Picture Frame ; Anchor Point ; Graphics Window - Page 155

2001/10/02 

CHAPTER 4 HP-GL/2 - 7 

3. 

TERMINOLOGY 

3.1. 

Picture Frame 

The printer frame is the rectangular area of the page on which graphic output can be printed.  This is based 
on the logical page defined for the selected paper size. 

3.2. 

Anchor Point 

The anchor point of the picture frame is the top left hand corner of the frame.   This can be moved on the 
page using PCL language page control commands. 

3.3. 

Graphics Window 

The graphics window is the rectangular area of the page on which you can generate graphic output using 
HP-GL/2 commands.  Initially the graphics window is the same as the picture frame but may be altered using 
the HP-GL/2 IW command. 

3.4. 

Hard Clip Limits 

Hard clip limits are the physical restrictions which define where printed output can appear on a page. 

3.5. 

Soft Clip Limits 

Soft clip limits are the user-defined restrictions which define where printed output can appear on a page. 

3.6. 

Graphics Units 

The initial coordinate system employs units of 1/1016" in both the x- and y -axes.   

3.7. 

User Units 

The HP-GL/2 graphics language uses a coordinate system.  You can impose your own x- and y -scale units 
on this system using the SC command. 

3.8. 

Current Units 

The units in use at a given time are called the current units.  Current units are either user units or graphics 
units,  depending on whether scaling has been turned on or not.  The SC command is used to turn scaling 
on,  that is,  to make user units the current units. 

3.9. 

Pens 

By convention, certain HP-GL/2 graphics language commands are thought of as using a pen,  which can be 
either up or down.  To produce plotted output the pen must be down.  To move to a location on the page 
without producing output the pen must be in the up position.  Some HP-GL/2 commands require you to 
specify the pen position before you use them, others have implied pen positions built into them,  so that 
you do not need to specify "Pen up" or "Pen down".