/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include "../SDL_sysvideo.h"

#include "SDL_x11video.h"

    /* The size of *all* SDL gamma ramps */

#define SDL_GammaRampSize (3 * 256 * sizeof(Uint16))

static int numCmaps = 0;

typedef struct

{

    Display *display;

    int scrNum;

    Colormap colormap;

    Visual visual;

    Uint16 *ramp;

} cmapTableEntry;

cmapTableEntry *cmapTable = NULL;

/* To reduce the overhead as much as possible lets do as little as

   possible. When we do have to create a colormap keep track of it and

   reuse it. We're going to do this for both DirectColor and

   PseudoColor colormaps. */

Colormap

X11_LookupColormap(Display * display, int scrNum, VisualID vid)

{

    int i;

    for (i = 0; i < numCmaps; i++) {

        if (cmapTable[i].display == display &&

            cmapTable[i].scrNum == scrNum &&

            cmapTable[i].visual.visualid == vid) {

            return cmapTable[i].colormap;

        }

    }

    return 0;

}

void

X11_TrackColormap(Display * display, int scrNum, Colormap colormap,

                  Visual * visual, XColor * ramp)

{

    int i;

    Uint16 *newramp;

    int ncolors;

    /* search the table to find out if we already have this one. We

       only want one entry for each display, screen number, visualid,

       and colormap combination */

    for (i = 0; i < numCmaps; i++) {

        if (cmapTable[i].display == display &&

            cmapTable[i].scrNum == scrNum &&

            cmapTable[i].visual.visualid == visual->visualid &&

            cmapTable[i].colormap == colormap) {

            return;

        }

    }

    /* increase the table by one entry. If the table is NULL create the

       first entrty */

    cmapTable =

        SDL_realloc(cmapTable, (numCmaps + 1) * sizeof(cmapTableEntry));

    if (NULL == cmapTable) {

        SDL_SetError("Out of memory in X11_TrackColormap()");

        return;

    }

    cmapTable[numCmaps].display = display;

    cmapTable[numCmaps].scrNum = scrNum;

    cmapTable[numCmaps].colormap = colormap;

    SDL_memcpy(&cmapTable[numCmaps].visual, visual, sizeof(Visual));

    cmapTable[numCmaps].ramp = NULL;

    if (ramp != NULL) {

        newramp = SDL_malloc(SDL_GammaRampSize);

        if (NULL == newramp) {

            SDL_SetError("Out of memory in X11_TrackColormap()");

            return;

        }

        SDL_memset(newramp, 0, SDL_GammaRampSize);

        cmapTable[numCmaps].ramp = newramp;

        ncolors = cmapTable[numCmaps].visual.map_entries;

        for (i = 0; i < ncolors; i++) {

            newramp[(0 * 256) + i] = ramp[i].red;

            newramp[(1 * 256) + i] = ramp[i].green;

            newramp[(2 * 256) + i] = ramp[i].blue;

        }

    }

    numCmaps++;

}

/* The problem is that you have to have at least one DirectColor

   colormap before you can set the gamma ramps or read the gamma

   ramps. If the application has created a DirectColor window then the

   cmapTable will have at least one colormap in it and everything is

   cool. If not, then we just fail  */

int

X11_SetDisplayGammaRamp(_THIS, SDL_VideoDisplay * sdl_display, Uint16 * ramp)

{

    Visual *visual;

    Display *display;

    Colormap colormap;

    XColor *colorcells;

    int ncolors;

    int rmask, gmask, bmask;

    int rshift, gshift, bshift;

    int i;

    int j;

    for (j = 0; j < numCmaps; j++) {

        if (cmapTable[j].visual.class == DirectColor) {

            display = cmapTable[j].display;

            colormap = cmapTable[j].colormap;

            ncolors = cmapTable[j].visual.map_entries;

            visual = &cmapTable[j].visual;

            colorcells = SDL_malloc(ncolors * sizeof(XColor));

            if (NULL == colorcells) {

                SDL_SetError("out of memory in X11_SetDisplayGammaRamp");

                return -1;

            }

            /* remember the new ramp */

            if (cmapTable[j].ramp == NULL) {

                Uint16 *newramp = SDL_malloc(SDL_GammaRampSize);

                if (NULL == newramp) {

                    SDL_SetError("Out of memory in X11_TrackColormap()");

                    return -1;

                }

                cmapTable[j].ramp = newramp;

            }

            SDL_memcpy(cmapTable[j].ramp, ramp, SDL_GammaRampSize);

            rshift = 0;

            rmask = visual->red_mask;

            while (0 == (rmask & 1)) {

                rshift++;

                rmask >>= 1;

            }

/*             printf("rmask = %4x rshift = %4d\n", rmask, rshift); */

            gshift = 0;

            gmask = visual->green_mask;

            while (0 == (gmask & 1)) {

                gshift++;

                gmask >>= 1;

            }

/*             printf("gmask = %4x gshift = %4d\n", gmask, gshift); */

            bshift = 0;

            bmask = visual->blue_mask;

            while (0 == (bmask & 1)) {

                bshift++;

                bmask >>= 1;

            }

/*             printf("bmask = %4x bshift = %4d\n", bmask, bshift); */

            /* build the color table pixel values */

            for (i = 0; i < ncolors; i++) {

                Uint32 rbits = (rmask * i) / (ncolors - 1);

                Uint32 gbits = (gmask * i) / (ncolors - 1);

                Uint32 bbits = (bmask * i) / (ncolors - 1);

                Uint32 pix =

                    (rbits << rshift) | (gbits << gshift) | (bbits << bshift);

                colorcells[i].pixel = pix;

                colorcells[i].flags = DoRed | DoGreen | DoBlue;

                colorcells[i].red = ramp[(0 * 256) + i];

                colorcells[i].green = ramp[(1 * 256) + i];

                colorcells[i].blue = ramp[(2 * 256) + i];

            }

            XStoreColors(display, colormap, colorcells, ncolors);

            XFlush(display);

            SDL_free(colorcells);

        }

    }

    return 0;

}

int

X11_GetDisplayGammaRamp(_THIS, SDL_VideoDisplay * display, Uint16 * ramp)

{

    int i;

    /* find the first DirectColor colormap and use it to get the gamma

       ramp */

    for (i = 0; i < numCmaps; i++) {

        if (cmapTable[i].visual.class == DirectColor) {

            SDL_memcpy(ramp, cmapTable[i].ramp, SDL_GammaRampSize);

            return 0;

        }

    }

    return -1;

}