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Manual Reference Pages  - poly2 (3)

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NAME

poly2(3f) - [M_pixel:POLYGONS] construct a polygon from an array of points (LICENSE:PD)

CONTENTS

Synopsis
Description
Example
Author
License

SYNOPSIS

definition:

   subroutine poly2(n, points)
   integer,intent(in) :: n
   real,intent(in)    :: points(2, n)

DESCRIPTION

Construct a polygon from an array of points

EXAMPLE

Sample program:

   program demo_poly2
   use M_pixel
   use M_writegif, only : writegif
   implicit none
   integer :: i, j, icolor
   real    :: xx, yy
      call prefsize(512,512)
      call vinit()
      call ortho2(0.0,256.0,0.0,256.0)
      call linewidth(1)
      ! 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
      call writegif(’poly2.3m_pixel.gif’,P_pixel,P_colormap)
      call vexit()
   contains

   subroutine setcolor(iset,xx,yy)
   use M_pixel,  only : i2s
   use M_pixel,  only : color_name2rgb
   integer,intent(in) :: iset
   real,intent(in)    :: xx,yy
   character(len=80)  :: echoname
   real               :: points(2,100)
   real               :: 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 nice RGB values to try from named colors known by M_pixel module
      call color_name2rgb(i2s(icolor),red,green,blue,echoname)
      if(echoname.eq.’Unknown’) return
      ! set a color number to the new RGB values
      write(*,*)icolor, nint(red*2.55), nint(green*2.55), nint(blue*2.55),trim(echoname)
      call mapcolor(icolor, nint(red*2.55), nint(green*2.55), nint(blue*2.55))
      ! set to the new color
      call color(icolor)
      ! fill the rectangle in that color
      call poly2(5,points)
   end subroutine setcolor

   end program demo_poly2

AUTHOR

John S. Urban

LICENSE

Public Domain

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poly2 (3)

March 11, 2021

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