Perfect Shape 1.0.0 was released today, providing the Ruby community with an open-source library of Pure Ruby Geometric Algorithms that are mostly useful for GUI (Graphical User Interface) manipulation like checking viewport rectangle intersection or containment of a mouse click point in popular geometry shapes such as rectangle, square, arc (open, chord, and pie), ellipse, circle, polygon, and paths containing lines, quadratic bézier curves, and cubic bezier curves, potentially with affine transforms applied like translation, scale, rotation, shear/skew, and inversion (including both Ray Casting Algorithm, aka Even-odd Rule, and Winding Number Algorithm, aka Nonzero Rule).

The reason behind creating this library was that before, there were no comprehensive geometric algorithm libraries in Ruby that covered all the geometric shapes mentioned above. Most of them either lacked support for certain shapes like arc or lacked algorithms for checking point containment in every shape, including Cubic Bezier Curves. Thankfully, Perfect Shape addresses that issue completely for the Ruby community.

Another reason why this library was created was to address the need for supporting automated declarative drag and drop features in Glimmer DSL for LibUI coming soon (right now, it supports manually implementing drag and drop with area listeners out of the box).

Below is a summary of the Perfect Shape library directly from its README. Put it to good use!

Perfect Shape 1.0.0

Geometric Algorithms

PerfectShape is a collection of pure Ruby geometric algorithms that are mostly useful for GUI (Graphical User Interface) manipulation like checking viewport rectangle intersection or containment of a mouse click point in popular geometry shapes such as rectangle, square, arc (open, chord, and pie), ellipse, circle, polygon, and paths containing lines, quadratic bézier curves, and cubic bezier curves, potentially with affine transforms applied like translation, scale, rotation, shear/skew, and inversion (including both Ray Casting Algorithm, aka Even-odd Rule, and Winding Number Algorithm, aka Nonzero Rule).

Additionally, PerfectShape::Math contains some purely mathematical algorithms, like IEEE 754-1985 Remainder.

To ensure high accuracy, this library does all its mathematical operations with BigDecimal numbers.

Setup

Run:

gem install perfect-shape -v 1.0.0

Or include in Bundler Gemfile:

gem 'perfect-shape', '~> 1.0.0'

And, run:

bundle

API

PerfectShape::Math

Module

• ::degrees_to_radians(angle): converts degrees to radians
• ::radians_to_degrees(angle): converts radians to degrees
• ::normalize_degrees(angle): normalizes the specified angle into the range -180 to 180.
• ::ieee_remainder(x, y) (alias: ieee754_remainder): IEEE 754-1985 Remainder (different from standard % modulo operator as it operates on floats and could return a negative result)

PerfectShape::Shape

Class

This is a base class for all shapes. It is not meant to be used directly. Subclasses implement/override its methods as needed.

• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width
• #height: height
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height just as those of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside if outline is false or if point is on the outline if outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a shape from its outline more successfully

PerfectShape::PointLocation

Module

• #initialize(x: 0, y: 0): initializes a point location, usually representing the top-left point in a shape
• #x: top-left x
• #y: top-left y
• #min_x: min x (x by default)
• #min_y: min y (y by default)

PerfectShape::RectangularShape

Module

Includes PerfectShape::PointLocation

• #initialize(x: 0, y: 0, width: 1, height: 1): initializes a rectangular shape
• #x: top-left x
• #y: top-left y
• #width: width
• #height: height
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y

PerfectShape::AffineTransform

Class

Affine transforms have the following matrix:

[ xxp xyp xt ]

[ yxp yyp yt ]

The matrix is used to transform (x,y) point coordinates as follows:

[ xxp xyp xt ] * [x] = [ xxp * x + xyp * y + xt ]

[ yxp yyp yt ] * [y] = [ yxp * x + yyp * y + yt ]

xxp is the x coordinate x product (m11)

xyp is the x coordinate y product (m12)

yxp is the y coordinate x product (m21)

yyp is the y coordinate y product (m22)

xt is the x coordinate translation (m13)

yt is the y coordinate translation (m23)

Affine transform mutation operations ending with ! can be chained as they all return self.

• ::new(xxp_element = nil, xyp_element = nil, yxp_element = nil, yyp_element = nil, xt_element = nil, yt_element = nil, xxp: nil, xyp: nil, yxp: nil, yyp: nil, xt: nil, yt: nil, m11: nil, m12: nil, m21: nil, m22: nil, m13: nil, m23: nil): The constructor accepts either the (x,y)-operation related argument/kwarg names or traditional matrix element kwarg names. If no arguments are supplied, it constructs an identity matrix (i.e. like calling ::new(xxp: 1, xyp: 0, yxp: 0, yyp: 1, xt: 0, yt: 0)).
• #matrix_3d: Returns Ruby Matrix object representing affine transform in 3D (used internally for performing multiplication)
• #==(other): Returns true if equal to other or false otherwise
• #identity! (alias: reset!): Resets to identity matrix (i.e. like calling ::new(xxp: 1, xyp: 0, yxp: 0, yyp: 1, xt: 0, yt: 0))
• #invertible? Returns true if matrix is invertible and false otherwise
• #invert!: Inverts affine transform matrix if invertible or raises an error otherwise
• #multiply!(other): Multiplies affine transform with another affine transform, storing resulting changes in matrix elements
• #translate!(x_or_point, y=nil): Translates affine transform with (x, y) translation values
• #scale!(x_or_point, y=nil): Scales affine transform with (x, y) scale values
• #rotate!(degrees): Rotates by angle degrees counter-clockwise if angle value is positive or clockwise if angle value is negative. Note that it returns very close approximate results for rotations that are 90/180/270 degrees (good enough for inverse-transform GUI point containment checks needed when checking if mouse-click-point is inside a transformed shape).
• #shear!(x_or_point, y=nil): Shears by x and y factors
• #clone: Returns a new AffineTransform with the same matrix elements
• #transform_point(x_or_point, y=nil): returns [xxp * x + xyp * y + xt, yxp * x + yyp * y + yt]. Note that result is a close approximation, but should be good enough for GUI mouse-click-point containment checks.
• #transform_points(*xy_coordinates_or_points): returns Array of (x,y) pair Arrays transformed with #transform_point method
• #inverse_transform_point(x_or_point, y=nil): returns inverse transform of a point (x,y) coordinates (clones self and inverts clone, and then transforms point). Note that result is a close approximation, but should be good enough for GUI mouse-click-point containment checks.
• #inverse_transform_points(*xy_coordinates_or_points): returns inverse transforms of a point Array of (x,y) coordinates

Example:

xxp = 2
xyp = 3
yxp = 4
yyp = 5
xt = 6
yt = 7
affine_transform1 = PerfectShape::AffineTransform.new(xxp: xxp, xyp: xyp, yxp: yxp, yyp: yyp, xt: xt, yt: yt) # (x,y)-operation kwarg names
affine_transform2 = PerfectShape::AffineTransform.new(m11: xxp, m12: xyp, m21: yxp, m22: yyp, m13: xt, m23: yt) # traditional matrix element kwarg names
affine_transform3 = PerfectShape::AffineTransform.new(xxp, xyp, yxp, yyp, xt, yt) # standard arguments

affine_transform2.matrix_3d == affine_transform1.matrix_3d # => true
affine_transform3.matrix_3d == affine_transform1.matrix_3d # => true

affine_transform = PerfectShape::AffineTransform.new.translate!(30, 20).scale!(2, 3)

affine_transform.transform_point(10, 10) # => approximately [50, 50]
affine_transform.inverse_transform_point(50, 50) # => approximately [10, 10]

PerfectShape::Point

Class

Extends PerfectShape::Shape

Includes PerfectShape::PointLocation

Points are simply represented by an Array of [x,y] coordinates when used within other shapes, but when needing point-specific operations like point_distance, the PerfectShape::Point class can come in handy.

• ::point_distance(x, y, px, py): Returns the distance from a point to another point
• ::normalize_point(x_or_point, y = nil): Normalizes point args whether two-number point Array or x, y args, returning normalized point Array of two BigDecimal's
• ::new(x_or_point=nil, y_arg=nil, x: nil, y: nil): constructs a point with (x,y) pair (default: 0,0) whether specified as Array of (x,y) pair, flat x,y args, or x:, y: kwargs.
• #min_x: min x (always x)
• #min_y: min y (always y)
• #max_x: max x (always x)
• #max_y: max y (always y)
• #width: width (always 0)
• #height: height (always 0)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x (always x)
• #center_y: center y (always y)
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: true, distance_tolerance: 0): checks if point matches self, with a distance tolerance (0 by default). Distance tolerance provides a fuzz factor that for example enables GUI users to mouse-click-select a point shape more successfully. outline option makes no difference on point
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #point_distance(x_or_point, y=nil): Returns the distance from a point to another point

Example:

require 'perfect-shape'

shape = PerfectShape::Point.new(x: 200, y: 150)

shape.contain?(200, 150) # => true
shape.contain?([200, 150]) # => true
shape.contain?(200, 151) # => false
shape.contain?([200, 151]) # => false
shape.contain?(200, 151, distance_tolerance: 5) # => true
shape.contain?([200, 151], distance_tolerance: 5) # => true

PerfectShape::Line

Class

Extends PerfectShape::Shape

Includes PerfectShape::MultiPoint

• ::relative_counterclockwise(x1, y1, x2, y2, px, py): Returns an indicator of where the specified point (px,py) lies with respect to the line segment from (x1,y1) to (x2,y2). The return value can be either 1, -1, or 0 and indicates in which direction the specified line must pivot around its first end point, (x1,y1), in order to point at the specified point (px,py). A return value of 1 indicates that the line segment must turn in the direction that takes the positive X axis towards the negative Y axis. In the default coordinate system, this direction is counterclockwise. A return value of -1 indicates that the line segment must turn in the direction that takes the positive X axis towards the positive Y axis. In the default coordinate system, this direction is clockwise. A return value of 0 indicates that the point lies exactly on the line segment. Note that an indicator value of 0 is rare and not useful for determining collinearity because of floating point rounding issues. If the point is colinear with the line segment, but not between the end points, then the value will be -1 if the point lies “beyond (x1,y1)” or 1 if the point lies “beyond (x2,y2)”.
• ::point_distance_square(x1, y1, x2, y2, px, py): Returns the square of distance from a point to a line segment.
• ::point_distance(x1, y1, x2, y2, px, py): Returns the distance from a point to a line segment.
• ::new(points: []): constructs a line with two points as Array of Arrays of [x,y] pairs or flattened Array of alternating x and y coordinates
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: true, distance_tolerance: 0): checks if point lies on line, with a distance tolerance (0 by default). Distance tolerance provides a fuzz factor that for example enables GUI users to mouse-click-select a line shape more successfully. outline option makes no difference on line
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #relative_counterclockwise(x_or_point, y=nil): Returns an indicator of where the specified point (px,py) lies with respect to the line segment from (x1,y1) to (x2,y2). The return value can be either 1, -1, or 0 and indicates in which direction the specified line must pivot around its first end point, (x1,y1), in order to point at the specified point (px,py). A return value of 1 indicates that the line segment must turn in the direction that takes the positive X axis towards the negative Y axis. In the default coordinate system, this direction is counterclockwise. A return value of -1 indicates that the line segment must turn in the direction that takes the positive X axis towards the positive Y axis. In the default coordinate system, this direction is clockwise. A return value of 0 indicates that the point lies exactly on the line segment. Note that an indicator value of 0 is rare and not useful for determining collinearity because of floating point rounding issues. If the point is colinear with the line segment, but not between the end points, then the value will be -1 if the point lies “beyond (x1,y1)” or 1 if the point lies “beyond (x2,y2)”.
• #point_distance(x_or_point, y=nil): Returns the distance from a point to a line segment.
• #rect_crossings(rxmin, rymin, rxmax, rymax, crossings = 0): rectangle crossings (adds to crossings arg)

Example:

require 'perfect-shape'

shape = PerfectShape::Line.new(points: [[0, 0], [100, 100]]) # start point and end point

shape.contain?(50, 50) # => true
shape.contain?([50, 50]) # => true
shape.contain?(50, 51) # => false
shape.contain?([50, 51]) # => false
shape.contain?(50, 51, distance_tolerance: 5) # => true
shape.contain?([50, 51], distance_tolerance: 5) # => true

PerfectShape::QuadraticBezierCurve

Class

Extends PerfectShape::Shape

Includes PerfectShape::MultiPoint

• ::tag(coord, low, high): Determine where coord lies with respect to the range from low to high. It is assumed that low < high. The return value is one of the 5 values BELOW, LOWEDGE, INSIDE, HIGHEDGE, or ABOVE.
• ::eqn(val, c1, cp, c2): Fill an array with the coefficients of the parametric equation in t, ready for solving against val with solve_quadratic. We currently have: val = Py(t) = C1*(1-t)^2 + 2*CP*t*(1-t) + C2*t^2 = C1 - 2*C1*t + C1*t^2 + 2*CP*t - 2*CP*t^2 + C2*t^2 = C1 + (2*CP - 2*C1)*t + (C1 - 2*CP + C2)*t^2; 0 = (C1 - val) + (2*CP - 2*C1)*t + (C1 - 2*CP + C2)*t^2; 0 = C + Bt + At^2; C = C1 - val; B = 2*CP - 2*C1; A = C1 - 2*CP + C2
• ::solve_quadratic(eqn): Solves the quadratic whose coefficients are in the eqn array and places the non-complex roots into the res array, returning the number of roots. The quadratic solved is represented by the equation:

  eqn = {C, B, A}; ax^2 + bx + c = 0

  A return value of -1 is used to distinguish a constant equation, which might be always 0 or never 0, from an equation that has no zeroes.
• ::eval_quadratic(vals, num, include0, include1, inflect, c1, ctrl, c2): Evaluate the t values in the first num slots of the vals[] array and place the evaluated values back into the same array. Only evaluate t values that are within the range <, >, including the 0 and 1 ends of the range iff the include0 or include1 booleans are true. If an "inflection" equation is handed in, then any points which represent a point of inflection for that quadratic equation are also ignored.
• ::new(points: []): constructs a quadratic bézier curve with three points (start point, control point, and end point) as Array of Arrays of [x,y] pairs or flattened Array of alternating x and y coordinates
• #points: points (start point, control point, and end point)
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape (bounding box only guarantees that the shape is within it, but it might be bigger than the shape)
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a quadratic bezier curve shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #curve_center_point: point at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #curve_center_x: point x coordinate at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #curve_center_y: point y coordinate at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #subdivisions(level=1): subdivides quadratic bezier curve at its center into into 2 quadratic bezier curves by default, or more if level of recursion is specified. The resulting number of subdivisions is 2 to the power of level.
• #point_distance(x_or_point, y=nil, minimum_distance_threshold: OUTLINE_MINIMUM_DISTANCE_THRESHOLD): calculates distance from point to curve segment. It does so by subdividing curve into smaller curves and checking against the curve center points until the distance is less than minimum_distance_threshold, to avoid being an overly costly operation.
• #rect_crossings(rxmin, rymin, rxmax, rymax, level, crossings = 0): rectangle crossings (adds to crossings arg)

Example:

require 'perfect-shape'

shape = PerfectShape::QuadraticBezierCurve.new(points: [[200, 150], [270, 320], [380, 150]]) # start point, control point, and end point

shape.contain?(270, 220) # => true
shape.contain?([270, 220]) # => true
shape.contain?(270, 220, outline: true) # => false
shape.contain?([270, 220], outline: true) # => false
shape.contain?(280, 235, outline: true) # => true
shape.contain?([280, 235], outline: true) # => true
shape.contain?(281, 235, outline: true) # => false
shape.contain?([281, 235], outline: true) # => false
shape.contain?(281, 235, outline: true, distance_tolerance: 1) # => true
shape.contain?([281, 235], outline: true, distance_tolerance: 1) # => true

PerfectShape::CubicBezierCurve

Class

Extends PerfectShape::Shape

Includes PerfectShape::MultiPoint

• ::new(points: []): constructs a cubic bézier curve with four points (start point, two control points, and end point) as Array of Arrays of [x,y] pairs or flattened Array of alternating x and y coordinates
• #points: points (start point, two control points, and end point)
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape (bounding box only guarantees that the shape is within it, but it might be bigger than the shape)
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a cubic bezier curve shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #curve_center_point: point at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #curve_center_x: point x coordinate at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #curve_center_y: point y coordinate at the center of the curve outline (not the center of the bounding box area like center_x and center_y)
• #subdivisions(level=1): subdivides cubic bezier curve at its center into into 2 cubic bezier curves by default, or more if level of recursion is specified. The resulting number of subdivisions is 2 to the power of level.
• #point_distance(x_or_point, y=nil, minimum_distance_threshold: OUTLINE_MINIMUM_DISTANCE_THRESHOLD): calculates distance from point to curve segment. It does so by subdividing curve into smaller curves and checking against the curve center points until the distance is less than minimum_distance_threshold, to avoid being an overly costly operation.
• #rectangle_crossings(rectangle): rectangle crossings (used to determine rectangle interior intersection), optimized to check if line represented by cubic bezier curve crosses the rectangle first, and if not then perform expensive check with #rect_crossings
• #rect_crossings(rxmin, rymin, rxmax, rymax, level, crossings = 0): rectangle crossings (adds to crossings arg)

Example:

require 'perfect-shape'

shape = PerfectShape::CubicBezierCurve.new(points: [[200, 150], [235, 235], [270, 320], [380, 150]]) # start point, two control points, and end point

shape.contain?(270, 220) # => true
shape.contain?([270, 220]) # => true
shape.contain?(270, 220, outline: true) # => false
shape.contain?([270, 220], outline: true) # => false
shape.contain?(261.875, 245.625, outline: true) # => true
shape.contain?([261.875, 245.625], outline: true) # => true
shape.contain?(261.875, 246.625, outline: true) # => false
shape.contain?([261.875, 246.625], outline: true) # => false
shape.contain?(261.875, 246.625, outline: true, distance_tolerance: 1) # => true
shape.contain?([261.875, 246.625], outline: true, distance_tolerance: 1) # => true

PerfectShape::Rectangle

Class

Extends PerfectShape::Shape

Includes PerfectShape::RectangularShape

• ::new(x: 0, y: 0, width: 1, height: 1): constructs a rectangle
• #x: top-left x
• #y: top-left y
• #width: width
• #height: height
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a rectangle shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #edges: edges of rectangle as PerfectShape::Line objects
• #out_state(x_or_point, y = nil): Returns "out state" of specified point (x,y) (whether it lies to the left, right, top, bottom of rectangle). If point is outside rectangle, it returns a bit mask combination of Rectangle::OUT_LEFT, Rectangle::OUT_RIGHT, Rectangle::OUT_TOP, or Rectangle::OUT_BOTTOM. Otherwise, it returns 0 if point is inside the rectangle.
• #empty?: Returns true if width or height are 0 (or negative) and false otherwise

Example:

require 'perfect-shape'

shape = PerfectShape::Rectangle.new(x: 15, y: 30, width: 200, height: 100)

shape.contain?(115, 80) # => true
shape.contain?([115, 80]) # => true
shape.contain?(115, 80, outline: true) # => false
shape.contain?([115, 80], outline: true) # => false
shape.contain?(115, 30, outline: true) # => true
shape.contain?([115, 30], outline: true) # => true
shape.contain?(115, 31, outline: true) # => false
shape.contain?([115, 31], outline: true) # => false
shape.contain?(115, 31, outline: true, distance_tolerance: 1) # => true
shape.contain?([115, 31], outline: true, distance_tolerance: 1) # => true

PerfectShape::Square

Class

Extends PerfectShape::Rectangle

• ::new(x: 0, y: 0, length: 1) (length alias: size): constructs a square
• #x: top-left x
• #y: top-left y
• #length: length
• #width: width (equal to length)
• #height: height (equal to length)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a square shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #edges: edges of square as PerfectShape::Line objects
• #empty?: Returns true if length is 0 (or negative) and false otherwise

Example:

require 'perfect-shape'

shape = PerfectShape::Square.new(x: 15, y: 30, length: 200)

shape.contain?(115, 130) # => true
shape.contain?([115, 130]) # => true
shape.contain?(115, 130, outline: true) # => false
shape.contain?([115, 130], outline: true) # => false
shape.contain?(115, 30, outline: true) # => true
shape.contain?([115, 30], outline: true) # => true
shape.contain?(115, 31, outline: true) # => false
shape.contain?([115, 31], outline: true) # => false
shape.contain?(115, 31, outline: true, distance_tolerance: 1) # => true
shape.contain?([115, 31], outline: true, distance_tolerance: 1) # => true

PerfectShape::Arc

Class

Extends PerfectShape::Shape

Includes PerfectShape::RectangularShape

Arcs can be of type :open, :chord, or :pie

Open Arc	Chord Arc	Pie Arc

• ::new(type: :open, x: 0, y: 0, width: 1, height: 1, start: 0, extent: 360, center_x: nil, center_y: nil, radius_x: nil, radius_y: nil): constructs an arc of type :open (default), :chord, or :pie
• #type: :open, :chord, or :pie
• #x: top-left x
• #y: top-left y
• #width: width
• #height: height
• #start: start angle in degrees
• #extent: extent angle in degrees
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #radius_x: radius along the x-axis
• #radius_y: radius along the y-axis
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select an arc shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #contain_angle?(angle): returns true if the angle is within the angular extents of the arc and false otherwise

Example:

require 'perfect-shape'

shape = PerfectShape::Arc.new(type: :open, x: 2, y: 3, width: 50, height: 60, start: 45, extent: 270)
shape2 = PerfectShape::Arc.new(type: :open, center_x: 2 + 25, center_y: 3 + 30, radius_x: 25, radius_y: 30, start: 45, extent: 270)

shape.contain?(39.5, 33.0) # => true
shape.contain?([39.5, 33.0]) # => true
shape2.contain?(39.5, 33.0) # => true
shape2.contain?([39.5, 33.0]) # => true
shape.contain?(39.5, 33.0, outline: true) # => false
shape.contain?([39.5, 33.0], outline: true) # => false
shape2.contain?(39.5, 33.0, outline: true) # => false
shape2.contain?([39.5, 33.0], outline: true) # => false
shape.contain?(2.0, 33.0, outline: true) # => true
shape.contain?([2.0, 33.0], outline: true) # => true
shape2.contain?(2.0, 33.0, outline: true) # => true
shape2.contain?([2.0, 33.0], outline: true) # => true
shape.contain?(3.0, 33.0, outline: true) # => false
shape.contain?([3.0, 33.0], outline: true) # => false
shape2.contain?(3.0, 33.0, outline: true) # => false
shape2.contain?([3.0, 33.0], outline: true) # => false
shape.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape2.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape2.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape.contain?(shape.center_x, shape.center_y, outline: true) # => false
shape.contain?([shape.center_x, shape.center_y], outline: true) # => false
shape2.contain?(shape2.center_x, shape2.center_y, outline: true) # => false
shape2.contain?([shape2.center_x, shape2.center_y], outline: true) # => false

shape3 = PerfectShape::Arc.new(type: :chord, x: 2, y: 3, width: 50, height: 60, start: 45, extent: 270)
shape4 = PerfectShape::Arc.new(type: :chord, center_x: 2 + 25, center_y: 3 + 30, radius_x: 25, radius_y: 30, start: 45, extent: 270)

shape3.contain?(39.5, 33.0) # => true
shape3.contain?([39.5, 33.0]) # => true
shape4.contain?(39.5, 33.0) # => true
shape4.contain?([39.5, 33.0]) # => true
shape3.contain?(39.5, 33.0, outline: true) # => false
shape3.contain?([39.5, 33.0], outline: true) # => false
shape4.contain?(39.5, 33.0, outline: true) # => false
shape4.contain?([39.5, 33.0], outline: true) # => false
shape3.contain?(2.0, 33.0, outline: true) # => true
shape3.contain?([2.0, 33.0], outline: true) # => true
shape4.contain?(2.0, 33.0, outline: true) # => true
shape4.contain?([2.0, 33.0], outline: true) # => true
shape3.contain?(3.0, 33.0, outline: true) # => false
shape3.contain?([3.0, 33.0], outline: true) # => false
shape4.contain?(3.0, 33.0, outline: true) # => false
shape4.contain?([3.0, 33.0], outline: true) # => false
shape3.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape3.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape4.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape4.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape3.contain?(shape3.center_x, shape3.center_y, outline: true) # => false
shape3.contain?([shape3.center_x, shape3.center_y], outline: true) # => false
shape4.contain?(shape4.center_x, shape4.center_y, outline: true) # => false
shape4.contain?([shape4.center_x, shape4.center_y], outline: true) # => false

shape5 = PerfectShape::Arc.new(type: :pie, x: 2, y: 3, width: 50, height: 60, start: 45, extent: 270)
shape6 = PerfectShape::Arc.new(type: :pie, center_x: 2 + 25, center_y: 3 + 30, radius_x: 25, radius_y: 30, start: 45, extent: 270)

shape5.contain?(39.5, 33.0) # => false
shape5.contain?([39.5, 33.0]) # => false
shape6.contain?(39.5, 33.0) # => false
shape6.contain?([39.5, 33.0]) # => false
shape5.contain?(9.5, 33.0) # => true
shape5.contain?([9.5, 33.0]) # => true
shape6.contain?(9.5, 33.0) # => true
shape6.contain?([9.5, 33.0]) # => true
shape5.contain?(39.5, 33.0, outline: true) # => false
shape5.contain?([39.5, 33.0], outline: true) # => false
shape6.contain?(39.5, 33.0, outline: true) # => false
shape6.contain?([39.5, 33.0], outline: true) # => false
shape5.contain?(2.0, 33.0, outline: true) # => true
shape5.contain?([2.0, 33.0], outline: true) # => true
shape6.contain?(2.0, 33.0, outline: true) # => true
shape6.contain?([2.0, 33.0], outline: true) # => true
shape5.contain?(3.0, 33.0, outline: true) # => false
shape5.contain?([3.0, 33.0], outline: true) # => false
shape6.contain?(3.0, 33.0, outline: true) # => false
shape6.contain?([3.0, 33.0], outline: true) # => false
shape5.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape5.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape6.contain?(3.0, 33.0, outline: true, distance_tolerance: 1.0) # => true
shape6.contain?([3.0, 33.0], outline: true, distance_tolerance: 1.0) # => true
shape5.contain?(shape5.center_x, shape5.center_y, outline: true) # => true
shape5.contain?([shape5.center_x, shape5.center_y], outline: true) # => true
shape6.contain?(shape6.center_x, shape6.center_y, outline: true) # => true
shape6.contain?([shape6.center_x, shape6.center_y], outline: true) # => true

PerfectShape::Ellipse

Class

Extends PerfectShape::Arc

• ::new(x: 0, y: 0, width: 1, height: 1, center_x: nil, center_y: nil, radius_x: nil, radius_y: nil): constructs an ellipse
• #x: top-left x
• #y: top-left y
• #width: width
• #height: height
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #radius_x: radius along the x-axis
• #radius_y: radius along the y-axis
• #type: always :open
• #start: always 0
• #extent: always 360
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select an ellipse shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing

Example:

require 'perfect-shape'

shape = PerfectShape::Ellipse.new(x: 2, y: 3, width: 50, height: 60)
shape2 = PerfectShape::Ellipse.new(center_x: 27, center_y: 33, radius_x: 25, radius_y: 30)

shape.contain?(27, 33) # => true
shape.contain?([27, 33]) # => true
shape2.contain?(27, 33) # => true
shape2.contain?([27, 33]) # => true
shape.contain?(27, 33, outline: true) # => false
shape.contain?([27, 33], outline: true) # => false
shape2.contain?(27, 33, outline: true) # => false
shape2.contain?([27, 33], outline: true) # => false
shape.contain?(2, 33, outline: true) # => true
shape.contain?([2, 33], outline: true) # => true
shape2.contain?(2, 33, outline: true) # => true
shape2.contain?([2, 33], outline: true) # => true
shape.contain?(1, 33, outline: true) # => false
shape.contain?([1, 33], outline: true) # => false
shape2.contain?(1, 33, outline: true) # => false
shape2.contain?([1, 33], outline: true) # => false
shape.contain?(1, 33, outline: true, distance_tolerance: 1) # => true
shape.contain?([1, 33], outline: true, distance_tolerance: 1) # => true
shape2.contain?(1, 33, outline: true, distance_tolerance: 1) # => true
shape2.contain?([1, 33], outline: true, distance_tolerance: 1) # => true

PerfectShape::Circle

Class

Extends PerfectShape::Ellipse

• ::new(x: 0, y: 0, diameter: 1, width: 1, height: 1, center_x: nil, center_y: nil, radius: nil, radius_x: nil, radius_y: nil): constructs a circle
• #x: top-left x
• #y: top-left y
• #diameter: diameter
• #width: width (equal to diameter)
• #height: height (equal to diameter)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #radius: radius
• #radius_x: radius along the x-axis (equal to radius)
• #radius_y: radius along the y-axis (equal to radius)
• #type: always :open
• #start: always 0
• #extent: always 360
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): checks if point is inside when outline is false or if point is on the outline when outline is true. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a circle shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing

Example:

require 'perfect-shape'

shape = PerfectShape::Circle.new(x: 2, y: 3, diameter: 60)
shape2 = PerfectShape::Circle.new(center_x: 2 + 30, center_y: 3 + 30, radius: 30)

shape.contain?(32, 33) # => true
shape.contain?([32, 33]) # => true
shape2.contain?(32, 33) # => true
shape2.contain?([32, 33]) # => true
shape.contain?(32, 33, outline: true) # => false
shape.contain?([32, 33], outline: true) # => false
shape2.contain?(32, 33, outline: true) # => false
shape2.contain?([32, 33], outline: true) # => false
shape.contain?(2, 33, outline: true) # => true
shape.contain?([2, 33], outline: true) # => true
shape2.contain?(2, 33, outline: true) # => true
shape2.contain?([2, 33], outline: true) # => true
shape.contain?(1, 33, outline: true) # => false
shape.contain?([1, 33], outline: true) # => false
shape2.contain?(1, 33, outline: true) # => false
shape2.contain?([1, 33], outline: true) # => false
shape.contain?(1, 33, outline: true, distance_tolerance: 1) # => true
shape.contain?([1, 33], outline: true, distance_tolerance: 1) # => true
shape2.contain?(1, 33, outline: true, distance_tolerance: 1) # => true
shape2.contain?([1, 33], outline: true, distance_tolerance: 1) # => true

PerfectShape::Polygon

Class

Extends PerfectShape::Shape

Includes PerfectShape::MultiPoint

A polygon can be thought of as a special case of path, consisting of lines only, is closed, and has the Even-Odd winding rule by default.

• ::new(points: [], winding_rule: :wind_even_odd): constructs a polygon with points as Array of Arrays of [x,y] pairs or flattened Array of alternating x and y coordinates and specified winding rule (:wind_even_odd or :wind_non_zero)
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): When outline is false, it checks if point is inside using either the Ray Casting Algorithm (aka Even-Odd Rule) or Winding Number Algorithm (aka Nonzero-Rule). Otherwise, when outline is true, it checks if point is on the outline. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a polygon shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #edges: edges of polygon as PerfectShape::Line objects

Example:

require 'perfect-shape'

shape = PerfectShape::Polygon.new(points: [[200, 150], [270, 170], [250, 220], [220, 190], [200, 200], [180, 170]])

shape.contain?(225, 185) # => true
shape.contain?([225, 185]) # => true
shape.contain?(225, 185, outline: true) # => false
shape.contain?([225, 185], outline: true) # => false
shape.contain?(200, 150, outline: true) # => true
shape.contain?([200, 150], outline: true) # => true
shape.contain?(200, 151, outline: true) # => false
shape.contain?([200, 151], outline: true) # => false
shape.contain?(200, 151, outline: true, distance_tolerance: 1) # => true
shape.contain?([200, 151], outline: true, distance_tolerance: 1) # => true

PerfectShape::Path

Class

Extends PerfectShape::Shape

Includes PerfectShape::MultiPoint

• ::new(shapes: [], closed: false, winding_rule: :wind_non_zero): constructs a path with shapes as Array of shape objects, which can be PerfectShape::Point (or Array of [x, y] coordinates), PerfectShape::Line, PerfectShape::QuadraticBezierCurve, or PerfectShape::CubicBezierCurve. If a path is closed, its last point is automatically connected to its first point with a line segment. The winding rule can be :wind_non_zero (default) or :wind_even_odd.
• #shapes: the shapes that the path is composed of (must always start with PerfectShape::Point or Array of [x,y] coordinates representing start point)
• #closed?: returns true if closed and false otherwise
• #winding_rule: returns winding rule (:wind_non_zero or :wind_even_odd)
• #points: path points calculated (derived) from shapes
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape (bounding box only guarantees that the shape is within it, but it might be bigger than the shape)
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): When outline is false, it checks if point is inside path utilizing the configured winding rule, which can be the Nonzero-Rule (aka Winding Number Algorithm) or the Even-Odd Rule (aka Ray Casting Algorithm). Otherwise, when outline is true, it checks if point is on the outline. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a path shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing
• #point_crossings(x_or_point, y=nil): calculates the number of times the given path crosses the ray extending to the right from (x,y)
• #disconnected_shapes: Disconnected shapes have their start point filled in so that each shape does not depend on the previous shape to determine its start point. Also, if a point is followed by a non-point shape, it is removed since it is augmented to the following shape as its start point. Lastly, if the path is closed, an extra shape is added to represent the line connecting the last point to the first

Example:

require 'perfect-shape'

path_shapes = []
path_shapes << PerfectShape::Point.new(x: 200, y: 150)
path_shapes << PerfectShape::Line.new(points: [250, 170]) # no need for start point, just end point
path_shapes << PerfectShape::QuadraticBezierCurve.new(points: [[300, 185], [350, 150]]) # no need for start point, just control point and end point
path_shapes << PerfectShape::CubicBezierCurve.new(points: [[370, 50], [430, 220], [480, 170]]) # no need for start point, just two control points and end point

shape = PerfectShape::Path.new(shapes: path_shapes, closed: false, winding_rule: :wind_even_odd)

shape.contain?(275, 165) # => true
shape.contain?([275, 165]) # => true
shape.contain?(275, 165, outline: true) # => false
shape.contain?([275, 165], outline: true) # => false
shape.contain?(shape.disconnected_shapes[1].curve_center_x, shape.disconnected_shapes[1].curve_center_y, outline: true) # => true
shape.contain?([shape.disconnected_shapes[1].curve_center_x, shape.disconnected_shapes[1].curve_center_y], outline: true) # => true
shape.contain?(shape.disconnected_shapes[1].curve_center_x + 1, shape.disconnected_shapes[1].curve_center_y, outline: true) # => false
shape.contain?([shape.disconnected_shapes[1].curve_center_x + 1, shape.disconnected_shapes[1].curve_center_y], outline: true) # => false
shape.contain?(shape.disconnected_shapes[1].curve_center_x + 1, shape.disconnected_shapes[1].curve_center_y, outline: true, distance_tolerance: 1) # => true
shape.contain?([shape.disconnected_shapes[1].curve_center_x + 1, shape.disconnected_shapes[1].curve_center_y], outline: true, distance_tolerance: 1) # => true

PerfectShape::CompositeShape

Class

Extends PerfectShape::Shape

A composite shape is simply an aggregate of multiple shapes (e.g. square and polygon)

• ::new(shapes: []): constructs a composite shape with shapes as Array of PerfectShape::Shape objects
• #shapes: the shapes that the composite shape is composed of
• #min_x: min x
• #min_y: min y
• #max_x: max x
• #max_y: max y
• #width: width (from min x to max x)
• #height: height (from min y to max y)
• #center_point: center point as Array of [center_x, center_y] coordinates
• #center_x: center x
• #center_y: center y
• #bounding_box: bounding box is a rectangle with x = min x, y = min y, and width/height of shape (bounding box only guarantees that the shape is within it, but it might be bigger than the shape)
• #==(other): Returns true if equal to other or false otherwise
• #contain?(x_or_point, y=nil, outline: false, distance_tolerance: 0): When outline is false, it checks if point is inside any of the shapes owned by the composite shape. Otherwise, when outline is true, it checks if point is on the outline of any of the shapes owned by the composite shape. distance_tolerance can be used as a fuzz factor when outline is true, for example, to help GUI users mouse-click-select a composite shape from its outline more successfully
• #intersect?(rectangle): Returns true if intersecting with interior of rectangle or false otherwise. This is useful for GUI optimization checks of whether a shape appears in a GUI viewport rectangle and needs redrawing

Example:

require 'perfect-shape'

shapes = []
shapes << PerfectShape::Square.new(x: 120, y: 215, length: 100)
shapes << PerfectShape::Polygon.new(points: [[120, 215], [170, 165], [220, 215]])

shape = PerfectShape::CompositeShape.new(shapes: shapes)

shape.contain?(170, 265) # => true inside square
shape.contain?([170, 265]) # => true inside square
shape.contain?(170, 265, outline: true) # => false
shape.contain?([170, 265], outline: true) # => false
shape.contain?(170, 315, outline: true) # => true
shape.contain?([170, 315], outline: true) # => true
shape.contain?(170, 316, outline: true) # => false
shape.contain?([170, 316], outline: true) # => false
shape.contain?(170, 316, outline: true, distance_tolerance: 1) # => true
shape.contain?([170, 316], outline: true, distance_tolerance: 1) # => true

shape.contain?(170, 190) # => true inside polygon
shape.contain?([170, 190]) # => true inside polygon
shape.contain?(170, 190, outline: true) # => false
shape.contain?([170, 190], outline: true) # => false
shape.contain?(145, 190, outline: true) # => true
shape.contain?([145, 190], outline: true) # => true
shape.contain?(145, 189, outline: true) # => false
shape.contain?([145, 189], outline: true) # => false
shape.contain?(145, 189, outline: true, distance_tolerance: 1) # => true
shape.contain?([145, 189], outline: true, distance_tolerance: 1) # => true

Process

Glimmer Process

Resources

• Rubydoc: https://www.rubydoc.info/gems/perfect-shape
• Point in Polygon: https://en.wikipedia.org/wiki/Point_in_polygon
• Even-Odd Rule: https://en.wikipedia.org/wiki/Even%E2%80%93odd_rule
• Nonzero Rule: https://en.wikipedia.org/wiki/Nonzero-rule
• IEEE 754-1985 Remainder: https://en.wikipedia.org/wiki/IEEE_754-1985

TODO

TODO.md

Change Log

CHANGELOG.md

Contributing

• Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet.
• Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it.
• Fork the project.
• Start a feature/bugfix branch.
• Commit and push until you are happy with your contribution.
• Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
• Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.

Copyright

MIT

Copyright (c) 2021-2022 Andy Maleh. See
LICENSE.txt for further details.