2d/clip.h

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