D2ROTATE

DOS SVGACC圖形開發庫函式

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

輸入　　numpoints - 被旋轉的點的個數

xorigin, yorigin - 旋轉中心

angle - 相對旋轉中心旋轉的角度

inary - 指向包含被旋轉點的D2Point型數組

輸出　　無返回值

outary - 指向旋轉後的點數組

用法　　D2ROTATE提取inary指定的二維點並且按照xorigin和yorigin將它們旋轉指定的角度。結果通過outary返回，outary可與inary共用一個空間。正的角度使螢幕上的圖形順時針旋轉，即從X軸正向向Y軸正向旋轉。此函式假定outary已合適分配。

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;

}