Graphics ITGS

Pixel Short for “Picture Element” A single dot on a monitor or printed document. The smallest rectangular area of an image that can be manipulated on a monitor or printer, or stored in memory. A pixel has a unique associated colour

Pixel colours/shades A pixel shows only one colour at a given instant, but the possible colours may vary according to the number of bits we assign to each pixel. If we assign a single bit (1 or 0) to a pixel we can give that pixel only two colours. If we assign two bits to a pixel we can give that pixel four colours (00,01,10,11).

More colours / shades Bits per pixelNumber of different colours n2n2n

Pictures & Formats A picture is a set of pixels of different colours placed in a particular pattern. Pictures must be saved to disks as a sequence of bits. There are several ways of translating a picture to a series of bits. This will give name to the format of the image file. Some of them highly compress the image (JPEG, GIF) occupying less space and some of them not so much (BMP). Examples: JPEG, GIF, BMP, TIFF, WPG, PIC,PIX.

Another graphic format distinction Graphic file formats can be: Pixeled or Bitmapped Object-oriented (or vector based)

Object-Oriented vs. Bitmapped Object oriented Are stored as a series of lines or vectors. Have smooth edges Can be enlarged without any loss of image quality. Not very good for photographs or complex pictures (they occupy too much) Bitmapped Are stored as pixels at given coordinates. Have sharp edges Cannot be enlarged without loss of image quality. Photographs and complex images can perfectly be stored (and compressed to a reasonable extent) Another comparison chart can be found in

Quality vs. Storage space Storage space quality

Drawing vs. Painting software Drawing software manages objects Painting software manages bitmaps

Graphics issues Monitor vs. Printer quality Image digitalisation methods Easy to replicate works of art Easy the violation of intellectual property (OCR)

Computer Aided Design (CAD) It is the use of computers to design products. Used mainly by engineers, designers and architects. It can help to visualize the product better It can prevent design error, therefore preventing serious catastrophes. It can take very much less time to design a product. It can lower the costs as the designer can avoid buying experimental material.

CAD...some disadvantages Unskilled designers can build design- poor products that may cause future accidents. It may require lots of storage capacity. The design may turn too complex and have design problems It is limited to the drawing skills of the CAD software.

Computer Aided Manufacture (CAM) CAM systems are sometimes integrated with a computer-aided design system (CAD). Very useful for circuit designers.