Changing the Scale

Graphics are drawn in the OSA window on the display, usually 800 dots wide by 384 dots high. Most graphics are drawn between the lower-left position, P1 , and the upper right position, P2, when the OSA has been assigned the full screen as shown in the following ￿gure. P1 is located at the left edge of the graticule, just above the data line. P2 is located at the right edge of the graticule at the top of the display.

Default Positions for P1 and P2

The scale of the coordinates that P1 and P2 de￿ne has a preset value of 0,0 and 1000,1000. Most graphics commands position the pen according to the scale between P1 and P2. Graphics can be drawn outside the window, but this is not recommended.

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