DOS SVGACC图形开发库函数

原型　extern void far d2rotate (int points, int xorigin, int yorigin, int ang, D2Point far *inary, D2Point far *outary)

输入　numpoints - 被旋转的点的个数

xorigin, yorigin - 旋转中心

angle - 相对旋转中心旋转的角度

inary - 指向包含被旋转点的D2Point型数组

输出　无返回值

outary - 指向旋转后的点数组

用法　D2ROTATE提取inary指定的二维点并且按照xorigin和yorigin将它们旋转指定的角度。结果通过outary返回，outary可与inary共用一个空间。正的角度使屏幕上的图形顺时针旋转，即从X轴正向向Y轴正向旋转。此函数假定outary已合适分配。

例子

/*

* shows d2rotate works

*/

#include <stdlib.h>

#include <conio.h>

#include "svgacc.h"

D2Point tri[3];

D2Point trio[3];

D2Point tri2[3];

void drwtri(void);

void ertri(void);

void main(void)

{

int vmode,i;

vmode = videomodeget();

if (!whichvga())

exit(1);

if (whichmem()<512)

exit(1);

res640();

trio[0].x = 0;

trio[0].y = 0;

trio[1].x = -80;

trio[1].y = 60;

trio[2].x = 80;

trio[2].y = 60;

drwtri();

for(i=0;i<=360;i+=2)

{

d2rotate(3,0,0,i,trio,tri);

drwtri();

sdelay(2);

ertri();

}

drwtri();

getch();

videomodeset(vmode);

exit(0);

}

void drwtri(void)

{

d2translate(3,320,240,tri,tri2);

drwline(1,10,tri2[0].x,tri2[0].y,tri2[1].x,tri2[1].y);

drwline(1,10,tri2[1].x,tri2[1].y,tri2[2].x,tri2[2].y);

drwline(1,10,tri2[2].x,tri2[2].y,tri2[0].x,tri2[0].y);

return;

}

void ertri(void)

{

d2translate(3,320,240,tri,tri2);

drwline(1,0,tri2[0].x,tri2[0].y,tri2[1].x,tri2[1].y);

drwline(1,0,tri2[1].x,tri2[1].y,tri2[2].x,tri2[2].y);

drwline(1,0,tri2[2].x,tri2[2].y,tri2[0].x,tri2[0].y);

return;

}