此程序用到两个文件，一个是被调用程序affine.c，另一个是主程序cuoqie.c，在运行前请注意自己设置好图形驱动程序的路径。 affine.c如下： double sin(),cos();double xmax=639.0,ymax=399.0;double f[3][3],xx,yy; scx(xj)double xj;{int x; x=(int)(xj+xmax/2); return(x);} scy(yj)double yj;{int y; y=(int)(ymax-(yj+(ymax/2))); return(y);} parallel(dx,dy)double dx,dy;{f[0][0]=1.0;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=0.0;f[1][1]=1.0;f[1][2]=0.0; f[2][0]=dx;f[2][1]=dy;f[2][2]=1.0;} rotate(theta)double theta;{double th; th=theta/180*3.1415927; f[0][0]=cos(th);f[0][1]=sin(th);f[0][2]=0.0;f[1][0]=-sin(th); f[1][1]=cos(th);f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} scale(s)double s;{f[0][0]=s;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=0.0;f[1][1]=s;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} taisho_x(){f[0][0]=1.0;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=0.0;f[1][1]=-1;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} taisho_y(){f[0][0]=-1.0;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=0.0;f[1][1]=1.0;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} taisho_o(){f[0][0]=-1.0;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=0.0;f[1][1]=1.0;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} taisho_xy(){f[0][0]=0.0;f[0][1]=0.0;f[0][2]=0.0; f[1][0]=1.0;f[1][1]=0.0;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} taishl(aa,bb,cc)double aa,bb,cc;{float y,p; y=bb*bb-aa*aa; p=aa*aa+bb*bb; f[0][0]=-y/p;f[2][1]=-2*aa*bb/p;f[2][2]=0.0; f[1][0]=-2*aa*bb/p;f[1][1]=-y/p;f[1][2]=0.0; f[2][0]=-2*aa*cc/p;f[2][1]=-2*bb*cc/p;f[2][2]=1.0;} axis(){line(scx(0),scy(-ymax/2),scx(0),scy(ymax/2)); line(scx(-xmax/2),scy(0.0),scx(xmax/2),scy(0.0));} tuoq(a,b)double a,b;{f[0][0]=1.0;f[0][1]=b;f[0][2]=1.0; f[1][0]=a;f[1][1]=1.0;f[1][2]=0.0; f[2][0]=0.0;f[2][1]=0.0;f[2][2]=1.0;} affinex(x,y,d)double x,y,d;{xx=x*f[0][0]+y*f[1][0]+d*f[2][0]; return(xx);} affiney(x,y,d)double x,y,d;{yy=x*f[0][1]+y*f[1][1]+d*f[2][1]; return(yy);} cuoqie.c如下： #include<graphics.h>#include"affine.c" main(){int driver=DETECT,mode; static double x1[]={0.0,10.0,100.0,110.0,0.0}; static double y1[]={0.0,50.0,50.0,-10.0,0.0}; static double x2[5],y2[5]; int i; double x,xx,yy; registerbgidriver(EGAVGA_driver); initgraph(&driver,&mode,""); axis(); for(x=-300;x<=200;x=x+10) {parallel(x,x/2); for(i=0;i<=4;i++) {x2[i]=affinex(x1[i],y1[i],1.0); y2[i]=affiney(x1[i],y1[i],1.0)/2; } for(i=0;i<=3;i++) {line(scx(x2[i]),scy(y2[i]),scx(x2[i+1]),scy(y2[i+1])); } } getch(); closegraph();} 运行后将出现坐标系和一系列错切的四边形。
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