Graphic packages are those programs that allow artiste and computer users to use computers to create, edit, display and print graphic images. A graphics package is an application that can be used to create and manipulate images on a computer. Examples include Paint, Adobe Photoshop, Corel draw, CAD (computer aided design). The ranges of pictures, drawings and images which can be produced by a computer are called graphics.
COMMON FEATURES OF GRAPHICS PACKAGES
1) Drawing straight lines and ‘freehand’ lines;
2) Drawing regular pre-defined shapes like squares, rectangles and circles using a special ‘tool’;
3) Entering text and changing the style and size of font;
4) Changing the size of an object, or scaling;
5) Rotating objects in either clockwise or anticlockwise by specifying the direction and angle of rotation;
6) Stretching objects either horizontally or vertically. ‘Flipping’ an object either horizontally or vertically.
7) A paint palette from which different colours and patterns can be chosen.
8) A fill option for colouring in a shape or area on the screen with a colour or pattern from the paint palette.
9) Most graphics packages have a built-in library of clipart pictures.
10) Zoom or magnify is a feature that allows an area of the screen to be seen close up for detailed work.
11) Special brushes such as an airbrush can be used to achieve different paint effects on the screen. In most graphics these features are chosen from a toolbar or tool palette where they are displayed as icons.
12) Exporting is a special way of saving a file produced using a graphics package so that it can be used in another application package.
13) When an exported file is needed in another application it is opened in a special way called importing.
TYPES OF GRAPHIC PACKAGES
The main types of graphics packages are
- Painting packages.
- Drawing packages.
- Photo editing.
- CAD.
A) PAINTING PACKAGES
A painting application allows freehand drawing and colouring, usually with a mouse. A painting package produces images by changing the colour of pixels on the screen. These are coded as a pattern of bits to create a bitmapped graphics file. Bitmapped graphics are used for images such as scanned photographs or pictures taken with a digital camera. Bitmap graphics made with painting packages consist of many tiny dots called pixels. It is possible to edit each individual pixel. Since the computer has to store information about every single pixel in the image, the file size of a bitmap graphic is often quite large. Bitmap graphics lose quality when they’re resized. Examples of graphics packages that produce bitmapped images include MS Paint, PC Paintbrush, Adobe Photoshop and JASC’s Paint Shop Pro.
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.
Advantage of Painting Packages
The main advantage offered by this type of graphic is that individual pixels can be changed which makes very detailed editing possible.
Disadvantages of painting packages
- Individual parts of an image cannot be resized;
- Only the whole picture can be increased or decreased in size.
- Information has to be stored about every pixel in an image which produces files that use large amounts of backing storage space.
B) DRAWING PACKAGES
Images made with drawing packages consist of lines, shapes and co-ordinates. A drawing package produces images that are made up from coloured lines and shapes such as circles, squares and rectangles. When an image is saved it is stored in a vector graphics file as a series of instructions, which can be used to recreate it. Drawing packages are also known as vector drawing packages. Generally a drawing package offers many similar features to a painting.
Examples of drawing graphics packages include CorelDraw, Micrographix Designer and computer aided design (CAD) packages such as AutoCAD.
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.
Advantages of vector graphics are:
- They use less storage space than bitmap graphics;
- Each part of an image is treated as a separate object, which means that individual parts can be easily modified.
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.
Advantages of Drawing Packages
- Smaller file size: Vector graphics, unless bitmap images, do not store data about each individual pixel. For a large illustration, such as a poster, a vector 10 29 graphic would have a significantly smaller file size compared to a bitmap image.
- Scalable: When you resize a vector graphic the mathematical relationships mean that the image does not lose quality. A vector graphic the size of a postage stamp could be resized to be used on a poster and the image would still be clear.
Disadvantage of Drawing Package
Vector graphics do not look as realistic as bitmap graphics or photos. They will always appear computer generated.
C) PHOTO EDITING
Photo editing software allows the user to edit and adjust photographs. Usually these photos come from a digital camera, but they could also be scanned from existing photos. Digital photos are bitmap images. There is a large range of photo editing software available, e.g. Adobe Photoshop, Corel Paint Shop Pro, GIMP and Paint.NET.
Features of Photo Editing Software
1) Crop: Cut off sides of an image to make it a suitable size or remove unwanted areas.
2) Adjust contrast and brightness.
3) Remove red-eye.
4) Layers: You can have several different elements of the graphic as separate layers. These layers can be made invisible or even deleted at any time.
5) Clone tool: Allows the user to clone one part of the picture to another to remove an unwanted element.
6) Special effects: The effects vary from one piece of software to another but usually include:
- Artistic effects: For example, making a picture look like an oil painting.
- Geometric effects: For example, making an image appear to be on the surface of a ball.
- Colour adjustments: For example, turning a photo into greyscale or brightening certain colours.
D) COMPUTER AIDED DESIGN (CAD)
Computer-aided design, or CAD, is the use of a computer to display designs, accept any changes to them and calculate and display the results. CAD packages are more sophisticated drawing packages. They are used by engineers, architects and designers to produce detailed design plans and technical drawings.
CAD software offers all the features of standard drawing software but in addition may also offer:
- greater accuracy (it is possible to work to within 1/72 of an inch).
- objects and drawings can be created in 2D, 3D, 2D CAD and 3D CAD.
- images can be viewed from any angle.
- powerful scaling, rotation and reflection.
- libraries of engineering components which can be imported.
- links to packages to calculate costs.
CAD has many different applications, which include:
- Designing new cars;
- Bridge and building design and testing;
- Printed circuit board (PCB) design;
- Designing new aircraft;
- Designing fitted kitchens.
Advantages of CAD systems
- Changes to a design can be made quickly and their effects seen straight away;
- Designs can be viewed from any angle without being re-drawn;
- Designs can be tested without the need to build expensive models or prototypes;
- Drawings can be stored on disk and reused at any time;
- Designs can be instantly sent anywhere in the world using electronic communications;
- Designs can be used directly in computer aided manufacturing processes.
