Essential Elements for the Raster Scan Display

Three elements are essential for the raster scan display. They are as:

1) The Frame Buffer that is also termed as the Refresh Buffer or Bitmap. This is the refresh storage region in the digital memory, wherein the matrix or array of intensity values and other parameters termed as attributes of all the pixels making up the image are stored in binary form.

2) The display device that converts the electrical signals in observable images, i.e. the VDU.

3) The Display Controller, the interface that sends the contents of the frame buffer to the VDU in a form compatible along with the display device, a specific number of i.e. 30 or more times a second. The display controller adjusts also and creates allowances for the dissimilarities in the operating speeds of the different devices involved and may also produce line segments and text characters.

Creating points, lines, characters and also filling in areas along with colours or shades are all accomplished through this scan technique, termed as the Frame Buffer Display. A usual method for storing characters is to store the pixel data for the entire matrix as 5*7 to 9*14, horizontal to vertical allocated to present a character.