17. What is a bitmapped font?
A simple method for representing the character shapes in a particular typeface is to use rectangular grid patterns. The set of characters are then referred to as a bitmap font.
18. What is an outline font?
A flexible scheme is to describe character shapes using straight-line and curve sections. In this case, the set of character is called an out line font.
19. What is an attribute parameter?
Any parameter that affects the way a primitive is to be displayed is referred to as an attribute parameter.
20. What are the various attributes of a line?
The line type, width and color are the attributes of the line. The line type include solid line, dashed lines, and dotted lines.
21. What is pixel mask?
Pixel mask is a string containing the digits 1 and 0 to indicate which positions to plot along the line path. The mask 1111000, could be used to display a dashed line with a dash length of 4 and inter dot spacing of three.
22. What is a Line cap?
Line caps can be used to adjust the shape of the line ends to give a better appearance. There are three types of line caps. Butt cap which has a square end, round cap which has a semi circle end, projecting square cap which has one half of the line width beyond the specified end points.
23. List out the methods used for smoothly joining two line segments?
- Mitter join-by extending the outer boundaries of each of the two lines until they meet.
- Round join – by capping the connection between the two segments with a circular boundary whose diameter is equal to the line width.
- Bevel join – by displaying the line segments with butt caps and filling in the triangular gap where the segment meet.
24. What is Color Look up table?
In color displays, 24 bits per pixel are commonly used, where 8 bits represent 256 level for each color. It is necessary to read 24-bit for each pixel from frame buffer. This is very time consuming. To avoid this video controller uses look up table to store many entries to pixel values in RGB format. This look up table is commonly known as colour table.
25. What is tiling patterns?
The process of filling an area with rectangular pattern is called tiling and rectangular fill patterns are sometimes referred to as tiling patterns.
26. What is soft fill?
Soft fill is a filling method in which fill color is combined with the background colors.
27. What is kerned character?
The characters which extend beyond the character body limits is known as kerned character. Example f and j.
28. What is character up vector?
The orientation for a displayed character string is set according to the direction of the character up vector.
29. Define bundled attributes?
Individual attribute commands provide a simple and direct method for specifying attributes when a single output device is used. When several kinds of output device are available at a graphics installation, it is convenient to set up a table for each output device that lists set of attribute values that are to be used on that device to display each primitive type. Attribute specified in this manner is known as bundled attribute.
30. What is aliasing?
In the line drawing algorithms, all rasterzed locations do not match with the true line and have to represent a straight line. This problem is severe in low resolution screens. In such screens line appears like a stair-step. This effect is known as aliasing.
31. What is antialiasing?
The process of adjusting intensities of the pixels along the line to minimize the effect of aliasing is called anti aliasing.
32. What is pixel phasing?
Pixel phasing is an antialiasing technique, stair steps are smoothed out by moving the electron beam to more nearly approximate positions specified by the object geometry.
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