void draw_page( PLINT mode, const char *title )
{
PLFLT xs[3], ys[3];
PLFLT over_x, over_y, over_r;
// A triangle for the background
xs[0] = 0.0;
xs[1] = 1.0;
xs[2] = 0.0;
ys[0] = 0.0;
ys[1] = 1.0;
ys[2] = 1.0;
// A circle for the foreground
over_x = 0.5;
over_y = 0.5;
over_r = 0.4;
plcol0( 1 );
// Setup a plot window
plenv( 0.0, 1.0, 0.0, 1.0, 1, 0 );
// Show which mode we're using
pllab( "", "", title );
// Draw a background triangle using the default drawing mode
plcol0( 2 );
plsdrawmode( PL_DRAWMODE_DEFAULT );
plfill( 3, xs, ys );
// Draw a circle in the given drawing mode
plcol0( 3 );
plsdrawmode( mode );
plarc( over_x, over_y, over_r, over_r, 0.0, 360.0, 0.0, 1 );
}
int
main( int argc, const char *argv[] )
{
int i;
PLFLT dtr, theta, dx, dy, r, offset;
char text[4];
static PLFLT x0[361], y0[361];
static PLFLT x[361], y[361];
dtr = M_PI / 180.0;
for ( i = 0; i <= 360; i++ )
{
x0[i] = cos( dtr * i );
y0[i] = sin( dtr * i );
}
// Parse and process command line arguments
(void) plparseopts( &argc, argv, PL_PARSE_FULL );
// Set orientation to portrait - note not all device drivers
// support this, in particular most interactive drivers do not
plsori( 1 );
// Initialize plplot
plinit();
// Set up viewport and window, but do not draw box
plenv( -1.3, 1.3, -1.3, 1.3, 1, -2 );
// Draw circles for polar grid
for ( i = 1; i <= 10; i++ )
{
plarc( 0.0, 0.0, 0.1 * i, 0.1 * i, 0.0, 360.0, 0.0, 0 );
}
plcol0( 2 );
for ( i = 0; i <= 11; i++ )
{
theta = 30.0 * i;
dx = cos( dtr * theta );
dy = sin( dtr * theta );
// Draw radial spokes for polar grid
pljoin( 0.0, 0.0, dx, dy );
sprintf( text, "%d", ROUND( theta ) );
// Write labels for angle
if ( theta < 9.99 )
{
offset = 0.45;
}
else if ( theta < 99.9 )
{
offset = 0.30;
}
else
{
offset = 0.15;
}
// Slightly off zero to avoid floating point logic flips at 90 and 270 deg.
if ( dx >= -0.00001 )
plptex( dx, dy, dx, dy, -offset, text );
else
plptex( dx, dy, -dx, -dy, 1. + offset, text );
}
// Draw the graph
for ( i = 0; i <= 360; i++ )
{
r = sin( dtr * ( 5 * i ) );
x[i] = x0[i] * r;
y[i] = y0[i] * r;
}
plcol0( 3 );
plline( 361, x, y );
plcol0( 4 );
plmtex( "t", 2.0, 0.5, 0.5, "#frPLplot Example 3 - r(#gh)=sin 5#gh" );
// Close the plot at end
plend();
exit( 0 );
}
