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/*
* BUGS:
* adjacient colours could have higher contrast
* negative angles
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
const float tau=(float)(M_PI*2);
// draw sector
void draw(float angle, char* label){
const float r=100;
static float progress=0;
static float overlap=0;
float fangle; if(angle<0)fangle=-angle;else fangle=angle-overlap;
// Mx,y : move to x,y
// Lx,y : draw line to x,y
// Arx,ry rot 0,0 x,y : arc with radii rx,ry rotated by rot large-arch or not,clockwise or not to point x,y
// z : closes the path
float x1=r*cosf(progress);
float y1=r*sinf(progress);
float x2=r*cosf(progress+fangle);
float y2=r*sinf(progress+fangle);
float divider=progress+fangle/2;
unsigned char rr=(unsigned char)(0xff*((divider)/(tau)));
unsigned char gg=(unsigned char)(0xff*((divider-tau/3)/(tau)));
unsigned char bb=(unsigned char)(0xff*((divider-2*tau/3)/(tau)));
printf("<path stroke=\"#000000\" fill=\"#%02x%02x%02x\" d=\"M250,250 L%f,%f A%f,%f 0 %d,%d %f,%f z\"/>",rr,gg,bb,250+x1,250+y1,r,r,(fangle>M_PI),1,250+x2,250+y2);
float xo=250+(3*r/2*cosf(divider));
float yo=250+(3*r/2*sinf(divider));
printf("<line stroke=\"#000000\" x1=\"%f\" y1=\"%f\" x2=\"%f\" y2=\"%f\" />",250+(2*r/3*cosf(divider)),250+(2*r/3*sinf(divider)),xo,yo);
printf("<text x=\"%f\" y=\"%f\">%s</text>\n",xo,yo,label);
progress+=fangle;
overlap-=angle; // multiple overlaps accumulate
if(overlap<0)overlap=0;
}
// put preliminary data on the stack
float scan_line (FILE* input, float sum){
char* line=NULL; size_t len=0;
if(getline(&line,&len,input) != -1){
{ // chomp
char* l=&(line[strlen(line)-1]);
if(*l=='\n')*l='\0';
}
/* at the very least, we need a true value.
* everything following it can be label or whatever.
* if strtof does not find anything (or the value is miniscule), the line is obviously a comment and should be ignored.
* (if the value is too huge to handle, the output will be meaningless.)
*
* If the value is negative, it is meant to overlap with the previous record. Or records.
* The value would have to be ignored for computing the sum total.
*/
char* label=line;
float number=strtof(label,&label);
if(number>0){
sum=scan_line(input,sum+number);
float angle=tau*number/sum;
draw(angle,label);
}else if(number<0){
sum=scan_line(input,sum);
float angle=tau*number/sum;
draw(angle,label);
}else{
sum=scan_line(input,sum);
printf("<!-- %s -->\n",label);
}
}
free(line);
return sum;
}
int main(int argc, char** argv){
FILE* input=stdin;
// getopts
// print boilerplate
puts("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n\
<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1/EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n\
<svg\n\
xmlns=\"http://www.w3.org/2000/svg\"\n\
version=\"1.1\"\n\
width=\"500\"\n\
height=\"500\"\n\
viewBox=\"0 0 500 500\"\n\
>");
scan_line(input,0);
puts("</svg>");
return 0;
}
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