ibgdpixmapread.c

有限元学习研究用源代码(老外的),供科研人员参考

/* last edit: Ilja Schmelzer -------------- 28-FEB-1995 11:16:00.49	*/
#include <stdio.h>
#include "ibg.h"       
#include "ibglib.h"       
#include "ibgoutput.h"
#include "ibgdpixmap.h"       

/* assumes that a positive number follows. Reads and returns this number.
   Returns -1 for other characters, -2 for EOF.
   # as comment up to the end of line is allowed
*/

typedef struct{
	char r;
	char g;
	char b;
}color;

static int getnumber(FILE *file)
{char cc;
 int n;
beg:
 cc = fgetc(file);
 if(feof(file)) return -2;
 if(cc=='#'){
	do{
		cc=fgetc(file); 
		if(feof(file)) return -2;
	}while((cc != '\n'));
	goto beg; 
 }
 if((cc==' ')||(cc=='\t')||(cc=='\n')) goto beg;
 n = 0;
 do{
	if((cc<'0')||(cc>'9')){
		if((cc==' ')||(cc=='\t')||(cc=='\n')) return n;
		return -1;
	}
	n *= 10; n += cc-'0';
	cc = fgetc(file);
	if(feof(file)) return n;
 }while(n<100000);
 return n;	
}


int ibgdPixmapRead(ibgPixmap *p, int *colors, ibgColor *colmap, char *fname)
{unsigned char c0,cf,rr,gg,bb,ff;
 unsigned char *cc,*prev,last;
 color *m;
 int f[3],fac,l1,l2,n,lines,rest,col,rc,i,j,k,c,c1,l,t,to,newt;
 FILE* file = fopen(fname,"r");
 if(file==NULL){
	fprintf(stderr,"pixmap file %s not found\n",fname);
  	return ibgError;
 }
 c0 = fgetc(file);
 cf = fgetc(file);
 if((c0 != 'P')||(cf < '1') || (cf > '6')){
/* to include other graphic formats describing a true color picture
   include here some other text reading this file format and go to colormap
*/
	fprintf(stderr,"unknown format - currently only PBM implemented\n");
	fprintf(stderr,"use f.e. xv to convert into PBM format\n");
  	return ibgError;
 }
 if((l1=getnumber(file)) < 0) goto error;
 if((l2=getnumber(file)) < 0) goto error;
 l  = l1*l2;
 m  = malloc((l+5)*sizeof(color));
 cc = malloc(l+5);
 prev = malloc((*colors)+2);
 switch(cf){
 case '1':
	for(i=0;i<l;i++){
		n = getnumber(file);
		if(n>0){
			      	m[i].r = m[i].g = m[i].b = 0;
		}else if(n==0){
			      	m[i].r = m[i].g = m[i].b = 255;
		}else{
			goto error;
		}
	}
	break;
 case '2':
	col = getnumber(file);
	if(col>255) goto error;
	if(col<255){
		fac = (256/(col+1));
		for(i=0;i<l;i++){
			n = getnumber(file);
			if(n>=0){
			       	m[i].r = m[i].g = m[i].b = n*fac;
			}else{
				goto error;
			}
		}
	}else{
		for(i=0;i<l;i++){
			n = getnumber(file);
			if(n>=0){
			       	m[i].r = m[i].g = m[i].b = n*255/col;
			}else{
				goto error;
			}
		}
	}
	break;
 case '3':
	col = getnumber(file);
	if(col>255){ goto error;
	}else if(col<255){fac = (256/(col+1));
		for(i=0;i<l;i++){
			m[i].r = getnumber(file)*fac;
			if(m[i].r < 0) goto error;
			m[i].g = getnumber(file)*fac;
			if(m[i].g < 0) goto error;
			m[i].b = getnumber(file)*fac;
			if(m[i].b < 0) goto error;
		}
	}else{
		for(i=0;i<l;i++){
			m[i].r = getnumber(file);
			if(m[i].r < 0) goto error;
			m[i].g = getnumber(file);
			if(m[i].g < 0) goto error;
		    	m[i].b = getnumber(file);
			if(m[i].b < 0) goto error;
		}
	}
	break;
 case '4':
	lines = l/8;
	rest  = l%8; c = 0;
	rc = fread(cc,1,lines+1,file);
	for(i=0;i<lines;i++){
	       	c1 = cc[i]; k=128;
	 	for(j=0;j<8;j++){
			if(c1 & k ){
			      	m[c].r = m[c].g = m[c].b = 0;
			}else{
			      	m[c].r = m[c].g = m[c].b = 255;
			}
			c++; k /= 2;
		}
	}
 	for(j=0;j<rest;j++){
			if(c1 & k ){
			      	m[i].r = m[i].g = m[i].b = 0;
			}else{
			      	m[i].r = m[i].g = m[i].b = 255;
			}
			c++; k *= 2;
	}
	break;
 case '5':
	col = getnumber(file);
	if(col > 255) goto error;
	if(col < 255){fac = 256 / (col+1);
		rc = fread(cc,sizeof(color),l,file);
	      	for(i=0;i<l;i++){
			m[i].r = m[i].g = m[i].b = cc[i]*fac;
		}
	}else{
		rc = fread(cc,sizeof(color),l,file);
	      	for(i=0;i<l;i++){
			m[i].r = m[i].g = m[i].b = cc[i];
		}
	}
	break;
 case '6':
	col = getnumber(file);
	if(col > 255) goto error;
	rc = fread(m,sizeof(color),l,file);
	if(col < 255){fac = 256 / (col+1);
	      	for(i=0;i<l;i++){
			m[i].r *= fac;
			m[i].g *= fac;
			m[i].b *= fac;
		}
	}
	break;
 }
 free(cc);
 fclose(file);
/* now we have a true color pixmap. Now we create a colormap with maximal
   number of colors defined by the initial value of colors:
*/
colormap:
 ibgPixmapLx(*p) = l1;
 ibgPixmapLy(*p) = l2;
 ibgPixmapAlloc(*p);
 f[0] = f[1] = f[2] = 1; ff = 1;       
start:
 c = 0; last = 255; newt=1;
 for(i=l2-1;i>=0;i--){
	for(j=0;j<l1;j++){
		rr = m[c].r/f[0];
		gg = m[c].g/f[1];
		bb = m[c].b/f[2];
		t = last;
		while(t<255){
			if(rr != colmap[t].r) {t = prev[to=t]; continue;}
			if(gg != colmap[t].g) {t = prev[to=t]; continue;}
			if(bb != colmap[t].b) {t = prev[to=t]; continue;}
			break;
		}
		if(t==255){
			t = newt;  newt++;
			if(newt>= *colors){
	 			ff++; ff %= 3; f[ff] *= 2; goto start;
			}
			colmap[t].r = rr;
			colmap[t].g = gg;
		   	colmap[t].b = bb;
		 	prev[t] = last; last = t;
		}else if(t != last){
			prev[to] = prev[t];
		 	prev[t] = last; last = t;
		}
		ibgPixmapSegment(*p,j,i) = t;
		c++;
	}
 }
 *colors = newt;
 for(t=1;t<*colors;t++){
	colmap[t].r = ((colmap[t].r*f[0])*(((long unsigned)ibgColOn)+1))/256;
	colmap[t].g = ((colmap[t].g*f[1])*(((long unsigned)ibgColOn)+1))/256;
	colmap[t].b = ((colmap[t].b*f[2])*(((long unsigned)ibgColOn)+1))/256;
 }
 free(m);
 free(prev);
 fprintf(stderr,"pixmap file %s with %d x %d pixels and %d colors loaded\n",
	fname,l1,l2,*colors-1);
 return ibgSuccess;
error:
 fprintf(stderr,"error reading pixmap file %s\n",fname);
 return ibgError;
 
}