This section provides quick introductions of some basic graphics concepts: dot, pixel, color, and resolution.
A computer graphics is organized as a matrix of rows and columns of dots.
Each dot carries a color value.
The resolution of a graphics is measured by 3 parameters:
1. Horizontal resolution: The number dots within an inch in the horizontal direction.
2. Vertical resolution: The number dots within an inch in the vertical direction.
3. Color resolution: The number of colors supported on a dot.
For example, if a graphics of 5 inches by 3 inches is stored in computer with a resolution of
72 DPI (Dots Per Inch) in both directions and 256 colors per dot, it will be stored with a matrix
3 x 72 = 216 rows and 5 x 72 = 360 columns of dots. A color value in the range of 0 and 255 is used
on each dot.
A dot is also called pixel, a short name for pic-ture el-ement.
The size of a computer graphics can be easily calculated by the its pixel size and number of colors,
if it is stored without any compression.
For example, the file size of a graphics of 360x216 pixels and 256 colors will be 360 x 216 x 8 bits
= 77,760 bytes.
