// A C++ program to illustrate the implementation of Scaling Transformation. //--------------------------- Header Files ----------------------------// # include <iostream.h> # include <graphics.h> # include <conio.h> # include <math.h> //----------------------- Function Prototypes -------------------------// void show_screen( ); void apply_scaling(const int,int [],const float,const float); void multiply_matrices(const float[3],const float[3][3],float[3]); void Polygon(const int,const int []); void Line(const int,const int,const int,const int); //------------------------------ main( ) ------------------------------// int main( ) { int driver=VGA; int mode=VGAHI; initgraph(&driver,&mode,"..\\Bgi"); show_screen( ); int polygon_points[10]={ 270,290, 270,190, 370,190, 370,290, 270,290 }; setcolor(15); Polygon(5,polygon_points); setcolor(15); settextstyle(0,0,1); outtextxy(50,415,"*** Use '+' and '-' Keys to apply Scaling."); int key_code=0; char Key=NULL; do { Key=NULL; key_code=0; Key=getch( ); key_code=int(Key); if(key_code==0) { Key=getch( ); key_code=int(Key); } if(key_code==27) break; else if(key_code==43) { setfillstyle(1,0); bar(40,70,600,410); apply_scaling(5,polygon_points,1.1,1.1); setcolor(10); Polygon(5,polygon_points); } else if(key_code==45) { setfillstyle(1,0); bar(40,70,600,410); apply_scaling(5,polygon_points,0.9,0.9); setcolor(12); Polygon(5,polygon_points); } } while(1); return 0; } //------------------------ Funcion Definitions ------------------------// /*************************************************************************/ //-------------------------- apply_scaling( ) -------------------------// void apply_scaling(const int n,int coordinates[], const float Sx,const float Sy) { for(int count_1=0;count_1<n;count_1++) { float matrix_a[3]={coordinates[(count_1*2)], coordinates[((count_1*2)+1)],1}; float matrix_b[3][3]={ {Sx,0,0} , {0,Sy,0} ,{ 0,0,1} }; float matrix_c[3]={0}; multiply_matrices(matrix_a,matrix_b,matrix_c); coordinates[(count_1*2)]=(int)(matrix_c[0]+0.5); coordinates[((count_1*2)+1)]=(int)(matrix_c[1]+0.5); } } //---------------------- multiply_matrices( ) ------------------------// void multiply_matrices(const float matrix_1[3], const float matrix_2[3][3],float matrix_3[3]) { for(int count_1=0;count_1<3;count_1++) { for(int count_2=0;count_2<3;count_2++) matrix_3[count_1]+= (matrix_1[count_2]*matrix_2[count_2][count_1]); } } //----------------------------- Polygon( ) ----------------------------// void Polygon(const int n,const int coordinates[]) { if(n>=2) { Line(coordinates[0],coordinates[1], coordinates[2],coordinates[3]); for(int count=1;count<(n-1);count++) Line(coordinates[(count*2)],coordinates[((count*2)+1)], coordinates[((count+1)*2)], coordinates[(((count+1)*2)+1)]); } } //------------------------------- Line( ) -----------------------------// void Line(const int x_1,const int y_1,const int x_2,const int y_2) { int color=getcolor( ); int x1=x_1; int y1=y_1; int x2=x_2; int y2=y_2; if(x_1>x_2) { x1=x_2; y1=y_2; x2=x_1; y2=y_1; } int dx=abs(x2-x1); int dy=abs(y2-y1); int inc_dec=((y2>=y1)?1:-1); if(dx>dy) { int two_dy=(2*dy); int two_dy_dx=(2*(dy-dx)); int p=((2*dy)-dx); int x=x1; int y=y1; putpixel(x,y,color); while(x<x2) { x++; if(p<0) p+=two_dy; else { y+=inc_dec; p+=two_dy_dx; } putpixel(x,y,color); } } else { int two_dx=(2*dx); int two_dx_dy=(2*(dx-dy)); int p=((2*dx)-dy); int x=x1; int y=y1; putpixel(x,y,color); while(y!=y2) { y+=inc_dec; if(p<0) p+=two_dx; else { x++; p+=two_dx_dy; } putpixel(x,y,color); } } } //-------------------------- show_screen( ) ---------------------------// void show_screen( ) { setfillstyle(1,1); bar(218,26,413,38); settextstyle(0,0,1); setcolor(15); outtextxy(5,5,"******************************************************************************"); outtextxy(5,17,"*-**************************************************************************-*"); outtextxy(5,29,"*------------------------ -------------------------*"); outtextxy(5,41,"*-**************************************************************************-*"); outtextxy(5,53,"*-**************************************************************************-*"); setcolor(11); outtextxy(226,29,"Scaling Transformation"); setcolor(15); for(int count=0;count<=30;count++) outtextxy(5,(65+(count*12)),"*-* *-*"); outtextxy(5,438,"*-**************************************************************************-*"); outtextxy(5,450,"*------------------------- -------------------------*"); outtextxy(5,462,"******************************************************************************"); setcolor(12); outtextxy(229,450,"Press any Key to exit."); } //----------------------------- THE END -------------------------------//