D2SCALE

DOS SVGACC圖形開發庫函式

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

輸入　　scalex - X向縮放因子

scaley - Y向縮放因子

inary - 指向原圖形的點數組的D2Point型指針

輸出　　無返回值

outary - 指向縮放後圖形的點數組的D2Point型指針

用法　　D2SCALE將二維數組inary中的每個坐標乘以相應的縮放因子。結果通過outary返回，outary可與inary共用一個空間。縮放因子為256(100hex)被認為是100%，結果無變化。同理，128(80hex)被認為縮小一半；512(200hex)則為放大一倍。此函式假定outary已合適分配.

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;

}