fbcompose.c

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

/*
 * $XdotOrg: xc/programs/Xserver/fb/fbcompose.c,v 1.5 2005/01/13 20:49:21 sandmann Exp $
 *
 * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
 *             2005 Lars Knoll & Zack Rusin, Trolltech
 *
 * 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.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS 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.
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "pixman-xserver-compat.h"
#include "fbpict.h"

#ifdef RENDER

#include "pixregionint.h"

#ifdef _MSC_VER
#define _USE_MATH_DEFINES
#endif

#include <math.h>

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

/* #define PIXMAN_CONVOLUTION */
/* #define PIXMAN_INDEXED_FORMATS */

static Bool
PictureTransformPoint3d (pixman_transform_t *transform,
                         PictVector *vector)
{
    PictVector	    result;
    int		    i, j;
    xFixed_32_32    partial;
    xFixed_48_16    v;

    for (j = 0; j < 3; j++)
    {
	v = 0;
	for (i = 0; i < 3; i++)
	{
	    partial = ((xFixed_48_16) transform->matrix[j][i] *
		       (xFixed_48_16) vector->vector[i]);
	    v += partial >> 16;
	}
	if (v > MAX_FIXED_48_16 || v < MIN_FIXED_48_16)
	    return FALSE;
	result.vector[j] = (xFixed) v;
    }
    if (!result.vector[2])
	return FALSE;
    *vector = result;
    return TRUE;
}

static unsigned int
SourcePictureClassify (PicturePtr pict,
		       int	  x,
		       int	  y,
		       int	  width,
		       int	  height)
{
    if (pict->pSourcePict->type == SourcePictTypeSolidFill)
    {
	pict->pSourcePict->solidFill.class = SourcePictClassHorizontal;
    }
    else if (pict->pSourcePict->type == SourcePictTypeLinear)
    {
	PictVector   v;
	xFixed_32_32 l;
	xFixed_48_16 dx, dy, a, b, off;
	xFixed_48_16 factors[4];
	int	     i;

	dx = pict->pSourcePict->linear.p2.x - pict->pSourcePict->linear.p1.x;
	dy = pict->pSourcePict->linear.p2.y - pict->pSourcePict->linear.p1.y;
	l = dx * dx + dy * dy;
	if (l)
	{
	    a = (dx << 32) / l;
	    b = (dy << 32) / l;
	}
	else
	{
	    a = b = 0;
	}

	off = (-a * pict->pSourcePict->linear.p1.x
	       -b * pict->pSourcePict->linear.p1.y) >> 16;

	for (i = 0; i < 3; i++)
	{
	    v.vector[0] = IntToxFixed ((i % 2) * (width  - 1) + x);
	    v.vector[1] = IntToxFixed ((i / 2) * (height - 1) + y);
	    v.vector[2] = xFixed1;

	    if (pict->transform)
	    {
		if (!PictureTransformPoint3d (pict->transform, &v))
		    return SourcePictClassUnknown;
	    }

	    factors[i] = ((a * v.vector[0] + b * v.vector[1]) >> 16) + off;
	}

	if (factors[2] == factors[0])
	    pict->pSourcePict->linear.class = SourcePictClassHorizontal;
	else if (factors[1] == factors[0])
	    pict->pSourcePict->linear.class = SourcePictClassVertical;
    }

    return pict->pSourcePict->solidFill.class;
}

#define mod(a,b)	((b) == 1 ? 0 : (a) >= 0 ? (a) % (b) : (b) - (-a) % (b))

#define SCANLINE_BUFFER_LENGTH 2048

typedef FASTCALL void (*fetchProc)(const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed);

/*
 * All of the fetch functions
 */

static FASTCALL void
fbFetch_a8r8g8b8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    memcpy(buffer, (const CARD32 *)bits + x, width*sizeof(CARD32));
}

static FASTCALL void
fbFetch_x8r8g8b8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD32 *pixel = (const CARD32 *)bits + x;
    const CARD32 *end = pixel + width;
    while (pixel < end) {
        *buffer++ = *pixel++ | 0xff000000;
    }
}

static FASTCALL void
fbFetch_a8b8g8r8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD32 *pixel = (CARD32 *)bits + x;
    const CARD32 *end = pixel + width;
    while (pixel < end) {
        *buffer++ =  ((*pixel & 0xff00ff00) |
                      ((*pixel >> 16) & 0xff) |
                      ((*pixel & 0xff) << 16));
        ++pixel;
    }
}

static FASTCALL void
fbFetch_x8b8g8r8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD32 *pixel = (CARD32 *)bits + x;
    const CARD32 *end = pixel + width;
    while (pixel < end) {
        *buffer++ =  0xff000000 |
                     ((*pixel & 0x0000ff00) |
                      ((*pixel >> 16) & 0xff) |
                      ((*pixel & 0xff) << 16));
        ++pixel;
    }
}

static FASTCALL void
fbFetch_r8g8b8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + 3*x;
    const CARD8 *end = pixel + 3*width;
    while (pixel < end) {
        CARD32 b = Fetch24(pixel) | 0xff000000;
        pixel += 3;
        *buffer++ = b;
    }
}

static FASTCALL void
fbFetch_b8g8r8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + 3*x;
    const CARD8 *end = pixel + 3*width;
    while (pixel < end) {
        CARD32 b = 0xff000000;
#if IMAGE_BYTE_ORDER == MSBFirst
        b |= (*pixel++);
        b |= (*pixel++ << 8);
        b |= (*pixel++ << 16);
#else
        b |= (*pixel++ << 16);
        b |= (*pixel++ << 8);
        b |= (*pixel++);
#endif
    }
}

static FASTCALL void
fbFetch_r5g6b5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32 r = (((p) << 3) & 0xf8) |
                   (((p) << 5) & 0xfc00) |
                   (((p) << 8) & 0xf80000);
        r |= (r >> 5) & 0x70007;
        r |= (r >> 6) & 0x300;
        *buffer++ = 0xff000000 | r;
    }
}

static FASTCALL void
fbFetch_b5g6r5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        b = ((p & 0xf800) | ((p & 0xe000) >> 5)) >> 8;
        g = ((p & 0x07e0) | ((p & 0x0600) >> 6)) << 5;
        r = ((p & 0x001c) | ((p & 0x001f) << 5)) << 14;
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a1r5g5b5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b, a;

        a = (CARD32) ((CARD8) (0 - ((p & 0x8000) >> 15))) << 24;
        r = ((p & 0x7c00) | ((p & 0x7000) >> 5)) << 9;
        g = ((p & 0x03e0) | ((p & 0x0380) >> 5)) << 6;
        b = ((p & 0x001c) | ((p & 0x001f) << 5)) >> 2;
        *buffer++ = (a | r | g | b);
    }
}

static FASTCALL void
fbFetch_x1r5g5b5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        r = ((p & 0x7c00) | ((p & 0x7000) >> 5)) << 9;
        g = ((p & 0x03e0) | ((p & 0x0380) >> 5)) << 6;
        b = ((p & 0x001c) | ((p & 0x001f) << 5)) >> 2;
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a1b5g5r5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b, a;

        a = (CARD32) ((CARD8) (0 - ((p & 0x8000) >> 15))) << 24;
        b = ((p & 0x7c00) | ((p & 0x7000) >> 5)) >> 7;
        g = ((p & 0x03e0) | ((p & 0x0380) >> 5)) << 6;
        r = ((p & 0x001c) | ((p & 0x001f) << 5)) << 14;
        *buffer++ = (a | r | g | b);
    }
}

static FASTCALL void
fbFetch_x1b5g5r5 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        b = ((p & 0x7c00) | ((p & 0x7000) >> 5)) >> 7;
        g = ((p & 0x03e0) | ((p & 0x0380) >> 5)) << 6;
        r = ((p & 0x001c) | ((p & 0x001f) << 5)) << 14;
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a4r4g4b4 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b, a;

        a = ((p & 0xf000) | ((p & 0xf000) >> 4)) << 16;
        r = ((p & 0x0f00) | ((p & 0x0f00) >> 4)) << 12;
        g = ((p & 0x00f0) | ((p & 0x00f0) >> 4)) << 8;
        b = ((p & 0x000f) | ((p & 0x000f) << 4));
        *buffer++ = (a | r | g | b);
    }
}

static FASTCALL void
fbFetch_x4r4g4b4 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        r = ((p & 0x0f00) | ((p & 0x0f00) >> 4)) << 12;
        g = ((p & 0x00f0) | ((p & 0x00f0) >> 4)) << 8;
        b = ((p & 0x000f) | ((p & 0x000f) << 4));
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a4b4g4r4 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b, a;

        a = ((p & 0xf000) | ((p & 0xf000) >> 4)) << 16;
        b = ((p & 0x0f00) | ((p & 0x0f00) >> 4)) << 12;
        g = ((p & 0x00f0) | ((p & 0x00f0) >> 4)) << 8;
        r = ((p & 0x000f) | ((p & 0x000f) << 4));
        *buffer++ = (a | r | g | b);
    }
}

static FASTCALL void
fbFetch_x4b4g4r4 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD16 *pixel = (const CARD16 *)bits + x;
    const CARD16 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        b = ((p & 0x0f00) | ((p & 0x0f00) >> 4)) << 12;
        g = ((p & 0x00f0) | ((p & 0x00f0) >> 4)) << 8;
        r = ((p & 0x000f) | ((p & 0x000f) << 4));
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        *buffer++ = (*pixel++) << 24;
    }
}

static FASTCALL void
fbFetch_r3g3b2 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        r = ((p & 0xe0) | ((p & 0xe0) >> 3) | ((p & 0xc0) >> 6)) << 16;
        g = ((p & 0x1c) | ((p & 0x18) >> 3) | ((p & 0x1c) << 3)) << 8;
        b = (((p & 0x03)     ) |
             ((p & 0x03) << 2) |
             ((p & 0x03) << 4) |
             ((p & 0x03) << 6));
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_b2g3r3 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32  r,g,b;

        b = (((p & 0xc0)     ) |
             ((p & 0xc0) >> 2) |
             ((p & 0xc0) >> 4) |
             ((p & 0xc0) >> 6));
        g = ((p & 0x38) | ((p & 0x38) >> 3) | ((p & 0x30) << 2)) << 8;
        r = (((p & 0x07)     ) |
             ((p & 0x07) << 3) |
             ((p & 0x06) << 6)) << 16;
        *buffer++ = (0xff000000 | r | g | b);
    }
}

static FASTCALL void
fbFetch_a2r2g2b2 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32   a,r,g,b;

        a = ((p & 0xc0) * 0x55) << 18;
        r = ((p & 0x30) * 0x55) << 12;
        g = ((p & 0x0c) * 0x55) << 6;
        b = ((p & 0x03) * 0x55);
        *buffer++ = a|r|g|b;
	}
}

static FASTCALL void
fbFetch_a2b2g2r2 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        CARD32   a,r,g,b;

        a = ((p & 0xc0) * 0x55) << 18;
        b = ((p & 0x30) * 0x55) >> 6;
        g = ((p & 0x0c) * 0x55) << 6;
        r = ((p & 0x03) * 0x55) << 16;
        *buffer++ = a|r|g|b;
    }
}

static FASTCALL void
fbFetch_c8 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{
    const CARD8 *pixel = (const CARD8 *)bits + x;
    const CARD8 *end = pixel + width;
    while (pixel < end) {
        CARD32  p = *pixel++;
        *buffer++ = indexed->rgba[p];
    }
}

#define Fetch8(l,o)    (((CARD8 *) (l))[(o) >> 2])
#if IMAGE_BYTE_ORDER == MSBFirst
#define Fetch4(l,o)    ((o) & 2 ? Fetch8(l,o) & 0xf : Fetch8(l,o) >> 4)
#else
#define Fetch4(l,o)    ((o) & 2 ? Fetch8(l,o) >> 4 : Fetch8(l,o) & 0xf)
#endif

static FASTCALL void
fbFetch_a4 (const FbBits *bits, int x, int width, CARD32 *buffer, miIndexedPtr indexed)
{