unit 35 p1

P1
Keyboard
Each button on a concept keyboard relates to a particular item or function. Buttons can be labelled with text or a picture.
Trackball
To operate it the user rotates the ball which moves the pointer on screen. They are particularly easy to use for those with limited movement in their hands and are often used in Computer Aided Design (CAD) for their increased precision over a mouse.
Digital camera
A digital camera takes pictures and can usually record video too. The pictures it takes and the videos it records are stored in files. These files can be copied to a computer and later edited.
Scanner
A scanner can be used to digitise images. They're similar to a photocopier but they make a digital copy instead of a physical copy. They can also be used with optical character recognition (OCR) software to scan in text that is then editable.
Graphics tablet
A graphics tablet consists of a flat pad (the tablet) on which the user draws with a special pen. As the user draws on the pad the image is created on the screen. Using a graphics tablet a designer can produce very accurate on-screen drawings as if they were drawing on paper.
Monitor
The most common output device is the monitor or VDU.
Modern monitors, where the case isn’t more than a few centimetres deep, are usually Liquid Crystal Displays (LCD) or Thin Film Transistors (TFT) monitors.
Older monitors, where the case is likely to be around 30 cm deep, are Cathode Ray Tube (CRT) monitors.
Printers
Laser printers are quite expensive to buy and run but produce a high quality output and are quiet and fast.
Ink-jet printers offer black and white or colour printing with reduced levels of quality and speed. Colour ink jet printers are cheaper to buy than colour laser printers.



Software

Painting packages
A painting application allows freehand drawing and colouring, usually with a mouse. Generally the features are:
·         a palette from which the user can choose colours
·         freehand pens and brushes offering different styles and line thickness
·         a range of standard shape tools such as rectangles and circles
·         colour fill tools
·         spray cans and eraser tools
·         cut, copy and paste
·         zoom

Bitmap graphics
Bitmap graphics made with painting packages consist of many tiny dots called pixels. It is possible to edit each individual pixel.
Drawing packages
Images made with drawing packages consist of lines, shapes and co-ordinates. Drawing packages are also known as vector drawing packages. Generally a drawing package offers many similar features to a painting.
Vector graphics
Vector graphics are based on mathematical relationships with control points that make up the image, information is not stored about each pixel. These points are connected by lines and curves called vector paths or vectors.
Vector objects
A vector object is a shape made up of vector paths. It is possible to edit each object separately, for example, change the shape, stroke, fill, size and position. A stroke follows the outline of the vector path and a fill adds a colour to the area inside the path.