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IDLgrSymbol Properties

IDLgrSymbol Properties

IDLgrSymbol objects have the following properties. Properties with the word “Yes” in the “Get” column of the property table can be retrieved via IDLgrSymbol::GetProperty. Properties with the word “Yes” in the “Init” column of the property table can be set via IDLgrSymbol::Init. Properties with the word “Yes” in the “Set” column in the property table can be set via IDLgrSymbol::SetProperty.

Note: For a discussion of the property description tables shown below, see Modifying Object Property Descriptions.

Objects of this class have the following properties.

ALL

An anonymous structure containing the values of all of the properties associated with the state of this object. State information about the object includes things like color, range, tick direction, etc., but not image, vertex, or connectivity data, or user values.

Note: The fields of this structure may change in subsequent releases of IDL.

Property Type

Structure

Name String

not displayed

Get: Yes

Set: No

Init: No

Registered: No

ALPHA_CHANNEL

A floating-point value in the range [0.0, 1.0] to specify the opacity of the symbol. The default value of 1.0 causes IDL to draw the symbol completely opaque. If the value of this property is less than 1.0, then the pixels of the symbol are blended with the pixels already on the screen, where the color of the symbol is multiplied by the alpha value and the pixels already on the screen are multiplied by 1.0-alpha.

Because an object can only be blended with objects already drawn on the screen, the drawing order of the objects must be considered carefully in order to obtain the desired results.

This property has no effect on devices using indexed color mode.

Some of the objects that use symbols have properties that control the alpha value that is ultimately used to render the symbol. This ultimate alpha value might come from the parent object’s ALPHA_CHANNEL property, an alpha value from a vertex color in the parent object, or the value of this property, depending on the settings of properties in the parent object. Refer to the reference guide for the parent properties for information on these controls.

Property Type

Float-point value

Name String

Transparency

Get: Yes

Set: Yes

Init: Yes

Registered: No

ANTIALIAS

A Boolean value that indicates whether anti-aliasing should be used when drawing the symbols. The default is 0, which disables anti-aliasing.

Property Type

BOOLEAN

Name String

Anti-aliasing

Get: Yes

Set: Yes

Init: Yes

Registered: No

COLOR

The color used to draw the symbol. The color may be specified as a color lookup table index or as a three-element vector [red, green, blue]. The default color is the color of the object for which this symbol is being used.

Property Type

Color

Name String

not displayed

Get: Yes

Set: Yes

Init: Yes

Registered: No

DATA

Either an integer value (from the following list), or an object reference to either an IDLgrModel object, or atomic graphic object.

Use one of the following scalar-represented internal default symbols:

  • 0 = No symbol
  • 1 = Plus sign, ‘+’ (default)
  • 2 = Asterisk
  • 3 = Period (Dot)
  • 4 = Diamond
  • 5 = Triangle
  • 6 = Square
  • 7 = X
  • 8 = “Greater-than” Arrow Head (>)
  • 9 = “Less-than” Arrow Head (<)
  • 10 = Triangle Down
  • 11 = Triangle Left
  • 12 = Triangle Right
  • 13 = Tri Up
  • 14 = Tri Down
  • 15 = Tri Left
  • 16 = Tri Right
  • 17 = Thin Diamond
  • 18 = Pentagon
  • 19 = Hexagon 1
  • 20 = Hexagon 2
  • 21 = Vertical Line
  • 22 = Horizontal Line
  • 23 = Star
  • 24 = Circle
  • 25 = Pin
  • 26 = Pushpin

If an instance of the IDLgrModel object class or an atomic graphic object is used, the object tree is used as the symbol. For best results, the object should fill the domain from -1 to +1 in all dimensions. The pre-defined symbols listed above are all defined in the domain -1 to +1.

Specifying this property is the same as specifying the optional Data argument to the IDLgrSymbol::Init method.

Note: Objects specified via this property are not automatically cleaned up when the IDLgrSymbol object is destroyed.

Property Type

Integer or object reference

Name String

not displayed

Get: Yes

Set: Yes

Init: Yes

Registered: No

FILL_COLOR

If the FILLED property has a non-zero value, this property sets the symbol fill color, which is a three-element vector [red, green, blue]. If FILL_COLOR is not set, symbols are filled with the color specified by the COLOR property.

Property Type

Integer or integer vector

Name String

Fill color

Get: Yes

Set: Yes

Init: Yes

Registered: No

FILLED

Set this property to a non-zero value to fill the symbol bitmap with the color specified by the FILL_COLOR property.

Property Type

Integer

Name String

Fill background

Get: Yes

Set: Yes

Init:Yes

Registered: No

NAME

A string giving the human-readable name of this object.

Property Type

STRING

Name String

Name

Get: Yes

Set: Yes

Init:Yes

Registered: No

SIZE

A one-, two-, or three-element floating-point vector describing the X, Y, and Z scaling factors to be applied to the symbol. The default is [1.0, 1.0, 1.0].

  • If SIZE is specified as a scalar, then the X, Y, and Z scale factors are all equal to the scalar value.
  • If SIZE is specified as a 2-element vector, then the X and Y scale factors are as specified by the vector, and the Z scale factor is 1.0.
  • If SIZE is specified as a 3-element vector, then the X, Y, and Z scale factors are as specified by the vector.

IDL converts, maintains, and returns this data as double-precision floating-point.

Property Type

Floating-point vector

Name String

not displayed

Get: Yes

Set: Yes

Init: Yes

Registered: No

THICK

A floating-point value between 0.0 and 10.0, specifying the line thickness to used to draw any lines that make up the symbol, in points. A thickness of 0 displays a thin hairline on the chosen device. Out-of-range values are quietly clamped to the allowed range. The default is 1.0 points.

Property Type

Floating-point

Name String

not displayed

Get: Yes

Set: Yes

Init: Yes

Registered: No

UVALUE

A value of any type containing any information you wish.

Note: Object references or pointers contained in the UVALUE property are not automatically cleaned up when the IDLgrSymbol object is destroyed.

Property Type

User Defined

Name String

not displayed

Get: Yes

Set: Yes

Init:Yes

Registered: No



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