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3—Programming
Note
Remember that values for X and W (Left and Right) must be
specified as even pixels, whereas, Y and H (Top and
Bottom) can accommodate both even and odd values.
Example
The following scenario will demonstrate how even and odd values work
with cropping values.
A DVI window is set to 1600 x 1200 with the following cropping values—
X=20 Y=20 W=20 H=20 through the commands:
+GalWinSys GetCrop { 10018 }
Returns:
=00000000 { 20 20 1560 1160 }
Next, cropping is set by 1 extra pixel for X and Y:
+GalWinSys SetCrop { 10018 } { 21 21 1559 1159 }
Returns:
=00000000
The odd values are accepted by the acknowledged return of =00000000,
however, the DVI Capture Window Properties (in the GUI) now report
the following values:
X=22 Y=21 W=18 H=20
Notice that the X-value has been adjusted to 22 and the W to 18 as only
even numbers are allowed for X and W, while the Y-value has accepted the
odd value of 21.
Only when another Get command is issued again does the corrected
X-value (by rounding of to the next even number) show up:
+GalWinSys GetCrop { 10018 }
Returns:
=00000000 { 22 21 1560 1159 }
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ControlPoint 2.10 Protocol Manual