i]Radio buttons    ii]Check boxes

• Combinations entry/selection controls
• A control can have characteristics of both a text field and a selection field
• Here information is either typed or selected and placed in it.
• Types:- 

                                           i]Spin boxes       

                                          ii]Attached combination boxes 

                                         iii]Drop-down/pop-up combination boxes

• Others operable controls:
• Slider
• A scale exhibiting a range of values.
• Used in smart phones for setting brightness,volume.In PC for setting screen size, resolution etc.
• Best example: MX player,VLC player
• Date picker
• A drop-down list box that display a 1-month calendar in the drop-down list box.so that month can be changed by pressing command buttons with left-and right pointing arrows
• Tree
• A special list box control that displays a set of objects as hierarchical view
• Scroll Bar
• A vertical or horizontal bar commonly located on the far right or bottom of window with the help of which we can move the viewing area up,down,left,right.