Describe any two methods for drawing thick lines.

Two method for drawing thick lines are: (1) Using the line- width command: "setline width scale factor (iw)" Line width parameter "iw" is assigned a positive number to indicate the relative width of the line to be displayed. A value of 1 specifies standard- width line. (2) For raster implementation, a standard width line is generated with single pixel at each sample position, as in the Bresenham algorithm. Other- width lines are displayed as positive integer multiples of the standard line by plotting additional pixel along adjacent parallel line paths. For lines with slope  magnitude less than 1, the line drawing routine can be modified to display thick lines by plotting a vertical span of pixels at each x position along the line. The number of pixel in each span is sat equal to the integer magnitude of parameter 1w. As shown in figure below a double width line is plotted by generating a parallel line above the original line path. For lines with slope magnitude greater then 1, thick lines can be plotted with horizontal spans, alternately picking up pixels to the right and left of the line path.