蝗ｳ縺ｮ繧医≧縺ｫ迚ｩ逅�ｺｧ讓咏ｳｻR縺九ｉ繝�ぅ繧ｹ繝励Ξ繧､蠎ｧ讓咏ｳｻG縺ｫ謌仙�繧貞､画鋤縺吶ｋ髢｢謨ｰ繝槭け繝ｭ
gx(),gy()繧剃ｽ懈�縺励ヽ荳翫�蠎ｧ讓吶〒荳弱∴繧峨ｌ縺溽ｷ壼�繧堤判髱｢縺ｫ陦ｨ遉ｺ縺励※荳九＆縺�ゆｽ�
縺励∝ｺｧ讓咏ｳｻR縺ｯ螳滓焚縺ｧ縲∝ｺｧ讓咏ｳｻG縺ｯ謨ｴ謨ｰ縺ｧ陦ｨ縺輔ｌ縲ヽ縺ｮ蜴溽せ縺ｮG荳翫〒縺ｮ蠎ｧ讓吶ｒ
(ORIGIN_X, ORIGIN_Y)縲ヽ荳翫�髟ｷ縺� REAL_SIZE(m) 縺ｯG荳翫〒 DISPLAY_SIZE(dot)縺ｧ陦ｨ縺輔ｌ繧九ｂ縺ｮ縺ｨ縺吶ｋ縲�
Figure 1: 迚ｩ逅�ｺｧ讓咏ｳｻ縺ｨ繝�ぅ繧ｹ繝励Ξ繧､蠎ｧ讓咏ｳｻ
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/* "ex4-1.c" --- */
#include <stdio.h>
#include <Xtc.h>
#define ORIGIN_X 320
#define ORIGIN_Y 200
#define REAL_SIZE 1.0
#define DISPLAY_SIZE 150
/* 蠎ｧ讓吝､画鋤 */
#define gx(x) ((int)(ORIGIN_X+(x)*DISPLAY_SIZE/REAL_SIZE))
#define gy(y) ((int)(ORIGIN_Y-(y)*DISPLAY_SIZE/REAL_SIZE))
int main(void)
{
int x,y;
initgraph(); /* 繧ｰ繝ｩ繝輔ぅ繝�け繧ｹ迺ｰ蠅��蛻晄悄蛹� */
setcolor( WHITE ); /* 蠎ｧ讓呵ｻｸ縺ｮ陦ｨ遉ｺ濶ｲ險ｭ螳� */
line( gx(0.0), gy(0.0), gx(1.0), gy(0.0) ); /* x霆ｸ縺ｮ謠冗判 */
line( gx(0.0), gy(0.0), gx(0.0), gy(1.0) ); /* y霆ｸ縺ｮ謠冗判 */
outtextxy( gx(0.0) - 20, gy(0.0) + 20, "0" ); /* 蜴溽せ陦ｨ遉ｺ */
setcolor( RED );
line( gx(0.0), gy(0.0), gx(0.2), gy(0.5) ); /* 邱壼�縺ｮ謠冗判 */
xtcmainloop( 3 ); /* 邨ゆｺ��蜉帛ｾ�■ */
closegraph(); /* 繧ｰ繝ｩ繝輔ぅ繝�け繧ｹ迺ｰ蠅��邨ゆｺ� */
}
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