/*****************************************************************/
/* CONVOLVE.C - Turbo C 2.0 implementation of image convolution */
/* ---------- by Wesley G. Faler. All code is "as is". There */
/* is NO copyright. Use this code as you will, and if you make */
/* money at it, good for you. */
/*****************************************************************/

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

int load_cut(char *fname);
int load_convolution_matrix(char *fname);
int convolve_image(void);
int swap_pictures(void);

int minx,maxx,miny,maxy;
int LOADPAGE=0;
int ENHANCEPAGE=1;
int *cmat, *pmat, *vmat;
int cmx,cmy,cmnum;

struct palettetype palette,newpal;
int driver,mode;

int cleancut=-1;

int init_graphics(void)
{
driver=DETECT; mode=0;
detectgraph(&driver,&mode);
if(driver==VGA) mode=VGAMED;
initgraph(&driver,&mode,"");
getpalette(&palette);
getpalette(&newpal);
}

int cleanup_image(void)
{
int i,j,num,x,y,k;

if(cleancut<0) return;
setactivepage(LOADPAGE);
setvisualpage(ENHANCEPAGE);
for(x=minx;x<maxx;x++) {
for(y=miny;y<maxy;y++) {
if(getpixel(x,y)!=0) num=-1;
else num=0;
for(j=-1;j<2;j++) {
for(i=-1;i<2;i++) {
if(getpixel(x+i,y+j)!=0) num++;
}
}
if(num>cleancut) {
k=getpixel(x,y);
setactivepage(ENHANCEPAGE);
putpixel(x,y,k);
setactivepage(LOADPAGE);
}
}
}
k=ENHANCEPAGE; ENHANCEPAGE=LOADPAGE; LOADPAGE=k;
}

void show_test_image(void)
{
int i;

minx=cmx; miny=cmy;
maxx=100+minx; maxy=100+miny;
setcolor(1);
moveto(minx,miny);
randomize();
for(i=0;i<20;i++)
lineto(random(100)+minx,random(100)+miny);
for(i=0;i<10;i++)
fillellipse(random(50)+25+minx,random(50)+25+miny,random(25),random(25));
}

main()
{
char fname[50];
int flag=0;

load_convolution_matrix("matrix.dat");
printf(".CUT file (1) or test image (0)?");
scanf("%d",&flag);
flag= flag? 1:0;
if(flag) {
fflush(stdin);
printf("filename to process:");
gets(fname);
}

printf("Delete pixels with x or fewer neighbors. x=");
scanf("%d",&cleancut);
if(cleancut>8) cleancut=8;

init_graphics();
setactivepage(1); cleardevice();
setactivepage(0); cleardevice();

setactivepage(LOADPAGE); setvisualpage(LOADPAGE);
if(flag) load_cut(fname);
else show_test_image();
cleanup_image();

setvisualpage(ENHANCEPAGE);
convolve_image();

swap_pictures();
restorecrtmode();
}

int toggle_colors(char c)
{
c=tolower(c);
c=c-'a';
if(c<0 || c>=palette.size) return 0;
newpal.colors[c]= palette.colors[c]-newpal.colors[c];
setpalette(c,newpal.colors[c]);
return 1;
}

int swap_pictures(void)
{
int mode=0;
char a;

setvisualpage(LOADPAGE);
for(;;) {
a=getch();
if(a==27) return;
if(toggle_colors(a)) continue;
if(mode==0) setvisualpage(ENHANCEPAGE);
if(mode==1) setvisualpage(LOADPAGE);
mode=1-mode;
}
}

int convolve_image(void)
{
int i,j,k,nval;
int *vx, *vy, *c;
int colmax,offset,end,midy;
char **lines=NULL;
char *temp=NULL;

offset=-minx+(cmx/2);
end=cmy-1; midy=cmy/2;
lines=(char **)malloc(cmy*sizeof(char *));
for(i=0;i<cmy;i++) lines[i]=(char *)malloc(sizeof(char)*(maxx-minx+cmx+1));
setactivepage(LOADPAGE);
for(j=-cmy/2;j<cmy/2;j++) {
for(i=minx-cmx/2;i<(maxx+cmx/2+1);i++) {
lines[j+midy][i+offset]=getpixel(i,j+miny);
}
}
colmax=getmaxcolor();
for(j=miny;j<maxy;j++) {
setactivepage(LOADPAGE);
for(i=j+cmy/2,k=minx-cmx/2,nval=maxx+cmx/2;k<nval;k++)
lines[end][k+offset]=getpixel(k,i);
for(i=minx;i<maxx;i++) {
/* Load & multiply neighbors into matrix */
setactivepage(LOADPAGE);
vx=vmat; vy=vmat+1; c=cmat; nval=0;
for(k=0;k<cmnum;k++) {
if(*c) nval+= lines[(*vy)+midy][i+(*vx)+offset]*(*c);
/* if(*c) nval+= getpixel(i+(*vx),j+(*vy)) * (*c); */
c++;
vx+=2; vy+=2;
}
/* Cut off values too high or too low */
if(nval<0) nval=0;
if(nval>colmax) nval=colmax;
/* Place new pixel value */
setactivepage(ENHANCEPAGE);
putpixel(i,j,nval);
}
if(kbhit()) { getch(); break; }
/* rotate line pointers */
temp=lines[0];
for(i=1;i<cmy;i++) lines[i-1]=lines[i];
lines[end]=temp;
}
for(i=0;i<cmy;i++) {
if(lines[i]!=NULL) free(lines[i]);
}
if(lines!=NULL) {
free(lines);
}
return;
}

int build_offset_vectors(void)
{
int *t;
int il,im,jl,jm,i,j;

il=-cmx/2; im=cmx+il;
jl=-cmy/2; jm=cmy+jl;
t=vmat;
for(j=jl;j<jm;j++) {
for(i=il;i<im;i++) {
*t++=i; *t++=j;
}
}
}

int load_convolution_matrix(char *fname)
{
/* Layout of matrix file:
#x #y
x0y0 x1y0 ... xny1
.... .... ... ....
x0ym x1ym ... xnym
*/
FILE *mf;
int *t;
int i,j,im,jm;

if( (mf=fopen(fname,"rt"))==NULL ) {
printf("Cannot load matrix file.\n");
abort();
}
fscanf(mf,"%d%d",&im,&jm);
if( (im&1)==0 || (jm&1)==0 ) {
printf("Convolution matrix MUST have a center point.\n");
abort();
}
if( (cmat=(int *)calloc(im*jm,sizeof(int)))==NULL ) {
printf("Unable to calloc convolution matrix.\n");
abort();
}
if( (vmat=(int *)calloc(2*im*jm,sizeof(int)))==NULL ) {
printf("Unable to calloc offset vector matrix.\n");
abort();
}
cmx=im; cmy=jm; cmnum=im*jm;
t=cmat;
for(j=0;j<jm;j++) {
for(i=0;i<im;i++) {
if( fscanf(mf,"%d",t++)!=1 ) {
printf("Unable to read matrix.\n");
abort();
}
}
}
fclose(mf);
build_offset_vectors();
}

int load_cut(char *fname)
{
static unsigned char st[3000];
char *sp=st,*spend;
int stp=0;
int width,height;
FILE *fp;
int x,y,xl,yl;
int i,n,len,d,j;

fp=fopen(fname,"rb");
width=getw(fp); height=getw(fp);
xl=cmx; yl=cmy;
minx=xl; miny=yl;
maxx=xl+width; maxy=yl+height;
if(maxy>(getmaxy()-cmy)) {
maxy=getmaxy()-cmy;
height=maxy-yl;
}
getw(fp);
y=yl-1;
for(sp=st,n=0;n<height;n++) {
stp=getw(fp);
for(sp=st,spend=st+stp;sp<spend;) *sp++=getc(fp);
sp=st; spend=sp+stp; x=xl; y++;
while(sp<spend) {
if(*((unsigned char *)sp)>0x80) {
len=(*sp++) & 0x7f;
if(!(*sp)) { x+=len; continue; }
setcolor(*sp++);
moveto(x,y);
linerel(len,0);
x+=len;
continue;
} else {
len=*sp++;
for(j=0;j<len;j++) putpixel(x++,y,*sp++);
continue;
}
}
}
fclose(fp);
}