2d/clip.h

   1 /* $Id: clip.h,v 1.3 2002-10-10 18:55:32 btb 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)