Line drawing is extremely simple. Pick two sets of graphic coordinates, and draw your line from one to the other. To draw a line from the current position of the graphics cursor, use DRAW TO followed by a single set of coordinates.

For example:

BITMAP ENABLE
CLS
INK RED
DRAW 50,50 TO 250,150
DRAW TO 275,175

Changing the appearance of straight lines is very simple with ugBASIC. Each line pattern is held in the form of a binary number made up of 16 bits, with zeros setting blank spaces in the current background colour, and ones setting the solid parts of the pattern in the current ink colour. So a normal solid line can be imagined as having all its bits set to one, like this:

%1111111111111111

The SET LINE command sets the style of all straight lines that are subsequently drawn. Theoretically, the 16-bit mask can generate values for different patterns between 0 and 65535, but here is a more practical example:

BITMAP ENABLE
CLS
INK YELLOW
SET LINE $F0F0
BOX 50,100 TO 150,140
SET LINE %1100110011001100
BOX 60,110 TO 160,160

Here is a range of ugBASIC short-cuts for drawing outline shapes on the screen.

The POLYLINE is identical to DRAW except that it accepts multiple coordinate settings at the same time. In this way, complex many-sided outlines can be drawn with a single statement. In its POLYLINE TO form, drawing begins at the current graphic cursor position. For example:

BITMAP ENABLE
CLS
CIRCLE 160,100,95
POLYLINE 160,6 TO 100,173 TO 250,69 TO 71,69 TO 222,173 TO 160,6

Boxed outlines are drawn at settings determined by the top left-hand and bottom right-hand coordinates, as in the following example:

BITMAP ENABLE
CLS
BOX 60,110 TO 160,160

To draw circles you can use the CIRCLE command, with a pair of coordinates sets the position of the centre point around which the shape is to be drawn, followed by the radius of the circle (the distance between the centre point and the circumference or rim of the circle). If the x,y-coordinates are omitted, the circle will be drawn from the current graphic cursor position.

BITMAP ENABLE
CLS
INK RED
GR LOCATE 160,100
CIRCLE ,,45
WAIT 100 MS
DO
   INK RND(SCREEN COLORS)
   x=RND(SCREEN WIDTH/2)
   y=RND(SCREEN HEIGHT/2)+1
   CIRCLE x,y,r
LOOP

An ellipse is drawn in a similar way. After the x,y-coordinates have set the centre location, two radii must be given, one to set the horizontal width and the second to set the height of the ellipse. Coordinates may be omitted as usual,providing the commas remain in place.

For example:

ELLIPSE 100,100,50,20
ELLIPSE ,,20,50

This section explains how the ugBASIC programmer is free to exploit the colour-handling features. Although the various targets provides different colour schema and registers, ugBASIC allows the use of colour numbers ranging from 0 to SCREEN COLORS (or COLOR COUNT).

You are not restricted to the pre-set colours that have been allocated for drawing operations. The INK command is used to specify which colour is to be used for subsequent drawing, and the number of the colour is set like this:
CLS
COLOR BACK RED
INK YELLOW
DRAW TO 319,199

The COLOR BACK command is used to assign your choice of color for the screen's background colour.

The ugBASIC language recognizes a series of keywords as colors: