A bit map (often spelled "bitmap") defines a display space and the color for each
pixel or "bit" in the display space. A
Graphics Interchange Format and a
JPEG are examples of graphic image file types that contain bit maps.
A bit map does not need to contain a bit of color-coded information for each pixel on every row. It only needs to contain information indicating a new color as the display scans along a row. Thus, an image with much solid color will tend to require a small bit map.
Because a bit map uses a fixed or
raster graphics method of specifying an image, the image cannot be immediately rescaled by a user without losing definition. A
vector graphics graphic image, however, is designed to be quickly rescaled. Typically, an image is created using vector graphics and then, when the artist is satisfied with the image, it is converted to (or saved as) a raster graphic file or bit map.
Advantages of bitmap
In paint programs, you see what you are getting, usually in real time when wielding a “paintbrush”
When you use a scanner, the output will normally be a bitmap
Much easier to create the appearance of “natural” media, such as areas of water colours bleeding into each other
More universally available interchange file formats; most bitmaps can be read by most bitmap-based software and certain file formats such as jpeg and png can be read and written by every paint program. This is not, unfortunately, the case with vector file formats where many programs can only deal with their own file formats and a very limited choice of others such as eps may be available.
Disadvantages of bitmap
Bitmap graphics should be created or scanned either at, or very close to, the size required for the finished product.
You can’t successfully change the size of the image in your word processor, or DTP package. You need to load the image into a suitable program and re-size it by re-sampling
If you do need to re-size an image, avoid drastic changes in size.
When re-sizing an image, always use a program that has some form of smart sizing feature and make sure that it is turned on.
If you are creating a large image, you will need plenty of memory available
Vector image
There are instances when working with vector tools and formats is the best practice, and instances when working with raster tools and formats is the best practice. There are times when both formats come together. An understanding of the advantages and limitations of each technology and the relationship between them is most likely to result in efficient and effective use of tools.
Vector of advantages
Scalability
File size based on complexity rather than sizes or colors depth
Easily generate by programs
Components can be individually manipulated
Processing done on client
Potential for animation, interaction
Vector of disadvantages
some image (complex curves) hard to reproduce
can be harder to write code for an image
vector images come up more slowly on client machines
many proprietary vector format and languages
Difference between vector and bitmap images
Examples vector image
Software for vector and bitmap
Bitmap
. Microsoft Paint
. Adobe Photoshop
. Corel Photo-Paint
. Corel Paint Shop Pro
. The GIMP
Vector
. AI (Adobe Illustrator)
. CDR (Corel DRAW)
. CMX (Corel Exchange)
. CGM Computer Graphics Metafile
. DXF AutoCAD
. WMF Windows Metafile
