DOS SVGACC图形开发库函数

原型　extern void far d2scale (int points, int scalex, int scaley,D2Point far *inary, D2Point far *outary)

输入　scalex - X向缩放因子

scaley - Y向缩放因子

inary - 指向原图形的点数组的D2Point型指针

输出　无返回值

outary - 指向缩放后图形的点数组的D2Point型指针

用法　D2SCALE将二维数组inary中的每个坐标乘以相应的缩放因子。结果通过outary返回，outary可与inary共用一个空间。缩放因子为256(100hex)被认为是100%，结果无变化。同理，128(80hex)被认为缩小一半；512(200hex)则为放大一倍。此函数假定outary已合适分配.

例子

/*

* shows d2scale 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=256;i<=512;i+=4)

{

d2scale(3,i,i,trio,tri);

drwtri();

sdelay(2);

ertri();

}

for(i=512;i>=128;i-=4)

{

d2scale(3,i,i,trio,tri);

drwtri();

sdelay(2);

ertri();

}

for(i=128;i<=256;i+=4)

{

d2scale(3,i,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;

}