y.view
Class BridgeCalculator

java.lang.Object
  y.view.BridgeCalculator

public class BridgeCalculator
extends java.lang.Object

Calculates and inserts "bridges" (also called "gaps" or "jumps") into PathIterators. Bridges are inserted when two (or more) segments cross, which can mean both segments of different paths or segments of one path.

Several different styles of bridges are supported: gaps, rectangular, trapezoidal, and round (using arcs). These bridge styles can also be scaled. Additionally, the orientation of bridges inserted into a PathIterator can be configured using a variety of schemes.
The calculation of the crossings can be determined using different crossing modes. This can be used for one-pass or two-pass calculation (see EdgeRealizer.registerObstacles(BridgeCalculator)).

See Also:

setCrossingMode(short), setCrossingStyle(short), setOrientationStyle(short), DefaultGraph2DRenderer.setBridgeCalculator(BridgeCalculator)

Field Summary

static short	CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL Crossing mode constant.
static short	CROSSING_MODE_ORDER_INDUCED Crossing mode constant.
static short	CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL Crossing mode constant.
static short	CROSSING_STYLE_ARC Crossing style constant.
static short	CROSSING_STYLE_ARC_SCALED Crossing style constant.
static short	CROSSING_STYLE_CUSTOM Crossing style constant.
static short	CROSSING_STYLE_GAP Crossing style constant.
static short	CROSSING_STYLE_SQUARE Crossing style constant.
static short	CROSSING_STYLE_SQUARE_SCALED Crossing style constant.
static short	CROSSING_STYLE_TWO_SIDES Crossing style constant.
static short	CROSSING_STYLE_TWO_SIDES_SCALED Crossing style constant.
static short	ORIENTATION_STYLE_DOWN Orientation style constant.
static short	ORIENTATION_STYLE_FLOW_LEFT Orientation style constant.
static short	ORIENTATION_STYLE_FLOW_RIGHT Orientation style constant.
static short	ORIENTATION_STYLE_LEFT Orientation style constant.
static short	ORIENTATION_STYLE_NEGATIVE Orientation style constant.
static short	ORIENTATION_STYLE_POSITIVE Orientation style constant.
static short	ORIENTATION_STYLE_RIGHT Orientation style constant.
static short	ORIENTATION_STYLE_UP Orientation style constant.

Constructor Summary

BridgeCalculator()
Creates a new BridgeCalculator instance using the default size for the storage of segments.

BridgeCalculator(int size)
Creates a new BridgeCalculator instance with given initial size for the storage of segments.

Method Summary

double	getBridgeHeight() Returns the default height for a bridge.
double	getBridgeWidth() Returns the default width for a bridge.
short	getCrossingMode() Returns the mode that is responsible for determining crossings in the drawing.
short	getCrossingStyle() Returns the current default crossing drawing style.
short	getOrientationStyle() Returns the current default orientation style.
java.awt.geom.PathIterator	insertBridges(java.awt.geom.PathIterator pi) Takes the given PathIterator, calculates and inserts bridges into those segments that intersect with other segments (from either this or another path), and returns a new PathIterator instance with bridges inserted.
protected void	insertCustomBridge(MutableGeneralPath mgp, MutableGeneralPath.Segment beforeSegment, double up, double x1, double y1, double down, double x2, double y2) Callback method that is called during insertBridges(java.awt.geom.PathIterator) to allow for custom modifications of the MutableGeneralPath and optionally recording of the bridges.
void	registerObstacleLine(double x1, double y1, double x2, double y2) Registers a line as an obstacle for subsequent insertBridges(java.awt.geom.PathIterator) calls.
void	registerObstacles(java.awt.geom.PathIterator pi) Iterates over the given Path and inserts all straight-line segments as obstacles via registerObstacleLine(double, double, double, double)
void	reset() Resets the internal segment storage.
void	setBridgeHeight(double bridgeHeight) Sets the default height for a bridge.
void	setBridgeWidth(double bridgeWidth) Sets the default width for a bridge.
void	setCrossingMode(short crossingMode) Sets the mode that is used for calculation of the crossings.
void	setCrossingStyle(short crossingStyle) Sets the current default crossing drawing style.
void	setOrientationStyle(short orientationStyle) Sets the current default orientation style.
void	setScope(double minX, double minY, double maxX, double maxY) Limits the scope of the calculation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CROSSING_STYLE_GAP

public static final short CROSSING_STYLE_GAP

Crossing style constant. This style will draw a gap for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_ARC

public static final short CROSSING_STYLE_ARC

Crossing style constant. This style will draw two pieces of an arc connected by a line for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_SQUARE

public static final short CROSSING_STYLE_SQUARE

Crossing style constant. This style will draw a rectangular bridge for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_TWO_SIDES

public static final short CROSSING_STYLE_TWO_SIDES

Crossing style constant. This style will draw trapezoidal bridge for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_ARC_SCALED

public static final short CROSSING_STYLE_ARC_SCALED

Crossing style constant. This style will draw a scaled arc for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_SQUARE_SCALED

public static final short CROSSING_STYLE_SQUARE_SCALED

Crossing style constant. This style will draw a scaled rectangle with varying height for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_TWO_SIDES_SCALED

public static final short CROSSING_STYLE_TWO_SIDES_SCALED

Crossing style constant. This style will draw a scaled trapezoidal bridge with varying height for each edge crossing.

See Also:

Constant Field Values

CROSSING_STYLE_CUSTOM

public static final short CROSSING_STYLE_CUSTOM

Crossing style constant. This style will result in insertCustomBridge(MutableGeneralPath,y.view.MutableGeneralPath.Segment,double,double,double,double,double,double) being called for each bridge to insert into the path.

See Also:

Constant Field Values

ORIENTATION_STYLE_UP

public static final short ORIENTATION_STYLE_UP

Orientation style constant. All bridges will be oriented upwards.

See Also:

Constant Field Values

ORIENTATION_STYLE_DOWN

public static final short ORIENTATION_STYLE_DOWN

Orientation style constant. All bridges will be oriented downwards.

See Also:

Constant Field Values

ORIENTATION_STYLE_LEFT

public static final short ORIENTATION_STYLE_LEFT

Orientation style constant. All bridges will be oriented leftwards.

See Also:

Constant Field Values

ORIENTATION_STYLE_RIGHT

public static final short ORIENTATION_STYLE_RIGHT

Orientation style constant. All bridges will be oriented rightwards.

See Also:

Constant Field Values

ORIENTATION_STYLE_POSITIVE

public static final short ORIENTATION_STYLE_POSITIVE

Orientation style constant. All bridges will be oriented in the direction of the positive axes.

See Also:

Constant Field Values

ORIENTATION_STYLE_NEGATIVE

public static final short ORIENTATION_STYLE_NEGATIVE

Orientation style constant. All bridges will be oriented in the direction of the negative axes.

See Also:

Constant Field Values

ORIENTATION_STYLE_FLOW_LEFT

public static final short ORIENTATION_STYLE_FLOW_LEFT

Orientation style constant. All bridges will be oriented leftwards in the flow of the edge.

See Also:

Constant Field Values

ORIENTATION_STYLE_FLOW_RIGHT

public static final short ORIENTATION_STYLE_FLOW_RIGHT

Orientation style constant. All bridges will be oriented rightwards in the flow of the edge.

See Also:

Constant Field Values

CROSSING_MODE_ORDER_INDUCED

public static final short CROSSING_MODE_ORDER_INDUCED

Crossing mode constant. The crossings are determined in one pass. Each segment painted will only produce crossings with segments painted before this segment.

See Also:

Constant Field Values

CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL

public static final short CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL

Crossing mode constant. The crossings are determined in two passes. Each horizontal segment painted will be tested against all vertical segments collected during the first pass. This will only produce crossings on horizontal segments.

See Also:

Constant Field Values

CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL

public static final short CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL

Crossing mode constant. The crossings are determined in two passes. Each vertical segment painted will be tested against all horizontal segments collected during the first pass. This will only produce crossings on vertical segments.

See Also:

Constant Field Values

Constructor Detail

BridgeCalculator

public BridgeCalculator(int size)

Creates a new BridgeCalculator instance with given initial size for the storage of segments.

Crossing style CROSSING_STYLE_ARC and orientation style ORIENTATION_STYLE_POSITIVE are used as the default settings.

BridgeCalculator

public BridgeCalculator()

Creates a new BridgeCalculator instance using the default size for the storage of segments.

Crossing style CROSSING_STYLE_ARC and orientation style ORIENTATION_STYLE_POSITIVE are used as the default settings.

Method Detail

reset

public void reset()

Resets the internal segment storage.

getCrossingMode

public short getCrossingMode()

Returns the mode that is responsible for determining crossings in the drawing. The default is CROSSING_MODE_ORDER_INDUCED

Returns:

the current mode - one of CROSSING_MODE_ORDER_INDUCED, CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL, or CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL.

See Also:

setCrossingMode(short)

setCrossingMode

public void setCrossingMode(short crossingMode)

Sets the mode that is used for calculation of the crossings. There are different approaches for determining the crossings: One pass crossing calculation: Edges are rendered in one pass one after the other and each segment of an edge is an obstacle that produces a crossing with segments rendered after this one. (CROSSING_MODE_ORDER_INDUCED)
Two-pass crossing calculation: Edges are queried for their segments in the first pass and during the second pass all edge paths are calculated taking into account all of the segments of the first pass. This way it becomes possible for each pair of edge paths to be rendered both "on top and below" each other. For the two pass rendering there are two possible modes, both of which are especially useful in scenarios, where this is a dominant orthogonal edge routing:

• CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL: Each vertical segment is stored as an obstacle during the first pass and each horizontal segment in the second pass is tested against all of the vertical segments from the first pass. Each resulting crossing is inserted into the horizontal segments only.
• CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL: Each horizontal segment is stored as an obstacle during the first pass and each vertical segment in the second pass is tested against all of the horizontal segments from the first pass. Each resulting crossing is inserted into the vertical segments only.

Parameters:

crossingMode - one of CROSSING_MODE_ORDER_INDUCED, CROSSING_MODE_HORIZONTAL_CROSSES_VERTICAL, or CROSSING_MODE_VERTICAL_CROSSES_HORIZONTAL.

getOrientationStyle

public short getOrientationStyle()

Returns the current default orientation style.

Returns:

one of ORIENTATION_STYLE_UP, ORIENTATION_STYLE_DOWN, ORIENTATION_STYLE_FLOW_LEFT, ORIENTATION_STYLE_FLOW_RIGHT, ORIENTATION_STYLE_LEFT, ORIENTATION_STYLE_RIGHT, ORIENTATION_STYLE_POSITIVE, ORIENTATION_STYLE_NEGATIVE.

setOrientationStyle

public void setOrientationStyle(short orientationStyle)

Sets the current default orientation style.

Parameters:

orientationStyle - one of ORIENTATION_STYLE_UP, ORIENTATION_STYLE_DOWN, ORIENTATION_STYLE_FLOW_LEFT, ORIENTATION_STYLE_FLOW_RIGHT, ORIENTATION_STYLE_LEFT, ORIENTATION_STYLE_RIGHT, ORIENTATION_STYLE_POSITIVE, ORIENTATION_STYLE_NEGATIVE.

setCrossingStyle

public void setCrossingStyle(short crossingStyle)

Sets the current default crossing drawing style.

Parameters:

crossingStyle - one of CROSSING_STYLE_ARC, CROSSING_STYLE_ARC_SCALED, CROSSING_STYLE_GAP, CROSSING_STYLE_SQUARE, CROSSING_STYLE_SQUARE_SCALED, CROSSING_STYLE_TWO_SIDES, CROSSING_STYLE_TWO_SIDES_SCALED, CROSSING_STYLE_CUSTOM.

getCrossingStyle

public short getCrossingStyle()

Returns the current default crossing drawing style.

Returns:

one of CROSSING_STYLE_ARC, CROSSING_STYLE_ARC_SCALED, CROSSING_STYLE_GAP, CROSSING_STYLE_SQUARE, CROSSING_STYLE_SQUARE_SCALED, CROSSING_STYLE_TWO_SIDES, CROSSING_STYLE_TWO_SIDES_SCALED, CROSSING_STYLE_CUSTOM.

getBridgeWidth

public double getBridgeWidth()

Returns the default width for a bridge.

Returns:

the length of a bridge

setBridgeWidth

public void setBridgeWidth(double bridgeWidth)

Sets the default width for a bridge.

Parameters:

bridgeWidth - the length of a bridge

getBridgeHeight

public double getBridgeHeight()

Returns the default height for a bridge.

Returns:

the height of a bridge/jump

setBridgeHeight

public void setBridgeHeight(double bridgeHeight)

Sets the default height for a bridge.

Parameters:

bridgeHeight - the height of a bridge/jump

setScope

public void setScope(double minX,
                     double minY,
                     double maxX,
                     double maxY)

Limits the scope of the calculation. Segments that do not intersect with the current scope will be discarded during the calculation.

insertBridges

public java.awt.geom.PathIterator insertBridges(java.awt.geom.PathIterator pi)

Takes the given PathIterator, calculates and inserts bridges into those segments that intersect with other segments (from either this or another path), and returns a new PathIterator instance with bridges inserted.

Parameters:

pi - The PathIterator that should be processed.

Returns:

A new PathIterator that contains the bridges. This path iterator is only valid until the next call to this method.

registerObstacles

public void registerObstacles(java.awt.geom.PathIterator pi)

Iterates over the given Path and inserts all straight-line segments as obstacles via registerObstacleLine(double, double, double, double)

Parameters:

pi - the PathIterator that describes the path

registerObstacleLine

public void registerObstacleLine(double x1,
                                 double y1,
                                 double x2,
                                 double y2)

Registers a line as an obstacle for subsequent insertBridges(java.awt.geom.PathIterator) calls. The obstacle will not be registered if it does not intersect with the current scope.

Parameters:

x1 - the x coordinate of the first point of the line

y1 - the y coordinate of the first point of the line

x2 - the x coordinate of the second point of the line

y2 - the y coordinate of the second point of the line

insertCustomBridge

protected void insertCustomBridge(MutableGeneralPath mgp,
                                  MutableGeneralPath.Segment beforeSegment,
                                  double up,
                                  double x1,
                                  double y1,
                                  double down,
                                  double x2,
                                  double y2)

Callback method that is called during insertBridges(java.awt.geom.PathIterator) to allow for custom modifications of the MutableGeneralPath and optionally recording of the bridges. This method will be called if the crossing style is set to CROSSING_STYLE_CUSTOM. This implementation does nothing. The path stays unmodified.

Parameters:

mgp - the path to be modified

beforeSegment - the segment (PathIterator.SEG_MOVETO) that should be modified

up - the distance from the start of the segment to the first point

x1 - the x coordinate of the beginning of the bridge

y1 - the y coordinate of the beginning of the bridge

down - the distance from the start of the segment to the second point

x2 - the x coordinate of the end of the bridge

y2 - the y coordinate of the end of the bridge