RT - Relative arc three point ; PE - Polyline encoded ; RT X- Page 170

2001/10/02 

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 0.5° to 180°. 

• 

The default chord angle is 5°. 

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.