graphic.part4.h

C语言库函数介绍

@函数名称:     getlinesettings
函数原型:     void far getlinesettings(struct linesettingstype far *lineinfo)
函数功能:     得到当前画线模式
函数返回:
参数说明:     lineinfo-保存画线模式信息，该结构的定义如下：
		struct linesettingstype{
 		  int linestyle;
  		  unsigned upattern;
   		  int thickness;
		};
	      其中linestyle的取值和含义如下:
		SOLID_LINE=0   实线  DOTTED_LINE=1   点线
		CENTER_LINE=2  中心线  DASHED_LINE=3 虚线
		USERBIT_LINE=4 用户自定义模式
		upattern-在linestyle=USERBIT_LINE时，表示自定义的线型,thickness-线宽，有2个取值:
		NORM_WIDTH=1  1个象素宽度
		THICK_WIDTH=3 3个象素宽度
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
char *lname[]={"SOLID_LINE","DOTTED_LINE","CENTER_LINE","DASHED_LINE","USERBIT_LINE"};
int main()
{
    int gdriver=DETECT,gmode,errorcode;
    struct linesettingstype lineinfo;
    int midx,midy;
    char lstyle[80],lpattern[80],lwidth[80];
    initgraph(&gdriver,&gmode,);
    errorcode=graphresult();
    if (errorcode!=grOk)
    {
        printf("Graphics error: %s",grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }
    midx=getmaxx()/2;
    midy=getmaxy()/2;
    getlinesettings(&lineinfo);
    sprintf(lstyle,"%s is the line style.",lname[lineinfo.linestyle]);
    sprintf(lpattern,"0x%X is the user-defined line pattern.",lineinfo.upattern);
    sprintf(lwidth,"%d is the line thickness.",lineinfo.thickness);
    settextjustify(CENTER_TEXT,CENTER_TEXT);
    outtextxy(midx,midy,lstyle);
    outtextxy(midx,midy+2*textheight("W"),lpattern);
    outtextxy(midx,midy+4*textheight("W"),lwidth);
    getch();
    closegraph();
    return 0;
}


@函数名称:     getmoderange
函数原型:     void far getmoderange(int graphdriver,int far *lomode,int far *himode)
函数功能:     得到某个图形驱动器driver的图形模式范围
函数返回:
参数说明:     driver 图形驱动器编号，含义如下：
		CGA      1	MCGA    2
		EGA      3	EGA64   4
		EGAMONO  5	IBM8514 6
		HERCMONO 7	ATT400  8
		VGA      9	PC3270 10
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
int main()
{
    int gdriver=DETECT,gmode,errorcode;
    int midx,midy;
    int low,high;
    char mrange[80];
    initgraph(&gdriver,&gmode,);
    errorcode=graphresult();
    if (errorcode!=grOk)
    {
        printf("Graphics error: %s",grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }
    midx=getmaxx()/2;
    midy=getmaxy()/2;
    getmoderange(gdriver,&low,&high);
    sprintf(mrange,"This driver supports modes %d..%d",low,high);
    settextjustify(CENTER_TEXT,CENTER_TEXT);
    outtextxy(midx,midy,mrange);
    getch();
    closegraph();
    return 0;
}


@函数名称:     getpixel
函数原型:     unsigned far getpixel(int x,int y)
函数功能:     得到坐标为x,y的象素颜色
函数返回:     该象素颜色数值
参数说明:     x,y-象素坐标
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <dos.h>

#define PIXEL_COUNT 1000
#define DELAY_TIME  100  /* in milliseconds */

int main(void)
{
   int gdriver=DETECT,gmode,errorcode;
   int i,x,y,color,maxx,maxy,maxcolor,seed;
   initgraph(&gdriver,&gmode,"");
   /* read result of initialization */
   errorcode=graphresult();
   if (errorcode!=grOk) {  /* an error occurred */
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);	/* terminate with an error code */
   }
   maxx=getmaxx()+1;
   maxy=getmaxy()+1;
   maxcolor=getmaxcolor()+1;
   while(!kbhit()){
      seed=random(32767);
      srand(seed);
      for(i=0;i<PIXEL_COUNT;i++){
         x=random(maxx);
         y=random(maxy);
         color=random(maxcolor);
         putpixel(x,y,color);
      }
      delay(DELAY_TIME);
      srand(seed);
      for(i=0;i<PIXEL_COUNT;i++){
         x=random(maxx);
         y=random(maxy);
         color=random(maxcolor);
         if(color==getpixel(x,y))
            putpixel(x,y,0);
      }
   }
   getch();
   closegraph();
   return 0;
}


@函数名称:     putpixel
函数原型:     void far putpixel(int x, int y, int color)
函数功能:     在屏幕上画一个点 
函数返回:
参数说明:     x,y 画点位置坐标，color 画点颜色
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <dos.h>

#define PIXEL_COUNT 1000
#define DELAY_TIME  100

int main()
{
   int gdriverDETECT,gmode,errorcode;
   int i,x,y,color,maxx,maxy,maxcolor,seed;
   initgraph(&gdriver,&gmode,"");
   errorcodegraphresult();
   if (errorcode != grOk){
      printf("Graphics error: %s\n",grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);
   }

   maxxgetmaxx()+1;
   maxygetmaxy()+1;
   maxcolorgetmaxcolor()+1;
   while (!kbhit())
   {
      seedrandom(32767);
      srand(seed);
      for (i=0;i<PIXEL_COUNT;i++){
         xrandom(maxx);
         yrandom(maxy);
         colorrandom(maxcolor);
         putpixel(x,y,color);
      }
      delay(DELAY_TIME);
      srand(seed);
      for (i=0;i<PIXEL_COUNT;i++){
         xrandom(maxx);
         yrandom(maxy);
         colorrandom(maxcolor);
         if (color==getpixel(x,y))
            putpixel(x,y,0);
      }
   }
   getch();
   closegraph();
   return 0;
}


@函数名称:     graphdefaults
函数原型:     void far graphdefaults(void)
函数功能:     将图形系统恢复为缺省状态
函数返回:
参数说明:
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int main()
{
   int gdriver=DETECT,gmode,errorcode;
   int maxx,maxy;
   initgraph(&gdriver,&gmode,"");
   errorcode=graphresult();
   if (errorcode!=grOk){
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);
   }
   maxx=getmaxx();
   maxy=getmaxy();
   /* output line with nondefault settings */
   setlinestyle(DOTTED_LINE,0,3);
   line(0,0,maxx,maxy);
   outtextxy(maxx/2,maxy/3,"Before default values are restored.");
   getch();
   /* restore default values for everything */
   graphdefaults();
   /* clear the screen */
   cleardevice();
   /* output line with default settings */
   line(0,0,maxx,maxy);
   outtextxy(maxx/2, maxy/3, "After restoring default values.");
   getch();
   closegraph();
   return 0;
}


@函数名称:     grapherrormsg
函数原型:     char far *grapherrormsg(int errorcode)
函数功能:     得到图形系统的错误信息指针
函数返回:     错误描述的文字字符串指针
参数说明:     errormode-错误信息编码，由graphresult()函数得到
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#define NONSENSE -50
int main()
{
    int gdriver=NONSENSE,gmode,errorcode;
    initgraph(&gdriver,&gmode,);
    errorcode=graphresult();
    if (errorcode!=grOk)
    {
        printf("Graphics error: %s",grapherrormsg(errorcode));
        printf("Press any key to halt:");
        getch();
        exit(1);
    }
    line(0,0,getmaxx(),getmaxy());
    getch();
    closegraph();
    return 0;
}


@函数名称:     _graphfreemem、_graphgetmem
函数原型:     void far _graphfreemem(void far *ptr, unsigned size)
              void far _graphgetmem(unsigned size)
函数功能:     释放图形系统所用的内存
              得到图形系统所用的内存
              实际上，它们调用的是malloc,free，因此它们常被重定义，以便图库管理模式能被程序员控制
函数返回:
参数说明:	此二函数由图形库内核调用
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#include <alloc.h>

int main()
{
	int gdriver=DETECT,gmode,errorcode;
	int midx,midy;
	clrscr();
	printf("Press any key to initialize graphics mode:");
	getch();
	clrscr();
	initgraph(&gdriver,&gmode,"");
	errorcode=graphresult();
	if(errorcode!=grOk)
	{
	   printf("Graphics error: %s\n",grapherrormsg(errorcode));
	   printf("Press any key to halt:");
	   getch();
	   exit(1); /* terminate with an error code */
	}
	midx=getmaxx()/2;
	midy=getmaxy()/2;
	/* display a message */
	settextjustify(CENTER_TEXT,CENTER_TEXT);
	outtextxy(midx,midy,"Press any key to exit graphics mode:");
	getch();
	closegraph();
	return 0;
 }

/* called by the graphics kernel to allocate memory */
void far * far _graphgetmem(unsigned size)
{
	printf("_graphgetmem called to allocate %d bytes.\n",size);
	printf("press any key:");
	getch();
	printf("\n");
	/* allocate memory from far heap */
	return farmalloc(size);
}

/* called by the graphics kernel to free memory */
void far _graphfreemem(void far *ptr, unsigned size)
{
	printf("_graphfreemem called to free %d bytes.\n",size);
	printf("press any key:");
	getch();
	printf("\n");
	/* free ptr from far heap */
	farfree(ptr);
}


@函数名称:     imagesize
函数原型:     unsigned far imagesize(int left, int top, int right, int bottom)
函数功能:     得到存储一块屏幕图象所需要的字节数
函数返回:     存储图象的字节数
参数说明:     left,top,right,bottom-矩形图形屏幕的坐标
所属文件:     <graphics.h>

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
#define ARROW_SIZE 10
void draw_arrow(int x,int y);
int main()
{
    int gdriver=DETECT,gmode,errorcode;
    void *arrow;
    int x,y,maxx;
    unsigned int size;
    initgraph(&gdriver,&gmode,);
    errorcode=graphresult();
    if (errorcode!=grOk)
    {
       printf("Graphics error: %s",grapherrormsg(errorcode));
       printf("Press any key to halt:");