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Diffstat (limited to 'graphics/pgf/base/tex/generic/graphdrawing/lua/pgf/gd/model/Coordinate.lua')
-rw-r--r-- | graphics/pgf/base/tex/generic/graphdrawing/lua/pgf/gd/model/Coordinate.lua | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/graphics/pgf/base/tex/generic/graphdrawing/lua/pgf/gd/model/Coordinate.lua b/graphics/pgf/base/tex/generic/graphdrawing/lua/pgf/gd/model/Coordinate.lua new file mode 100644 index 0000000000..3a4448ab08 --- /dev/null +++ b/graphics/pgf/base/tex/generic/graphdrawing/lua/pgf/gd/model/Coordinate.lua @@ -0,0 +1,306 @@ +-- Copyright 2012 by Till Tantau +-- +-- This file may be distributed an/or modified +-- +-- 1. under the LaTeX Project Public License and/or +-- 2. under the GNU Public License +-- +-- See the file doc/generic/pgf/licenses/LICENSE for more information + +-- @release $Header$ + + +--- +-- A Coordinate models a position on the drawing canvas. +-- +-- It has an |x| field and a |y| field, which are numbers that will be +-- interpreted as \TeX\ points (1/72.27th of an inch). The $x$-axis goes +-- right and the $y$-axis goes up. +-- +-- @field x +-- @field y +-- +-- There is also a static field called |origin| that is always equal to the origin. + +local Coordinate = {} +Coordinate.__index = Coordinate + + +-- Namespace + +require("pgf.gd.model").Coordinate = Coordinate + + + + +--- Creates a new coordinate. +-- +-- @param x The $x$ value +-- @param y The $y$ value +-- +-- @return A coordinate +-- +function Coordinate.new(x,y) + return setmetatable( {x=x, y=y}, Coordinate) +end + + +Coordinate.origin = Coordinate.new(0,0) + + +--- Creates a new coordinate that is a copy of an existing one. +-- +-- @return A new coordinate at the same location as |self| +-- +function Coordinate:clone() + return setmetatable( { x = self.x, y = self.y }, Coordinate) +end + + + +--- Apply a transformation matrix to a coordinate, +-- see |pgf.gd.lib.Transform| for details. +-- +-- @param t A transformation. + +function Coordinate:apply(t) + local x = self.x + local y = self.y + self.x = t[1]*x + t[2]*y + t[5] + self.y = t[3]*x + t[4]*y + t[6] +end + + +--- Shift a coordinate +-- +-- @param a An $x$ offset +-- @param b A $y$ offset + +function Coordinate:shift(a,b) + self.x = self.x + a + self.y = self.y + b +end + + +--- +-- ``Unshift'' a coordinate (which is the same as shifting by the +-- inversed coordinate; only faster). +-- +-- @param a An $x$ offset +-- @param b A $y$ offset + +function Coordinate:unshift(a,b) + self.x = self.x - a + self.y = self.y - b +end + + +--- +-- Like |shift|, only for coordinate parameters. +-- +-- @param c Another coordinate. The $x$- and $y$-values of |self| are +-- increased by the $x$- and $y$-values of this coordinate. + +function Coordinate:shiftByCoordinate(c) + self.x = self.x + c.x + self.y = self.y + c.y +end + + +--- +-- Like |unshift|, only for coordinate parameters. +-- +-- @param c Another coordinate. + +function Coordinate:unshiftByCoordinate(c) + self.x = self.x - c.x + self.y = self.y - c.y +end + + +--- +-- Moves the coordinate a fraction of |f| along a straight line to |c|. +-- +-- @param c Another coordinate +-- @param f A fraction + +function Coordinate:moveTowards(c,f) + self.x = self.x + f*(c.x-self.x) + self.y = self.y + f*(c.y-self.y) +end + + + +--- Scale a coordinate by a factor +-- +-- @param s A factor. + +function Coordinate:scale(s) + self.x = s*self.x + self.y = s*self.y +end + + + + +--- +-- Add two coordinates, yielding a new coordinate. Note that it will +-- be a lot faster to call shift, whenever this is possible. +-- +-- @param a A coordinate +-- @param b A coordinate + +function Coordinate.__add(a,b) + return setmetatable({ x = a.x + b.x, y = a.y + b.y }, Coordinate) +end + + +--- +-- Subtract two coordinates, yielding a new coordinate. Note that it will +-- be a lot faster to call unshift, whenever this is possible. +-- +-- @param a A coordinate +-- @param b A coordinate + +function Coordinate.__sub(a,b) + return setmetatable({ x = a.x - b.x, y = a.y - b.y }, Coordinate) +end + + +--- +-- The unary minus (mirror the coordinate against the origin). +-- +-- @param a A coordinate + +function Coordinate.__unm(a) + return setmetatable({ x = - a.x, y = - a.y }, Coordinate) +end + + +--- +-- The multiplication operator. Its effect depends on the parameters: +-- If both are coordinates, their dot-product is returned. If exactly +-- one of them is a coordinate and the other is a number, the scalar +-- multiple of this coordinate is returned. +-- +-- @param a A coordinate or a scalar +-- @param b A coordinate or a scalar +-- @return The dot product or scalar product. + +function Coordinate.__mul(a,b) + if getmetatable(a) == Coordinate then + if getmetatable(b) == Coordinate then + return a.x * b.x + a.y * b.y + else + return setmetatable({ x = a.x * b, y = a.y *b }, Coordinate) + end + else + return setmetatable({ x = a * b.x, y = a * b.y }, Coordinate) + end +end + +--- +-- The division operator. Returns the scalar division of a coordinate +-- by a scalar. +-- +-- @param a A coordinate +-- @param b A scalar (not equal to zero). +-- @return The scalar product or a * (1/b). + +function Coordinate.__div(a,b) + return setmetatable({ x = a.x / b, y = a.y / b }, Coordinate) +end + + +--- +-- The norm function. Returns the norm of a coordinate. +-- +-- @param a A coordinate +-- @return The norm of the coordinate + +function Coordinate:norm() + return math.sqrt(self.x * self.x + self.y * self.y) +end + + +--- +-- Normalize a vector: Ensure that it has length 1. If the vector used +-- to be the 0-vector, it gets replaced by (1,0). +-- + +function Coordinate:normalize() + local x, y = self.x, self.y + if x == 0 and y == 0 then + self.x = 1 + else + local norm = math.sqrt(x*x+y*y) + self.x = x / norm + self.y = y / norm + end +end + + +--- +-- Normalized version of a vector: Like |normalize|, only the result is +-- returned in a new vector. +-- +-- @return Normalized version of |self| + +function Coordinate:normalized() + local x, y = self.x, self.y + if x == 0 and y == 0 then + return setmetatable({ x = 1, y = 0 }, Coordinate) + else + local norm = math.sqrt(x*x+y*y) + return setmetatable({ x = x/norm, y = y/norm }, Coordinate) + end +end + + + +--- +-- Compute a bounding box around an array of coordinates +-- +-- @param array An array of coordinates +-- +-- @return |min_x| The minimum $x$ value of the bounding box of the array +-- @return |min_y| The minimum $y$ value +-- @return |max_x| +-- @return |max_y| +-- @return |center_x| The center of the bounding box +-- @return |center_y| + +function Coordinate.boundingBox(array) + if #array > 0 then + local min_x, min_y = math.huge, math.huge + local max_x, max_y = -math.huge, -math.huge + + for i=1,#array do + local c = array[i] + local x = c.x + local y = c.y + if x < min_x then min_x = x end + if y < min_y then min_y = y end + if x > max_x then max_x = x end + if y > max_y then max_y = y end + end + + return min_x, min_y, max_x, max_y, (min_x+max_x) / 2, (min_y+max_y) / 2 + end +end + + + + +-- Returns a string representation of an arc. This is mainly for debugging +-- +-- @return The Arc as string. +-- +function Coordinate:__tostring() + return "(" .. self.x .. "pt," .. self.y .. "pt)" +end + + +-- Done + +return Coordinate
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