2d/clip.h

   1 /* $Id: clip.h,v 1.4 2004-08-28 23:17:45 schaffner 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  */
  19
  20
  21 /*#define MIN(a,b)    (((a) < (b)) ? (a) : (b))
  22 #define MAX(a,b)        (((a) > (b)) ? (a) : (b))
  23 */
  24 #define IABS(x)         (((x) < 0) ?  -(x) : (x))
  25
  26 #define EXCHG(a,b) do {                                                 \
  27         int __temp__ = (a);                                                 \
  28         (a) = (b);                                                          \
  29         (b) = __temp__;                                                     \
  30 } while(0)
  31
  32 // sort two values
  33 #define SORT2(a,b) do {                                                 \
  34         if((a) > (b)) EXCHG(a,b);                                           \
  35 } while(0)
  36
  37 # define SCALE(var,arg,num,den)                                         \
  38         ((var) = ((arg) * (num)) / (den))
  39
  40 # define USCALE(var,arg,num,den)                                        \
  41         ((var) = ((unsigned)(arg) * (unsigned)(num)) / (unsigned)(den))
  42
  43 # define FSCALE(var,arg,num,den) ((var) = fixmuldiv((arg),(num),(den)))
  44
  45 #define CLIPDOT(xx,yy,WHEN_OUTSIDE,WHEN_CLIPPED) {                      \
  46         if((xx > XMAX) || (xx < XMIN)) { WHEN_OUTSIDE; }                    \
  47         if((yy > YMAX) || (yy < YMIN)) { WHEN_OUTSIDE; }                    \
  48 }
  49
  50 #define CLIPHLINE(x1,x2,yy,WHEN_OUTSIDE,WHEN_CLIPPED) {                 \
  51         if(x1 > x2) EXCHG(x1,x2);                                           \
  52         if((x1 > XMAX) || (x2 < XMIN)) { WHEN_OUTSIDE; }                    \
  53         if((yy > YMAX) || (yy < YMIN)) { WHEN_OUTSIDE; }                    \
  54         if(x1 < XMIN) { x1 = XMIN; WHEN_CLIPPED; }                          \
  55         if(x2 > XMAX) { x2 = XMAX; WHEN_CLIPPED; }                          \
  56 }
  57
  58 #define CLIPVLINE(xx,y1,y2,WHEN_OUTSIDE,WHEN_CLIPPED) {                 \
  59         if(y1 > y2) EXCHG(y1,y2);                                           \
  60         if((xx > XMAX) || (xx < XMIN)) { WHEN_OUTSIDE; }                    \
  61         if((y1 > YMAX) || (y2 < YMIN)) { WHEN_OUTSIDE; }                    \
  62         if(y1 < YMIN) { y1 = YMIN; WHEN_CLIPPED; }                          \
  63         if(y2 > YMAX) { y2 = YMAX; WHEN_CLIPPED; }                          \
  64 }
  65
  66 #define CLIPBOX(x1,y1,x2,y2,WHEN_OUTSIDE,WHEN_CLIPPED) {                \
  67         if(x1 > x2) EXCHG(x1,x2);                                           \
  68         if(y1 > y2) EXCHG(y1,y2);                                           \
  69         if((x1 > XMAX) || (x2 < 0)) { WHEN_OUTSIDE; }                       \
  70         if((y1 > YMAX) || (y2 < 0)) { WHEN_OUTSIDE; }                       \
  71         if(x1 < 0) { x1 = 0; WHEN_CLIPPED; }                                \
  72         if(y1 < 0) { y1 = 0; WHEN_CLIPPED; }                                \
  73         if(x2 > XMAX) { x2 = XMAX; WHEN_CLIPPED; }                          \
  74         if(y2 > YMAX) { y2 = YMAX; WHEN_CLIPPED; }                          \
  75 }
  76
  77 #define CLIPLINE(x1,y1,x2,y2,XMIN,YMIN,XMAX,YMAX,WHEN_OUTSIDE,WHEN_CLIPPED,MY_SCALE) do {       \
  78         register int temp;                                                  \
  79         if(y1 > y2)                                                         \
  80                 { EXCHG(y1,y2); EXCHG(x1,x2); }                                 \
  81         if((y2 < YMIN) || (y1 > YMAX))                                      \
  82                 { WHEN_OUTSIDE; }                                               \
  83         if(x1 < x2) {                                                       \
  84                 if((x2 < XMIN) || (x1 > XMAX)) {                                \
  85                         WHEN_OUTSIDE;                                               \
  86                 }                                                               \
  87                 if(x1 < XMIN) {                                                 \
  88                         MY_SCALE(temp,(y2 - y1),(XMIN - x1),(x2 - x1)); \
  89                         if((y1 += temp) > YMAX) { WHEN_OUTSIDE; }                   \
  90                         x1 = XMIN;                                                  \
  91                         WHEN_CLIPPED;                                               \
  92                 }                                                               \
  93                 if(x2 > XMAX) {                                                 \
  94                         MY_SCALE(temp,(y2 - y1),(x2 - XMAX),(x2 - x1)); \
  95                         if((y2 -= temp) < YMIN) { WHEN_OUTSIDE; }                   \
  96                         x2 = XMAX;                                                  \
  97                         WHEN_CLIPPED;                                               \
  98                 }                                                               \
  99                 if(y1 < YMIN) {                                                 \
 100                         MY_SCALE(temp,(x2 - x1),(YMIN - y1),(y2 - y1)); \
 101                         x1 += temp;                                                 \
 102                         y1 = YMIN;                                                  \
 103                         WHEN_CLIPPED;                                               \
 104                 }                                                               \
 105                 if(y2 > YMAX) {                                                 \
 106                         MY_SCALE(temp,(x2 - x1),(y2 - YMAX),(y2 - y1)); \
 107                         x2 -= temp;                                                 \
 108                         y2 = YMAX;                                                  \
 109                         WHEN_CLIPPED;                                               \
 110                 }                                                               \
 111         }                                                                   \
 112         else {                                                              \
 113                 if((x1 < XMIN) || (x2 > XMAX)) {                                \
 114                         WHEN_OUTSIDE;                                               \
 115                 }                                                               \
 116                 if(x1 > XMAX) {                                                 \
 117                         MY_SCALE(temp,(y2 - y1),(x1 - XMAX),(x1 - x2)); \
 118                         if((y1 += temp) > YMAX) { WHEN_OUTSIDE; }                   \
 119                         x1 = XMAX;                                                  \
 120                         WHEN_CLIPPED;                                               \
 121                 }                                                               \
 122                 if(x2 < XMIN) {                                                 \
 123                         MY_SCALE(temp,(y2 - y1),(XMIN - x2),(x1 - x2)); \
 124                         if((y2 -= temp) < YMIN) { WHEN_OUTSIDE; }                   \
 125                         x2 = XMIN;                                                  \
 126                         WHEN_CLIPPED;                                               \
 127                 }                                                               \
 128                 if(y1 < YMIN) {                                                 \
 129                         MY_SCALE(temp,(x1 - x2),(YMIN - y1),(y2 - y1)); \
 130                         x1 -= temp;                                                 \
 131                         y1 = YMIN;                                                  \
 132                         WHEN_CLIPPED;                                               \
 133                 }                                                               \
 134                 if(y2 > YMAX) {                                                 \
 135                         MY_SCALE(temp,(x1 - x2),(y2 - YMAX),(y2 - y1)); \
 136                         x2 += temp;                                                 \
 137                         y2 = YMAX;                                                  \
 138                         WHEN_CLIPPED;                                               \
 139                 }                                                               \
 140         }                                                                   \
 141 } while(0)