| 1 | /*
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| 2 | * $Id: fbedgeimp.h,v 1.4 2005/08/30 03:05:21 anholt Exp $
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| 3 | *
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| 4 | * Copyright © 2004 Keith Packard
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| 5 | *
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| 6 | * Permission to use, copy, modify, distribute, and sell this software and its
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| 7 | * documentation for any purpose is hereby granted without fee, provided that
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| 8 | * the above copyright notice appear in all copies and that both that
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| 9 | * copyright notice and this permission notice appear in supporting
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| 10 | * documentation, and that the name of Keith Packard not be used in
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| 11 | * advertising or publicity pertaining to distribution of the software without
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| 12 | * specific, written prior permission. Keith Packard makes no
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| 13 | * representations about the suitability of this software for any purpose. It
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| 14 | * is provided "as is" without express or implied warranty.
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| 15 | *
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| 16 | * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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| 17 | * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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| 18 | * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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| 19 | * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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| 20 | * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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| 21 | * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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| 22 | * PERFORMANCE OF THIS SOFTWARE.
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| 23 | */
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| 24 |
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| 25 | #ifdef HAVE_DIX_CONFIG_H
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| 26 | #include <dix-config.h>
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| 27 | #endif
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| 28 |
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| 29 | #ifndef rasterizeSpan
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| 30 | #endif
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| 31 |
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| 32 | static void
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| 33 | rasterizeEdges (FbBits *buf,
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| 34 | int width,
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| 35 | int stride,
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| 36 | RenderEdge *l,
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| 37 | RenderEdge *r,
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| 38 | xFixed t,
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| 39 | xFixed b)
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| 40 | {
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| 41 | xFixed y = t;
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| 42 | FbBits *line;
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| 43 |
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| 44 | line = buf + xFixedToInt (y) * stride;
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| 45 |
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| 46 | for (;;)
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| 47 | {
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| 48 | xFixed lx, rx;
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| 49 | int lxi, rxi;
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| 50 |
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| 51 | /* clip X */
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| 52 | lx = l->x;
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| 53 | if (lx < 0)
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| 54 | lx = 0;
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| 55 | rx = r->x;
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| 56 | if (xFixedToInt (rx) >= width)
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| 57 | rx = IntToxFixed (width);
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| 58 |
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| 59 | /* Skip empty (or backwards) sections */
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| 60 | if (rx > lx)
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| 61 | {
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| 62 |
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| 63 | /* Find pixel bounds for span */
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| 64 | lxi = xFixedToInt (lx);
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| 65 | rxi = xFixedToInt (rx);
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| 66 |
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| 67 | #if N_BITS == 1
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| 68 | {
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| 69 | FbBits *a = line;
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| 70 | FbBits startmask, endmask;
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| 71 | int nmiddle;
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| 72 | int width = rxi - lxi;
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| 73 | int x = lxi;
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| 74 |
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| 75 | a += x >> FB_SHIFT;
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| 76 | x &= FB_MASK;
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| 77 |
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| 78 | FbMaskBits (x, width, startmask, nmiddle, endmask);
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| 79 | if (startmask)
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| 80 | *a++ |= startmask;
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| 81 | while (nmiddle--)
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| 82 | *a++ = FB_ALLONES;
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| 83 | if (endmask)
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| 84 | *a |= endmask;
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| 85 | }
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| 86 | #else
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| 87 | {
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| 88 | DefineAlpha(line,lxi);
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| 89 | int lxs, rxs;
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| 90 |
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| 91 | /* Sample coverage for edge pixels */
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| 92 | lxs = RenderSamplesX (lx, N_BITS);
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| 93 | rxs = RenderSamplesX (rx, N_BITS);
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| 94 |
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| 95 | /* Add coverage across row */
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| 96 | if (lxi == rxi)
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| 97 | {
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| 98 | AddAlpha (rxs - lxs);
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| 99 | }
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| 100 | else
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| 101 | {
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| 102 | int xi;
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| 103 |
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| 104 | AddAlpha (N_X_FRAC(N_BITS) - lxs);
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| 105 | StepAlpha;
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| 106 | for (xi = lxi + 1; xi < rxi; xi++)
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| 107 | {
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| 108 | AddAlpha (N_X_FRAC(N_BITS));
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| 109 | StepAlpha;
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| 110 | }
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| 111 | /* Do not add in a 0 alpha here. This check is necessary
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| 112 | * to avoid a buffer overrun when rx is exactly on a pixel
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| 113 | * boundary.
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| 114 | */
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| 115 | if (rxs != 0)
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| 116 | AddAlpha (rxs);
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| 117 | }
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| 118 | }
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| 119 | #endif
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| 120 | }
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| 121 |
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| 122 | if (y == b)
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| 123 | break;
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| 124 |
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| 125 | #if N_BITS > 1
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| 126 | if (xFixedFrac (y) != Y_FRAC_LAST(N_BITS))
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| 127 | {
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| 128 | RenderEdgeStepSmall (l);
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| 129 | RenderEdgeStepSmall (r);
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| 130 | y += STEP_Y_SMALL(N_BITS);
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| 131 | }
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| 132 | else
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| 133 | #endif
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| 134 | {
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| 135 | RenderEdgeStepBig (l);
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| 136 | RenderEdgeStepBig (r);
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| 137 | y += STEP_Y_BIG(N_BITS);
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| 138 | line += stride;
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| 139 | }
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| 140 | }
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| 141 | }
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| 142 |
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| 143 | #undef rasterizeSpan
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