pal::LabelPosition class

LabelPosition is a candidate feature label position.

Reference

Base classes

class PointSet

Public types

enum Quadrant { QuadrantAboveLeft, QuadrantAbove, QuadrantAboveRight, QuadrantLeft, QuadrantOver, QuadrantRight, QuadrantBelowLeft, QuadrantBelow, QuadrantBelowRight }: Position of label candidate relative to feature.

Public static functions

static auto pruneCallback(LabelPosition* candidatePosition, void* ctx) -> bool: Check whether the candidate in ctx overlap with obstacle feat.

Constructors, destructors, conversion operators

LabelPosition(int id, double x1, double y1, double w, double h, double alpha, double cost, FeaturePart* feature, bool isReversed = false, Quadrant quadrant = QuadrantOver): create a new LabelPosition
LabelPosition(const LabelPosition& other): Copy constructor.

Public functions

auto conflictsWithObstacle() const -> bool: Returns whether the position is marked as conflicting with an obstacle feature.
auto cost() const -> double: Returns the candidate label position's geographical cost.
auto crossesBoundary(PointSet* polygon) const -> bool: Returns true if this label crosses the boundary of the specified polygon.
auto crossesLine(PointSet* line) const -> bool: Returns true if this label crosses the specified line.
auto getAlpha() const -> double: Returns the angle to rotate text (in rad).
void getBoundingBox(double amin[2], double amax[2]) const: Returns bounding box - amin: xmin,ymin - amax: xmax,ymax.
auto getDistanceToPoint(double xp, double yp) const -> double: Gets distance from this label to a point. If point lies inside, returns negative number.
auto getFeaturePart() -> FeaturePart*: Returns the feature corresponding to this labelposition.
auto getId() const -> int: Returns the id.
auto getX(int i = 0) const -> double: Returns the down-left x coordinate.
auto getY(int i = 0) const -> double: Returns the down-left y coordinate.
auto incrementUpsideDownCharCount() -> int: Increases the count of upside down characters for this label position.
auto intersects(const GEOSPreparedGeometry* geometry) -> bool: Returns true if the label position intersects a geometry.
auto intersectsWithPolygon(PointSet* polygon) const -> bool: Returns true if any intersection between polygon and position exists.
auto isIn(double* bbox) -> bool: Is the labelposition in the bounding-box ? (intersect or inside????)
auto isInConflict(LabelPosition* ls) -> bool: Check whether or not this overlap with another labelPosition.
auto isInside(double* bbox) -> bool: Is the labelposition inside the bounding-box ?
auto isIntersect(double* bbox) -> bool: Is the labelposition intersect the bounding-box ?
void offsetPosition(double xOffset, double yOffset): Shift the label by specified offset.
auto polygonIntersectionCost(PointSet* polygon) const -> int: Returns cost of position intersection with polygon (testing area of intersection and center).
void setConflictsWithObstacle(bool conflicts): Sets whether the position is marked as conflicting with an obstacle feature.
void setCost(double newCost): Sets the candidate label position's geographical cost.
void setProblemIds(int probFid, int lpId): Set problem feature ID and assigned label candidate ID.
auto upsideDownCharCount() const -> int: Returns the number of upside down characters for this label position.
void validateCost(): Make sure the cost is less than 1.
auto within(const GEOSPreparedGeometry* geometry) -> bool: Returns true if the label position is within a geometry.

Function documentation

pal::LabelPosition::LabelPosition(int id, double x1, double y1, double w, double h, double alpha, double cost, FeaturePart* feature, bool isReversed = false, Quadrant quadrant = QuadrantOver)

create a new LabelPosition

Parameters
id	id of this labelposition
x1	down-left x coordinate
y1	down-left y coordinate
w	label width
h	label height
alpha	rotation in rad
cost	geographic cost
feature	labelpos owners
isReversed	label is reversed
quadrant	relative position of label to feature

bool pal::LabelPosition::conflictsWithObstacle() const

Returns whether the position is marked as conflicting with an obstacle feature.

double pal::LabelPosition::cost() const

Returns the candidate label position's geographical cost.

double pal::LabelPosition::getX(int i = 0) const

Returns the down-left x coordinate.

double pal::LabelPosition::getY(int i = 0) const

Returns the down-left y coordinate.

bool pal::LabelPosition::isIn(double* bbox)

Is the labelposition in the bounding-box ? (intersect or inside????)

Parameters
bbox	the bounding-box double[4] = {xmin, ymin, xmax, ymax}

bool pal::LabelPosition::isInConflict(LabelPosition* ls)

Check whether or not this overlap with another labelPosition.

Parameters
ls	other labelposition
Returns	true or false

bool pal::LabelPosition::isInside(double* bbox)

Is the labelposition inside the bounding-box ?

Parameters
bbox	the bounding-box double[4] = {xmin, ymin, xmax, ymax}

bool pal::LabelPosition::isIntersect(double* bbox)

Is the labelposition intersect the bounding-box ?

Parameters
bbox	the bounding-box double[4] = {xmin, ymin, xmax, ymax}

int pal::LabelPosition::polygonIntersectionCost(PointSet* polygon) const

Returns cost of position intersection with polygon (testing area of intersection and center).

Cost ranges between 0 and 12, with extra cost if center of label position is covered.

void pal::LabelPosition::setConflictsWithObstacle(bool conflicts)

Sets whether the position is marked as conflicting with an obstacle feature.

Parameters
conflicts	set to true to mark candidate as being in conflict

void pal::LabelPosition::setCost(double newCost)

Sets the candidate label position's geographical cost.

Parameters
newCost	new cost for position

void pal::LabelPosition::setProblemIds(int probFid, int lpId)

Set problem feature ID and assigned label candidate ID.

called from pal.cpp during extraction