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Annotation of researchv9/jerq/src/lib/layer/layerop.c, revision 1.1

1.1     ! root        1: #include <jerq.h>
        !             2: #include "layer.h"
        !             3: 
        !             4: /*
        !             5:  * Magic
        !             6:  *
        !             7:  * Intersect a rectangle to a layer, doing all subdivision into rectangles.
        !             8:  * layerop() clips rectangle to outer edge of layer, then calls mRlayerop
        !             9:  * which recursively chains along the layer list, doing op's (specified
        !            10:  * by a pointer to a function) whenever there is an intersection.  Differs
        !            11:  * from rob's by taking a direction of evaluation, so that the subrectangles
        !            12:  * produced are properly sorted for bitblt from a layer to itself.
        !            13:  *
        !            14:  */
        !            15: 
        !            16: /* For the portion outside the current layer, we use recursion */
        !            17: #define        out(or,co)      mRlayerop(l, fn, Rpt(or,co), fp, o->back)
        !            18: 
        !            19: /* For the portion inside, we perform the function */
        !            20: #define in(r)  (*fn)(l, r, (l?l->obs:0), fp, o)
        !            21: 
        !            22: #define C_DONE 0
        !            23: #define C_UP   1
        !            24: #define C_LEFT 2
        !            25: #define C_MID  3
        !            26: #define C_RIGHT        4
        !            27: #define C_DOWN 5
        !            28: 
        !            29: int blitdir = 0;       /* direction from source to destination */
        !            30: 
        !            31: /*
        !            32:  * directions:  0 = up and left,
        !            33:  *             1 = up and right,
        !            34:  *             2 = down and left,
        !            35:  *             3 = down and right
        !            36:  */
        !            37: 
        !            38: static short nextcase[4][6] = {
        !            39:        C_UP, C_LEFT, C_MID, C_RIGHT, C_DOWN, C_DONE,
        !            40:        C_UP, C_RIGHT, C_MID, C_LEFT, C_DOWN, C_DONE,
        !            41:        C_DOWN, C_LEFT, C_MID, C_RIGHT, C_UP, C_DONE,
        !            42:        C_DOWN, C_RIGHT, C_MID, C_LEFT, C_UP, C_DONE,
        !            43: };
        !            44: 
        !            45: mRlayerop(l, fn, r, fp, o)
        !            46:        register Layer *l;
        !            47:        void (*fn)();
        !            48:        Rectangle r;    /* Screen coords */
        !            49:        int *fp;
        !            50:        register Layer *o;
        !            51: {
        !            52:        Rectangle clipr;
        !            53:        register Rectangle *rp= &r, *cp= &clipr, *bp;
        !            54:        register short *next;
        !            55: 
        !            56:        *cp = *rp;
        !            57: Top:
        !            58:        bp= &o->rect;
        !            59:        if((o==l) || (o==0))    /* We have a piece that wasn't obscured */
        !            60:                (*fn)(l, r, l, fp, o);
        !            61:        else if (rectclip(cp, *bp)==0) {        /* note side-effect to clipr */
        !            62:                o=o->back;      /* efficiency hack */
        !            63:                goto Top;
        !            64:        } else {
        !            65:                /* They must overlap */
        !            66:                for (next=&nextcase[blitdir][0]; *next != C_DONE; )
        !            67:                        switch(*next++) {
        !            68:                        case C_UP:
        !            69:                                if (rp->origin.y<bp->origin.y)
        !            70:                                        out(rp->origin,
        !            71:                                            Pt(rp->corner.x, bp->origin.y));
        !            72:                                break;
        !            73:                        case C_DOWN:
        !            74:                                if (rp->corner.y>bp->corner.y)
        !            75:                                        out(Pt(rp->origin.x, bp->corner.y),
        !            76:                                            rp->corner);
        !            77:                                break;
        !            78:                        case C_LEFT:
        !            79:                                if (rp->origin.x<bp->origin.x)
        !            80:                                        out(Pt(rp->origin.x, cp->origin.y),
        !            81:                                            Pt(bp->origin.x, cp->corner.y));
        !            82:                                break;
        !            83:                        case C_RIGHT:
        !            84:                                if (rp->corner.x>bp->corner.x)
        !            85:                                        out(Pt(bp->corner.x, cp->origin.y),
        !            86:                                            Pt(rp->corner.x, cp->corner.y));
        !            87:                                break;
        !            88:                        case C_MID:
        !            89:                                in(*cp);
        !            90:                                break;
        !            91:                        }
        !            92:        }
        !            93: }
        !            94: 
        !            95: /*
        !            96:  * Clip to outer rectangle of layer, then call layerop
        !            97:  */
        !            98: /*VARARGS3*/
        !            99: layerop(l, fn, r, f)
        !           100:        register Layer *l;
        !           101:        void (*fn)();
        !           102:        Rectangle r;    /* Screen coords */
        !           103:        int f;
        !           104: {
        !           105:        if(l && (rectclip(&r, l->rect)==0))
        !           106:                return;
        !           107:        if (l && (l->someobs == l->nonevis))
        !           108:                (*fn)(l, r, l->nonevis?l->obs:(Bitmap *)l, &f,
        !           109:                      (l->nonevis?lfront:l));
        !           110:        else
        !           111:                mRlayerop(l, fn, r, &f, lfront);
        !           112: }

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