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Diffstat (limited to 'pixman/src/fbedge.c')
| -rw-r--r-- | pixman/src/fbedge.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/pixman/src/fbedge.c b/pixman/src/fbedge.c new file mode 100644 index 0000000..15835f3 --- /dev/null +++ b/pixman/src/fbedge.c @@ -0,0 +1,304 @@ +/* + * $Id: fbedge.c,v 1.3 2005/08/02 01:01:24 vektor Exp $ + * + * Copyright © 2004 Keith Packard + * + * Permission to use, copy, modify, distribute, and sell this software and its + * documentation for any purpose is hereby granted without fee, provided that + * the above copyright notice appear in all copies and that both that + * copyright notice and this permission notice appear in supporting + * documentation, and that the name of Keith Packard not be used in + * advertising or publicity pertaining to distribution of the software without + * specific, written prior permission. Keith Packard makes no + * representations about the suitability of this software for any purpose. It + * is provided "as is" without express or implied warranty. + * + * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO + * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +#include <string.h> +#include "pixman-xserver-compat.h" + +#ifdef RENDER + +/* + * 4 bit alpha + */ + +#define N_BITS 4 +#define rasterizeEdges fbRasterizeEdges4 + +#if BITMAP_BIT_ORDER == LSBFirst +#define Shift4(o) ((o) << 2) +#else +#define Shift4(o) ((1-(o)) << 2) +#endif + +#define Get4(x,o) (((x) >> Shift4(o)) & 0xf) +#define Put4(x,o,v) (((x) & ~(0xf << Shift4(o))) | (((v) & 0xf) << Shift4(o))) + +#define DefineAlpha(line,x) \ + CARD8 *__ap = (CARD8 *) line + ((x) >> 1); \ + int __ao = (x) & 1 + +#define StepAlpha ((__ap += __ao), (__ao ^= 1)) + +#define AddAlpha(a) { \ + CARD8 __o = *__ap; \ + CARD8 __a = (a) + Get4(__o, __ao); \ + *__ap = Put4 (__o, __ao, __a | (0 - ((__a) >> 4))); \ +} + +#include "fbedgeimp.h" + +#undef AddAlpha +#undef StepAlpha +#undef DefineAlpha +#undef rasterizeEdges +#undef N_BITS + + +/* + * 1 bit alpha + */ + +#define N_BITS 1 +#define rasterizeEdges fbRasterizeEdges1 + +#include "fbedgeimp.h" + +#undef rasterizeEdges +#undef N_BITS + +/* + * 8 bit alpha + */ + +static INLINE CARD8 +clip255 (int x) +{ + if (x > 255) return 255; + return x; +} + +static INLINE void +add_saturate_8 (CARD8 *buf, int value, int length) +{ + while (length--) + { + *buf = clip255 (*buf + value); + buf++; + } +} + +/* + * We want to detect the case where we add the same value to a long + * span of pixels. The triangles on the end are filled in while we + * count how many sub-pixel scanlines contribute to the middle section. + * + * +--------------------------+ + * fill_height =| \ / + * +------------------+ + * |================| + * fill_start fill_end + */ +static void +fbRasterizeEdges8 (FbBits *buf, + int width, + int stride, + RenderEdge *l, + RenderEdge *r, + xFixed t, + xFixed b) +{ + xFixed y = t; + FbBits *line; + int fill_start = -1, fill_end = -1; + int fill_size = 0; + + line = buf + xFixedToInt (y) * stride; + + for (;;) + { + CARD8 *ap = (CARD8 *) line; + xFixed lx, rx; + int lxi, rxi; + + /* clip X */ + lx = l->x; + if (lx < 0) + lx = 0; + rx = r->x; + if (xFixedToInt (rx) >= width) + rx = IntToxFixed (width); + + /* Skip empty (or backwards) sections */ + if (rx > lx) + { + int lxs, rxs; + + /* Find pixel bounds for span. */ + lxi = xFixedToInt (lx); + rxi = xFixedToInt (rx); + + /* Sample coverage for edge pixels */ + lxs = RenderSamplesX (lx, 8); + rxs = RenderSamplesX (rx, 8); + + /* Add coverage across row */ + if (lxi == rxi) + { + ap[lxi] = clip255 (ap[lxi] + rxs - lxs); + } + else + { + ap[lxi] = clip255 (ap[lxi] + N_X_FRAC(8) - lxs); + + /* Move forward so that lxi/rxi is the pixel span */ + lxi++; + + /* Don't bother trying to optimize the fill unless + * the span is longer than 4 pixels. */ + if (rxi - lxi > 4) + { + if (fill_start < 0) + { + fill_start = lxi; + fill_end = rxi; + fill_size++; + } + else + { + if (lxi >= fill_end || rxi < fill_start) + { + /* We're beyond what we saved, just fill it */ + add_saturate_8 (ap + fill_start, + fill_size * N_X_FRAC(8), + fill_end - fill_start); + fill_start = lxi; + fill_end = rxi; + fill_size = 1; + } + else + { + /* Update fill_start */ + if (lxi > fill_start) + { + add_saturate_8 (ap + fill_start, + fill_size * N_X_FRAC(8), + lxi - fill_start); + fill_start = lxi; + } + else if (lxi < fill_start) + { + add_saturate_8 (ap + lxi, N_X_FRAC(8), + fill_start - lxi); + } + + /* Update fill_end */ + if (rxi < fill_end) + { + add_saturate_8 (ap + rxi, + fill_size * N_X_FRAC(8), + fill_end - rxi); + fill_end = rxi; + } + else if (fill_end < rxi) + { + add_saturate_8 (ap + fill_end, + N_X_FRAC(8), + rxi - fill_end); + } + fill_size++; + } + } + } + else + { + add_saturate_8 (ap + lxi, N_X_FRAC(8), rxi - lxi); + } + + /* Do not add in a 0 alpha here. This check is + * necessary to avoid a buffer overrun, (when rx + * is exactly on a pixel boundary). */ + if (rxs) + ap[rxi] = clip255 (ap[rxi] + rxs); + } + } + + if (y == b) { + /* We're done, make sure we clean up any remaining fill. */ + if (fill_start != fill_end) { + if (fill_size == N_Y_FRAC(8)) + { + memset (ap + fill_start, 0xff, fill_end - fill_start); + } + else + { + add_saturate_8 (ap + fill_start, fill_size * N_X_FRAC(8), + fill_end - fill_start); + } + } + break; + } + + if (xFixedFrac (y) != Y_FRAC_LAST(8)) + { + RenderEdgeStepSmall (l); + RenderEdgeStepSmall (r); + y += STEP_Y_SMALL(8); + } + else + { + RenderEdgeStepBig (l); + RenderEdgeStepBig (r); + y += STEP_Y_BIG(8); + if (fill_start != fill_end) + { + if (fill_size == N_Y_FRAC(8)) + { + memset (ap + fill_start, 0xff, fill_end - fill_start); + } + else + { + add_saturate_8 (ap + fill_start, fill_size * N_X_FRAC(8), + fill_end - fill_start); + } + fill_start = fill_end = -1; + fill_size = 0; + } + line += stride; + } + } +} + +void +fbRasterizeEdges (FbBits *buf, + int bpp, + int width, + int stride, + RenderEdge *l, + RenderEdge *r, + xFixed t, + xFixed b) +{ + switch (bpp) { + case 1: + fbRasterizeEdges1 (buf, width, stride, l, r, t, b); + break; + case 4: + fbRasterizeEdges4 (buf, width, stride, l, r, t, b); + break; + case 8: + fbRasterizeEdges8 (buf, width, stride, l, r, t, b); + break; + } +} + +#endif /* RENDER */ |