
Class: Point
Object

+Magnitude

+ArithmeticValue

+Point
 Package:
 stx:libbasic
 Category:
 GraphicsGeometry
 Version:
 rev:
1.78
date: 2016/08/26 10:15:15
 user: cg
 file: Point.st directory: libbasic
 module: stx stcclassLibrary: libbasic
 Author:
 Claus Gittinger
I represent a point in 2D space. Or I can be used to represent
an extent (of a rectangle, for example), in which case my xcoordinate
represents the width, and ycoordinate the height of something.
The x and y coordinates are usually numbers.
[Instance variables:]
x <Number> the xcoordinate of myself
y <Number> the ycoordinate of myself
Rectangle
Polygon
LayoutOrigin
LayoutFrame
AlignmentOrigin
Layout
View
GraphicsContext
constants

unity

return the neutral element for multiplication

zero

return the neutral element for addition
initialization

initialize

instance creation

decodeFromLiteralArray: anArray

create & return a new instance from information encoded in anArray.
Redefined for faster creation.
usage example(s):
Point
decodeFromLiteralArray:#(Point 10 10)


r: distance angle: angle

create and return a new point given polar coordinates.
The angle is given in degrees.
OBSOLETE STX interface, use #r:theta:
** This is an obsolete interface  do not use it (it may vanish in future versions) **

r: distance degrees: angle

create and return a new point given polar coordinates.
The angle is given in degrees.
Added for Squeak compatibility
usage example(s):

r: distance theta: angleInRadians

create and return a new point given polar coordinates.
The angle is given in radians
usage example(s):
Point r:100 theta:0
Point r:100 theta:Float pi/2


readFrom: aStringOrStream onError: exceptionBlock

return the next Point from the (character)stream aStream;
skipping all whitespace first; return the value of exceptionBlock,
if no point can be read.
usage example(s):
Point readFrom:'1.234 @ 5.678'
Point readFrom:'1'
Point readFrom:'1' onError:[1@1]
Point readFrom:'fooBar' onError:[0@0]


x: newX y: newY

create and return a new point with coordinates newX and newY
queries

isBuiltInClass

return true if this class is known by the runtimesystem.
Here, true is returned for myself, false for subclasses.
CompatibilitySqueak

adhereTo: aRectangle

If the receiver lies outside aRectangle, return the nearest point on the boundary of the rectangle, otherwise return self.

area


asFloatPoint

Squeak mimicri return the receiver as Point  this is the receiver

asLargerPowerOfTwo


asSmallerPowerOfTwo


maxDimension

Answer the larger of the two dimensions.
accessing

x

return the x coordinate

x: newX

set the x coordinate to be the argument, aNumber.
This is destructive (modifies the receiver, not a copy) and
should only be used if you know, that you are the exclusive owner
of the receiver.

x: newX y: newY

set both the x and y coordinates.
This is destructive (modifies the receiver, not a copy) and
should only be used if you know, that you are the exclusive owner
of the receiver.

y

return the y coordinate

y: newY

set the y coordinate to be the argument, aNumber.
This is destructive (modifies the receiver, not a copy) and
should only be used if you know, that you are the exclusive owner
of the receiver.
coercing & converting

coerce: anObject

convert the argument aNumber into an instance of the receiver's class and return it.

generality

return the generality value  see ArithmeticValue>>retry:coercing:
comparing

< aPoint

return true if the receiver is above and to the left
of the argument, aPoint
usage example(s):
notice the funny result if one coordinate has the same value ...
(3@4) < (4@4)
(3@4) <= (4@4)
(3@4) > (4@4)
(4@4) >= (3@4)
(4@4) > (3@4)


= aPoint

return true if the receiver represents the same point as
the argument, aPoint

> aPoint

return true if the receiver is below and to the right
of the argument, aPoint

hash

return a number for hashing

isLeftOrAbove: aPoint

return true if the receiver is above or to the left
of the argument, aPoint.
When sorting this enumerates points from left to right and top to bottom

max: aPoint

return the lower right corner of the rectangle uniquely defined by
the receiver and the argument, aPoint

min: aPoint

return the upper left corner of the rectangle uniquely defined by
the receiver and the argument, aPoint
converting

asComplex

Return a complex number whose real and imaginary components are the x and y
coordinates of the receiver.

asFractionalLayout

return a LayoutOrigin from the receiver,
treating the receiver coordinates as fractional parts
(i.e. relative to superview).
Notice: in 10.5.x LayoutOrigin is not yet officially released.
usage example(s):
(0@0.5) asFractionalLayout
(0@0.5) asLayout
(0@10) asLayout
(0@10) asOffsetLayout


asIntegerPoint


asLayout

return a LayoutOrigin from the receiver.
If the receiver coordinates are between 0 and 1, take
them as fractional parts (relative to superview).
Otherwise, treat them as absolute offsets.
Notice: in 10.5.x LayoutOrigin is not yet released.
usage example(s):
(0@0.5) asFractionalLayout
(0@0.5) asLayout
(0@10) asLayout
(0@10) asOffsetLayout


asOffsetLayout

return a LayoutOrigin from the receiver,
treating the receiver coordinates as absolute offsets.
Notice: in 10.5.x LayoutOrigin is not yet released.
usage example(s):
(0@0.5) asFractionalLayout
(0@0.5) asLayout
(0@10) asLayout
(0@10) asOffsetLayout


asPoint

return the receiver as Point  this is the receiver

asRectangle

return a zerowidth rectangle consisting of origin
and corner being the receiver
usage example(s):

corner: aPoint

return a rectangle whose origin is self and corner is aPoint

extent: aPoint

return a rectangle whose origin is self and extent is aPoint

fromLiteralArrayEncoding: encoding

read my values from an encoding.
The encoding is supposed to be of the form: (Point xValue yValue)
usage example(s):
Point new fromLiteralArrayEncoding:#(Point 10 20)


literalArrayEncoding

encode myself as an array, from which a copy of the receiver
can be reconstructed with #decodeAsLiteralArray.
The encoding is: (Point xValue yValue)
usage example(s):
Point new fromLiteralArrayEncoding:#(Point 10 20)
(10@20) literalArrayEncoding


rectangleRelativeTo: aRectangle preferred: prefRectHolder

compute a displayRectangle, treating the receiver like a
layoutorigin. This allows point to be used interchangable with
LayoutOrigins.
usage example(s):
consider the case, where a view has a preferred extent of 50@50
and is to be positioned in its superview which has size 100@100.
For absolute origin:
(10@20) rectangleRelativeTo:(0@0 corner:100@100) preferred:(0@0 corner:50@50)
for relative origin:
(0.5@0.5) rectangleRelativeTo:(0@0 corner:100@100) preferred:(0@0 corner:50@50)

destructive transformations

scaleBy: aScale

scale the receiver, by replacing coordinates by the product
of the receiver's coordinates and the scale (a Point or Number).
This is destructive (modifies the receiver, not a copy) and
should only be used if you know, that you are the exclusive owner
of the receiver.

translateBy: anOffset

translate the receiver, by replacing coordinates by the sum
of the receiver's coordinated and the scale (a Point or Number).
This is destructive (modifies the receiver, not a copy) and
should only be used if you know, that you are the exclusive owner
of the receiver.
inspecting

inspectorValueStringInListFor: anInspector
( an extension from the stx:libtool package )

returns a string to be shown in the inspector's list
interpolating

interpolateTo: end at: amountDone

Interpolate between the instance and end after the specified amount has been done (0  1).
usage example(s):
(10@10) interpolateTo:(20@20) at:0.5
(10@10) interpolateTo:(20@20) at:0.3
(0@0) interpolateTo:(0@20) at:0.5

misc

abs

return a new point with my coordinates taken from the absolute values.

ceiling

return a new point with my coordinates truncated towards positive infinity.
Return the receiver if its coordinates are already integral.

floor

return a new point with my coordinates truncated towards negative infinity.
Return the receiver if its coordinates are already integral.

quadrant

return the number of the quadrant containing the receiver.
quadrants are named as follows:
^ 2  3
Y 
1  0
X >
Q: what is to be returned if any coordinate is 0 ?
usage example(s):
(1@1) quadrant
(1@1) quadrant
(1@1) quadrant
(1@1) quadrant
(0@0) quadrant


quadrantContaining: aPoint

return the number of the quadrant containing aPoint placing
the receiver at the origin, where the quadrants are numbered as
follows:
^ 2  3
Y 
1  0
X >
This can be used for polygon operations (see Foley for examples).
usage example(s):
(10 @ 10) quadrantContaining:(15 @ 15)
(10 @ 10) quadrantContaining:(5 @ 5)
(10 @ 10) quadrantContaining:(5 @ 15)
(10 @ 10) quadrantContaining:(15 @ 5)


rounded

return a new point with my coordinates rounded to the next integer.
Return the receiver if its coordinates are already integral.
usage example(s):
(1.5 @ 2.6) rounded
(1 @ 2) rounded


truncateTo: aNumber

return a new point with my coordinates truncated towards zero to the next
multiple of aNumber.

truncated

return a new point with my coordinates truncated as integer.
Return the receiver if its coordinates are already integral.
point functions

crossProduct: aPoint

Return a number that is the cross product of the receiver and the
argument, aPoint.

dist: aPoint

return the distance between aPoint and the receiver.

dotProduct: aPoint

return a number that is the dot product of the receiver and
the argument, aPoint. That is, the two points are
multiplied and the coordinates of the result summed.

fourNeighbors


grid: gridPoint

return a new point with coordinates grided (i.e. rounded to the
nearest point on the grid)

nearestIntegerPointOnLineFrom: point1 to: point2

return the closest integer point to the receiver on the line
determined by (point1, point2)much faster than the more
accurate version if the receiver and arguments are integer points.
This method was found in the Manchester goody library.
usage example(s):
120@40 nearestIntegerPointOnLineFrom: 30@120 to: 100@120
0@0 nearestIntegerPointOnLineFrom: 10@10 to: 100@100


normalized

interpreting myself as the endPoint of a 0@0 based vector,
return the endPoint of the corresponding normalized vector.
(that is the endPoint of a vector with the same direction but length 1)
usage example(s):
(10 @ 10) normalized
(1 @ 1) normalized
(10 @ 0) normalized
(0 @ 10) normalized
(10 @ 0) normalized
(0 @ 10) normalized
(0 @ 0) normalized


transposed

return a new point with x and y coordinates exchanged
polar coordinates

angle

return the receiver's angle (in degrees) in a polar coordinate system.
(i.e. the angle of a vector from 0@0 to the receiver).
OBSOLETE ST/X interface; use theta for ST80 compatibility.
** This is an obsolete interface  do not use it (it may vanish in future versions) **

degrees

return the receiver's angle (in degrees) in a polar coordinate system.
(i.e. the angle of a vector from 0@0 to the receiver).
The angle is counted counterclockwise, starting with 0 for a horizontal
line (i.e. 0@0 > 100@0 has an angle of 0 and 0@0 > 0@100 has an angle of 90).
Added for Squeak compatibility.
usage example(s):
(1@1) degrees
(2@1) degrees


r

return the receiver's radius in a polar coordinate system.
(i.e. the length of a vector from 0@0 to the receiver)
usage example(s):
(1@1) r
(2@1) r
(2@0) r
(0@2) r
(2@2) r
(2@2) r


theta

return the receiver's angle (in radians) in a polar coordinate system.
(i.e. the angle of a vector from 0@0 to the receiver)
usage example(s):
(1@1) theta
(2@1) theta
(2@1) theta
(2@1) theta
(0@1) theta

printing & storing

printOn: aStream

append a printed representation of the receiver to aStream

storeOn: aStream

append my storeString to aStream
queries

isPoint

return true, if the receiver is some kind of point
testing

isFinite


isInfinite

transformations

* scale

Return a new Point that is the product of the
receiver and scale (which is a Point or Number).

+ translation

Return a new Point that is the sum of the
receiver and translation (which is a Point or Number).

 translation

Return a new Point that is the difference of the
receiver and translation (which is a Point or Number).

/ scale

Return a new Point that is the integer quotient of the
receiver and scale (which is a Point or Number).

// scale

Return a new Point that is the quotient of the
receiver and scale (which is a Point or Number).

negated

return a new point with my coordinates negated
i.e. the receiver mirrored at the origin
usage example(s):

reciprocal

return a new point where the coordinates are
the reciproce of mine

rotateBy: angle about: center

Return a new point, generated by rotating the receiver
counterClockWise by some angle in radians around the given center point.
Even though Point.theta is measured CW,
this rotates with the more conventional CCW interpretateion of angle.
usage example(s):
(10@10) rotateBy:Float pi about:0@0
(10@0) rotateBy:Float pi about:0@0


scaledBy: aScale

return a new Point that is the product of the
receiver and scale (which is a Point or Number).

translatedBy: anOffset

return a new Point that is the sum of the
receiver and scale (which is a Point or Number).
