This node defines one or more strings of 2D text. The text is always horizontal, aligned with the screen and does not change size with distance from the camera. However the position of the text is specified in 3D units and is affected by viewing and modeling transformations. 2D text cannot be rotated, but because it always faces the user, it is often used for annotation, for example labels on axes.

The text position is always at the local origin (0,0,0). Rotations and scales have no effect on the orientation or size of 2D text, just the location.

Note: A transform node, e.g. OIV.Inventor.Nodes.SoTranslation, must be used to position the text in 3D space.

Text supports both single byte Latin1 (ISO8859-1) characters and multi-byte UNICODE characters. ISO8859-1 is an 8-bit character set which is a superset of the older 7-bit ASCII character set. See the String class for more information.

Rendering:

The typeface and size (default = 10) are specified using an OIV.Inventor.Nodes.SoFont node. Note that for OIV.Inventor.Nodes.SoText2 the size is interpreted as a value in pixels, not 3D units.

Setting the OIV.Inventor.Nodes.SoFont renderStyle field to TEXTURE is recommended for best appearance and performance. (antialiasing is applied).

Additional rendering styles can be applied using an OIV.Inventor.Nodes.SoTextProperty node, including underline, overline, strikethrough, background and background outline.

OIV.Inventor.Nodes.SoText2 is drawn using the diffuse color of the current material (OIV.Inventor.Nodes.SoMaterial). Lighting is not applied, regardless of the lighting model. Textures do not affect OIV.Inventor.Nodes.SoText2 (note this is independent of the fact that textures are used internally to render OIV.Inventor.Nodes.SoText2). Complexity (OIV.Inventor.Nodes.SoComplexity) does not affect OIV.Inventor.Nodes.SoText2. Drawing styles (OIV.Inventor.Nodes.SoDrawStyle) other than INVISIBLE do not affect OIV.Inventor.Nodes.SoText2.

Justification:

Horizontal alignment of the text can be specified using the OIV.Inventor.Nodes.SoText2.justification field. Both horizontal and vertical alignment can be controlled using an OIV.Inventor.Nodes.SoTextProperty node, however the justification setting in the OIV.Inventor.Nodes.SoText2 node overrides the horizontal setting unless it is explicitly set to INHERITED.

Clipping:

If the transformed position (origin point) of the OIV.Inventor.Nodes.SoText2 is clipped, then the entire string is clipped, even if some part of the string should conceptually be visible. If the origin point is inside the view volume then the string is clipped similar to other geometry.

Bounding box:

Because 2D text is screen-aligned, it has some unusual characteristics. For example, the 3D bounding box surrounding a 2D text string depends on the current camera and the current viewport size, since changing the field of view or the mapping onto the window changes the relative size of the text with respect to the rest of the scene.

When computing the bounding box of a 2D text node (see OIV.Inventor.Actions.SoGetBoundingBoxAction), be careful to:

• Initialize the bounding box action with the correct viewport region. Typically this information is queried from the viewer.

• Make sure the action will traverse the camera node. Apply the action to a node above the camera or create a path to the 2D text node from the root of the scene graph (e.g. using OIV.Inventor.Actions.SoSearchAction).

Picking:

Text can be picked (OIV.Inventor.Actions.SoRayPickAction) like any other geometry. If a text node has been picked then OIV.Inventor.SoPickedPoint can return an OIV.Inventor.Details.SoTextDetail object. This object contains information about which string (in a multi-string text node) was picked and which character within the string was picked.

Render caching:

If your Open Inventor version is older than 9.2, then OIV.Inventor.Nodes.SoText2 nodes using CENTER or RIGHT justification cannot be render cached because the bounding box and justification offset depend on the camera. As a result, no OIV.Inventor.Nodes.SoSeparator above the OIV.Inventor.Nodes.SoText2 will be able to build a render cache or a bounding box cache and this can reduce performance. If possible put other geometry, that can be cached, under its own OIV.Inventor.Nodes.SoSeparator. OIV.Inventor.Nodes.SoText2 nodes using LEFT justification (the default) can be cached. Since Open Inventor 9.2, OIV.Inventor.Nodes.SoText2 nodes can be render cached in all cases.

Antialiasing: Shape Antialiasing type is OIV.Inventor.Nodes.SoShape.ShapeTypes.TEXT.

Export limitations:

• OIV.Inventor.Nodes.SoText2 can be exported to PDF3D/U3D (OIV.HardCopy.SoToPDFAction), but... due to limitations of that file format, the text will not be "screen locked".

• OIV.Inventor.Nodes.SoText2 can be exported to various Hardcopy formats (OIV.HardCopy.SoVectorizeAction), but... native fonts are used, so the requested font name must be available on the rendering device.

FILE FORMAT/DEFAULT

Text2 {

string	""
spacing	1
justification	LEFT

}

ACTION BEHAVIOR

OIV.Inventor.Actions.SoGLRenderAction Draws text based on the current font, at a location based on the current transformation.

OIV.Inventor.Actions.SoRayPickAction Performs a pick on the text. Text will be picked if the picking ray intersects the bounding box of the strings. The string index and character position are available from the OIV.Inventor.Details.SoTextDetail.

OIV.Inventor.Actions.SoGetBoundingBoxAction Computes the bounding box that encloses the text.

Reference