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#----------------------------------------------------------------------------
# $Id: x03.tcl,v 1.12 2001/12/21 01:27:49 airwin Exp $
#----------------------------------------------------------------------------
proc x03 {{w loopback}} {
set twopi [expr 2. * 3.14159265358979323846]
# Set up viewport and window, but do not draw box
$w cmd plenv -1.3 1.3 -1.3 1.3 1 -2
# Draw circles for polar grid
set ni 10
set nj 360
set nj1 [expr $nj + 1]
set dr [expr 1. / $ni]
set dtheta [expr $twopi / $nj]
matrix xj f $nj1
matrix yj f $nj1
for {set i 1} {$i <= $ni} {incr i} {
for {set j 0} {$j < $nj1} {incr j} {
set r [expr $i * $dr]
set theta [expr $j * $dtheta]
xj $j = [expr $r * cos($theta)]
yj $j = [expr $r * sin($theta)]
}
$w cmd plline $nj1 xj yj
}
# Draw radial spokes for polar grid and write labels for angle
$w cmd plcol0 2
for {set j 0} {$j <= 11} {incr j} {
set theta [expr $j * $twopi / 12.]
set xg [expr cos($theta)]
set yg [expr sin($theta)]
$w cmd pljoin 0.0 0.0 $xg $yg
# Slightly off zero to avoid floating point logic flips at 90 and 270 deg.
if {$xg >= -0.00001} {
set dx $xg
set dy $yg
set just -0.15
} else {
set dx [expr -$xg]
set dy [expr -$yg]
set just 1.15
}
set label [expr round($theta*360./$twopi)]
# N.B. cannot get this command to give same postscript output. Also visual
# inspection shows 90 deg label jumping around slightly compared to python
# and C front ends. No idea why (AWI comment).
$w cmd plptex $xg $yg $dx $dy $just $label
}
# Draw the graph
set npts 360
set npts1 [expr $npts+1]
set dtheta [expr $twopi / $npts]
matrix x f $npts1
matrix y f $npts1
for {set j 0} {$j <= $npts} {incr j} {
set theta [expr $j * $dtheta]
set r [expr sin(5 * $theta)]
x $j = [expr $r * cos($theta)]
y $j = [expr $r * sin($theta)]
}
$w cmd plcol0 3
$w cmd plline $npts1 x y
$w cmd plcol0 4
$w cmd plmtex "t" 2.0 0.5 0.5 "#frPLplot Example 3 - r(#gh)=sin 5#gh"
# Restore defaults
$w cmd plcol0 1
}
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