-- *****************************************************************************
--                              Geometric Functions                                
-- *****************************************************************************


--adjust point to the discretized grid used by the minimum path algorithm

function Adjust(x1,y1)

 local x2,y2
 local Ximg,Yimg,Xdim,Ydim,xOrg,yOrg
 local R

 R = Saaap.Project.r

 Ximg = Saaap.Project.Dimension.w
 Yimg = Saaap.Project.Dimension.h

 Xdim = floor((Ximg-1)/R+1);
 Ydim = floor((Yimg-1)/R+1);
 xOrg = floor((Ximg - R*(Xdim-1)-1)/2);
 yOrg = floor((Yimg - R*(Ydim-1)-1)/2); 
 x1   = floor((x1 - xOrg)/R);
 y1   = floor((y1 - yOrg)/R);

 if (x1<0) then 
     x1=0 
 end

 if (x1>Xdim-1) then
     x1=Xdim-1
 end

 if (y1<0) then 
     y1=0
 end 

 if (y1>Ydim-1) then
     y1=Ydim-1 
 end

 x2 = floor(xOrg + R*x1)
 y2 = floor(yOrg + R*y1)
 
 return x2,y2

end


function CalculateScale(imageWidth,imageHeight,mapWidth,mapHeight)

 local sx,sy

 sx = mapWidth/imageWidth
 sy = mapHeight/imageHeight

 return sx,sy

end


function Dist(x0,y0,x1,y1)

 local dist = sqrt((x1-x0)*(x1-x0)+(y1-y0)*(y1-y0))

 return dist

end


function IsEqual(x0,y0,x1,y1)

 local ok = 0

 if (Dist(x0,y0,x1,y1)<(2/Saaap.Project.ratio)) then
    
	 ok = 1

 end

 return ok

end

-- path pick functions

function isOnLine(x,y,x0,y0,x1,y1)

 local picked = 0
 local a,b,c
 local dist,lengh
 local t = {}

 t.x = x1-x0
 t.y = y1-y0

 lengh = sqrt(t.x*t.x+t.y*t.y)

 a =  t.y/lengh
 b = -t.x/lengh
 c = -(a*x1+b*y1)

 dist = a*x+b*y+c


 if (abs(dist)<(Saaap.Project.PickTol/Saaap.Project.ratio)) then 
--  if (abs(dist)<(Saaap.Project.PickTol)) then 


  local dx = x1-x0
  local dy = y1-y0
  local tol


  if (abs(dx)>abs(dy)) then
  
     ld  = (x-x0)/dx 
--	 tol = abs((Saaap.Project.PickTol)/dx)
   tol = abs((Saaap.Project.PickTol/Saaap.Project.ratio)/dx)

          
  else

     ld  = (y-y0)/dy
--	 tol = abs((Saaap.Project.PickTol)/dy)
   tol = abs((Saaap.Project.PickTol/Saaap.Project.ratio)/dy)
     
  end

--  print("dx "..dx)
--  print("dy "..dy)
--  print("tol"..tol)
--  print("ok")

  if (ld>=(-tol)) and (ld<=(1+tol)) then
      
     picked  = 1

  end

 end

 return picked

end


function PickPath(x,y,path)

local pck = 0
local ok  = 0
local i   = 0
local x0,y0,x1,y1

 i=1

 while (i<path.numPoints) do
    
   x0 = path.Points[i].x
   y0 = path.Points[i].y
   x1 = path.Points[i+1].x
   y1 = path.Points[i+1].y

   pck = isOnLine(x,y,x0,y0,x1,y1)

   if pck==1 then
	
     ok = 1
	   	   
   end

   i=i+1

 end

 return (ok)

end