//-------------------------------------------------------------------------- // Copyright (C) 2004 Andrew Ross // Copyright (C) 2004-2014 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; version 2 of the License. // // 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 //-------------------------------------------------------------------------- // //-------------------------------------------------------------------------- // Implementation of PLplot example 4 in C++. //-------------------------------------------------------------------------- #include "plc++demos.h" #ifdef PL_USE_NAMESPACE using namespace std; #endif class x04 { public: x04( int, char ** ); void plot1( int ); private: // Class data plstream *pls; }; x04::x04( int argc, char ** argv ) { // plplot initialization pls = new plstream(); // Parse and process command line arguments. pls->parseopts( &argc, argv, PL_PARSE_FULL ); // Initialize PLplot. pls->init(); pls->font( 2 ); // Make log plots using two different styles. plot1( 0 ); plot1( 1 ); // pls->end(); delete pls; } // Log-linear plot. void x04::plot1( int type ) { int i; PLFLT *freql = new PLFLT[101]; PLFLT *ampl = new PLFLT[101]; PLFLT *phase = new PLFLT[101]; PLFLT f0, freq; PLINT nlegend; const char *text[2], *symbols[2]; PLINT opt_array[2]; PLINT text_colors[2]; PLINT line_colors[2]; PLINT line_styles[2]; PLFLT line_widths[2]; PLINT symbol_numbers[2], symbol_colors[2]; PLFLT symbol_scales[2]; PLFLT legend_width, legend_height; pls->adv( 0 ); // Set up data for log plot. f0 = 1.0; for ( i = 0; i <= 100; i++ ) { freql[i] = -2.0 + i / 20.0; freq = pow( 10.0, freql[i] ); ampl[i] = 20.0 * log10( 1.0 / sqrt( 1.0 + pow( ( freq / f0 ), 2. ) ) ); phase[i] = -( 180.0 / M_PI ) * atan( (PLFLT) ( freq / f0 ) ); } pls->vpor( 0.15, 0.85, 0.1, 0.9 ); pls->wind( -2.0, 3.0, -80.0, 0.0 ); // Try different axis and labelling styles. pls->col0( 1 ); switch ( type ) { case 0: pls->box( "bclnst", 0.0, 0, "bnstv", 0.0, 0 ); break; case 1: pls->box( "bcfghlnst", 0.0, 0, "bcghnstv", 0.0, 0 ); break; } // Plot ampl vs freq. pls->col0( 2 ); pls->line( 101, freql, ampl ); pls->col0( 2 ); pls->ptex( 1.6, -30.0, 1.0, -20.0, 0.5, "-20 dB/decade" ); // Put labels on. pls->col0( 1 ); pls->mtex( "b", 3.2, 0.5, 0.5, "Frequency" ); pls->mtex( "t", 2.0, 0.5, 0.5, "Single Pole Low-Pass Filter" ); pls->col0( 2 ); pls->mtex( "l", 5.0, 0.5, 0.5, "Amplitude (dB)" ); nlegend = 1; // For the gridless case, put phase vs freq on same plot. if ( type == 0 ) { pls->col0( 1 ); pls->wind( -2.0, 3.0, -100.0, 0.0 ); pls->box( "", 0.0, 0, "cmstv", 30.0, 3 ); pls->col0( 3 ); pls->line( 101, freql, phase ); pls->string( 101, freql, phase, "#(728)" ); pls->col0( 3 ); pls->mtex( "r", 5.0, 0.5, 0.5, "Phase shift (degrees)" ); nlegend = 2; } // Draw a legend // First legend entry. opt_array[0] = PL_LEGEND_LINE; text_colors[0] = 2; text[0] = "Amplitude"; line_colors[0] = 2; line_styles[0] = 1; line_widths[0] = 1.0; // note from the above opt_array the first symbol (and box) indices // do not have to be specified // Second legend entry. opt_array[1] = PL_LEGEND_LINE | PL_LEGEND_SYMBOL; text_colors[1] = 3; text[1] = "Phase shift"; line_colors[1] = 3; line_styles[1] = 1; line_widths[1] = 1.0; symbol_colors[1] = 3; symbol_scales[1] = 1.; symbol_numbers[1] = 4; symbols[1] = "#(728)"; // from the above opt_arrays we can completely ignore everything // to do with boxes. pls->scol0a( 15, 32, 32, 32, 0.70 ); pls->legend( &legend_width, &legend_height, PL_LEGEND_BACKGROUND | PL_LEGEND_BOUNDING_BOX, 0, 0.0, 0.0, 0.1, 15, 1, 1, 0, 0, nlegend, opt_array, 1.0, 1.0, 2.0, 1., text_colors, (const char * const *) text, NULL, NULL, NULL, NULL, line_colors, line_styles, line_widths, symbol_colors, symbol_scales, symbol_numbers, (const char **) symbols ); delete[] freql; delete[] ampl; delete[] phase; } int main( int argc, char ** argv ) { x04 *x = new x04( argc, argv ); delete x; } //-------------------------------------------------------------------------- // End of x04.cc //--------------------------------------------------------------------------