10/10/03

6.PREPARING TO PRINT GRAPHIC IMAGES

6.1.Setting Up the Graphics Window

Before entering HP-GL/2 mode you will probably want to set the dimensions and position of the PCL picture frame and hence the graphics window. (Remember that when you enter HP-GL/2 mode they are initially the same). To do this you will need to send some preparatory PCL commands while in LaserJet mode. Use the Esc*c0T command to position the picture frame and the Esc*c#X and Esc*c#Y commands to determine it's horizontal and vertical dimensions respectively. These commands are described fully in the sub-section Vector Graphics in the LaserJet section of this manual. ( Section 2 )

If you do not specify a position and dimensions for the picture frame, the default picture frame is used. This is described in the sub-section ‘The Page in LaserJet mode’ section of this manual.

6.2.Using Existing Image Plots

If you are importing an existing HP-GL/2 plot you can easily determine the size and position on the page of the resulting printed graphic. Images are automatically scaled and fitted to the picture frame ( the HP-GL/2 graphics window ) in either of the following two cases.

1)If you use the Esc*c#K and Esc*c#L PCL commands to specify the width and height of the original plot before entering HP-GL/2 mode. These commands are explained in the sub-section ‘Vector Graphics

in LaserJet mode’ section of this manual. Only use these commands if you are importing an existing plot.

2)If the imported image code is page-size independent.

An image is page-size independent if it's HP-GL/2 code satisfies the following conditions.

User units are used exclusively, that is, an SC command is used before any drawing commands

 

are issued.

Note in particular that if the graphics window is changed from the default using the IW

 

command,

it must be specified in user units.

No absolute units are used or implied, that is, drawing commands use relative movement only

 

and character size, pattern length and pen width are always specified as relative measurements.

 

Commands like IP and PA, which imply the use of absolute units even if none are explicitly

 

supplied,

should not be used at all.

If you import an image without fulfilling these two criteria, that is, the image is not page size independent and you do not specify its horizontal and vertical plot sizes, the plot will be drawn actual size. Any part of the plot that falls outside the effective window will not appear on the printed page.

6.3.Printing an Image

When you have carried out any necessary preliminary steps that your particular application requires, as described in the preceding sections, enter HP-GL/2 mode using the Esc%#B command and send the sequence of HP-GL/2 commands to generate the image.

6.4.Entering HP-GL/2 Mode

To enter graphics mode from PCL printer control language use the Esc%#B command. Set # to 0 if you want the pen to start from the previous HP-GL/2 pen position. Set # to 1 if you want to the pen to start from the current PCL cursor position. You must specify either one setting or the other.

6.5.Quitting HP-GL/2 Mode

To quit graphics mode use the Esc%#A command. PCL cursor position. This is the default setting. HP-GL/2 pen position.

Set # to 0 if you want to place the cursor at the previous Set # to 1 if you want to place the cursor at the current

CHAPTER 4 HP-GL/2 - 11

Page 151
Image 151
Homelite HL-1070, HL-P2500, HL-1660E, HL-2400CE, HL-1450, HL-1050, HL-1250, HL-1470N, 2060 manual Preparing to Print Graphic Images