bitmap.c

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#include "stdio.h"
#include "dir.h"
#include "dos.h"
#include "graphics.h"

char *malloc();/*malloc转换*/

char bmp_to_dat(char *bmp,char *dat)
/*将16色BMP文件转换为可以用putimage输出的格式，bmp为原BMP文件，dat为转化文件*/
{
	unsigned char c[8],scan_times,scan_pixs;
	unsigned char workpos;int i,j,k,n,nowpos,iw,ih;
	static int color[16]={0,4,2,6,1,5,3,7,8,12,10,14,9,13,11,15};
	unsigned char workline[640],scanline[640];
	FILE *fp,*targetfp;
	union
	{
		unsigned char value;
		struct
		{
			unsigned cl:4;
			unsigned ch:4;
		}color;
	}mycolor;
	
	if((fp=fopen(bmp,"rb"))==NULL)return(0);
	targetfp=fopen(dat,"wb");
	
	fseek(fp,18,SEEK_SET);
	iw=0;ih=0;
	fread(&iw,4,1,fp);		/*读图像宽度*/
	fread(&ih,4,1,fp);		/*读图像高度*/
	if(iw==0&&ih==0&&iw>640&&ih>480)
	{fclose(fp);fclose(targetfp);return(0);}
	
	iw--;ih--;			/*∵putimage中的长宽比实际数值少1*/
	scan_times=iw/8+1;		/*行处理单位数*/
	scan_pixs=scan_times*4;		/*行像素字节数∵1单位=4字节*/
	
	fputc(iw%256,targetfp);		/*填充信息头：长、宽部分*/
	fputc(iw/256,targetfp);
	fputc(ih%256,targetfp);
	fputc(ih/256,targetfp);
	fseek(fp,-scan_pixs,SEEK_END);
	
	for(j=0;j<=ih;j++)
	{nowpos=0;
	fread(scanline,scan_pixs,1,fp);
	fseek(fp,-scan_pixs*2,SEEK_CUR);
	for(n=3;n>=0;n--)		/*解码4个位面*/
	{for(i=0;i<scan_times;i++)	/*解码各编码单位*/
	{workpos=0;
    for(k=0;k<4;k++)		/*分离出8个像素*/
    {mycolor.value=scanline[i*4+k];
	c[k*2]=color[mycolor.color.ch];
	c[k*2+1]=color[mycolor.color.cl];
    }
    for(k=0;k<8;k++)workpos+=(c[k]>>n&1)<<(7-k);
    workline[nowpos]=workpos;nowpos++;
	}}
	fwrite(workline,scan_pixs,1,targetfp);
	}
	fclose(fp);fclose(targetfp);
	return(1);
}

main()
{
	int gd=VGA,gm=VGAHI,n;
	char *buffer,bmpfile[13],_16file[13]={0};
	FILE *fp;
	struct ffblk *ff;
	registerbgidriver(EGAVGA_driver);
	initgraph(&gd,&gm,"f:\\tc30\\bgi");
	printf("现在开始显示16色位图...\n\n");
	puts("请进行选择:");
	printf("0. 退出\n1. BMP文件名\n");
	while(1)
	{
		n=getch();
		switch(n)
		{
		case 0  :continue;
		case '0':exit(0);
		case '1':
			{
				printf("请输入文件名(*.bmp):");
				gets(bmpfile);
				goto OUT;
			}
		}
	}
OUT:
	strncpy(_16file,bmpfile,strlen(bmpfile)-3);
	strcat(_16file,"dat");
	if(!bmp_to_dat(bmpfile,_16file))
	{
		puts("无法打开文件!");
		closegraph();
		exit(0);
	}
	fp=fopen(_16file,"rb");
	findfirst(_16file,ff,FA_ARCH);
	if((buffer=malloc(ff->ff_fsize))==NULL)exit(0);
	n=0;
	while(!feof(fp))
	{
		buffer[n]=fgetc(fp);
		n++;
	}
	for(n=0;n<100;n++)
	{
		putimage(350-n,n/2,buffer,COPY_PUT);
	}
	getch();
	closegraph();
	free(buffer);
	fclose(fp);
}