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! $Id: x03f.f90,v 1.1 2006/05/16 20:24:12 airwin Exp $
! Generates polar plot with, 1-1 scaling
!
! Copyright (C) 2004 Alan W. Irwin
!
! This file is part of PLplot.
!
! PLplot is free software; you can redistribute it and/or modify
! it under the terms of the GNU General Library Public License as
! published by the Free Software Foundation; either version 2 of the
! License, or (at your option) any later version.
!
! PLplot is distributed in the hope that it will be useful,
! but WITHOUT ANY WARRANTY; without even the implied warranty of
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
! GNU Library General Public License for more details.
!
! You should have received a copy of the GNU Library General Public
! License along with PLplot; if not, write to the Free Software
! Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
use plplot, PI => PL_PI
implicit none
character*3 text
real(kind=plflt) x0(0:360), y0(0:360)
real(kind=plflt) x(0:360), y(0:360), dtr, theta, dx, dy, r
integer i, j, nsp
! Process command-line arguments
call plparseopts(PL_PARSE_FULL)
dtr = PI/180.0_plflt
do i=0,360
x0(i) = cos(dtr * dble (i))
y0(i) = sin(dtr * dble (i))
enddo
! Initialize PLplot
call plinit()
! Set up viewport and window, but do not draw box
call plenv(-1.3_plflt, 1.3_plflt, -1.3_plflt, 1.3_plflt, 1, -2)
do i = 1,10
do j = 0,360
x(j) = 0.1_plflt*i*x0(j)
y(j) = 0.1_plflt*i*y0(j)
enddo
! Draw circles for polar grid
call plline(x,y)
enddo
call plcol0(2)
do i = 0,11
theta = 30.0_plflt*i
dx = cos(dtr*theta)
dy = sin(dtr*theta)
! Draw radial spokes for polar grid
call pljoin(0.0_plflt, 0.0_plflt, dx, dy)
write (text,'(i3)') nint(theta)
! Write labels for angle
text = text(nsp(text):)
! Slightly off zero to avoid floating point logic flips at
! 90 and 270 deg.
if (dx.ge.-0.00001_plflt) then
call plptex(dx, dy, dx, dy, -0.15_plflt, text)
else
call plptex(dx, dy, -dx, -dy, 1.15_plflt, text)
end if
enddo
! Draw the graph
do i=0,360
r = sin(dtr*dble (5*i))
x(i) = x0(i) * r
y(i) = y0(i) * r
enddo
call plcol0(3)
call plline(x,y)
call plcol0(4)
call plmtex('t', 2.0_plflt, 0.5_plflt, 0.5_plflt, &
'#frPLplot Example 3 - r(#gh)=sin 5#gh')
! Close the plot at end
call plend
end
integer function nsp(text)
! ==================
! Find first non-space character
use plplot
implicit none
character*(*) text
integer l, len
l = len(text)
nsp = 1
do while(text(nsp:nsp).eq.' ' .and. nsp.lt.l)
nsp = nsp+1
enddo
end
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