Return to elarc.c CVS log

Up to [Research Unix] / researchv9 / jerq / src / lib / j

Annotation of researchv9/jerq/src/lib/j/elarc.c, revision 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: #define        lsegment(l, p, q, f)    segment(l, p, q, f)
        !             6: #endif
        !             7: 
        !             8: #include       <jerq.h>
        !             9: #define        DB              ((Word *)0x700000)
        !            10: #define        ONSCREEN(b)     (b->base>=DB && b->base<DB+XMAX/WORDSIZE*YMAX)
        !            11: #define HUGE 017777777777
        !            12: #define        sgn(x)  ((x)<0? -1 : (x)==0? 0 : 1)
        !            13: 
        !            14: #ifdef MUX
        !            15: #define        POINT   Tvoid(26)       /* really lpoint, but we're dealing with the cursor */
        !            16: #else
        !            17: extern void point();
        !            18: #define        POINT   point
        !            19: #endif
        !            20: 
        !            21: static struct dist {
        !            22:        Point s;
        !            23:        Point m;
        !            24:        long e;
        !            25: } d1, d2;
        !            26: 
        !            27: static void
        !            28: test(x, p)
        !            29:        Point x;
        !            30:        register struct dist *p;
        !            31: {
        !            32:        register long dx = x.x - p->s.x;
        !            33:        register long dy = x.y - p->s.y;
        !            34:        register long e = dx*dx+dy*dy;
        !            35: 
        !            36:        if(e <= p->e) {
        !            37:                p->m = x;
        !            38:                p->e = e;
        !            39:        }
        !            40: }
        !            41: 
        !            42: static void
        !            43: survey(bp, x, f)
        !            44:        Bitmap *bp;
        !            45:        Point x;
        !            46:        Code f;
        !            47: {
        !            48:        test(x, &d1);
        !            49:        test(x, &d2);
        !            50: }
        !            51: /*
        !            52:  * elarc(bp,p0,a,b,p1,p2,f) draws in bitmap bp an arc of the ellipse
        !            53:  * centered at p0 with half-axes a,b extending counterclockwise
        !            54:  * from a point near p1 to a point near p2
        !            55:  * args reversed because ellip1 draws clockwise 
        !            56:  */
        !            57: elarc(bp,p0,a,b,p1,p2,f)
        !            58:        Bitmap *bp;
        !            59:        Point p0, p1, p2;
        !            60:        Code f;
        !            61: {
        !            62:        short inhibited;
        !            63:        inhibited=0;
        !            64:        if(f!=F_XOR && ONSCREEN(bp)){
        !            65:                Jcursinhibit();
        !            66:                inhibited=1;
        !            67:        }
        !            68:        if(a==0)
        !            69:                lsegment(bp, Pt(p0.x, p1.y), Pt(p0.x, p2.y), f);
        !            70:        else if(b==0)
        !            71:                lsegment(bp, Pt(p1.x, p0.y), Pt(p2.x, p0.y), f);
        !            72:        else {
        !            73:                int sx1;
        !            74:                int sy1;
        !            75:                int sx2;
        !            76:                int sy2;
        !            77: 
        !            78:                d1.s = sub(p1, p0);
        !            79:                d2.s = sub(p2, p0);
        !            80:                sx1 = sgn(d1.s.x);
        !            81:                sy1 = sgn(d1.s.y);
        !            82:                sx2 = sgn(d2.s.x);
        !            83:                sy2 = sgn(d2.s.y);
        !            84:                d1.s.x *= sx1;
        !            85:                d1.s.y *= sy1;
        !            86:                d2.s.x *= sx2;
        !            87:                d2.s.y *= sy2;
        !            88:                d1.e = d2.e = HUGE;
        !            89:                survey(bp, Pt(0, b), f);
        !            90:                ellip1(bp, Pt(0, 0), a, b, survey, Pt(0,b), Pt(a, 0), f);
        !            91:                if(!eqpt(d1.m, d2.m))
        !            92:                        POINT(bp, d1.m, f);
        !            93:                ellip1(bp, p0, a, b, POINT,
        !            94:                        Pt(d1.m.x*sx1, d1.m.y*sy1), Pt(d2.m.x*sx2, d2.m.y*sy2), f);
        !            95:        }
        !            96:        if(inhibited)
        !            97:                Jcursallow();
        !            98: }

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.