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! Illustration of logarithmic axes, and redefinition of window.
!
! Copyright (C) 2004-2016 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 Library General 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
! N.B. the pl_test_flt parameter used in this code is only
! provided by the plplot module to allow convenient developer
! testing of either kind(1.0) or kind(1.0d0) floating-point
! precision regardless of the floating-point precision of the
! PLplot C libraries. We do not guarantee the value of this test
! parameter so it should not be used by users, and instead user
! code should replace the pl_test_flt parameter by whatever
! kind(1.0) or kind(1.0d0) precision is most convenient for them.
! For further details on floating-point precision issues please
! consult README_precision in this directory.
!
program x04f
use plplot, double_PI => PL_PI
use plfortrandemolib
implicit none
real(kind=pl_test_flt), parameter :: PI = double_PI
real(kind=pl_test_flt) :: freql(0:100),ampl(0:100),phase(0:100)
integer :: plparseopts_rc
! Process command-line arguments
plparseopts_rc = plparseopts(PL_PARSE_FULL)
if(plparseopts_rc .ne. 0) stop "plparseopts error"
call plinit
call plfont(2)
! Make log plots using two different styles.
call plot1(0)
call plot1(1)
call plend
contains
subroutine plot1(type)
integer :: type
integer :: nlegend
real(kind=pl_test_flt) :: legend_width, legend_height
integer :: opt_array(2), text_colors(2), line_colors(2), &
line_styles(2), symbol_colors(2), symbol_numbers(2)
real(kind=pl_test_flt) :: line_widths(2), symbol_scales(2), box_scales(2)
integer :: box_colors(2), box_patterns(2)
real(kind=pl_test_flt) :: box_line_widths(2)
character(len=20) :: text(2)
character(len=20) :: symbols(2)
call pladv(0)
! Set up data for log plot.
call setdata
call plvpor(0.15_pl_test_flt, 0.85_pl_test_flt, 0.1_pl_test_flt, 0.9_pl_test_flt)
call plwind(-2.0_pl_test_flt, 3.0_pl_test_flt, -80.0_pl_test_flt, 0.0_pl_test_flt)
call plcol0(1)
! Try different axis and labelling styles.
if (type.eq.0) then
call plbox('bclnst', 0.0_pl_test_flt, 0, 'bnstv', 0.0_pl_test_flt, 0)
elseif (type.eq.1) then
call plbox('bcfghlnst', 0.0_pl_test_flt, 0, 'bcghnstv', 0.0_pl_test_flt, 0)
else
stop 'plot1: invalid type'
endif
! Plot ampl vs freq.
call plcol0(2)
call plline(freql,ampl)
call plcol0(2)
call plptex(1.6_pl_test_flt, -30.0_pl_test_flt, 1.0_pl_test_flt, -20.0_pl_test_flt, 0.5_pl_test_flt, &
'-20 dB/decade')
! Put labels on.
call plcol0(1)
call plmtex('b', 3.2_pl_test_flt, 0.5_pl_test_flt, 0.5_pl_test_flt, 'Frequency')
call plmtex('t', 2.0_pl_test_flt, 0.5_pl_test_flt, 0.5_pl_test_flt, &
'Single Pole Low-Pass Filter')
call plcol0(2)
call plmtex('l', 5.0_pl_test_flt, 0.5_pl_test_flt, 0.5_pl_test_flt, 'Amplitude (dB)')
nlegend = 1
! For the gridless case, put phase vs freq on same plot.
if(type == 0) then
call plcol0(1)
call plwind(-2.0_pl_test_flt, 3.0_pl_test_flt, -100.0_pl_test_flt, 0.0_pl_test_flt)
call plbox(' ', 0.0_pl_test_flt, 0, 'cmstv', 30.0_pl_test_flt, 3)
call plcol0(3)
call plline(freql, phase)
call plstring(freql, phase, "#(728)")
call plcol0(3)
call plmtex('r', 5.0_pl_test_flt, 0.5_pl_test_flt, 0.5_pl_test_flt, &
'Phase shift (degrees)')
nlegend = 2
endif
! Draw a legend
! First legend entry.
opt_array(1) = PL_LEGEND_LINE
text_colors(1) = 2
text(1) = 'Amplitude'
line_colors(1) = 2
line_styles(1) = 1
line_widths(1) = 1
! note from the above opt_array the first symbol (and box) indices
! do not have to be specified, at least in C. For Fortran we need
! to set the symbols to be something, since the string is always
! copied as part of the bindings.
symbols(1) = ''
! Second legend entry.
opt_array(2) = PL_LEGEND_LINE + PL_LEGEND_SYMBOL
text_colors(2) = 3
text(2) = 'Phase shift'
line_colors(2) = 3
line_styles(2) = 1
line_widths(2) = 1
symbol_colors(2) = 3
symbol_scales(2) = 1.0
symbol_numbers(2) = 4
symbols(2) = "#(728)"
! from the above opt_arrays we can completely ignore everything
! to do with boxes. (Hence the size 0 for the associated arrays)
call plscol0a( 15, 32, 32, 32, 0.70_pl_test_flt )
call pllegend( legend_width, legend_height, &
PL_LEGEND_BACKGROUND + PL_LEGEND_BOUNDING_BOX, 0, &
0.0_pl_test_flt, 0.0_pl_test_flt, 0.1_pl_test_flt, 15, &
1, 1, 0, 0, &
opt_array(1:nlegend), &
1.0_pl_test_flt, 1.0_pl_test_flt, 2.0_pl_test_flt, &
1.0_pl_test_flt, text_colors(1:nlegend), text(1:nlegend), &
box_colors(1:nlegend), box_patterns(1:nlegend), box_scales(1:nlegend), box_line_widths(1:nlegend), &
line_colors(1:nlegend), line_styles(1:nlegend), line_widths(1:nlegend), &
symbol_colors(1:nlegend), symbol_scales(1:nlegend), symbol_numbers(1:nlegend), symbols(1:nlegend) )
end subroutine plot1
subroutine setdata
real(kind=pl_test_flt), dimension(lbound(freql,1):ubound(freql,1)) :: freq
real(kind=pl_test_flt) :: f0
f0 = 1._pl_test_flt
freql = -2.0_pl_test_flt + arange(lbound(freql,1),ubound(freql,1)+1) / 20.0_pl_test_flt
freq = 10.0_pl_test_flt ** freql
ampl = 20.0_pl_test_flt * log10(1.0_pl_test_flt/sqrt(1.0_pl_test_flt+(freq/f0)**2))
phase = -(180.0_pl_test_flt/PI)*atan(freq/f0)
end subroutine setdata
end program x04f
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