18-20 Programming
Example
ARC 0;0;2;0;2π:
FREEZE:
Draws a circle centered 
at (0,0) of radius 2. The 
FREEZE command 
causes the circle to 
remain displayed on the screen until you press a key.
BOX Draws a box with diagonally opposite corners (x1,y1) and 
(x2,y2).
BOX x1;y1;x2;y2:
Example
BOX -1;-1;1;1:
FREEZE:
Draws a box, lower 
corner at (–1,–1), 
upper corner at (1,1)
ERASE Clears the display
ERASE:
FREEZE Halts the program, freezing the current display.  
Execution resumes when any key is pressed.
LINE Draws a line from (x1, y1) to (x2, y2).
LINE x1;y1;x2;y2:
PIXOFF Turns off the pixel at the specified coordinates (x,y).
PIXOFF x;y:
PIXON Turns on the pixel at the specified coordinates (x,y).
PIXON x;y:
TLINE Toggles the pixels along the line from (x1, y1) to (x2, y2) 
on and off. Any pixel that was turned off, is turned on; 
any pixel that was turned on, is turned off. TLINE can be 
used to erase a line.
TLINE x1;y1;x2;y2:
HP 39gs English.book  Page 20  Wednesday, December 7, 2005  11:24 PM