2d/clip.h

   1 /* $Id: clip.h,v 1.2 2002-07-17 21:55:19 bradleyb Exp $ */
   2 /*
   3 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
   4 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
   5 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
   6 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
   7 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
   8 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
   9 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
  10 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
  11 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
  12 COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
  13 */
  14 /*
  15  *
  16  * Macros used for clipping
  17  *
  18  * Old Log:
  19  *
  20  * Revision 1.3  1993/10/15  16:22:28  john
  21  * *** empty log message ***
  22  *
  23  * Revision 1.2  1993/09/29  16:14:31  john
  24  * made work with fix point
  25  *
  26  * Revision 1.1  1993/09/08  11:40:53  john
  27  * Initial revision
  28  *
  29  *
  30  */
  31
  32
  33 /*#define MIN(a,b)        (((a) < (b)) ? (a) : (b))
  34 #define MAX(a,b)        (((a) > (b)) ? (a) : (b))
  35 */
  36 #define IABS(x)         (((x) < 0) ?  -(x) : (x))
  37
  38 #define EXCHG(a,b) do {                                                 \
  39     int __temp__ = (a);                                                 \
  40     (a) = (b);                                                          \
  41     (b) = __temp__;                                                     \
  42 } while(0)
  43
  44 // sort two values
  45 #define SORT2(a,b) do {                                                 \
  46     if((a) > (b)) EXCHG(a,b);                                           \
  47 } while(0)
  48
  49 # define SCALE(var,arg,num,den)                                         \
  50     ((var) = ((arg) * (num)) / (den))
  51
  52 # define USCALE(var,arg,num,den)                                        \
  53         ((var) = ((unsigned)(arg) * (unsigned)(num)) / (unsigned)(den))
  54
  55 # define FSCALE(var,arg,num,den) ((var) = fixmuldiv((arg),(num),(den)))
  56
  57 #define CLIPDOT(xx,yy,WHEN_OUTSIDE,WHEN_CLIPPED) {                      \
  58     if((xx > XMAX) || (xx < XMIN)) { WHEN_OUTSIDE; }                    \
  59     if((yy > YMAX) || (yy < YMIN)) { WHEN_OUTSIDE; }                    \
  60 }
  61
  62 #define CLIPHLINE(x1,x2,yy,WHEN_OUTSIDE,WHEN_CLIPPED) {                 \
  63     if(x1 > x2) EXCHG(x1,x2);                                           \
  64     if((x1 > XMAX) || (x2 < XMIN)) { WHEN_OUTSIDE; }                    \
  65     if((yy > YMAX) || (yy < YMIN)) { WHEN_OUTSIDE; }                    \
  66     if(x1 < XMIN) { x1 = XMIN; WHEN_CLIPPED; }                          \
  67     if(x2 > XMAX) { x2 = XMAX; WHEN_CLIPPED; }                          \
  68 }
  69
  70 #define CLIPVLINE(xx,y1,y2,WHEN_OUTSIDE,WHEN_CLIPPED) {                 \
  71     if(y1 > y2) EXCHG(y1,y2);                                           \
  72     if((xx > XMAX) || (xx < XMIN)) { WHEN_OUTSIDE; }                    \
  73     if((y1 > YMAX) || (y2 < YMIN)) { WHEN_OUTSIDE; }                    \
  74     if(y1 < YMIN) { y1 = YMIN; WHEN_CLIPPED; }                          \
  75     if(y2 > YMAX) { y2 = YMAX; WHEN_CLIPPED; }                          \
  76 }
  77
  78 #define CLIPBOX(x1,y1,x2,y2,WHEN_OUTSIDE,WHEN_CLIPPED) {                \
  79     if(x1 > x2) EXCHG(x1,x2);                                           \
  80     if(y1 > y2) EXCHG(y1,y2);                                           \
  81     if((x1 > XMAX) || (x2 < 0)) { WHEN_OUTSIDE; }                       \
  82     if((y1 > YMAX) || (y2 < 0)) { WHEN_OUTSIDE; }                       \
  83     if(x1 < 0) { x1 = 0; WHEN_CLIPPED; }                                \
  84     if(y1 < 0) { y1 = 0; WHEN_CLIPPED; }                                \
  85     if(x2 > XMAX) { x2 = XMAX; WHEN_CLIPPED; }                          \
  86     if(y2 > YMAX) { y2 = YMAX; WHEN_CLIPPED; }                          \
  87 }
  88
  89 #define CLIPLINE(x1,y1,x2,y2,XMIN,YMIN,XMAX,YMAX,WHEN_OUTSIDE,WHEN_CLIPPED,MY_SCALE) do {       \
  90     register int temp;                                                  \
  91     if(y1 > y2)                                                         \
  92         { EXCHG(y1,y2); EXCHG(x1,x2); }                                 \
  93     if((y2 < YMIN) || (y1 > YMAX))                                      \
  94         { WHEN_OUTSIDE; }                                               \
  95     if(x1 < x2) {                                                       \
  96         if((x2 < XMIN) || (x1 > XMAX)) {                                \
  97             WHEN_OUTSIDE;                                               \
  98         }                                                               \
  99         if(x1 < XMIN) {                                                 \
 100                         MY_SCALE(temp,(y2 - y1),(XMIN - x1),(x2 - x1)); \
 101             if((y1 += temp) > YMAX) { WHEN_OUTSIDE; }                   \
 102             x1 = XMIN;                                                  \
 103             WHEN_CLIPPED;                                               \
 104         }                                                               \
 105         if(x2 > XMAX) {                                                 \
 106                         MY_SCALE(temp,(y2 - y1),(x2 - XMAX),(x2 - x1)); \
 107             if((y2 -= temp) < YMIN) { WHEN_OUTSIDE; }                   \
 108             x2 = XMAX;                                                  \
 109             WHEN_CLIPPED;                                               \
 110         }                                                               \
 111         if(y1 < YMIN) {                                                 \
 112                         MY_SCALE(temp,(x2 - x1),(YMIN - y1),(y2 - y1)); \
 113             x1 += temp;                                                 \
 114             y1 = YMIN;                                                  \
 115             WHEN_CLIPPED;                                               \
 116         }                                                               \
 117         if(y2 > YMAX) {                                                 \
 118                         MY_SCALE(temp,(x2 - x1),(y2 - YMAX),(y2 - y1)); \
 119             x2 -= temp;                                                 \
 120             y2 = YMAX;                                                  \
 121             WHEN_CLIPPED;                                               \
 122         }                                                               \
 123     }                                                                   \
 124     else {                                                              \
 125         if((x1 < XMIN) || (x2 > XMAX)) {                                \
 126             WHEN_OUTSIDE;                                               \
 127         }                                                               \
 128         if(x1 > XMAX) {                                                 \
 129                         MY_SCALE(temp,(y2 - y1),(x1 - XMAX),(x1 - x2)); \
 130             if((y1 += temp) > YMAX) { WHEN_OUTSIDE; }                   \
 131             x1 = XMAX;                                                  \
 132             WHEN_CLIPPED;                                               \
 133         }                                                               \
 134         if(x2 < XMIN) {                                                 \
 135                         MY_SCALE(temp,(y2 - y1),(XMIN - x2),(x1 - x2)); \
 136             if((y2 -= temp) < YMIN) { WHEN_OUTSIDE; }                   \
 137             x2 = XMIN;                                                  \
 138             WHEN_CLIPPED;                                               \
 139         }                                                               \
 140         if(y1 < YMIN) {                                                 \
 141                         MY_SCALE(temp,(x1 - x2),(YMIN - y1),(y2 - y1)); \
 142             x1 -= temp;                                                 \
 143             y1 = YMIN;                                                  \
 144             WHEN_CLIPPED;                                               \
 145         }                                                               \
 146         if(y2 > YMAX) {                                                 \
 147                         MY_SCALE(temp,(x1 - x2),(y2 - YMAX),(y2 - y1)); \
 148             x2 += temp;                                                 \
 149             y2 = YMAX;                                                  \
 150             WHEN_CLIPPED;                                               \
 151         }                                                               \
 152     }                                                                   \
 153 } while(0)