render/mitrap.c

   1 /*
   2  *
   3  * Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc.
   4  *
   5  * Permission to use, copy, modify, distribute, and sell this software and its
   6  * documentation for any purpose is hereby granted without fee, provided that
   7  * the above copyright notice appear in all copies and that both that
   8  * copyright notice and this permission notice appear in supporting
   9  * documentation, and that the name of Keith Packard not be used in
  10  * advertising or publicity pertaining to distribution of the software without
  11  * specific, written prior permission.  Keith Packard makes no
  12  * representations about the suitability of this software for any purpose.  It
  13  * is provided "as is" without express or implied warranty.
  14  *
  15  * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  16  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  17  * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  18  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  19  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  20  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  21  * PERFORMANCE OF THIS SOFTWARE.
  22  */
  23
  24 #ifdef HAVE_DIX_CONFIG_H
  25 #include <dix-config.h>
  26 #endif
  27
  28 #include "scrnintstr.h"
  29 #include "gcstruct.h"
  30 #include "pixmapstr.h"
  31 #include "windowstr.h"
  32 #include "servermd.h"
  33 #include "mi.h"
  34 #include "picturestr.h"
  35 #include "mipict.h"
  36
  37 static xFixed
  38 miLineFixedX(xLineFixed * l, xFixed y, Bool ceil)
  39 {
  40     xFixed dx = l->p2.x - l->p1.x;
  41     xFixed_32_32 ex = (xFixed_32_32) (y - l->p1.y) * dx;
  42     xFixed dy = l->p2.y - l->p1.y;
  43
  44     if (ceil)
  45         ex += (dy - 1);
  46     return l->p1.x + (xFixed) (ex / dy);
  47 }
  48
  49 void
  50 miTrapezoidBounds(int ntrap, xTrapezoid * traps, BoxPtr box)
  51 {
  52     box->y1 = MAXSHORT;
  53     box->y2 = MINSHORT;
  54     box->x1 = MAXSHORT;
  55     box->x2 = MINSHORT;
  56     for (; ntrap; ntrap--, traps++) {
  57         INT16 x1, y1, x2, y2;
  58
  59         if (!xTrapezoidValid(traps))
  60             continue;
  61         y1 = xFixedToInt(traps->top);
  62         if (y1 < box->y1)
  63             box->y1 = y1;
  64
  65         y2 = xFixedToInt(xFixedCeil(traps->bottom));
  66         if (y2 > box->y2)
  67             box->y2 = y2;
  68
  69         x1 = xFixedToInt(min(miLineFixedX(&traps->left, traps->top, FALSE),
  70                              miLineFixedX(&traps->left, traps->bottom, FALSE)));
  71         if (x1 < box->x1)
  72             box->x1 = x1;
  73
  74         x2 = xFixedToInt(xFixedCeil
  75                          (max
  76                           (miLineFixedX(&traps->right, traps->top, TRUE),
  77                            miLineFixedX(&traps->right, traps->bottom, TRUE))));
  78         if (x2 > box->x2)
  79             box->x2 = x2;
  80     }
  81 }