简介这篇文章主要介绍了计算机图形学DDA画线法+中点画线法+Bresenham画线法(示例代码)以及相关的经验技巧，文章约9131字，浏览量322，点赞数4，值得参考！

#include

#include

#include

#include

void line1(){

line(100, 100, 200, 400);

line(100, 400, 200, 100);

line(0, 200, 300, 300);

line(0, 300, 300, 200);

}

void lineDDA(int x0, int y0, int x1, int y1, int color){

int x;

float dy, dx, y, m;

dx = x1 - x0;

dy = y1 - y0;

m = dy / dx;

y = y0;

for (x = x0; x <= x1; x++){

putpixel(x, (int)(y + 0.5), color);

y += m;

}

}

void lineDDA(){

lineDDA(100, 100, 200, 400, RED);

lineDDA(100, 400, 200, 100, RED);

lineDDA(0, 200, 300, 300, RED);

lineDDA(0, 300, 300, 200, RED);

}

void lineMidPoint(int x0, int y0, int x1, int y1, int color){

int x = x0, y = y0;

int a = y0 - y1, b = x1 - x0;

int cx = (b >= 0 ? 1 : (b = -b, -1));

int cy = (a <= 0 ? 1 : (a = -a, -1));

putpixel(x, y, color);

int d, d1, d2;

if (-a <= b) // 斜率绝对值 <= 1

{

d = 2 * a + b;

d1 = 2 * a;

d2 = 2 * (a + b);

while (x != x1)

{

if (d < 0)

y += cy, d += d2;

else

d += d1;

x += cx;

putpixel(x, y, color);

}

}

else // 斜率绝对值 > 1

{

d = 2 * b + a;

d1 = 2 * b;

d2 = 2 * (a + b);

while (y != y1)

{

if (d < 0)

d += d1;

else

x += cx, d += d2;

y += cy;

putpixel(x, y, color);

}

}

}

void lineMidPoint(){

lineMidPoint(100, 100, 200, 400, GREEN);

lineMidPoint(100, 400, 200, 100, GREEN);

lineMidPoint(0, 200, 300, 300, GREEN);

lineMidPoint(0, 300, 300, 200, GREEN);

}

void lineBresenham(int x0, int y0, int x1, int y1, int color)

{

int dx = x1 - x0;

int dy = y1 - y0;

int ux = dx >0 ? 1 : -1;//x伸展方向

int uy = dy >0 ? 1 : -1;//y伸展方向

int dx2 = dx << 1;//x偏移量乘2

int dy2 = dy << 1;//y偏移量乘2

if (abs(dx)>abs(dy))

{//以x为增量方向计算

int e = -dx; //e = -0.5 * 2 * dx,把e 用2 * dx* e替换

int x = x0;

int y = y0;//起点y坐标

for (x = x0; x < x1; x += ux)

{

putpixel(x, y, color);

e = e + dy2;//来自 2*e*dx= 2*e*dx + 2dy (原来是 e = e + k)

if (e > 0)//e是整数且大于0时表示要取右上的点(否则是右下的点)

{

y += uy;

e = e - dx2;//2*e*dx = 2*e*dx - 2*dx (原来是 e = e -1)

}

}

}

else

{//以y为增量方向计算

int e = -dy; //e = -0.5 * 2 * dy,把e 用2 * dy* e替换

int x = x0;

int y = y0;

for (y = y0; y < y1; y += uy)

{

putpixel(x, y, color);

e = e + dx2;//来自 2*e*dy= 2*e*dy + 2dy (原来是 e = e + k)

if (e > 0)//e是整数且大于0时表示要取右上的点(否则是右下的点)

{

x += ux;

e = e - dy2;//2*e*dy = 2*e*dy - 2*dy (原来是 e = e -1)

}

}

}

}

void lineBresenham1(int x0, int y0, int x1, int y1, long color)

{

int dx = abs(x1 - x0);

int dy = abs(y1 - y0);

int x = x0;

int y = y0;

int stepX = 1;

int stepY = 1;

if (x0 > x1) //从右向左画

stepX = -1;

if (y0 > y1)

stepY = -1;

if (dx > dy) //沿着最长的那个轴前进

{

int e = dy * 2 - dx;

for (int i = 0; i <= dx; i++)

{

putpixel(x, y, color);

x += stepX;

e += dy;

if (e >= 0)

{

y += stepY;

e -= dx;

}

}

}

else

{

int e = 2 * dx - dy;

for (int i = 0; i <= dy; i++)

{

putpixel(x, y, color);

y += stepY;

e += dx;

if (e >= 0)

{

x += stepX;

e -= dy;

}

}

}

}

void lineBresenham(){

lineBresenham1(100, 100, 200, 400, YELLOW);

lineBresenham1(100, 400, 200, 100, YELLOW);

lineBresenham1(0, 200, 300, 300, YELLOW);

lineBresenham1(0, 300, 300, 200, YELLOW);

}

void showWord(int code){

outtextxy(200, 30, "单击右键退出");

switch (code){

case 1://原画

outtextxy(200, 10, "easyX系统画线算法");

break;

case 2://DDA算法

outtextxy(200, 10, "DDA算法");

break;

case 3://中点画线算法

outtextxy(200, 10, "中点画线算法");

break;

case 4://Bresenham算法

outtextxy(200, 10, "Bresenham算法");

break;

default:

line1();

break;

}

}

void drawLine(int code){

switch (code){

case 1://原画

line1();

break;

case 2://DDA算法

lineDDA();

break;

case 3://中点画线算法

lineMidPoint();

break;

case 4://Bresenham算法

lineBresenham();

break;

default:

line1();

break;

}

}

void drawLine(int x0,int y0,int x1,int y1,int code){

showWord(code);

switch (code){

case 1://原画

line(x0,y0,x1,y1);

break;

case 2://DDA算法

lineDDA(x0, y0, x1, y1,WHITE);

break;

case 3://中点画线算法

lineMidPoint(x0, y0, x1, y1, WHITE);

break;

case 4://Bresenham算法

lineBresenham1(x0, y0, x1, y1, WHITE);

break;

default:

line1();

break;

}

}

void showWORDXY(int x, int y, int showX, int showY,int flag){

char dintX[5] = { 0 };

char dintY[5] = { 0 };

_itoa_s(showX, dintX, 10);//把整数showX转成字符串dintX

_itoa_s(showY, dintY, 10);//把整数showY转成字符串dintY

char str1[100] = "第一个点的坐标：(";//此时数组没有定义长度 元素的个数应该为strlen +1 因为字符串末尾有 ‘\0‘结束

char str2[100] = "第二个点的坐标：(";

if (flag == 1){

// _countof(dintX)能够获取到数组中元素的个数 含‘\0’

strcat_s(str1, strlen(str1) + strlen(dintX)+1, dintX);

strcat_s(str1, strlen(str1) + strlen(",")+1, ",");

strcat_s(str1, strlen(str1) + strlen(dintY)+1, dintY);

strcat_s(str1, strlen(str1) + strlen(")")+1, ")");

outtextxy(x, y, str1);

}

else if (flag == 2){

strcat_s(str2, strlen(str2) + strlen(dintX)+1, dintX);

strcat_s(str2, strlen(str2) + strlen(",")+1, ",");

strcat_s(str2, strlen(str2) + strlen(dintY)+1, dintY);

strcat_s(str2, strlen(str2) + strlen(")")+1, ")");

outtextxy(x, y, str2);

}

}

//调用easyX

void easyX(int code){

initgraph(640, 480); //初始化

showWord(code);

MOUSEMSG m; // 定义鼠标消息

int n=0;//读取两个点

int exit = false;

int x0=0, y0=0,x1=0,y1=0;

while (n<2 && !exit)

{

m = GetMouseMsg();

switch (m.uMsg)

{

case WM_RBUTTONDOWN:

outtextxy(200, 300, "再次点击键退出");

exit = true;

break; // 按鼠标右键退出程序

}

while (m.uMsg != WM_LBUTTONDOWN){

m = GetMouseMsg();

switch (m.uMsg)

{

case WM_RBUTTONDOWN:

outtextxy(200, 300, "再次点击键退出");

exit = true;

break; // 按鼠标右键退出程序

}

}

while (m.uMsg != WM_LBUTTONUP){

m = GetMouseMsg();

cleardevice();

showWord(code);

if (n == 0){

showWORDXY(200, 430, x0, y0,1);

x0 = m.x;

y0 = m.y;

}

else{

showWORDXY(200, 430, x0, y0, 1);

showWORDXY(200, 450, x1, y1, 2);

x1 = m.x;

y1 = m.y;

}

}

n++;

if (n == 2){

//画线

drawLine(x0, y0, x1, y1, code);

//重置

n = 0;

}

}

//_getch(); //等待用户操作

closegraph(); //关闭图形

}

int main(){

int n = 1;

printf("请选择画线算法画线：\n");

printf("1.easyX系统画线函数.\n");

printf("2.DDA画线算法函数.\n");

printf("3.中点画线算法函数.\n");

printf("4.Bresenham画线算法函数.\n");

printf("0.退出.\n");

while (n != 0){

scanf_s("%d", &n);

if (n == 0){

exit(0);

}

easyX(n);

}

return 0;

}

效果图：