Package org.eclipse.jface.util

Class Geometry

java.lang.Object

org.eclipse.jface.util.Geometry

public class Geometry
extends Object

Contains static methods for performing simple geometric operations on the SWT geometry classes.

Since:

3.0

Method Summary

Modifier and Type	Method	Description
static Point	add(Point point1, Point point2)	Adds two points as 2d vectors.
static Rectangle	add(Rectangle rect1, Rectangle rect2)	Returns a new Rectangle whose x, y, width, and height is the sum of the x, y, width, and height values of both rectangles respectively.
static Point	centerPoint(Rectangle rect)	Returns the point in the center of the given rectangle.
static Point	copy(Point toCopy)	Returns a copy of the given point
static Rectangle	copy(Rectangle toCopy)	Returns a copy of the given rectangle
static Rectangle	createDiffRectangle(int left, int right, int top, int bottom)	Returns a rectangle which, when added to another rectangle, will expand each side by the given number of units.
static Rectangle	createRectangle(Point position, Point size)	Returns a new rectangle with the given position and dimensions, expressed as points.
static int	distanceSquared(Point p1, Point p2)	Returns the square of the distance between two points.
static Point	divide(Point toDivide, int scalar)	Divides both coordinates of the given point by the given scalar.
static int	dotProduct(Point p1, Point p2)	Returns the dot product of the given vectors (expressed as Points)
static void	expand(Rectangle rect, int left, int right, int top, int bottom)	Moves each edge of the given rectangle outward by the given amount.
static void	expand(Rectangle rect, Rectangle differenceRect)	Moves each edge of the given rectangle outward by the given amount.
static void	flipXY(Point toFlip)	Swaps the X and Y coordinates of the given point.
static void	flipXY(Rectangle toFlip)	Swaps the X and Y coordinates of the given rectangle, along with the height and width.
static int	getClosestSide(Rectangle boundary, Point toTest)	Returns the edge of the given rectangle is closest to the given point.
static int	getCoordinate(Point toMeasure, boolean width)	Returns the x or y coordinates of the given point.
static int	getCoordinate(Rectangle toMeasure, boolean width)	Returns the x or y coordinates of the given rectangle.
static int	getDimension(Rectangle toMeasure, boolean width)	Returns the height or width of the given rectangle.
static Point	getDirectionVector(int distance, int direction)	Returns a vector in the given direction with the given magnitude.
static int	getDistanceFrom(Rectangle boundary, Point toTest)	Returns the distance from the point to the nearest edge of the given rectangle.
static int	getDistanceFromEdge(Rectangle rectangle, Point testPoint, int edgeOfInterest)	Returns the distance of the given point from a particular side of the given rectangle.
static Rectangle	getExtrudedEdge(Rectangle toExtrude, int size, int orientation)	Extrudes the given edge inward by the given distance.
static Point	getLocation(Rectangle toQuery)	Returns the x,y position of the given rectangle.
static int	getOppositeSide(int swtDirectionConstant)	Returns the opposite of the given direction.
static int	getRelativePosition(Rectangle boundary, Point toTest)	Determines where the given point lies with respect to the given rectangle.
static Point	getSize(Rectangle rectangle)	Returns the size of the rectangle, as a Point
static int	getSwtHorizontalOrVerticalConstant(boolean horizontal)	Converts the given boolean into an SWT orientation constant.
static boolean	isHorizontal(int swtSideConstant)	Returns true iff the given SWT side constant corresponds to a horizontal side of a rectangle.
static double	magnitude(Point p)	Returns the magnitude of the given 2d vector (represented as a Point)
static int	magnitudeSquared(Point p)	Returns the square of the magnitude of the given 2-space vector (represented using a point)
static Point	max(Point p1, Point p2)	Returns a new point whose coordinates are the maximum of the coordinates of the given points
static Point	min(Point p1, Point p2)	Returns a new point whose coordinates are the minimum of the coordinates of the given points
static void	moveInside(Rectangle inner, Rectangle outer)	Repositions the 'inner' rectangle to lie completely within the bounds of the 'outer' rectangle if possible.
static void	moveRectangle(Rectangle rect, Point delta)	Moves the given rectangle by the given delta.
static void	normalize(Rectangle rect)	Normalizes the given rectangle.
static void	set(Point result, Point toCopy)	Sets result equal to toCopy
static void	set(Rectangle result, Rectangle toCopy)	Sets result equal to toCopy
static void	setCoordinate(Point toSet, boolean width, int newCoordinate)	Sets one coordinate of the given point.
static void	setCoordinate(Rectangle toSet, boolean width, int newCoordinate)	Sets one coordinate of the given rectangle.
static void	setDimension(Rectangle toSet, boolean width, int newCoordinate)	Sets one dimension of the given rectangle.
static void	setLocation(Rectangle rectangle, Point newLocation)	Sets the x,y position of the given rectangle.
static void	setSize(Rectangle rectangle, Point newSize)	Sets the size of the given rectangle to the given size
static Point	subtract(Point point1, Point point2)	Performs vector subtraction on two points.
static Rectangle	subtract(Rectangle rect1, Rectangle rect2)	Returns a new difference Rectangle whose x, y, width, and height are equal to the difference of the corresponding attributes from the given rectangles
static Rectangle	toControl(Control coordinateSystem, Rectangle toConvert)	Converts the given rectangle from display coordinates to the local coordinate system of the given object into display coordinates.
static Rectangle	toDisplay(Control coordinateSystem, Rectangle toConvert)	Converts the given rectangle from the local coordinate system of the given object into display coordinates.

Methods inherited from class java.lang.Object

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

Method Detail

distanceSquared

public static int distanceSquared(Point p1,
                                  Point p2)

Returns the square of the distance between two points.

This is preferred over the real distance when searching for the closest point, since it avoids square roots.

Parameters:

p1 - first endpoint

p2 - second endpoint

Returns:

the square of the distance between the two points

Since:

3.0

magnitude

public static double magnitude(Point p)

Returns the magnitude of the given 2d vector (represented as a Point)

Parameters:

p - point representing the 2d vector whose magnitude is being computed

Returns:

the magnitude of the given 2d vector

Since:

3.0

magnitudeSquared

public static int magnitudeSquared(Point p)

Returns the square of the magnitude of the given 2-space vector (represented using a point)

Parameters:

p - the point whose magnitude is being computed

Returns:

the square of the magnitude of the given vector

Since:

3.0

dotProduct

public static int dotProduct(Point p1,
                             Point p2)

Returns the dot product of the given vectors (expressed as Points)

Parameters:

p1 - the first vector

p2 - the second vector

Returns:

the dot product of the two vectors

Since:

3.0

min

public static Point min(Point p1,
                        Point p2)

Returns a new point whose coordinates are the minimum of the coordinates of the given points

Parameters:

p1 - a Point

p2 - a Point

Returns:

a new point whose coordinates are the minimum of the coordinates of the given points

Since:

3.0

max

public static Point max(Point p1,
                        Point p2)

Returns a new point whose coordinates are the maximum of the coordinates of the given points

Parameters:

p1 - a Point

p2 - a Point

Returns:

point a new point whose coordinates are the maximum of the coordinates

Since:

3.0

getDirectionVector

public static Point getDirectionVector(int distance,
                                       int direction)

Returns a vector in the given direction with the given magnitude. Directions are given using SWT direction constants, and the resulting vector is in the screen's coordinate system. That is, the vector (0, 1) is down and the vector (1, 0) is right.

Parameters:

distance - magnitude of the vector

direction - one of SWT.TOP, SWT.BOTTOM, SWT.LEFT, or SWT.RIGHT

Returns:

a point representing a vector in the given direction with the given magnitude

Since:

3.0

centerPoint

public static Point centerPoint(Rectangle rect)

Returns the point in the center of the given rectangle.

Parameters:

rect - rectangle being computed

Returns:

a Point at the center of the given rectangle.

Since:

3.0

copy

public static Point copy(Point toCopy)

Returns a copy of the given point

Parameters:

toCopy - point to copy

Returns:

a copy of the given point

set

public static void set(Point result,
                       Point toCopy)

Sets result equal to toCopy

Parameters:

result - object that will be modified

toCopy - object that will be copied

Since:

3.1

set

public static void set(Rectangle result,
                       Rectangle toCopy)

Sets result equal to toCopy

Parameters:

result - object that will be modified

toCopy - object that will be copied

Since:

3.1

subtract

public static Rectangle subtract(Rectangle rect1,
                                 Rectangle rect2)

Returns a new difference Rectangle whose x, y, width, and height are equal to the difference of the corresponding attributes from the given rectangles

Example: Compute the margins for a given Composite, and apply those same margins to a new GridLayout

 
      // Compute the client area, in the coordinate system of the input composite's parent
      Rectangle clientArea = Display.getCurrent().map(inputComposite,
        inputComposite.getParent(), inputComposite.getClientArea());

      // Compute the margins for a given Composite by subtracting the client area from the composite's bounds
      Rectangle margins = Geometry.subtract(inputComposite.getBounds(), clientArea);

      // Now apply these margins to a new GridLayout
      GridLayout layout = GridLayoutFactory.fillDefaults().margins(margins).create();
 
 

Parameters:

rect1 - first rectangle

rect2 - rectangle to subtract

Returns:

the difference between the two rectangles (computed as rect1 - rect2)

Since:

3.3

add

public static Rectangle add(Rectangle rect1,
                            Rectangle rect2)

Returns a new Rectangle whose x, y, width, and height is the sum of the x, y, width, and height values of both rectangles respectively.

Parameters:

rect1 - first rectangle to add

rect2 - second rectangle to add

Returns:

a new rectangle whose x, y, height, and width attributes are the sum of the corresponding attributes from the arguments.

Since:

3.3

add

public static Point add(Point point1,
                        Point point2)

Adds two points as 2d vectors. Returns a new point whose coordinates are the sum of the original two points.

Parameters:

point1 - the first point (not null)

point2 - the second point (not null)

Returns:

a new point whose coordinates are the sum of the given points

Since:

3.0

divide

public static Point divide(Point toDivide,
                           int scalar)

Divides both coordinates of the given point by the given scalar.

Parameters:

toDivide - point to divide

scalar - denominator

Returns:

a new Point whose coordinates are equal to the original point divided by the scalar

Since:

3.1

subtract

public static Point subtract(Point point1,
                             Point point2)

Performs vector subtraction on two points. Returns a new point equal to (point1 - point2).

Parameters:

point1 - initial point

point2 - vector to subtract

Returns:

the difference (point1 - point2)

Since:

3.0

flipXY

public static void flipXY(Point toFlip)

Swaps the X and Y coordinates of the given point.

Parameters:

toFlip - modifies this point

Since:

3.1

flipXY

public static void flipXY(Rectangle toFlip)

Swaps the X and Y coordinates of the given rectangle, along with the height and width.

Parameters:

toFlip - modifies this rectangle

Since:

3.1

getDimension

public static int getDimension(Rectangle toMeasure,
                               boolean width)

Returns the height or width of the given rectangle.

Parameters:

toMeasure - rectangle to measure

width - returns the width if true, and the height if false

Returns:

the width or height of the given rectangle

Since:

3.0

getCoordinate

public static int getCoordinate(Point toMeasure,
                                boolean width)

Returns the x or y coordinates of the given point.

Parameters:

toMeasure - point being measured

width - if true, returns x. Otherwise, returns y.

Returns:

the x or y coordinate

Since:

3.1

getCoordinate

public static int getCoordinate(Rectangle toMeasure,
                                boolean width)

Returns the x or y coordinates of the given rectangle.

Parameters:

toMeasure - rectangle being measured

width - if true, returns x. Otherwise, returns y.

Returns:

the x or y coordinate

Since:

3.1

setDimension

public static void setDimension(Rectangle toSet,
                                boolean width,
                                int newCoordinate)

Sets one dimension of the given rectangle. Modifies the given rectangle.

Parameters:

toSet - rectangle to modify

width - if true, the width is modified. If false, the height is modified.

newCoordinate - new value of the width or height

Since:

3.1

setCoordinate

public static void setCoordinate(Rectangle toSet,
                                 boolean width,
                                 int newCoordinate)

Sets one coordinate of the given rectangle. Modifies the given rectangle.

Parameters:

toSet - rectangle to modify

width - if true, the x coordinate is modified. If false, the y coordinate is modified.

newCoordinate - new value of the x or y coordinates

Since:

3.1

setCoordinate

public static void setCoordinate(Point toSet,
                                 boolean width,
                                 int newCoordinate)

Sets one coordinate of the given point. Modifies the given point.

Parameters:

toSet - point to modify

width - if true, the x coordinate is modified. If false, the y coordinate is modified.

newCoordinate - new value of the x or y coordinates

Since:

3.1

getDistanceFromEdge

public static int getDistanceFromEdge(Rectangle rectangle,
                                      Point testPoint,
                                      int edgeOfInterest)

Returns the distance of the given point from a particular side of the given rectangle. Returns negative values for points outside the rectangle.

Parameters:

rectangle - a bounding rectangle

testPoint - a point to test

edgeOfInterest - side of the rectangle to test against

Returns:

the distance of the given point from the given edge of the rectangle

Since:

3.0

getExtrudedEdge

public static Rectangle getExtrudedEdge(Rectangle toExtrude,
                                        int size,
                                        int orientation)

Extrudes the given edge inward by the given distance. That is, if one side of the rectangle was sliced off with a given thickness, this returns the rectangle that forms the slice. Note that the returned rectangle will be inside the given rectangle if size > 0.

Parameters:

toExtrude - the rectangle to extrude. The resulting rectangle will share three sides with this rectangle.

size - distance to extrude. A negative size will extrude outwards (that is, the resulting rectangle will overlap the original iff this is positive).

orientation - the side to extrude. One of SWT.LEFT, SWT.RIGHT, SWT.TOP, or SWT.BOTTOM. The resulting rectangle will always share this side with the original rectangle.

Returns:

a rectangle formed by extruding the given side of the rectangle by the given distance.

Since:

3.0

getOppositeSide

public static int getOppositeSide(int swtDirectionConstant)

Returns the opposite of the given direction. That is, returns SWT.LEFT if given SWT.RIGHT and visa-versa.

Parameters:

swtDirectionConstant - one of SWT.LEFT, SWT.RIGHT, SWT.TOP, or SWT.BOTTOM

Returns:

one of SWT.LEFT, SWT.RIGHT, SWT.TOP, or SWT.BOTTOM

Since:

3.0

getSwtHorizontalOrVerticalConstant

public static int getSwtHorizontalOrVerticalConstant(boolean horizontal)

Converts the given boolean into an SWT orientation constant.

Parameters:

horizontal - if true, returns SWT.HORIZONTAL. If false, returns SWT.VERTICAL

Returns:

SWT.HORIZONTAL or SWT.VERTICAL.

Since:

3.0

isHorizontal

public static boolean isHorizontal(int swtSideConstant)

Returns true iff the given SWT side constant corresponds to a horizontal side of a rectangle. That is, returns true for the top and bottom but false for the left and right.

Parameters:

swtSideConstant - one of SWT.TOP, SWT.BOTTOM, SWT.LEFT, or SWT.RIGHT

Returns:

true iff the given side is horizontal.

Since:

3.0

moveRectangle

public static void moveRectangle(Rectangle rect,
                                 Point delta)

Moves the given rectangle by the given delta.

Parameters:

rect - rectangle to move (will be modified)

delta - direction vector to move the rectangle by

Since:

3.0

expand

public static void expand(Rectangle rect,
                          Rectangle differenceRect)

Moves each edge of the given rectangle outward by the given amount. Negative values cause the rectangle to contract. Does not allow the rectangle's width or height to be reduced below zero.

Parameters:

rect - normalized rectangle to modify

differenceRect - difference rectangle to be added to rect

Since:

3.3

createDiffRectangle

public static Rectangle createDiffRectangle(int left,
                                            int right,
                                            int top,
                                            int bottom)

Returns a rectangle which, when added to another rectangle, will expand each side by the given number of units.

This is commonly used to store margin sizes. For example:

 
     // Expands the left, right, top, and bottom
     // of the given control by 10, 5, 1, and 15 units respectively

     Rectangle margins = Geometry.createDifferenceRect(10,5,1,15);
     Rectangle bounds = someControl.getBounds();
     someControl.setBounds(Geometry.add(bounds, margins));
 
 

Parameters:

left - distance to expand the left side (negative values move the edge inward)

right - distance to expand the right side (negative values move the edge inward)

top - distance to expand the top (negative values move the edge inward)

bottom - distance to expand the bottom (negative values move the edge inward)

Returns:

a difference rectangle that, when added to another rectangle, will cause each side to expand by the given number of units

Since:

3.3

expand

public static void expand(Rectangle rect,
                          int left,
                          int right,
                          int top,
                          int bottom)

Moves each edge of the given rectangle outward by the given amount. Negative values cause the rectangle to contract. Does not allow the rectangle's width or height to be reduced below zero.

Parameters:

rect - normalized rectangle to modify

left - distance to move the left edge outward (negative values move the edge inward)

right - distance to move the right edge outward (negative values move the edge inward)

top - distance to move the top edge outward (negative values move the edge inward)

bottom - distance to move the bottom edge outward (negative values move the edge inward)

Since:

3.1

normalize

public static void normalize(Rectangle rect)

Normalizes the given rectangle. That is, any rectangle with negative width or height becomes a rectangle with positive width or height that extends to the upper-left of the original rectangle.

Parameters:

rect - rectangle to modify

Since:

3.0

toControl

public static Rectangle toControl(Control coordinateSystem,
                                  Rectangle toConvert)

Converts the given rectangle from display coordinates to the local coordinate system of the given object into display coordinates.

Parameters:

coordinateSystem - local coordinate system being converted to

toConvert - rectangle to convert

Returns:

a rectangle in control coordinates

Since:

3.0

toDisplay

public static Rectangle toDisplay(Control coordinateSystem,
                                  Rectangle toConvert)

Converts the given rectangle from the local coordinate system of the given object into display coordinates.

Parameters:

coordinateSystem - local coordinate system being converted from

toConvert - rectangle to convert

Returns:

a rectangle in display coordinates

Since:

3.0

getRelativePosition

public static int getRelativePosition(Rectangle boundary,
                                      Point toTest)

Determines where the given point lies with respect to the given rectangle. Returns a combination of SWT.LEFT, SWT.RIGHT, SWT.TOP, and SWT.BOTTOM, combined with bitwise or (for example, returns SWT.TOP | SWT.LEFT if the point is to the upper-left of the rectangle). Returns 0 if the point lies within the rectangle. Positions are in screen coordinates (ie: a point is to the upper-left of the rectangle if its x and y coordinates are smaller than any point in the rectangle)

Parameters:

boundary - normalized boundary rectangle

toTest - point whose relative position to the rectangle is being computed

Returns:

one of SWT.LEFT | SWT.TOP, SWT.TOP, SWT.RIGHT | SWT.TOP, SWT.LEFT, 0, SWT.RIGHT, SWT.LEFT | SWT.BOTTOM, SWT.BOTTOM, SWT.RIGHT | SWT.BOTTOM

Since:

3.0

getDistanceFrom

public static int getDistanceFrom(Rectangle boundary,
                                  Point toTest)

Returns the distance from the point to the nearest edge of the given rectangle. Returns negative values if the point lies outside the rectangle.

Parameters:

boundary - rectangle to test

toTest - point to test

Returns:

the distance between the given point and the nearest edge of the rectangle. Returns positive values for points inside the rectangle and negative values for points outside the rectangle.

Since:

3.1

getClosestSide

public static int getClosestSide(Rectangle boundary,
                                 Point toTest)

Returns the edge of the given rectangle is closest to the given point.

Parameters:

boundary - rectangle to test

toTest - point to compare

Returns:

one of SWT.LEFT, SWT.RIGHT, SWT.TOP, or SWT.BOTTOM

Since:

3.0

copy

public static Rectangle copy(Rectangle toCopy)

Returns a copy of the given rectangle

Parameters:

toCopy - rectangle to copy

Returns:

a copy of the given rectangle

Since:

3.0

getSize

public static Point getSize(Rectangle rectangle)

Returns the size of the rectangle, as a Point

Parameters:

rectangle - rectangle whose size is being computed

Returns:

the size of the given rectangle

Since:

3.0

setSize

public static void setSize(Rectangle rectangle,
                           Point newSize)

Sets the size of the given rectangle to the given size

Parameters:

rectangle - rectangle to modify

newSize - new size of the rectangle

Since:

3.0

setLocation

public static void setLocation(Rectangle rectangle,
                               Point newLocation)

Sets the x,y position of the given rectangle. For a normalized rectangle (a rectangle with positive width and height), this will be the upper-left corner of the rectangle.

Parameters:

rectangle - rectangle to modify

newLocation - new location of the rectangle

Since:

3.0

getLocation

public static Point getLocation(Rectangle toQuery)

Returns the x,y position of the given rectangle. For normalized rectangles (rectangles with positive width and height), this is the upper-left corner of the rectangle.

Parameters:

toQuery - rectangle to query

Returns:

a Point containing the x,y position of the rectangle

Since:

3.0

createRectangle

public static Rectangle createRectangle(Point position,
                                        Point size)

Returns a new rectangle with the given position and dimensions, expressed as points.

Parameters:

position - the (x,y) position of the rectangle

size - the size of the new rectangle, where (x,y) -> (width, height)

Returns:

a new Rectangle with the given position and size

Since:

3.0

moveInside

public static void moveInside(Rectangle inner,
                              Rectangle outer)

Repositions the 'inner' rectangle to lie completely within the bounds of the 'outer' rectangle if possible. One use for this is to ensure that, when setting a control's bounds, that they will always lie within its parent's client area (to avoid clipping).

Parameters:

inner - The 'inner' rectangle to be repositioned (should be smaller than the 'outer' rectangle)

outer - The 'outer' rectangle