/*
 * $XFree86: xc/programs/Xserver/render/miindex.c,v 1.8 2002/11/06 22:45:36 keithp Exp $
 *
 * Copyright © 2001 Keith Packard, member of The XFree86 Project, Inc.
 *
 * 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.
 */

#ifndef _MIINDEX_H_
#define _MIINDEX_H_

#include "scrnintstr.h"
#include "gcstruct.h"
#include "pixmapstr.h"
#include "windowstr.h"
#include "mi.h"
#include "picturestr.h"
#include "mipict.h"
#include "colormapst.h"

#define NUM_CUBE_LEVELS	4
#define NUM_GRAY_LEVELS	13

static Bool
miBuildRenderColormap (ColormapPtr  pColormap, Pixel *pixels, int *nump)
{
    int		r, g, b;
    unsigned short  red, green, blue;
    Pixel	pixel;
    Bool	used[MI_MAX_INDEXED];
    int		needed;
    int		policy;
    int		cube, gray;
    int		i, n;
    
    if (pColormap->mid != pColormap->pScreen->defColormap)
    {
	policy = PictureCmapPolicyAll;
    }
    else
    {
	int	avail = pColormap->pVisual->ColormapEntries;
	policy = PictureCmapPolicy;
	if (policy == PictureCmapPolicyDefault)
	{
	    if (avail >= 256 && (pColormap->pVisual->class|DynamicClass) == PseudoColor)
		policy = PictureCmapPolicyColor;
	    else if (avail >= 64)
		policy = PictureCmapPolicyGray;
	    else
		policy = PictureCmapPolicyMono;
	}
    }
    /*
     * Make sure enough cells are free for the chosen policy
     */
    for (;;)
    {
	switch (policy) {
	case PictureCmapPolicyAll:
	    needed = 0;
	    break;
	case PictureCmapPolicyColor:
	    needed = 71;
	    break;
	case PictureCmapPolicyGray:
	    needed = 11;
	    break;
	case PictureCmapPolicyMono:
	default:
	    needed = 0;
	    break;
	}
	if (needed <= pColormap->freeRed)
	    break;
	policy--;
    } 
    
    /*
     * Compute size of cube and gray ramps
     */
    cube = gray = 0;
    switch (policy) {
    case PictureCmapPolicyAll:
	/*
	 * Allocate as big a cube as possible
	 */
	if ((pColormap->pVisual->class|DynamicClass) == PseudoColor)
	{
	    for (cube = 1; cube * cube * cube < pColormap->pVisual->ColormapEntries; cube++)
		;
	    cube--;
	    if (cube == 1)
		cube = 0;
	}
	else
	    cube = 0;
	/*
	 * Figure out how many gray levels to use so that they
	 * line up neatly with the cube
	 */
	if (cube)
	{
	    needed = pColormap->pVisual->ColormapEntries - (cube*cube*cube);
	    /* levels to fill in with */
	    gray = needed / (cube - 1);
	    /* total levels */
	    gray = (gray + 1) * (cube - 1) + 1;
	}
	else
	    gray = pColormap->pVisual->ColormapEntries;
	break;
		
    case PictureCmapPolicyColor:
	cube = NUM_CUBE_LEVELS;
	/* fall through ... */
    case PictureCmapPolicyGray:
	gray = NUM_GRAY_LEVELS;
	break;
    case PictureCmapPolicyMono:
    default:
	gray = 2;
	break;
    }
    
    memset (used, '\0', pColormap->pVisual->ColormapEntries * sizeof (Bool));
    for (r = 0; r < cube; r++)
	for (g = 0; g < cube; g++)
	    for (b = 0; b < cube; b++)
	    {
		red = (r * 65535 + (cube-1)/2) / (cube - 1);
		green = (g * 65535 + (cube-1)/2) / (cube - 1);
		blue = (b * 65535 + (cube-1)/2) / (cube - 1);
		if (AllocColor (pColormap, &red, &green, 
				&blue, &pixel, 0) != Success)
		    return FALSE;
		used[pixel] = TRUE;
	    }
    for (g = 0; g < gray; g++)
    {
	red = green = blue = (g * 65535 + (gray-1)/2) / (gray - 1);
	if (AllocColor (pColormap, &red, &green, &blue, &pixel, 0) != Success)
	    return FALSE;
	used[pixel] = TRUE;
    }
    n = 0;
    for (i = 0; i < pColormap->pVisual->ColormapEntries; i++)
	if (used[i])
	    pixels[n++] = i;

    *nump = n;
    
    return TRUE;
}

/* 0 <= red, green, blue < 32 */
static Pixel
FindBestColor (miIndexedPtr pIndexed, Pixel *pixels, int num,
	       int red, int green, int blue)
{
    Pixel   best = pixels[0];
    int	    bestDist = 1 << 30;
    int	    dist;
    int	    dr, dg, db;
    while (num--)
    {
	Pixel	pixel = *pixels++;
	CARD32	v = pIndexed->rgba[pixel];

	dr = ((v >> 19) & 0x1f);
	dg = ((v >> 11) & 0x1f);
	db = ((v >> 3) & 0x1f);
	dr = dr - red;
	dg = dg - green;
	db = db - blue;
	dist = dr * dr + dg * dg + db * db;
	if (dist < bestDist)
	{
	    bestDist = dist;
	    best = pixel;
	}
    }
    return best;
}

/* 0 <= gray < 32768 */
static Pixel
FindBestGray (miIndexedPtr pIndexed, Pixel *pixels, int num, int gray)
{
    Pixel   best = pixels[0];
    int	    bestDist = 1 << 30;
    int	    dist;
    int	    dr;
    int	    r;
    
    while (num--)
    {
	Pixel   pixel = *pixels++;
	CARD32	v = pIndexed->rgba[pixel];

	r = v & 0xff;
	r = r | (r << 8);
	dr = gray - (r >> 1);
	dist = dr * dr;
	if (dist < bestDist)
	{
	    bestDist = dist;
	    best = pixel;
	}
    }
    return best;
}

Bool
miInitIndexed (ScreenPtr	pScreen,
	       PictFormatPtr	pFormat)
{
    ColormapPtr	    pColormap = pFormat->index.pColormap;
    VisualPtr	    pVisual = pColormap->pVisual;
    miIndexedPtr    pIndexed;
    Pixel	    pixels[MI_MAX_INDEXED];
    xrgb	    rgb[MI_MAX_INDEXED];
    int		    num;
    int		    i;
    Pixel	    p, r, g, b;

    if (pVisual->ColormapEntries > MI_MAX_INDEXED)
	return FALSE;
    
    if (pVisual->class & DynamicClass)
    {
	if (!miBuildRenderColormap (pColormap, pixels, &num))
	    return FALSE;
    }
    else
    {
	num = pVisual->ColormapEntries;
	for (p = 0; p < num; p++)
	    pixels[p] = p;
    }
    
    pIndexed = xalloc (sizeof (miIndexedRec));
    if (!pIndexed)
	return FALSE;
    
    pFormat->index.nvalues = num;
    pFormat->index.pValues = xalloc (num * sizeof (xIndexValue));
    if (!pFormat->index.pValues)
    {
	xfree (pIndexed);
	return FALSE;
    }
    
    
    /*
     * Build mapping from pixel value to ARGB
     */
    QueryColors (pColormap, num, pixels, rgb);
    for (i = 0; i < num; i++)
    {
	p = pixels[i];
	pFormat->index.pValues[i].pixel = p;
	pFormat->index.pValues[i].red   = rgb[i].red;
	pFormat->index.pValues[i].green = rgb[i].green;
	pFormat->index.pValues[i].blue  = rgb[i].blue;
	pFormat->index.pValues[i].alpha = 0xffff;
	pIndexed->rgba[p] = (0xff000000 |
			     ((rgb[i].red   & 0xff00) << 8) |
			     ((rgb[i].green & 0xff00)     ) |
			     ((rgb[i].blue  & 0xff00) >> 8));
    }

    /*
     * Build mapping from RGB to pixel value.  This could probably be
     * done a bit quicker...
     */
    switch (pVisual->class | DynamicClass) {
    case GrayScale:
	pIndexed->color = FALSE;
	for (r = 0; r < 32768; r++)
	    pIndexed->ent[r] = FindBestGray (pIndexed, pixels, num, r);
	break;
    case PseudoColor:
	pIndexed->color = TRUE;
	p = 0;
	for (r = 0; r < 32; r++)
	    for (g = 0; g < 32; g++)
		for (b = 0; b < 32; b++)
		{
		    pIndexed->ent[p] = FindBestColor (pIndexed, pixels, num,
						      r, g, b);
		    p++;
		}
	break;
    }
    pFormat->index.devPrivate = pIndexed;
    return TRUE;
}

void
miCloseIndexed (ScreenPtr	pScreen,
		PictFormatPtr	pFormat)
{
    if (pFormat->index.devPrivate)
    {
	xfree (pFormat->index.devPrivate);
	pFormat->index.devPrivate = 0;
    }
    if (pFormat->index.pValues)
    {
	xfree (pFormat->index.pValues);
	pFormat->index.pValues = 0;
    }
}

void
miUpdateIndexed (ScreenPtr	pScreen,
		 PictFormatPtr	pFormat,
		 int		ndef,
		 xColorItem	*pdef)
{
    miIndexedPtr pIndexed = pFormat->index.devPrivate;

    if (pIndexed)
    {
	while (ndef--)
	{
	    pIndexed->rgba[pdef->pixel] = (0xff000000 |
					   ((pdef->red   & 0xff00) << 8) |
					   ((pdef->green & 0xff00)     ) |
					   ((pdef->blue  & 0xff00) >> 8));
	    pdef++;
	}
    }
}

#endif /* _MIINDEX_H_ */
