source/libs/pixman/pixman-src/pixman/pixman-edge-imp.h

   1 /*
   2  * Copyright © 2004 Keith Packard
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that
   7  * copyright notice and this permission notice appear in supporting
   8  * documentation, and that the name of Keith Packard not be used in
   9  * advertising or publicity pertaining to distribution of the software without
  10  * specific, written prior permission.  Keith Packard makes no
  11  * representations about the suitability of this software for any purpose.  It
  12  * is provided "as is" without express or implied warranty.
  13  *
  14  * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  20  * PERFORMANCE OF THIS SOFTWARE.
  21  */
  22
  23 #ifndef rasterize_span
  24 #endif
  25
  26 static void
  27 RASTERIZE_EDGES (pixman_image_t  *image,
  28                 pixman_edge_t   *l,
  29                 pixman_edge_t   *r,
  30                 pixman_fixed_t          t,
  31                 pixman_fixed_t          b)
  32 {
  33     pixman_fixed_t  y = t;
  34     uint32_t  *line;
  35     uint32_t *buf = (image)->bits.bits;
  36     int stride = (image)->bits.rowstride;
  37     int width = (image)->bits.width;
  38
  39     line = buf + pixman_fixed_to_int (y) * stride;
  40
  41     for (;;)
  42     {
  43         pixman_fixed_t  lx;
  44         pixman_fixed_t      rx;
  45         int     lxi;
  46         int rxi;
  47
  48         lx = l->x;
  49         rx = r->x;
  50 #if N_BITS == 1
  51         /* For the non-antialiased case, round the coordinates up, in effect
  52          * sampling just slightly to the left of the pixel. This is so that
  53          * when the sample point lies exactly on the line, we round towards
  54          * north-west.
  55          *
  56          * (The AA case does a similar  adjustment in RENDER_SAMPLES_X)
  57          */
  58         lx += X_FRAC_FIRST(1) - pixman_fixed_e;
  59         rx += X_FRAC_FIRST(1) - pixman_fixed_e;
  60 #endif
  61         /* clip X */
  62         if (lx < 0)
  63             lx = 0;
  64         if (pixman_fixed_to_int (rx) >= width)
  65 #if N_BITS == 1
  66             rx = pixman_int_to_fixed (width);
  67 #else
  68             /* Use the last pixel of the scanline, covered 100%.
  69              * We can't use the first pixel following the scanline,
  70              * because accessing it could result in a buffer overrun.
  71              */
  72             rx = pixman_int_to_fixed (width) - 1;
  73 #endif
  74
  75         /* Skip empty (or backwards) sections */
  76         if (rx > lx)
  77         {
  78
  79             /* Find pixel bounds for span */
  80             lxi = pixman_fixed_to_int (lx);
  81             rxi = pixman_fixed_to_int (rx);
  82
  83 #if N_BITS == 1
  84             {
  85
  86 #define LEFT_MASK(x)                                                    \
  87                 (((x) & 0x1f) ?                                         \
  88                  SCREEN_SHIFT_RIGHT (0xffffffff, (x) & 0x1f) : 0)
  89 #define RIGHT_MASK(x)                                                   \
  90                 (((32 - (x)) & 0x1f) ?                                  \
  91                  SCREEN_SHIFT_LEFT (0xffffffff, (32 - (x)) & 0x1f) : 0)
  92
  93 #define MASK_BITS(x,w,l,n,r) {                                          \
  94                     n = (w);                                            \
  95                     r = RIGHT_MASK ((x) + n);                           \
  96                     l = LEFT_MASK (x);                                  \
  97                     if (l) {                                            \
  98                         n -= 32 - ((x) & 0x1f);                         \
  99                         if (n < 0) {                                    \
 100                             n = 0;                                      \
 101                             l &= r;                                     \
 102                             r = 0;                                      \
 103                         }                                               \
 104                     }                                                   \
 105                     n >>= 5;                                            \
 106                 }
 107
 108                 uint32_t  *a = line;
 109                 uint32_t  startmask;
 110                 uint32_t  endmask;
 111                 int         nmiddle;
 112                 int         width = rxi - lxi;
 113                 int         x = lxi;
 114
 115                 a += x >> 5;
 116                 x &= 0x1f;
 117
 118                 MASK_BITS (x, width, startmask, nmiddle, endmask);
 119
 120                 if (startmask) {
 121                     WRITE(image, a, READ(image, a) | startmask);
 122                     a++;
 123                 }
 124                 while (nmiddle--)
 125                     WRITE(image, a++, 0xffffffff);
 126                 if (endmask)
 127                     WRITE(image, a, READ(image, a) | endmask);
 128             }
 129 #else
 130             {
 131                 DEFINE_ALPHA(line,lxi);
 132                 int         lxs;
 133                 int     rxs;
 134
 135                 /* Sample coverage for edge pixels */
 136                 lxs = RENDER_SAMPLES_X (lx, N_BITS);
 137                 rxs = RENDER_SAMPLES_X (rx, N_BITS);
 138
 139                 /* Add coverage across row */
 140                 if (lxi == rxi)
 141                 {
 142                     ADD_ALPHA (rxs - lxs);
 143                 }
 144                 else
 145                 {
 146                     int xi;
 147
 148                     ADD_ALPHA (N_X_FRAC(N_BITS) - lxs);
 149                     STEP_ALPHA;
 150                     for (xi = lxi + 1; xi < rxi; xi++)
 151                     {
 152                         ADD_ALPHA (N_X_FRAC(N_BITS));
 153                         STEP_ALPHA;
 154                     }
 155                     ADD_ALPHA (rxs);
 156                 }
 157             }
 158 #endif
 159         }
 160
 161         if (y == b)
 162             break;
 163
 164 #if N_BITS > 1
 165         if (pixman_fixed_frac (y) != Y_FRAC_LAST(N_BITS))
 166         {
 167             RENDER_EDGE_STEP_SMALL (l);
 168             RENDER_EDGE_STEP_SMALL (r);
 169             y += STEP_Y_SMALL(N_BITS);
 170         }
 171         else
 172 #endif
 173         {
 174             RENDER_EDGE_STEP_BIG (l);
 175             RENDER_EDGE_STEP_BIG (r);
 176             y += STEP_Y_BIG(N_BITS);
 177             line += stride;
 178         }
 179     }
 180 }
 181
 182 #undef rasterize_span