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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: filling area by color atack safety
Date: Tue, 09 Apr 2024 01:00:34 -0700
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Michael S <already5chosen@yahoo.com> writes:

> On Sat, 30 Mar 2024 00:54:19 -0700
> Tim Rentsch <tr.17687@z991.linuxsc.com> wrote:
[...]
>> Something that would help is to have a library of test cases,
>> by which I mean patterns to be colored, so that a set of
>> methods could be tried, and timed, over all the patterns in
>> the library.  Do you have something like that?  So far all
>> my testing has been ad hoc.
>
> I am not 100% sure about the meaning of 'ad hoc', but I'd guess
> that mine are ad hoc too.  Below are shapes that I use apart from
> solid rectangles.  I run them at 5 sizes: 25x19, 200x200,
> 1280x720, 1920x1080, 3840x2160.  That is certainly not enough for
> correction tests, but feel that it is sufficient for speed tests.
>
> [code]

I got these, thank you.

Here is a pattern generating function I wrote for my own
testing.  Disclaimer: slightly changed from my original
source, hopefully any errors inadvertently introduced can
be corrected easily.  Also, it uses the value 0 for the
background and the value 1 for the pattern to be colored.

#include <math.h>
#include <stddef.h>
#include <string.h>

typedef unsigned char Pixel;

extern void
ellipse_with_hole( Pixel *field, unsigned w, unsigned h ){
    size_t i, j;
    double wc = w/2, hc = h/2;

    double a = (w > h ? wc : hc) -1;
    double b = (w > h ? hc : wc) -1;

    double b3 = 1+6*b/8;
    double radius = b/2.5;
    double cx = w > h ? wc   : b3+1;
    double cy = w > h ? b3+1 : hc;

    double focus = sqrt( a*a - b*b );
    double f1x = w > h ? wc - focus : wc;
    double f1y = w > h ? hc : hc - focus;
    double f2x = w > h ? wc + focus : wc;
    double f2y = w > h ? hc : hc + focus;

    memset( field, 0, w*h );

    for(  i = 0;  i < w;  i++  ){
    for(  j = 0;  j < h;  j++  ){
        double dx = i - cx, dy = j - cy;
        double r2 = radius * radius;
        if(  dx * dx + dy*dy <= r2  )  continue;
        double dx1 = i - f1x, dy1 = j - f1y;
        double dx2 = i - f2x, dy2 = j - f2y;
        double sum2 = a*2;
        double d1 = sqrt( dx1*dx1 + dy1*dy1 );
        double d2 = sqrt( dx2*dx2 + dy2*dy2 );
        if(  d1 + d2 > 2*a  )  continue;
        field[ i+j*w ] = 1;
    }}
}