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Annotation of researchv9/jerq/src/lib/j/discture.c, revision 1.1.1.1

1.1       root        1: #ifndef        MUX
                      2: #define        Jcursinhibit()  cursinhibit()
                      3: #define        Jcursallow()    cursallow()
                      4: #define        lrectf(l, r, f) rectf(l, r, f)
                      5: #endif
                      6: 
                      7: #include <jerq.h>
                      8: /*     Fill a disc of radius r centered at x1,y1
                      9:  *     The boundary is a sequence of vertically, horizontally,
                     10:  *     or diagonally adjacent points that minimize 
                     11:  *     abs(x^2+y^2-r^2).
                     12:  *
                     13:  *     The circle is guaranteed to be symmetric about
                     14:  *     the horizontal, vertical, and diagonal axes
                     15:  */
                     16: discture(b, p, r, t, f)
                     17:        Bitmap *b;
                     18:        Point p;
                     19:        Texture *t;
                     20: {
                     21:        short inhibited;
                     22:        int eps,exy,dxsq,dysq;
                     23:        register x0,y0,x1,y1;
                     24:        r--;
                     25:        eps = 0;
                     26:        dxsq = 1;
                     27:        dysq = 1 - 2*r;
                     28:        x0 = p.x-1;
                     29:        x1 = p.x+1;
                     30:        y0 = p.y-r-1;
                     31:        y1 = p.y+r;
                     32:        inhibited=0;
                     33:        if(f!=F_XOR){
                     34:                Jcursinhibit();
                     35:                inhibited=1;
                     36:        }
                     37:        while(y1 > y0) {
                     38:                exy = eps + dxsq + dysq;
                     39:                if(-exy <= eps+dxsq) {
                     40:                        ltexture(b, Rect(x0, y0, x1, y0+1), t, f);
                     41:                        ltexture(b, Rect(x0, y1, x1, y1+1), t, f);
                     42:                        y1--;
                     43:                        y0++;
                     44:                        eps += dysq;
                     45:                        dysq += 2;
                     46:                }
                     47:                if(exy <= -eps) {
                     48:                        x1++;
                     49:                        x0--;
                     50:                        eps += dxsq;
                     51:                        dxsq += 2;
                     52:                }
                     53:        }
                     54:        if(inhibited)
                     55:                Jcursallow();
                     56: }

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