-- This file:
--   http://anggtwu.net/LUA/Tracinhos1.lua.html
--   http://anggtwu.net/LUA/Tracinhos1.lua
--          (find-angg "LUA/Tracinhos1.lua")
-- Author: Eduardo Ochs <eduardoochs@gmail.com>
--
-- (defun e () (interactive) (find-angg "LUA/Tracinhos1.lua"))
-- Supersedes:
--   (find-angg "LUA/Pict2e1-1.lua")

-- «.Tracinhos»			(to "Tracinhos")
-- «.Tracinhos-test»		(to "Tracinhos-test")

require "Pict3"       -- (find-angg "LUA/Pict3.lua")
require "Piecewise2"  -- (find-angg "LUA/Piecewise2.lua")

local v = MiniV.fromab

--  _____               _       _               
-- |_   _| __ __ _  ___(_)_ __ | |__   ___  ___ 
--   | || '__/ _` |/ __| | '_ \| '_ \ / _ \/ __|
--   | || | | (_| | (__| | | | | | | | (_) \__ \
--   |_||_|  \__,_|\___|_|_| |_|_| |_|\___/|___/
--                                              
-- «Tracinhos»  (to ".Tracinhos")
Tracinhos = Class {
  type = "Tracinhos",
  new = function (r)
      r = r or 0.2
      return Tracinhos { r=r, p=Pict {} }
    end,
  from = function (r, f)
      return Tracinhos.new(r):setf(f):drawf()
    end,
  __index = {
    setf = function (tr, f)
        if type(f) == "string" then f = Code.ve("x,y => "..f) end
        tr.f = f
        return tr
      end,
    v = function (tr, Dy, Dx)
        Dx = Dx or 1
        if Dx == 0 then
          if Dy == 0 then return nil end
          return v(0, tr.r)
        end
        local v0 = v(Dx, Dy)
        local v1 = v0 * (1 / v0:norm())
        local v2 = v1 * tr.r
        return v2
      end,
    tracinho = function (tr, xy, Dy, Dx)
        local vv = tr:v(Dy, Dx)
        if not vv then return tr end
        tr.p:addline(xy-vv, xy+vv)
      end,
    drawfxy0 = function (tr,x,y) return tr.f(x,y) end,
    drawfxy  = function (tr,x,y) tr:tracinho(v(x,y), tr.f(x,y)) end,
    drawf    = function (tr)
        for y=2,-2,-1 do
          for x=-2,2 do
            tr:drawfxy(x,y)
          end
        end
        return tr
      end,
    show0 = function (tr) return tr.p:pgat("pNc") end,
    show  = function (tr) return tr.p:pgat("pNc"):show("") end,
  },
}

-- «Tracinhos-test»  (to ".Tracinhos-test")
--[==[
** (find-code-show2 "~/LATEX/Show2.tex")
*       (code-show2 "~/LATEX/Show2.tex")
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Tracinhos1.lua"
tr = Tracinhos.new(0.2)
PictBounds.setbounds(v(-2,-2), v(2,2))
for y=2,-2,-1 do
  for x=-2,2 do
    tr:tracinho(v(x,y), -y, x)
  end
end
= tr.p:pgat("pN"):show("")
* (etv)

** (find-code-show2 "~/LATEX/Show2.tex")
*       (code-show2 "~/LATEX/Show2.tex")
* (eepitch-lua51)
* (eepitch-kill)
* (eepitch-lua51)
dofile "Tracinhos1.lua"
PictBounds.setbounds(v(-2,-2), v(2,2))
tr = Tracinhos.from(0.2, "1,x")
=    Tracinhos.from(0.2, "1,x"):show0()
=    Tracinhos.from(0.2, "1,x"):show()
* (etv)

=    Tracinhos.from(0.2, "-y,x"):show()
* (etv)

=    Tracinhos.from(0.2, "-x,y"):show()
* (etv)

=    Tracinhos.from(0.2, "x,y"):show()
* (etv)

=    Tracinhos.from(0.2, "x+y,2"):show()
* (etv)

--]==]




-- Local Variables:
-- coding:  utf-8-unix
-- End: