QuickTime 3 Reference
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The Parameter Data Range atom defines the legal range of values that the parameter can take. It also defines a scaling constant that defines how the legal range of values can be translated into a range that is more suitable for display in a user interface.
The atom's data is structured as a RangeRecord , defined below. The exact format of this data depends on the data type of the parameter being described.
// 'text'
typedef struct
{
long maxChars; // Maximum length of the string
long maxLines; // Number of editing lines (typically 1)
} StringRangeRecord;
// 'long'
typedef struct
{
long minValue; // Minimum value the long can be
long maxValue; // Maximum value the long can be
long scaleValue; // Scaling constant
long precisionDigits; // number of digits of precision
// when editing via typing
} LongRangeRecord;
// 'enum'
typedef struct
{
long enumID; // The ID of the 'enum' atom in the
// root container to search
} EnumRangeRecord;
// 'fixd'
typedef struct
{
Fixed minValue; // Minimum value the Fixed can be
Fixed maxValue; // Maximum value the Fixed can be
Fixed scaleValue; // Scaling constant
long precisionDigits; // number of digits of precision
// when editing via typing
} FixedRangeRecord;
// 'doub'
typedef struct
{
QTFloatDouble minValue; // Minimum value of parameter
QTFloatDouble maxValue; // Maximum value of parameter
QTFloatDouble scaleValue; // Scaling constant
long precisionDigits; // number of digits of precision
// when editing via typing
} DoubleRangeRecord;
// 'bool'
typedef struct
{
long maskValue; // value to mask on/off to set/clear the
// boolean
} BooleanRangeRecord;
// 'rgb '
typedef struct
{
RGBColor minColor; // Minimum value the RGBColor can be
RGBColor maxColor; // Maximum value the RGBColor can be
} RGBRangeRecord;
// The RangeRecord data structure is the union of all of the above
typedef struct
{
union
{
LongRangeRecord longRange;
EnumRangeRecord enumRange;
FixedRangeRecord fixedRange;
DoubleRangeRecord doubleRange;
StringRangeRecord stringRange;
BooleanRangeRecord booleanRange;
RGBRangeRecord rgbRange;
} u;
} RangeRecord;
The minValue and maxValue fields of the DoubleRangeRecord data structure can take, in addition to an actual QTFloatDouble value, the following predefined values:
The minValue and MaxValue fields of the LongRangeRecord data structure can take, in addition to an actual long integer value, the following predefined values:
The Parameter Data Range atom is required, except for group descriptions.
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