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3.3.1. Controlling the Object Modes
When an object is selected the MODE button is used to control its modes (such as aspect ratio, and
whether it is centred or not). Pressing the MODE button cycles through a list of possible modes for the
currently selected object, and the shaft encoders will change the setting for that mode. After a 30-second
timeout, the Graticule Generator exits from the mode select menu. If the ESC button is pressed, the
Graticule Generator also exits from the mode select menu. When an object is selected, the last modes in
use by that object are enabled.
3.3.1.1. Display Mode
Display modes are used to control the appearance of the object on the output video, ex. dashed and solid
lines.
3.3.1.2. Centre Mode
If the object's centre mode is enabled, the object's centre will be fixed to the horizontal and vertical centre
of the clean aperture. The centre mode will not be available when the Force Centre Setup Menu item is
set to yes.
3.3.2. Aspect Ratio Mode
The aspect ratio mode of the mask, box, and circle objects forces the selected object's size parameters to
follow one of the following fixed aspect ratios: 1:1, 4:3(1.33:1), 14:9 (1.55:1), 1.67:1, 16:9 (1.78:1), 1.85:1,
2.35:1. When the object aspect ratio is set to Off the object's dimensions are not constrained to follow a
fixed aspect ratio.
When an object is being controlled in aspect ratio mode, the horizontal size will be adjusted first, then the
aspect ratio applied to determine the correct vertical size. The pixel aspect ratio and the object aspect
ratio are both used to calculate the vertical size of an object of a given horizontal size. The following
formula is used to calculate the vertical size:
Number of V lines = Number of H pixels x (Pixel aspect ratio / Object aspect ratio)
This calculation will be rounded to the closest line or to the closest line pair if object centring is on.
Example: Draw a box in 525/4:3 mode with an aspect ratio of 4:3, with a width of 708 pixels.
V lines = H pixels x (Pixel AR / Object AR
= 708 x ((160/177) / (4/3))
= 480
The selected object aspect ratio defines the ideal dimensions of the object. The on screen and front panel
aspect ratio displays show the actual object aspect ratio rounded to 2 decimal places. It may vary slightly
from the selected object aspect ratio due to the effects of rounding to the closest line, and object centring.
RACK MOUNT PANEL OPERATION
Models 9590 & HD9590 Graticule Generator Manual
Page 3-11
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