IDLgrSymbol Properties

IDLgrSymbol objects have the following properties in addition to properties inherited from any superclasses. 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.

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.

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.

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.

DATA

Either an integer value (from the following list), or an object reference to either an IDLgrModel object, or atomic graphic object. Setting this property is equivalent to setting the Data argument.

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

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.

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].

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

THICK

A floating-point value between 1.0 and 10.0, specifying the line thickness to used to draw any lines that make up the symbol, in points. The default is 1.0 points.

Version History

ALPHA_CHANNEL added: 6.1