在Windows中顯示多幅彩色圖像的技術(shù)

寬、高和各調(diào)色板的顏色分量,并把文件指針指向圖像的開始處*/
FILE *get-bitmap-file(char*fname)
{
unsigned char ch;
int i,j,n;
FILE *fp;
fp=fopen(fname,"rb+");
if (fp==NULL) return NULL;
fseek(fp,18L,SEEK-SET);
fread(&width,2,1,fp);fseek(fp,2L,SEEK-CUR);
fread(&depth,2,1,fp);fseek(fp,2L,SEEK-CUR);
n=width/4;
if (width%4 !=0) n++;
bytes=n*4;
fseek(fp,54L,SEEK-SET);
fread(&palette[0][0],4,256,fp);
return fp;
}
/*該函數(shù)實現(xiàn)顏色的壓縮*/
void zh_fan-tu(FILE *fp,int color1,int color2)
{
unsigned char *p,*q,cc,ch;
long len;
int max-no, i,j,m,n,r0,b0,g0,r1,b1,g1;
double dd,dmin;
char s[4];
max-no=color2-color1+1;
for (i=0;i<256;i++) TAB[i]=0;
p=(char *)malloc(bytes+1);
for (i=0;i<depth;i++) {
fread(p,bytes,1,fp);
q=p;
for (j=0;j<bytes;j++,q++) if(j>=width) break;
else {
ch=(unsigned char)*q;
TAB[ch]++;
}
}
for (i=0;i<256;i++) tt[i]=(unsigned char)i;
for (i=0;i<255;i++) for (j=i+1;j<256;j++)
if (TAB[i]<TAB[j]){
len=TAB[i];TAB[i]=TAB[j];TAB[j]=len;
cc=TT[i];TT[i]=TT[j];TT[j]=cc;
memcpy(s,&palette[i][0],4);
memcpy(&palette[i][0],&palette[j][0],4);
memcpy(&palette[j][0],s,4);
}
for (i=color2;i>=color1;i--)
memcpy(&palette[i][0],&palette[i-color1][0],4);
for (i=0;i<max-no;i++) BB[TT[i]]=(unsigned char)i;
for (i=max-no;i<256;i++) {
r0=palette[i][2];
g0=palette[i][1];
b0=palette[i][0];
dmin=256.0*256.0*256.0;
m=0;
for (j=0;j<max-no;j++) {
r1=palette[j][2];
g1=palette[j][1];
b1=palette[j][0];
dd=1.0*(r0-r1)*(r0-r1)+1.0*(g0-g1)*(g0-g1)+1.0*(b0-b1)*(b0-b1);
dd=sqrt(dd);
if (dmin>dd) {dmin=dd;m=j;}
}
BB[TT[i]]=(unsigned char)m;
}
for (i=0;i<256;i++) BB[i]+=color1;
}
void w-create-bitmap(FILE *fp)
{
int i,j,n,m,t;
long len;
unsigned char far *p,far *q,cc,ch;
unsigned nn;
fseek(fp,54L,SEEK-SET);
len=ftell(fp);
fwrite(&pale

tte[0][0],4,256,fp);
p=(unsigned char far *)farmalloc(bytes+1);
len=ftell(fp);
for (i=0;i<depth;i++) {
fseek(fp,len,SEEK-SET);
fread(p,bytes,1,fp);
fseek(fp,len,SEEK-SET);
len+=bytes;
q=p;
for (j=0;j<width;j++,q++) {
cc=(unsigned char)(*q);
ch=BB[cc];
*q=ch;
}
fwrite(p,bytes,1,fp);
}
farfree(p);
}
main(int argc,char *args[])
{
FILE *fp;
if (argc<4) {
printf("參數(shù):文件名 顏色下限 顏色上限\n");
return;
}
fp=get-bitmap-file(args[1]);
if (fp==NULL) return;
zh-fan-tu(fp,atoi(args[2],atoi(args[3]));
w-create-bitmap(fp);
fclose(fp);
}

參考文獻
王旭 張軍譯.Microsoft Windows 3.1程序員參考手冊.北京:清華大學(xué)出版社,1994.