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Parameter Data Usage
The parameter data usage atom defines the intended use of the data in the parameter. This information can be used by your application to provide a more appropriate user interface for a parameter or group of parameters. For example, if your application knows that a set of four long integer values actually represent a rectangle, it can present a graphical display of the rectangle, rather than simply displaying four numeric input fields.
The data in this atom is stored in the following data structure:
typedef struct
{
OSType usageType;
} ParameterDataUsage;
- usageType
- This field defines the actual use that a parameter or group of parameters. It can take one of the following values:
- kParameterUsagePixels - The parameters in the group contain a set of pixels.
- kParameterUsageRectangle
- - The parameters in the group contain the top-left and bottom-right coordinates of a rectangle.
- kParameterUsagePoint
- - The parameters in the group contain the coordinates of a point.
- kParameterUsage3DPoint
- - The parameters in the group contain the X,Y,Z coordinates of a 3D point.
- kParameterUsage3by3Matrix
- - The parameters in the group contain a 3x3 matrix of
- values.
- kParameterUsageDegree
- s - The parameter contains degrees.
- kParameterUsageRadians
- - The parameter contains radians.
- kParameterUsagePercent
- - The parameter contains a percentage.
- kParameterUsageSeconds
- - The parameter contains seconds.
- kParameterUsageMilliseconds
- - The parameter contains milliseconds.
- kParameterUsageMicroseconds - The parameter contains microseconds.
The parameter data usage atom is optional.
© 1999 Apple Computer, Inc.
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