SoPolyLineScreenDrawer Class Reference

Interactively draw a polyline in normalized screen space. More...

#include <Inventor/drawers/SoPolyLineScreenDrawer.h>

Inheritance diagram for SoPolyLineScreenDrawer:

Classes
struct	EventArg
	Structure given to callback when an event is raised. More...

Public Member Functions
virtual SoType	getTypeId () const
	Returns the type identifier for this specific instance.
	SoPolyLineScreenDrawer ()
	Constructor.
virtual void	clear ()
	Convenience method to clear the points in the line.
virtual void	reset ()
	Clears the points in the line and resets internal state to initial values.
Public Member Functions inherited from SoScreenDrawer
	SoScreenDrawer ()
	Constructor.
Public Member Functions inherited from SoNode
virtual void	setOverride (const SbBool state)
	Turns the override flag on or off.
virtual SbBool	isOverride () const
	Returns the state of the override flag.
virtual SoNode *	copy (SbBool copyConnections=FALSE) const
	Creates and returns an exact copy of the node.
virtual SbBool	affectsState () const
	Returns TRUE if a node has an effect on the state during traversal.
virtual void	touch ()
	Marks an instance as modified, simulating a change to it.
Public Member Functions inherited from SoFieldContainer
void	setToDefaults ()
	Sets all fields in this object to their default values.
SbBool	hasDefaultValues () const
	Returns TRUE if all of the object's fields have their default values.
SbBool	fieldsAreEqual (const SoFieldContainer *fc) const
	Returns TRUE if this object's fields are exactly equal to fc's fields.
void	copyFieldValues (const SoFieldContainer *fc, SbBool copyConnections=FALSE)
	Copies the contents of fc's fields into this object's fields.
SoNONUNICODE SbBool	set (const char *fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
SbBool	set (const SbString &fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
void	get (SbString &fieldDataString)
	Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.
virtual int	getFields (SoFieldList &list) const
	Appends references to all of this object's fields to resultList, and returns the number of fields appended.
virtual int	getAllFields (SoFieldList &list) const
	Returns a list of fields, including the eventIn's and eventOut's.
virtual SoField *	getField (const SbName &fieldName) const
	Returns a the field of this object whose name is fieldName.
virtual SoField *	getEventIn (const SbName &fieldName) const
	Returns a the eventIn with the given name.
virtual SoField *	getEventOut (const SbName &fieldName) const
	Returns the eventOut with the given name.
SbBool	getFieldName (const SoField *field, SbName &fieldName) const
	Returns the name of the given field in the fieldName argument.
SbBool	enableNotify (SbBool flag)
	Notification at this Field Container is enabled (if flag == TRUE) or disabled (if flag == FALSE).
SbBool	isNotifyEnabled () const
	Notification is the process of telling interested objects that this object has changed.
virtual void	setUserData (void *data)
	Sets application data.
void *	getUserData (void) const
	Gets user application data.
Public Member Functions inherited from SoBase
virtual SbName	getName () const
	Returns the name of an instance.
virtual void	setName (const SbName &name)
	Sets the name of an instance.
void	setSynchronizable (const bool b)
	Sets this to be a ScaleViz synchronizable object.
bool	isSynchronizable () const
	Gets the ScaleViz synchronizable state of this object.
Public Member Functions inherited from SoRefCounter
void	ref () const
	Adds a reference to an instance.
void	unref () const
	Removes a reference from an instance.
void	unrefNoDelete () const
	unrefNoDelete() should be called when it is desired to decrement the reference count, but not delete the instance if this brings the reference count to zero.
int	getRefCount () const
	Returns current reference count.
void	lock () const
	lock this instance.
void	unlock () const
	unlock this instance.
Public Member Functions inherited from SoTypedObject
SbBool	isOfType (const SoType &type) const
	Returns TRUE if this object is of the type specified in type or is derived from that type.
template<typename TypedObjectClass >
SbBool	isOfType () const
	Returns TRUE if this object is of the type of class TypedObjectClass or is derived from that class.

Static Public Member Functions
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoScreenDrawer
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoNode
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
static SoNode *	getByName (const SbName &name)
	A node's name can be set using SoBase::setName().
static int	getByName (const SbName &name, SoNodeList &list)
	A node's name can be set using SoBase::setName().
Static Public Member Functions inherited from SoFieldContainer
static SoType	getClassTypeId ()
	Returns the type of this class.
Static Public Member Functions inherited from SoBase
static SoType	getClassTypeId ()
	Returns type identifier for this class.
Static Public Member Functions inherited from SoTypedObject
static SoType	getClassTypeId ()
	Returns the type identifier for this class.

Public Attributes
SoSFUInt32	simplificationThreshold
	Threshold (in pixels) used to simplify line when it is finished.
SoSFBool	doCCW
	Make the line counter-clockwise when it is finalized.
SoSFColor	color
	Color of line.
SoMFVec2f	point
	Points of line.
SoSFBool	isClosed
	Close the line during display (connect last point to first point).
SoSFUShort	linePattern
	Stipple pattern.
SoSFInt32	linePatternScaleFactor
	Stipple pattern scale factor.
SoSFFloat	lineWidth
	Width of lines.
SbEventHandler< const EventArg & >	onStart
	Event raised when starting to draw a polyline.
SbEventHandler< const EventArg & >	onMove
	Event raised during polyline drawing.
SbEventHandler< EventArg & >	onFinish
	Event raised when the line is finished.
Public Attributes inherited from SoScreenDrawer
SoSFNode	sceneGraph
	Scene graph to render.

Detailed Description

Interactively draw a polyline in normalized screen space.

This class is a base class used to allow the user to dynamically draw line-based shapes (lasso, circle, rectangle, ...) on screen. The geometry is defined in normalized screen space ([-1, 1]x[-1, 1]).

Applications will typically use one of the derived classes, for example, SoEllipseScreenDrawer, SoRectangleScreenDrawer, SoPolygonScreenDrawer or SoLassoScreenDrawer.

The line color is specified by the color field (default is red).

SoPolyLineScreenDrawer classes can automatically reduce the number of points in the shape drawn by the user. This is especially useful with SoLassoScreenDrawer. See the simplificationThreshold field.

Sub-classes can implement the onMouseDown, onMouseMove, etc... methods, to add and edit points.

Notes:

• Viewer:
  
  • Screen drawers, like draggers, depend on SoHandleEventAction to get events. Therefore when using one of the Open Inventor viewer classes, screen drawers will only work when the viewer is in "selection" mode (arrow cursor). (In "viewing" mode, mouse events are handled by the viewer to control the camera.)
    
    
  • The escape key (ESC) can be used to cancel creation of the polyline. However, currently it also changes the viewer mode (this is a known problem).
• Event handling:
  The drawer will automatically begin a new polyline when it sees a mouse button 1 down event. However the drawer does not call setHandled(), so other nodes in the scene graph, e.g. SoEventCallback or a dragger, may also handle this event.
• Finish notification:
  
  • An event is raised to notify the application when the line is finished. (see onFinish ). This event is called at the end of line finalization (after simplification etc). See SbEventHandler for methods to set a callback to be notified when this event is raised.
    
    
  • In this callback the application can retrieve coordinates from the point field. These points are in Open Inventor normalized device coordinates (-1 to 1), not pixel coordinates.
    
    
  • The drawer does not call the SoHandleEventAction's setHandled() method for the event that finished the polyline. The application can call setHandled() in this callback.
    
    
  • With some drawers it is possible to get a call with zero points if the user pressed ESC to cancel the interaction. Applications should check for this case.
    
    
  • With some drawers it is also possible to get a call with a non-zero number of points, but all points are the same coordinate. E.g. SoRectangleScreenDrawer stores four points even if the mouse down/up events are at the same location.
    
    
  • Typically the application will want to remove the polyline from the screen in this callback. See the next note.
• Part of the scene graph:
  
  • Note that the polyline remains on the screen (because it is part of the scene graph) until clear() is called or the user starts a new interaction.
    
    
  • Changing the color field or the isClosed field will immediately change the appearance of a polyline currently on the screen.
• Simplification:
  Simplification is done (if > 0) when the user releases the mouse button and also if the simplificationThreshold is changed. But note that the old points are thrown away, so you can't re-simplify with a different value.
• isClosed field:
  If true (default), the polyline will be closed while being drawn (not just when the user releases the mouse button). The default in this class is false, but most sub-classes set it to true.
• Coordinates:
  This node and its subclasses use screen coordinates ranging from -1 to 1. (Because this is the default view volume for an SoOrthographicCamera node.) Be careful because other classes in Open Inventor use normalized screen coordinates ranging from 0 to 1. In particular the SbViewportRegion normalize() methods and the SbViewVolume methods that project from 3D to 2D and vice-versa.
• There should only be one SoScreenDrawer derived node in the sceneGraph (to avoid conflicts in mouse events).

• [C++]
  Screen drawer classes must be initialized by calling SoInteraction::init(). High level viewer init methods, like SoWin::init(), automatically do this. However, if the application is calling SoDB::init() directly, then it is usually necessary to also call SoInteraction::init() before using the screen drawer classes.

EXAMPLE

Create a screen drawer, set the callback and add it to the scene graph:

SoRectangleScreenDrawer* drawer = new SoRectangleScreenDrawer();
  drawer->onFinish.add( lineDrawerCallback );
  root->addChild( drawer );

A finish callback that gets the number of points created by the screen drawer:

void lineDrawerCallback( SoPolyLineScreenDrawer::EventArg& eventArg )
{
  SoPolyLineScreenDrawer *drawer = eventArg.getSource();
  SoHandleEventAction *action = eventArg.getAction();
 
  int numPoints = drawer->point.getNum();
  if (numPoints > 0) {
    // Use points
    SbVec2f pt = drawer->point[0];
  }
  drawer->clear();  // Remove polyline from screen
  action->setHandled();
}

SEE ALSO

SoEllipseScreenDrawer, SoLassoScreenDrawer, SoPolygonScreenDrawer, SoRectangleScreenDrawer, SoScreenDrawer

Definition at line 213 of file SoPolyLineScreenDrawer.h.

Constructor & Destructor Documentation

SoPolyLineScreenDrawer()

SoPolyLineScreenDrawer::SoPolyLineScreenDrawer

(

)

Constructor.

Member Function Documentation

clear()

virtual void SoPolyLineScreenDrawer::clear ( )

inlinevirtual

Convenience method to clear the points in the line.

Reimplemented in SoPolygonScreenDrawer.

Definition at line 337 of file SoPolyLineScreenDrawer.h.

getClassTypeId()

static SoType SoPolyLineScreenDrawer::getClassTypeId ( )

static

Returns the type identifier for this class.

getTypeId()

virtual SoType SoPolyLineScreenDrawer::getTypeId ( ) const

virtual

Returns the type identifier for this specific instance.

Reimplemented from SoScreenDrawer.

Reimplemented in SoEllipseScreenDrawer, SoLassoScreenDrawer, SoPolygonScreenDrawer, and SoRectangleScreenDrawer.

reset()

virtual void SoPolyLineScreenDrawer::reset ( )

virtual

Clears the points in the line and resets internal state to initial values.

This cancels any current drawing.

Since Open Inventor 10.7.3

Reimplemented from SoScreenDrawer.

Reimplemented in SoEllipseScreenDrawer, SoLassoScreenDrawer, and SoRectangleScreenDrawer.

Member Data Documentation

color

SoSFColor SoPolyLineScreenDrawer::color

Color of line.

Default value is red.

Definition at line 238 of file SoPolyLineScreenDrawer.h.

doCCW

SoSFBool SoPolyLineScreenDrawer::doCCW

Make the line counter-clockwise when it is finalized.

This can change order of points. Default is TRUE.

Note

Some shapes (like "8") do not have a defined clockwiseness. In these cases, the result is undefined.

NOTE: field available since Open Inventor 9.0

Definition at line 235 of file SoPolyLineScreenDrawer.h.

isClosed

SoSFBool SoPolyLineScreenDrawer::isClosed

Close the line during display (connect last point to first point).

Default is FALSE (but most sub-classes automatically set it to TRUE).

Warning

This only affects the display.

Definition at line 248 of file SoPolyLineScreenDrawer.h.

linePattern

SoSFUShort SoPolyLineScreenDrawer::linePattern

Stipple pattern.

This specifies how dashed or dotted lines will be drawn. The pattern is a 16-bit series of 0s and 1s and is repeated as necessary to stipple a given line. A 1 indicates that drawing occurs, and a 0 that it does not, on a pixel-by-pixel basis, starting with the low-order bits of the pattern. Values can range from 0 (invisible) to 0xffff (solid). Default is 0xffff.

The line pattern can be stretched using the linePatternScaleFactor field.

Definition at line 261 of file SoPolyLineScreenDrawer.h.

linePatternScaleFactor

SoSFInt32 SoPolyLineScreenDrawer::linePatternScaleFactor

Stipple pattern scale factor.

It stretches the line pattern (see linePattern) by multiplying each subseries of consecutive 1s and 0s. Scale factors are clamped to lie between 1 and 255. Default is 1.

Definition at line 268 of file SoPolyLineScreenDrawer.h.

lineWidth

SoSFFloat SoPolyLineScreenDrawer::lineWidth

Width of lines.

The default line width is 0, meaning to use the default OpenGL value (1). Line widths greater than zero are considered to be specified in printer's points, where 1 inch = 72 printer's points. However the default pixels-per-inch value (managed by SbViewportRegion) is also 72. So effectively line width is specified in pixels unless the application sets a different pixels-per-inch value.

Definition at line 278 of file SoPolyLineScreenDrawer.h.

onFinish

SbEventHandler<EventArg&> SoPolyLineScreenDrawer::onFinish

Event raised when the line is finished.

See SbEventHandler for methods to set a callback to be notified when this event is raised. The callback will be called with a line drawer specific EventArg from which you can query the current action and drawer objects. Note that the callback parameter in this case is not const.

Definition at line 334 of file SoPolyLineScreenDrawer.h.

onMove

SbEventHandler<const EventArg&> SoPolyLineScreenDrawer::onMove

Event raised during polyline drawing.

See SbEventHandler for methods to set a callback to be notified when this event is raised. The callback will be called with an EventArg from which it can query the current action and drawer objects. Note that the callback parameter must be declared const .

Definition at line 325 of file SoPolyLineScreenDrawer.h.

onStart

SbEventHandler<const EventArg&> SoPolyLineScreenDrawer::onStart

Event raised when starting to draw a polyline.

See SbEventHandler for methods to set a callback to be notified when this event is raised. The callback will be called with an EventArg from which it can query the current action and drawer objects.
Note that the callback parameter must be declared const .

Definition at line 316 of file SoPolyLineScreenDrawer.h.

point

SoMFVec2f SoPolyLineScreenDrawer::point

Points of line.

Default is empty.

Definition at line 241 of file SoPolyLineScreenDrawer.h.

simplificationThreshold

SoSFUInt32 SoPolyLineScreenDrawer::simplificationThreshold

Threshold (in pixels) used to simplify line when it is finished.

A value of 0 means no simplification. Default value is 5 pixels.

Definition at line 225 of file SoPolyLineScreenDrawer.h.

---

The documentation for this class was generated from the following file:

• Inventor/drawers/SoPolyLineScreenDrawer.h