Graphics are visual presentations on some surface, such as a wall, canvas, computer screen, paper, or stone to brand, inform, illustrate, or entertain.
Graphics often combine text, illustration, and color.
There are two types of computer graphics:
i. Raster graphics
ii. Vector graphics
*Raster graphics, where each pixel is separately defined (as in a digital photograph).
*In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium.
*Raster graphics are resolution dependent.
* A raster is a grid of x and y coordinates on a display space. (And for three-dimensional images, a z coordinate.)
*A raster image file identifies which of these coordinates to illuminate in monochrome or color values
* Raster graphics are digital images represented by a matrix or grid of pixels commonly called a bitmap.
*On a Black- and- White system with one bit per pixel,the frame buffer is commonly called BITMAP.for systems with multiple bits per pixel,the frame buffer is called PIXMAP.
*Each pixel or dot displays a unique color and together all of these colored dots create an image.
*Raster graphics with a greater number of colors and pixels will require more bits and take up more memory.
*Typical file formats for raster graphics include .jpg, .gif, .tiff, and .bmp.
*Since raster graphics are represented in a grid structure, the width and height are usually indicated by the number of rows and columns rather than a particular unit of measurement.
*The size of an image might be described as 640 x 480 meaning that there are 640 pixels in a row and 480 pixels in a column.
* A higher resolution raster graphic will have smaller pixels that result in a more detailed image.
*Black and white raster graphics contain only black and white pixels and each pixel requires just one bit in memory.
*A colored raster graphic requires additional bits because three values are necessary to represent each of the red, green, and blue components of the pixel.
*The color depth for an image is represented by the number of bits per pixel and as the color depth increases, more colors are available for display.
* Raster graphics are only one of the two common graphic types used to digitally represent 2-D images.
* Raster graphic is resolution dependent and changes in size will detrimentally affect the visual quality of the image.
* Raster graphics are most suitable for photographs and images with continuous tones and shading.
* If you blow up a raster graphic, it will look blocky, or “pixelated.
*Vector graphics, where mathematical formulas are used to draw lines and shapes, which are then interpreted at the viewer’s end to produce the graphic.
*Vector graphics is the creation of digital images through a sequence of commands or mathematical statements that place lines and shapes in a given two-dimensional or three-dimensional space
*Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical expressions, to represent images in computer graphics.
*Vector graphics is based on images made up of vectors.
*Vector graphics are comprised of paths, which are defined by a start and end point, along with other points, curves, and angles along the way.A path can be a line, a square, a triangle, or a curvy shape.
*These paths can be used to create simple drawings or complex diagrams.
*Paths are even used to define the characters of specific typefaces.
*Because vector-based images are not made up of a specific number of dots, they can be scaled to a larger size and not lose any image quality.
*When you blow up a vector graphic, the edges of each object within the graphic stay smooth and clean.
*Common types of vector graphics include Adobe Illustrator, Macromedia Freehand, and EPS files.
* Many Flash animations also use vector graphics, since they scale better and typically take up less space than bitmap images.
* In physics, a vector is a representation of both a quantity and a direction at the same time.
* A vector file is sometimes called a geometric file.
* All computer-aided design (CAD), drawing and diagramming programs create vector images.
*Vector graphics and “bitmapped graphics” are the two fundamental structures for digital images.
*Vector images are very space efficient compared to bitmapped images, and they maintain all their detail when zoomed in and out.
Submitted by Ramya. I MJMC, December 2011