Graphics Basic Concepts 1

 A graphic is an image or visual representation of an object.  A visual representation such as a photo, illustration or diagram.  A graphic may contain text, but text by itself is not considered a graphic unless it is done in a stylized fashion.  Graphics are an element that virtually all multimedia applications include. Graphics in Multimedia

 A graphic can be a:  Chart  Drawing  Painting  Photograph  Logo  Navigation button  Diagram What is a graphic?

 Graphics can be:  Black and White  Grayscale  Color  Still  Animated What do graphics look like?

 Graphics can:  Illustrate or demonstrate procedures  Clarify data  Convey ideas  Tell stories  Add visual appeal What do graphics do?

 The image that is displayed on the screen is composed of thousands (or millions) of small dots; these are called pixels  The word is a contraction of the phrase "picture (pix) element (el)".  The pixel is the smallest element of a video image but it is not the smallest element of a monitor's screen 6 Pixels

 Since each pixel on a color display must be made up of three separate colors, there are in fact smaller red, green and blue dots (RGB) on the surface of the CRT that make up the image.  The term dot is used to refer to these small elements that make up the displayed image on the screen. 7 Dots

 The number of pixels that can be displayed on the screen is referred to as the resolution of the image  Normally displayed as a pair of numbers, such as 640 x 480, 800 x 600, 1024 x 768, etc.  The first is the number of pixels that can be displayed horizontally on the screen  The second how many can be displayed vertically. 8 Resolution

 The higher the resolution, the more pixels that can be displayed and therefore the more that can be shown on the monitor at once 9 Resolution

 Monitor comes in various sizes  14”, 15”, 17”, 19”, 21”, 22”  What does the number represents?  diagonal width of the computer, one corner to another  known as the nominal size  Is a 17” monitor actually 17”?  Actually your monitor is around 15.8”  This is known as the viewable size  So what really matters?  Nominal size or viewable size? 10 Computer Monitor Nominal Size vs. Viewable Size

 The maximum resolution of a monitor is roughly related to its size  small monitors can't generally display in very high resolution.  Higher resolutions mean that the pixels become smaller  using a high-resolution mode on a small monitor can be painful to the eye.  your 17" monitor may support 1400 x1050 resolution, but are you going to be able to see anything? 11 Size and Resolution Matching

 Images created or edited on computers are either:  Bitmapped graphics  Vector graphics Computer Graphics Technology

 Vector graphics use mathematical formulas to define lines, curves, and other attributes.  Generally much smaller than raster graphic files  Vector graphic editors are called draw programs  Do not lose clarity as you enlarge them.  Appear as bitmaps on computer monitors because computer monitors consist of pixels What are vector graphics?

 Made of lines and curves defined by mathematical objects called vectors.  Vectors describe graphics according to their geometric characteristics.  For example, a bicycle tire in a vector graphic is made up of a mathematical definition of a circle drawn with a certain radius, set at a specific location, and filled with a specific color.  You can move, resize, or change the color of the tire without losing the quality of the graphic. 14 Vector Image

 Resolution-independent--that is, it can be scaled to any size and printed on any output device at any resolution without losing its detail or clarity.  The best choice for type (especially small type) and bold graphics that must retain crisp lines when scaled to various sizes--for example, logos. 15 Vector Image

 Because computer monitors represent images by displaying them on a grid, both vector and bitmap images are displayed as pixels on-screen.  Good for reproducing crisp outlines, as in logos or illustrations.  Can be printed or displayed at any resolution without losing detail. 16 Vector Image

17 Vector Image

 Bitmapped graphics, also known as raster graphics, consist of grids of tiny dots called pixels. Each pixel is assigned a color.  Can be a continuous-tone image, such as a photograph  Bitmap graphic editors are called paint programs  Enlarging a bitmap graphic may cause the image to lose crispness and clarity What are bitmapped graphics?

 Also called raster images  The images use a grid (also known as a bitmap or raster) of small squares, known as pixels, to represent graphics.  Each pixel in a bitmap image has a specific location and color value assigned to it.  For example, a bicycle tire in a bitmap image is made up of a collection of pixels in that location, 19 Bitmap Image

 When working with bitmap images, you edit pixels rather than objects or shapes.  Best for continuous-tone images, such as photographs or images created in painting programs, because they can represent subtle gradations of shades and color.  Resolution dependent--that is, they represent a fixed number of pixels. As a result, they can appear jagged and lose detail if they are scaled on-screen or if they are printed at a higher resolution than they were created for. 20 Bitmap Image

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