// uniformly illuminated parabolic dish, beam // // compile with: cc -o adish03 adish03.c -lgd -lpng -lm # define NAME "adish03" // // Uses the libgd library. For documentation see the file: // /usr/share/doc/gd-*/index.html // or the website: http://www.libgd.org/Reference // // You will need truetype fonts, "apt search dejavu" returns // fonts-dejavu-core/focal,focal,now 2.37-1 all [installed,automatic] // // Uses /usr/local/bin/apngasm to make APNG animation from frames // /home/keithl/src/apngasm/apngasm-2.91-src.zip // // now uses j1 function and math.h // // This constructs 30 images then dups them forward and reverse. #include "gd.h" #include "math.h" #include #include #include #define RMMKDIR "rm -rf adish03dir ; mkdir adish03dir" #define PNG2APNG "/usr/local/bin/apngasm adish03.png adish03dir/* 1 10" #define PNGFMT "adish03dir/a%04d.png" #define YCENT 130 #define INTPTS 100 // integration points #define WAVELENGTH 86.0 // radio wavelength in pixel units #define SCALE 200.0 // disk scaling in pixel units #define NPICS 40 // number of frames #define XSIZE 1000 // display window in pixels #define YSIZE 750 // display window in pixels #define FNT "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf" #define FSZ 10 double amult[XSIZE][YSIZE] ; // double aphase[XSIZE][YSIZE] ; // double behind[XSIZE][YSIZE] ; // // ========================================================================== int main() { gdImagePtr im ; // pixel image map used by gd gdPoint beam[4] ; // trapezoidal output beam double lambda = WAVELENGTH ; // double scale = (double) SCALE ; // dish scale double yacent = (double) YCENT ; // center of upper drawing double xsize = (double) XSIZE ; // width of pixels double ysize = (double) YSIZE ; // height of pixels int ybot = 2*YCENT ; // top of output pixel array double dybot = (double) ybot ; // real "" double pi2 = 8.0*atan(1.0) ; // two times PI double d2r = pi2/360.0 ; // degrees to radians conversion factor int oxc = XSIZE/2 ; // center of output pixel array int oyc = YSIZE/2 ; // center of output pixel array double xacent = (double) oxc ; // real "" int brect[8] ; // this returns an (ignored) bounding box FILE *pngout ; // file handle for PNG output frame char dirname[200] ; // frame output directory char framename[200] ; // directory/name of frame char labstring[200] ; // used for labellin char rmmkdir[200] ; // remove and make frame directory char link0[200] ; // directory/name of source char link1[200] ; // directory/name of target hardlink int black, sun1, white, red ; // color map numbers int green, blue, gray ; // color map numbers int dgray, trans ; // color map numbers int bcolor[256] ; // color map numbers int gcolor[256] ; // color map numbers int ox, oy ; // output pixel position int oxm ; // int i ; // general counter int fs ; // big label font size int cir ; // double dcir ; // int icolor ; // int jcolor ; // int mag ; // pixel magnitude, 0-255 int frame ; // animation frame count int pct=0 ; // percentage of complete frame int pct0=0 ; // previous percentage int ya= YCENT ; // antenna height double bx ; // bessel argument double j ; // double j0 ; // double ffrac ; // frame scaling of variable, 0 to 1 double phase ; // phase double k=pi2/lambda ; // wavenumber double oxd ; // double oxd2 ; // double oyd ; // double oyd2 ; // double oym ; // double dis ; // distance from focus spot double dis2 ; // int rate = 20 ; // swf rate double xm ; // double max ; // normalize beam amplitude double norm ; // normalize beam amplitude double delta ; // double sumsin ; // double sumcos ; // double sum ; // double adis ; // double amp[INTPTS] ; // double dn, da, di ; // // set up target directory system( RMMKDIR ); // make array amplitude values ------------------------------------------ for( i=0 ; i dcir ) { sum = sqrt( sumsin*sumsin + sumcos*sumcos ) ; // normalization kludge !!! sum *= oym*sqrt(oxd*oxd + oyd*oyd); amult[ox][oy] = sum ; aphase[ox][oy] = atan2( sumsin, sumcos ); if( max < sum ) { max = sum ; } } else { amult[ox][oy] = 0.0 ; aphase[ox][oy] = 0.0 ; } } } // normalize and mirror norm = 1.0 / max ; for( oy=0 ; oy 1.0 ) { j= 1.0; } if( j < -1.0 ) { j=-1.0; } mag = (int) ( 127.5*(1.0 + j )); gdImageSetPixel( im, ox, oy, gcolor[mag] ) ; } } // labels ----------------------------------------------------------------- fs= ybot/6 ; gdImageStringTTF( im, brect, // imagespace, bounding box white , FNT, fs, 0.0, // color, font, fontsize, angle 15 , fs+15 , // x, y "Dish Antenna" ); // text // draw dish -------------------------------------------------------------- jcolor = bcolor[255] ; // disk gdImageFilledEllipse( im, oxc, ya, 4*cir, cir, jcolor ); // square feed beam[0].x = oxc+6 ; beam[0].y = ya+cir-1 ; beam[1].x = oxc-6 ; beam[1].y = ya+cir-1 ; beam[2].x = oxc-6 ; beam[2].y = ya+cir+15 ; beam[3].x = oxc+6 ; beam[3].y = ya+cir+15 ; gdImageFilledPolygon( im, beam, 4, jcolor ); // feed struts gdImageLine( im, oxc-2*cir, ya, oxc, ya+cir, jcolor ); gdImageLine( im, oxc+2*cir, ya, oxc, ya+cir, jcolor ); gdImageLine( im, oxc, ya, oxc, ya+cir, jcolor ); // labels on array ------------------------------------------------------- fs= ybot/8 ; gdImageStringTTF( im, brect, // imagespace, bounding box white , FNT, fs, 0.0, // color, font, fontsize, angle 15, YSIZE-15, // x, y "Ground Pattern" ); // text // output the frame ------------------------------------------------------ sprintf( framename, PNGFMT , frame ); pngout = fopen( framename, "wb"); gdImagePngEx( im, pngout, 1 ); gdImageDestroy(im); fclose(pngout); } // end of single frame loop printf( "frames complete, now run\n"); printf( "%s\n", PNG2APNG ); }