Homelite HL-1470N, HL-1450 HP-GL Graphics Window, Units, Scaling Points P1 and P2, Transformation

10/10/03

5.THE HP-GL GRAPHICS WINDOW

5.1.Units

When you first enter graphics mode, the prevailing coordinate system has its origin in the bottom left hand corner of the graphics window and has x- and y-units of 1/1016". Using the SC command you can divide the axes into more convenient units. The size of the graphics window remains unaltered.

5.2.The Scaling Points P1 and P2

Many instructions use two reference scaling points, P1 and P2. Initially these are in the bottom left and top right hand corners of the graphics window respectively. You can alter the position of these points relative to the graphics window, or relative to one another, by using the IP or IR commands.

5.3.Scaling

You can easily scale images up or down by increasing or decreasing the distance between P1 and P2. You can do this both with existing images that are to be imported and with images that are generated by a string of HP-GL and HP-GL/2 commands, identical commands can be used to create the same image in different sizes.

5.4.Transformation

You can transform images horizontally or vertically by changing the relative positions of P1 and P2. You can do this both with existing images that are to be imported and with images that are generated by a string of HP-GL/2 commands.

CHAPTER 4 HP-GL/2 - 10