This report will discuss what digital graphics are and how this relates to producing graphics and images for games.

Digital graphics and digital imaging is the creation of digital images, from a physical scene. The term is often assumed to be the processing, compression, storage, printing and display of images.

There are two types of digital images which are Bitmap and Vector.

Unit 13: Assignment 1

Digital graphics technology

Harley jones 12c

Bitmap (Raster)

In computer graphics the raster image, or bitmap is a dot matrix which is a 2-dimentional patterned array, used to represent characters, symbols and images. Most types of technology uses dot matrices for display of information including mobile phones, TV's and printers. A bitmap corresponds bit-for-bit with images displayed on the screen. A bitmap is technically characterized by the width and height of the image in pixels and by the number of bits per pixel a color depth, which determines the number of colors it can represent. Unlike vector graphics, when zooming in on an image it tends to loose its quality.

Common bitmap files: jpg, ipeg, gif, png, tif, tiff, bmpCommon bitmap programmes: paint, PhotoshopCommon bitmap images: photographs and paintings.

In uncompressed bitmaps, image pixels are generally stored with a color depth of 1, 4, 8, 16, 24, 32, 48, or 64 bits per pixel.

Bitmap Advantages

Bitmaps are very easy to create and easy to come by.Bitmaps are fairly simple to output, as long as your RIP or printer has sufficient memory.

They are very cost effective. You can take a picture or scan in a drawing, and easily show it on the Internet or send in an email.

A bitmap image uses solid color pixels, which can be identified and recolored easily.

The geographic location of each cell is implied by its position in the cell matrix. Other than an origin point, e.g. bottom left corner, no geographic coordinates are stored.

Bitmap Disadvantages

The most common disadvantage of this image format is that they are not upward scalable. You can make a bitmap smaller without too much loss, but you cannot make it larger without loosing quality. If you ever see a bitmap image blown up, you’ll notice it has little individual squares or dots that make up the image. When you see it at its optimal size you don’t notice the individual dots, but if you try to make it bigger, the image become fuzzy or pixelated.

Another disadvantage of bitmap images is that they require higher resolutions for a smooth appearance.

Examples of bitmap graphics

These are bitmap images, as you can see that when zoomed in to an image the pixels are clearly visible and distort the picture however from distance the picture quality is fine.

Vector graphics

Vector graphics is the use of points, lines, curves and shapes which are all based on mathematical expressions to represent images in computer graphics. These graphics are based on vectors which lead through locations called control points.

Common file formats: ai, cdr, ps, pdfs

Common vector graphic programmes: adobe illustrator, CorelDraw,

Common uses of vector graphics; drawing, illustrations, cartoons

Vector graphics can be resized and will not lose clarity and be printed at any resolution .

Advantages of Vector images:

The most important point of vector images is their power of scalability. Vector images remain smooth because your computer re-computes the coordinates of the points and adjusts the vector equation constants.

Each set of lines in a vector image represent separate and distinct objects. therefore every object can be re-edited at any time. For example, if you created a vector art file with a circle in the background. You could open the drawing file at any time and change the circle to a square.

Another very important reason of using vector images instead of bitmaps is their size. Vector images are much smaller in size than the bitmap image format.

Disadvantages of Vector images:

Drawings containing trapping information can only be scaled up to 20 percent larger or smaller.

Thin lines may disappear if a vector drawing is reduced too much.

Small errors in a drawing may become visible as soon as it is enlarged too much.

Another important disadvantage of vector is the time and talent needed to create it. You cannot take a photograph in vector. Vector images are drawn on the computer by a graphic artist using vector editing software such as Adobe Illustrator.

Examples of vector graphics

These are vector images, here the pictures show that when zoomed in the quality isn’t ruined and no pixels are visible and they remain in focus.

Pixels

In digital imaging, a pixel is a physical point in a raster image, it is the smallest controllable element of a picture represented on the screen. LCD pixels are manufactured in a two-dimensional grid, and are often represented using dots or squares, but CRT pixels correspond to their timing mechanisms and sweep rates.

Each pixel is a sample of an original image, more samples typically provide more accurate representations of the original. The intensity of each pixel is variable. In color image systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black.

When zoomed in the picture resizes and loses its quality.

A normal bitmap image.

Factors that effect quality

Capturing images

Drawing in to a sketch pad

Advantages:It makes it easier to edit your design and add different affects to it.If you’re good at drawing, you can make it look realistic.

Disadvantages:It takes time to get used to the sketch pad and the different tools used on the programme.

Scanning an image

Advantages:The scanned image allows you to trace over the image on the programme and makes it easier to complete the design.The programme also makes it easier to edit on the programme.

Disadvantages:The detail on the scanned image may be faint and will make it harder to see it all.

Taking a photograph

Advantages:The finished design will then become photorealistic.

Disadvantages:You need a good equality camera to take HD photos.There could be potential equipment failures.

Capturing images

Sketch pads can be used to draw an image on an online website called Pixlr where images can be uploaded to draw over or to start from scratch.

When finished the image can be saved as a picture.

Output

When using paper to look at your work the image is made up of pixels containing a colour model. For paper the colour model is Black, Yellow, Cyan and Magenta.

When using a screen to look at your work the image is also made up of pixels containing a colour model. For screens, the colour model is Red, Green and Blue.

The difference between the two is that they both use separate colour wheels.

Organisation

Keep folders numbered for easy navigation.Make sure the named folders have the necessary documents included.Make sure you save every piece of the work you add.Keeping files organized is important because if you lose any valuable information it could ruin your work.

Report conclusion

In this report I have covered the advantages and disadvantages of both bitmap and vector graphics and what they are and used for.