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C Library Functions  - poly2 (3)

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NAME

poly2(3f) - [M_draw:POLYGONS] Construct an (x, y) polygon from an array of points (LICENSE:PD)

CONTENTS

Synopsis
Description
Examples

SYNOPSIS

subroutine poly2(n, points)

     integer,intent(in) :: n
     real,intent(in) :: points(2, n)

DESCRIPTION

Construct an (x, y) polygon from an array of points provided by the user.

EXAMPLES

Sample program:

     program demo_poly2
     use M_draw
     implicit none
     integer :: i,j
     integer :: ipaws, icolor
     real    :: xx,yy
        call prefsize(512,512)
        call vinit(’ ’) ! start graphics using device $M_DRAW_DEVICE
        call ortho2(0.0,256.0,0.0,256.0)
        call linewidth(1)
        call polyfill(.true.)
        ! step thru a series of rectangular cells
        icolor=0
        xx=0.0
        do i=1,16
           yy=0.0
           do j=1,16
              yy=yy+16.0
              icolor=icolor+1
              call setcolor(icolor,xx,yy)
           enddo
           xx=xx+16.0
        enddo
        ipaws=getkey()
        call vexit()
     contains

     subroutine setcolor(iset,xx,yy)
     integer,intent(in) :: iset
     real,intent(in)    :: xx,yy
     real    :: points(2,100)
     integer :: red, green, blue
     if(iset.gt.255)return
     ! determine coordinates of next square
     points(1:2,1)=[xx,      yy      ]
     points(1:2,2)=[xx,      yy+16.0 ]
     points(1:2,3)=[xx+16.0, yy+16.0 ]
     points(1:2,4)=[xx+16.0, yy      ]
     points(1:2,5)=[xx,      yy      ]
     ! get some RGB values to try
     red=irand(0,255)
     green=irand(0,255)
     blue=irand(0,255)
     ! set a color number to the new RGB values
     call mapcolor(icolor, red, green, blue)
     ! set to the new color
     call color(icolor)
     ! fill the rectangle in that color
     call poly2(5,points)
     end subroutine setcolor

     function irand(first,last) result(rand_int)
     use, intrinsic :: iso_fortran_env, only : dp=>real64
     integer,intent(in) :: first
     integer,intent(in) :: last
     integer              :: rand_int
     real(kind=dp)        :: rand_val
        call random_number(rand_val)
        rand_int = first + FLOOR((last+1-first)*rand_val)
     end function irand

     end program demo_poly2

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Nemo Release 3.1

poly2 (3)

February 23, 2025

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