图形学_画线算法（DDA、Bresenham）
时间：2014-04-27 20:51:40
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1. DDA算法实现直线绘制（需先安装easyx，百度下载即可）
1 #include "easyx.h" 2 #include "math.h" 3 #include "windows.h" 4 #include "stdio.h" 5 #include "stdlib.h" 6 #include "conio.h" 7 #include "graphics.h" 8 9 void dda(int x1,int y1,int x2,int y2,int color) 10 { 11 int steps; 12 double xin,yin,dx,dy,x,y; 13 dx = x2 - x1; 14 dy = y2 - y1; 15 if(fabs(dx) > fabs(dy)) 16 steps = fabs(dx); 17 else 18 steps = fabs(dy); 19 xin = (double)(dx/steps); 20 yin = (double)(dy/steps); //possible loss of data 21 x = x1; 22 y = y1; 23 putpixel(x,y,color); 24 for(int i = 0;i <= steps;i ++) 25 { 26 x = x + xin; 27 y = y + yin; 28 putpixel(x,y,color); 29 } 30 31 } 32 33 int main() 34 { 35 //硬件测试，将gd装入图形驱动器，gm置入最大图形模式。 36 int gd=DETECT,gm,x1,y1,x2,y2,color; 37 printf("input x1,y1,x2,y2,color is:"); 38 //输入直线参数。 39 scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&color); 40 //图形初始化 41 initgraph(&gd,&gm,"c:\\tc"); 42 //设置兰背景。 43 setbkcolor(BLUE); 44 cleardevice(); 45 dda(x1,y1,x2,y2,color); 46 getch(); 47 closegraph(); 48 49 return 0; 50 }
2.Bresenham算法绘制直线
1 #include "easyx.h" 2 #include "math.h" 3 #include "windows.h" 4 #include "stdio.h" 5 #include "stdlib.h" 6 #include "conio.h" 7 #include "graphics.h" 8 9 void Bresenham(int x1,int y1,int x2,int y2,int color) 10 { 11 int x,y,d,dx,dy; 12 dx = x2 - x1; 13 dy = y2 - y1; 14 d = -dx; //误差 15 x = x1; 16 y = y1; 17 18 while(x <= x2) 19 { 20 putpixel(x,y,color); 21 x = x + 1; 22 if(d >= 0) 23 { 24 y = y + 1; 25 d = d - 2 * dx; 26 } 27 d = d + 2 * dy; 28 } 29 } 30 31 int main() 32 { 33 //硬件测试，将gd装入图形驱动器，gm置入最大图形模式。 34 int gd=DETECT,gm,x1,y1,x2,y2,color; 35 printf("input x1,y1,x2,y2,color is:"); 36 //输入直线参数。 37 scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&color); 38 //图形初始化 39 initgraph(&gd,&gm,"c:\\tc"); 40 //设置兰背景。 41 setbkcolor(BLUE); 42 cleardevice(); 43 Bresenham(x1,y1,x2,y2,color); 44 getch(); 45 closegraph(); 46 47 return 0; 48 }
3.改进的Bresenham画线算法
改进后的算法可用于绘制任意斜率，任意方向的直线
1 #include "easyx.h" 2 #include "math.h" 3 #include "windows.h" 4 #include "stdio.h" 5 #include "stdlib.h" 6 #include "conio.h" 7 #include "graphics.h" 8 9 int Bresenham(int x1,int y1,int x2,int y2,int color) 10 { 11 int tempx,tempy; 12 if(x1 > x2) 13 { 14 tempx = x1; 15 x1 = x2; 16 x2 = tempx; 17 tempy = y1; 18 y1 = y2; 19 y2 = tempy; 20 } 21 22 int x,y,dx,dy; 23 double e,k; 24 dx = x2 - x1; 25 dy = y2 - y1; 26 27 if(dx == 0) 28 { 29 if(y1 > y2) 30 { 31 tempy = y1; 32 y1 = y2; 33 y2 = tempy; 34 } 35 for(int p = 0;p <= fabs(dy);p++) 36 { 37 putpixel(x1,y1,color); 38 y1 = y1+1; 39 } 40 return 1; 41 } 42 43 if(dy == 0) 44 { 45 for(int q = 0;q <= fabs(dx);q++) 46 { 47 putpixel(x1,y1,color); 48 x1 = x1 + 1; 49 } 50 return 1; 51 } 52 53 k = (double)dy/dx; 54 e = 0; 55 x = x1; 56 y = y1; 57 58 59 for(int i = 0;i <= dx;i++) 60 { 61 if(k > 0) 62 { 63 putpixel(x,y,color); 64 x++; 65 e = e + k; 66 if(e - int(e) >= 0.5) 67 { 68 y = y + int(e) + 1; 69 e = e - int(e) - 1; 70 } 71 else 72 { 73 y = y + int(e); 74 e = e - int(e); 75 } 76 } 77 78 else 79 { 80 putpixel(x,y,color); 81 x++; 82 e = e + k; 83 if(e - int(e) <= -0.5) 84 { 85 y = y + int(e) - 1; 86 e = e - int(e) + 1; 87 } 88 else 89 { 90 y = y + int(e); 91 e = e - int(e); 92 } 93 94 } 95 96 97 } 98 return 1; 99 } 100 101 int main() 102 { 103 //硬件测试，将gd装入图形驱动器，gm置入最大图形模式。 104 int gd=DETECT,gm,x1,y1,x2,y2,color; 105 printf("input x1,y1,x2,y2,color is:"); 106 //输入直线参数。 107 scanf("%d%d%d%d%d",&x1,&y1,&x2,&y2,&color); 108 //图形初始化 109 initgraph(&gd,&gm,"c:\\tc"); 110 //设置兰背景。 111 setbkcolor(BLUE); 112 cleardevice(); 113 int tempx,tempy; 114 if(x1 > x2) 115 { 116 tempx = x1; 117 x1 = x2; 118 x2 = tempx; 119 tempy = y1; 120 y1 = y2; 121 y2 = tempy; 122 } 123 Bresenham(x1,y1,x2,y2,color); 124 getch(); 125 closegraph(); 126 127 return 0; 128 }
4.Bresenham画线算法绘制任意多边形
1 #include "easyx.h" 2 #include "math.h" 3 #include "windows.h" 4 #include "stdio.h" 5 #include "stdlib.h" 6 #include "conio.h" 7 #include "graphics.h" 8 9 int Bresenham(int x1,int y1,int x2,int y2,int color) 10 { 11 int tempx,tempy; 12 if(x1 > x2) 13 { 14 tempx = x1; 15 x1 = x2; 16 x2 = tempx; 17 tempy = y1; 18 y1 = y2; 19 y2 = tempy; 20 } 21 22 int x,y,dx,dy; 23 double e,k; 24 dx = x2 - x1; 25 dy = y2 - y1; 26 27 if(dx == 0) 28 { 29 if(y1 > y2) 30 { 31 tempy = y1; 32 y1 = y2; 33 y2 = tempy; 34 } 35 for(int p = 0;p <= fabs(dy);p++) 36 { 37 putpixel(x1,y1,color); 38 y1 = y1+1; 39 } 40 return 1; 41 } 42 43 if(dy == 0) 44 { 45 for(int q = 0;q <= fabs(dx);q++) 46 { 47 putpixel(x1,y1,color); 48 x1 = x1 + 1; 49 } 50 return 1; 51 } 52 53 k = (double)dy/dx; 54 e = 0; 55 x = x1; 56 y = y1; 57 58 59 for(int i = 0;i <= dx;i++) 60 { 61 if(k > 0) 62 { 63 putpixel(x,y,color); 64 x++; 65 e = e + k; 66 if(e - int(e) >= 0.5) 67 { 68 y = y + int(e) + 1; 69 e = e - int(e) - 1; 70 } 71 else 72 { 73 y = y + int(e); 74 e = e - int(e); 75 } 76 } 77 78 else 79 { 80 putpixel(x,y,color); 81 x++; 82 e = e + k; 83 if(e - int(e) <= -0.5) 84 { 85 y = y + int(e) - 1; 86 e = e - int(e) + 1; 87 } 88 else 89 { 90 y = y + int(e); 91 e = e - int(e); 92 } 93 94 } 95 96 97 } 98 return 1; 99 } 100 101 int main() 102 { 103 //硬件测试，将gd装入图形驱动器，gm置入最大图形模式。 104 int gd=DETECT,gm; 105 int x[100],y[100],color; 106 int n; //代表边的个数 107 printf("请输入多边形边的个数： "); 108 scanf("%d",&n); 109 printf("\n请依次输入多边形每一个点的坐标：\n"); 110 for(int i = 0;i < n;i ++) 111 scanf("%d%d",&x[i],&y[i]); 112 scanf("%d",&color); 113 114 //图形初始化 115 initgraph(&gd,&gm,"c:\\tc"); 116 //设置兰背景。 117 setbkcolor(BLUE); 118 cleardevice(); 119 120 for(int j = 1;j < n;j ++) 121 Bresenham(x[j - 1],y[j - 1],x[j],y[j],color); 122 123 Bresenham(x[0],y[0],x[n-1],y[n-1],color); 124 125 getch(); 126 closegraph(); 127 128 return 0; 129 }
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