RT - Relative arc three point ; PE - Polyline encoded ; RT X- Page 178

CHAPTER 4 HP-GL/2 - 22 

RT - Relative arc three point 

RT X

1

, Y

1

, X

2

, Y

2

 [,qd] [;] 

X

1

 ; x-coordinate of intermediate point 

Y

2

 ; y-coordinate of intermediate point 

X

2

 ; x-coordinate of end point 

y

2

 ; y-coordinate of end point 

qd

 ; the chord angle used to draw the arc   



The specified coordinates of the two points are relative to the current pen position. 



The command draws an arc from the current position,    through the specified intermediate position and 
finishing at the specified end position. 



After completion of the command the current cursor position is at the end of the arc. 



An arc can be drawn clockwise or anti-clockwise. 



If the current scaling mode is not isotropic,    the arc may be elliptical rather than circular. 



The chord angle must be in the range 0.5º to 180º. 



The default chord angle is 5º. 

10 '--Relative Arc Three Point-- 
20 WIDTH "LPT1:",255 
30 LPRINT CHR$(27); "E"; 
40 LPRINT CHR$(27); "&0B"; 
50 LPRINT "IN;SP1;"; 
60 LPRINT "PA1000,100;PR;PD1500,0;" 
70 LPRINT "PU-1850,1050;PD350,0;" 
80 LPRINT "PU-350,-700;PD350;0;" 
90 LPRINT "PU0,-350;PD0,1500,1500,0;" 
100 LPRINT "RT800,-750,0,-1500;" 
110 LPRINT "PU700,850;PD;" 
120 LPRINT "RT100,-100,0,-200;" 
130 LPRINT "PU100,100;PD200,0;" 
140 LPRINT CHR&(27); "%0A"; 
150 LPRINT CHR$(27); "E"; 
160 END 
 
<Sample 29> 

PE - Polyline encoded 

PE [ [

flag

] [

value

] | X

i

Y

i

 ... [

flag

] [

value

] | X

i

Y

i

 ] ]; 

flag

    ; a command or mode that applies to the data that follows 

value

; parameter data for the preceding flag 

X   

; X-coordinate of a cursor movement destination 

Y   

; Y-coordinate of a cursor movement destination 



This command allows you to combine a sequence of PA, PR, PU, PD and SP commands into a coded format.   
This reduces file size and transmission time. 



Do not use commas within the PE command.    Parameters either have their own terminators or do not 
require them. 



The PE command must be terminated with a semi-colon. 



The command draws lines using the current line type and current units. 



The command draws lines to all coordinate points specified unless you precede the coordinate pair with a 
pen up flag. 



On completion of the command, the pen is down unless the final move was made with the pen up. 



All coordinate points are interpreted as relative unless preceded by the absolute flag (=). 



On completion of the command,    the previous plotting mode is restored. 



Flags are not encoded.    They are sent as ASCII characters.    The MSB of the code is ignored, thus 60 and 
188 can both represent <, the flag for pen up.